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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.12 12-Jan-2011
5    ------------------------
6    
7    1.  Fixed some typos in the markup of the man pages, and wrote a script that
8        checks for such things as part of the documentation building process.
9    
10    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
11        --match-limit and --recursion-limit options (added for 8.11). In
12        particular, this made one of the standard tests crash. (The integer value
13        went into the wrong half of a long int.)
14    
15    3.  If the --colour option was given to pcregrep with -v (invert match), it
16        did strange things, either producing crazy output, or crashing. It should,
17        of course, ignore a request for colour when reporting lines that do not
18        match.
19    
20    4.  Another pcregrep bug caused similar problems if --colour was specified with
21        -M (multiline) and the pattern match finished with a line ending.
22    
23    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
24        matched in multiline mode, the following line was shown as part of the
25        match. This seems wrong, so I have changed it.
26    
27    6.  If pcregrep was compiled under Windows, there was a reference to the
28        function pcregrep_exit() before it was defined. I am assuming this was
29        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
30        reported by a user. I've moved the definition above the reference.
31    
32    
33    Version 8.11 10-Dec-2010
34    ------------------------
35    
36    1.  (*THEN) was not working properly if there were untried alternatives prior
37        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
38        backtracked to try for "b" instead of moving to the next alternative branch
39        at the same level (in this case, to look for "c"). The Perl documentation
40        is clear that when (*THEN) is backtracked onto, it goes to the "next
41        alternative in the innermost enclosing group".
42    
43    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
44        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
45        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
46        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
47        (*THEN).
48    
49    3.  If \s appeared in a character class, it removed the VT character from
50        the class, even if it had been included by some previous item, for example
51        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
52        of \s, but is part of the POSIX "space" class.)
53    
54    4.  A partial match never returns an empty string (because you can always
55        match an empty string at the end of the subject); however the checking for
56        an empty string was starting at the "start of match" point. This has been
57        changed to the "earliest inspected character" point, because the returned
58        data for a partial match starts at this character. This means that, for
59        example, /(?<=abc)def/ gives a partial match for the subject "abc"
60        (previously it gave "no match").
61    
62    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
63        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
64        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
65        has an implication that the given string is incomplete (because a partial
66        match is preferred over a full match). For this reason, these items now
67        give a partial match in this situation. [Aside: previously, the one case
68        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
69        match rather than a full match, which was wrong by the old rules, but is
70        now correct.]
71    
72    6.  There was a bug in the handling of #-introduced comments, recognized when
73        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
74        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
75        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
76        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
77        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
78        places in pcre_compile().
79    
80    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
81        comments when looking ahead for named forward references to subpatterns,
82        the only newline sequence it recognized was NL. It now handles newlines
83        according to the set newline convention.
84    
85    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
86        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
87        cater for a lack of strerror(). These oversights have been fixed.
88    
89    9.  Added --match-limit and --recursion-limit to pcregrep.
90    
91    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
92    
93    11. When the -o option was used, pcregrep was setting a return code of 1, even
94        when matches were found, and --line-buffered was not being honoured.
95    
96    12. Added an optional parentheses number to the -o and --only-matching options
97        of pcregrep.
98    
99    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
100        can match an empty string. The code to do it in pcretest and pcredemo
101        needed fixing:
102    
103        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
104            only one byte after an empty string match just before CRLF (this case
105            just got forgotten; "any" and "anycrlf" were OK).
106    
107        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
108            mode when an empty string match preceded an ASCII character followed by
109            a non-ASCII character. (The code for advancing by one character rather
110            than one byte was nonsense.)
111    
112        (c) The pcredemo.c sample program did not have any code at all to handle
113            the cases when CRLF is a valid newline sequence.
114    
115    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
116        as a starting offset was within the subject string. There is now a new
117        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
118        negative or greater than the length of the string. In order to test this,
119        pcretest is extended to allow the setting of negative starting offsets.
120    
121    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
122        starting offset points to the beginning of a UTF-8 character was
123        unnecessarily clumsy. I tidied it up.
124    
125    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
126        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
127    
128    17. Nobody had reported that the --include_dir option, which was added in
129        release 7.7 should have been called --include-dir (hyphen, not underscore)
130        for compatibility with GNU grep. I have changed it to --include-dir, but
131        left --include_dir as an undocumented synonym, and the same for
132        --exclude-dir, though that is not available in GNU grep, at least as of
133        release 2.5.4.
134    
135    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
136        characters from a string of bytes) have been redefined so as not to use
137        loops, in order to improve performance in some environments. At the same
138        time, I abstracted some of the common code into auxiliary macros to save
139        repetition (this should not affect the compiled code).
140    
141    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
142        compile-time error is now given if \c is not followed by an ASCII
143        character, that is, a byte less than 128. (In EBCDIC mode, the code is
144        different, and any byte value is allowed.)
145    
146    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
147        START_OPTIMIZE option, which is now allowed at compile time - but just
148        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
149        to pcregrep and other applications that have no direct access to PCRE
150        options. The new /Y option in pcretest sets this option when calling
151        pcre_compile().
152    
153    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
154        back references. Groups containing recursive back references were forced to
155        be atomic by that change, but in the case of named groups, the amount of
156        memory required was incorrectly computed, leading to "Failed: internal
157        error: code overflow". This has been fixed.
158    
159    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
160        pcretest.c, to avoid build problems in some Borland environments.
161    
162    
163    Version 8.10 25-Jun-2010
164    ------------------------
165    
166    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
167        THEN.
168    
169    2.  (*ACCEPT) was not working when inside an atomic group.
170    
171    3.  Inside a character class, \B is treated as a literal by default, but
172        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
173        causes the error). The code is unchanged, but I tidied the documentation.
174    
175    4.  Inside a character class, PCRE always treated \R and \X as literals,
176        whereas Perl faults them if its -w option is set. I have changed PCRE so
177        that it faults them when PCRE_EXTRA is set.
178    
179    5.  Added support for \N, which always matches any character other than
180        newline. (It is the same as "." when PCRE_DOTALL is not set.)
181    
182    6.  When compiling pcregrep with newer versions of gcc which may have
183        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
184        declared with attribute warn_unused_result" were given. Just casting the
185        result to (void) does not stop the warnings; a more elaborate fudge is
186        needed. I've used a macro to implement this.
187    
188    7.  Minor change to pcretest.c to avoid a compiler warning.
189    
190    8.  Added four artifical Unicode properties to help with an option to make
191        \s etc use properties (see next item). The new properties are: Xan
192        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
193    
194    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
195        use Unicode properties. (*UCP) at the start of a pattern can be used to set
196        this option. Modified pcretest to add /W to test this facility. Added
197        REG_UCP to make it available via the POSIX interface.
198    
199    10. Added --line-buffered to pcregrep.
200    
201    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
202        studied, and the match started with a letter with a code point greater than
203        127 whose first byte was different to the first byte of the other case of
204        the letter, the other case of this starting letter was not recognized
205        (#976).
206    
207    12. If a pattern that was studied started with a repeated Unicode property
208        test, for example, \p{Nd}+, there was the theoretical possibility of
209        setting up an incorrect bitmap of starting bytes, but fortunately it could
210        not have actually happened in practice until change 8 above was made (it
211        added property types that matched character-matching opcodes).
212    
213    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
214        possible starting bytes for non-anchored patterns.
215    
216    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
217        \R, and also a number of cases that involve Unicode properties, both
218        explicit and implicit when PCRE_UCP is set.
219    
220    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
221        input, it could crash or give wrong results if characters with values
222        greater than 0xc0 were present in the subject string. (Detail: it assumed
223        UTF-8 input when processing these items.)
224    
225    16. Added a lot of (int) casts to avoid compiler warnings in systems where
226        size_t is 64-bit (#991).
227    
228    17. Added a check for running out of memory when PCRE is compiled with
229        --disable-stack-for-recursion (#990).
230    
231    18. If the last data line in a file for pcretest does not have a newline on
232        the end, a newline was missing in the output.
233    
234    19. The default pcre_chartables.c file recognizes only ASCII characters (values
235        less than 128) in its various bitmaps. However, there is a facility for
236        generating tables according to the current locale when PCRE is compiled. It
237        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
238        characters, are recognized by isspace() and therefore were getting set in
239        these tables, and indeed these tables seem to approximate to ISO 8859. This
240        caused a problem in UTF-8 mode when pcre_study() was used to create a list
241        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
242        which of course cannot start UTF-8 characters. I have changed the code so
243        that only real ASCII characters (less than 128) and the correct starting
244        bytes for UTF-8 encodings are set for characters greater than 127 when in
245        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
246        altogether.)
247    
248    20. Added the /T option to pcretest so as to be able to run tests with non-
249        standard character tables, thus making it possible to include the tests
250        used for 19 above in the standard set of tests.
251    
252    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
253        reference to a subpattern the other side of a comment that contains an
254        opening parenthesis caused either an internal compiling error, or a
255        reference to the wrong subpattern.
256    
257    
258    Version 8.02 19-Mar-2010
259    ------------------------
260    
261    1.  The Unicode data tables have been updated to Unicode 5.2.0.
262    
263    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
264        configured.
265    
266    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
267        original author of that file, following a query about its status.
268    
269    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
270        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
271    
272    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
273        quantifier applied to a forward-referencing subroutine call, could compile
274        incorrect code or give the error "internal error: previously-checked
275        referenced subpattern not found".
276    
277    6.  Both MS Visual Studio and Symbian OS have problems with initializing
278        variables to point to external functions. For these systems, therefore,
279        pcre_malloc etc. are now initialized to local functions that call the
280        relevant global functions.
281    
282    7.  There were two entries missing in the vectors called coptable and poptable
283        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
284        I've fixed the data, and added a kludgy way of testing at compile time that
285        the lengths are correct (equal to the number of opcodes).
286    
287    8.  Following on from 7, I added a similar kludge to check the length of the
288        eint vector in pcreposix.c.
289    
290    9.  Error texts for pcre_compile() are held as one long string to avoid too
291        much relocation at load time. To find a text, the string is searched,
292        counting zeros. There was no check for running off the end of the string,
293        which could happen if a new error number was added without updating the
294        string.
295    
296    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
297    
298    11. \K was not working if it appeared in an atomic group or in a group that
299        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
300        \K is "not well defined" if used in an assertion. PCRE now accepts it if
301        the assertion is positive, but not if it is negative.
302    
303    12. Change 11 fortuitously reduced the size of the stack frame used in the
304        "match()" function of pcre_exec.c by one pointer. Forthcoming
305        implementation of support for (*MARK) will need an extra pointer on the
306        stack; I have reserved it now, so that the stack frame size does not
307        decrease.
308    
309    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
310        item in branch that calls a recursion is a subroutine call - as in the
311        second branch in the above example - was incorrectly given the compile-
312        time error "recursive call could loop indefinitely" because pcre_compile()
313        was not correctly checking the subroutine for matching a non-empty string.
314    
315    14. The checks for overrunning compiling workspace could trigger after an
316        overrun had occurred. This is a "should never occur" error, but it can be
317        triggered by pathological patterns such as hundreds of nested parentheses.
318        The checks now trigger 100 bytes before the end of the workspace.
319    
320    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
321    
322    
323    Version 8.01 19-Jan-2010
324    ------------------------
325    
326    1.  If a pattern contained a conditional subpattern with only one branch (in
327        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
328        computed the wrong minimum data length (which is of course zero for such
329        subpatterns). This could cause incorrect "no match" results.
330    
331    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
332        the pattern is reset in the first branch, pcre_compile() failed with
333        "internal error: code overflow at offset...". This happened only when
334        the reset was to the original external option setting. (An optimization
335        abstracts leading options settings into an external setting, which was the
336        cause of this.)
337    
338    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
339        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
340        assertion pattern did not match (meaning that the assertion was true), it
341        was incorrectly treated as false if the SKIP had been reached during the
342        matching. This also applied to assertions used as conditions.
343    
344    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
345        assertion subpattern, including such a pattern used as a condition,
346        unpredictable results occurred, instead of the error return
347        PCRE_ERROR_DFA_UITEM.
348    
349    5.  The C++ GlobalReplace function was not working like Perl for the special
350        situation when an empty string is matched. It now does the fancy magic
351        stuff that is necessary.
352    
353    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
354        removed. (These were left over from very, very early versions of PCRE.)
355    
356    7.  Some cosmetic changes to the code to make life easier when compiling it
357        as part of something else:
358    
359        (a) Change DEBUG to PCRE_DEBUG.
360    
361        (b) In pcre_compile(), rename the member of the "branch_chain" structure
362            called "current" as "current_branch", to prevent a collision with the
363            Linux macro when compiled as a kernel module.
364    
365        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
366            prevent a collision with the Linux macro when compiled as a kernel
367            module.
368    
369    8.  In pcre_compile() there are some checks for integer overflows that used to
370        cast potentially large values to (double). This has been changed to that
371        when building, a check for int64_t is made, and if it is found, it is used
372        instead, thus avoiding the use of floating point arithmetic. (There is no
373        other use of FP in PCRE.) If int64_t is not found, the fallback is to
374        double.
375    
376    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
377        2005 (difference between two addresses compared to an unsigned value).
378    
379    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
380        custom one, because of the following reported problem in Windows:
381    
382          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
383              under Win32.
384          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
385              therefore missing the function definition.
386          - The compiler thus generates a "C" signature for the test function.
387          - The linker fails to find the "C" function.
388          - PCRE fails to configure if asked to do so against libbz2.
389    
390    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
391        messages were output:
392    
393          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
394          rerunning libtoolize, to keep the correct libtool macros in-tree.
395          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
396    
397        I have done both of these things.
398    
399    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
400        most of the time, it *can* run out if it is given a pattern that contains a
401        runaway infinite recursion. I updated the discussion in the pcrestack man
402        page.
403    
404    13. Now that we have gone to the x.xx style of version numbers, the minor
405        version may start with zero. Using 08 or 09 is a bad idea because users
406        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
407        interpreted as invalid octal numbers. I've updated the previous comment in
408        configure.ac, and also added a check that gives an error if 08 or 09 are
409        used.
410    
411    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
412        causing partial matching to fail when the end of the subject matched \W
413        in a UTF-8 pattern where \W was quantified with a minimum of 3.
414    
415    15. There were some discrepancies between the declarations in pcre_internal.h
416        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
417        their definitions. The declarations used "const uschar *" and the
418        definitions used USPTR. Even though USPTR is normally defined as "const
419        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
420        reported that: "This difference in casting confuses some C++ compilers, for
421        example, SunCC recognizes above declarations as different functions and
422        generates broken code for hbpcre." I have changed the declarations to use
423        USPTR.
424    
425    16. GNU libtool is named differently on some systems. The autogen.sh script now
426        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
427        (FreeBSD).
428    
429    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
430        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
431        comment: "Figure out how to create a longlong from a string: strtoll and
432        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
433        instance, but it only takes 2 args instead of 3!"
434    
435    18. A subtle bug concerned with back references has been fixed by a change of
436        specification, with a corresponding code fix. A pattern such as
437        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
438        refers, was giving matches when it shouldn't. For example, xa=xaaa would
439        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
440        same bug. Such groups have to be quantified to be useful, or contained
441        inside another quantified group. (If there's no repetition, the reference
442        can never match.) The problem arises because, having left the group and
443        moved on to the rest of the pattern, a later failure that backtracks into
444        the group uses the captured value from the final iteration of the group
445        rather than the correct earlier one. I have fixed this in PCRE by forcing
446        any group that contains a reference to itself to be an atomic group; that
447        is, there cannot be any backtracking into it once it has completed. This is
448        similar to recursive and subroutine calls.
449    
450    
451    Version 8.00 19-Oct-09
452    ----------------------
453    
454    1.  The table for translating pcre_compile() error codes into POSIX error codes
455        was out-of-date, and there was no check on the pcre_compile() error code
456        being within the table. This could lead to an OK return being given in
457        error.
458    
459    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
460        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
461        in a Windows environment.
462    
463    3.  The pcregrep --count option prints the count for each file even when it is
464        zero, as does GNU grep. However, pcregrep was also printing all files when
465        --files-with-matches was added. Now, when both options are given, it prints
466        counts only for those files that have at least one match. (GNU grep just
467        prints the file name in this circumstance, but including the count seems
468        more useful - otherwise, why use --count?) Also ensured that the
469        combination -clh just lists non-zero counts, with no names.
470    
471    4.  The long form of the pcregrep -F option was incorrectly implemented as
472        --fixed_strings instead of --fixed-strings. This is an incompatible change,
473        but it seems right to fix it, and I didn't think it was worth preserving
474        the old behaviour.
475    
476    5.  The command line items --regex=pattern and --regexp=pattern were not
477        recognized by pcregrep, which required --regex pattern or --regexp pattern
478        (with a space rather than an '='). The man page documented the '=' forms,
479        which are compatible with GNU grep; these now work.
480    
481    6.  No libpcreposix.pc file was created for pkg-config; there was just
482        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
483    
484    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
485        when UCP support is not needed, by modifying the Python script that
486        generates it from Unicode data files. This should not matter if the module
487        is correctly used as a library, but I received one complaint about 50K of
488        unwanted data. My guess is that the person linked everything into his
489        program rather than using a library. Anyway, it does no harm.
490    
491    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
492        was a minimum greater than 1 for a wide character in a possessive
493        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
494        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
495        character. Chaos in the form of incorrect output or a compiling loop could
496        result.
497    
498    9.  The restrictions on what a pattern can contain when partial matching is
499        requested for pcre_exec() have been removed. All patterns can now be
500        partially matched by this function. In addition, if there are at least two
501        slots in the offset vector, the offset of the earliest inspected character
502        for the match and the offset of the end of the subject are set in them when
503        PCRE_ERROR_PARTIAL is returned.
504    
505    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
506        synonymous with PCRE_PARTIAL, for backwards compatibility, and
507        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
508        and may be more useful for multi-segment matching.
509    
510    11. Partial matching with pcre_exec() is now more intuitive. A partial match
511        used to be given if ever the end of the subject was reached; now it is
512        given only if matching could not proceed because another character was
513        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
514        string "Z", which now yields "no match" instead of "partial match". In the
515        case of pcre_dfa_exec(), "no match" is given if every matching path for the
516        final character ended with (*FAIL).
517    
518    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
519        if the pattern had a "must contain" character that was already found in the
520        earlier partial match, unless partial matching was again requested. For
521        example, with the pattern /dog.(body)?/, the "must contain" character is
522        "g". If the first part-match was for the string "dog", restarting with
523        "sbody" failed. This bug has been fixed.
524    
525    13. The string returned by pcre_dfa_exec() after a partial match has been
526        changed so that it starts at the first inspected character rather than the
527        first character of the match. This makes a difference only if the pattern
528        starts with a lookbehind assertion or \b or \B (\K is not supported by
529        pcre_dfa_exec()). It's an incompatible change, but it makes the two
530        matching functions compatible, and I think it's the right thing to do.
531    
532    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
533        so that the demonstration program is easily available in environments where
534        PCRE has not been installed from source.
535    
536    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
537        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
538        library.
539    
540    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
541        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
542        is not the first non-POSIX option to be added. Clearly some people find
543        these options useful.
544    
545    17. If a caller to the POSIX matching function regexec() passes a non-zero
546        value for nmatch with a NULL value for pmatch, the value of
547        nmatch is forced to zero.
548    
549    18. RunGrepTest did not have a test for the availability of the -u option of
550        the diff command, as RunTest does. It now checks in the same way as
551        RunTest, and also checks for the -b option.
552    
553    19. If an odd number of negated classes containing just a single character
554        interposed, within parentheses, between a forward reference to a named
555        subpattern and the definition of the subpattern, compilation crashed with
556        an internal error, complaining that it could not find the referenced
557        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
558        [The bug was that it was starting one character too far in when skipping
559        over the character class, thus treating the ] as data rather than
560        terminating the class. This meant it could skip too much.]
561    
562    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
563        /g option in pcretest when the pattern contains \K, which makes it possible
564        to have an empty string match not at the start, even when the pattern is
565        anchored. Updated pcretest and pcredemo to use this option.
566    
567    21. If the maximum number of capturing subpatterns in a recursion was greater
568        than the maximum at the outer level, the higher number was returned, but
569        with unset values at the outer level. The correct (outer level) value is
570        now given.
571    
572    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
573        PCRE did not set those parentheses (unlike Perl). I have now found a way to
574        make it do so. The string so far is captured, making this feature
575        compatible with Perl.
576    
577    23. The tests have been re-organized, adding tests 11 and 12, to make it
578        possible to check the Perl 5.10 features against Perl 5.10.
579    
580    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
581        pattern matches a fixed length string. PCRE did not allow this; now it
582        does. Neither allows recursion.
583    
584    25. I finally figured out how to implement a request to provide the minimum
585        length of subject string that was needed in order to match a given pattern.
586        (It was back references and recursion that I had previously got hung up
587        on.) This code has now been added to pcre_study(); it finds a lower bound
588        to the length of subject needed. It is not necessarily the greatest lower
589        bound, but using it to avoid searching strings that are too short does give
590        some useful speed-ups. The value is available to calling programs via
591        pcre_fullinfo().
592    
593    26. While implementing 25, I discovered to my embarrassment that pcretest had
594        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
595        study optimizations had never been tested with that matching function.
596        Oops. What is worse, even when it was passed study data, there was a bug in
597        pcre_dfa_exec() that meant it never actually used it. Double oops. There
598        were also very few tests of studied patterns with pcre_dfa_exec().
599    
600    27. If (?| is used to create subpatterns with duplicate numbers, they are now
601        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
602        on the other side of the coin, they are no longer allowed to have different
603        names, because these cannot be distinguished in PCRE, and this has caused
604        confusion. (This is a difference from Perl.)
605    
606    28. When duplicate subpattern names are present (necessarily with different
607        numbers, as required by 27 above), and a test is made by name in a
608        conditional pattern, either for a subpattern having been matched, or for
609        recursion in such a pattern, all the associated numbered subpatterns are
610        tested, and the overall condition is true if the condition is true for any
611        one of them. This is the way Perl works, and is also more like the way
612        testing by number works.
613    
614    
615    Version 7.9 11-Apr-09
616    ---------------------
617    
618    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
619        (pcretest), all targets were linked against these libraries. This included
620        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
621        libraries. This caused unwanted dependencies to be created. This problem
622        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
623        pcretest is linked with readline.
624    
625    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
626        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
627        moved outside it again, because FALSE and TRUE are already defined in AIX,
628        but BOOL is not.
629    
630    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
631        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
632    
633    4.  The pcregrep documentation said spaces were inserted as well as colons (or
634        hyphens) following file names and line numbers when outputting matching
635        lines. This is not true; no spaces are inserted. I have also clarified the
636        wording for the --colour (or --color) option.
637    
638    5.  In pcregrep, when --colour was used with -o, the list of matching strings
639        was not coloured; this is different to GNU grep, so I have changed it to be
640        the same.
641    
642    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
643        each matching line was coloured. Now it goes on to look for further matches
644        of any of the test patterns, which is the same behaviour as GNU grep.
645    
646    7.  A pattern that could match an empty string could cause pcregrep to loop; it
647        doesn't make sense to accept an empty string match in pcregrep, so I have
648        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
649        seems to be how GNU grep behaves.
650    
651    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
652        start or after a newline", because the conditional assertion was not being
653        correctly handled. The rule now is that both the assertion and what follows
654        in the first alternative must satisfy the test.
655    
656    9.  If auto-callout was enabled in a pattern with a conditional group whose
657        condition was an assertion, PCRE could crash during matching, both with
658        pcre_exec() and pcre_dfa_exec().
659    
660    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
661        used for matching.
662    
663    11. Unicode property support in character classes was not working for
664        characters (bytes) greater than 127 when not in UTF-8 mode.
665    
666    12. Added the -M command line option to pcretest.
667    
668    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
669    
670    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
671    
672    16. Added comments and documentation about mis-use of no_arg in the C++
673        wrapper.
674    
675    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
676        from Martin Jerabek that uses macro names for all relevant character and
677        string constants.
678    
679    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
680        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
681        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
682        these, but not everybody uses configure.
683    
684    19. A conditional group that had only one branch was not being correctly
685        recognized as an item that could match an empty string. This meant that an
686        enclosing group might also not be so recognized, causing infinite looping
687        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
688        with the subject "ab", where knowledge that the repeated group can match
689        nothing is needed in order to break the loop.
690    
691    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
692        exec(), but without supplying a callout function, matching went wrong.
693    
694    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
695        leak if the size of the offset vector was greater than 30. When the vector
696        is smaller, the saved offsets during recursion go onto a local stack
697        vector, but for larger vectors malloc() is used. It was failing to free
698        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
699        error, in fact).
700    
701    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
702        heapframe that is used only when UTF-8 support is enabled. This caused no
703        problem, but was untidy.
704    
705    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
706        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
707        included within another project.
708    
709    24. Steven Van Ingelgem's patches to add more options to the CMake support,
710        slightly modified by me:
711    
712          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
713              not building pcregrep.
714    
715          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
716              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
717    
718    25. Forward references, both numeric and by name, in patterns that made use of
719        duplicate group numbers, could behave incorrectly or give incorrect errors,
720        because when scanning forward to find the reference group, PCRE was not
721        taking into account the duplicate group numbers. A pattern such as
722        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
723    
724    26. Changed a few more instances of "const unsigned char *" to USPTR, making
725        the feature of a custom pointer more persuasive (as requested by a user).
726    
727    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
728        pcretest.c, inside #ifndefs, because it seems they are sometimes already
729        pre-defined.
730    
731    28. Added support for (*UTF8) at the start of a pattern.
732    
733    29. Arrange for flags added by the "release type" setting in CMake to be shown
734        in the configuration summary.
735    
736    
737    Version 7.8 05-Sep-08
738    ---------------------
739    
740    1.  Replaced UCP searching code with optimized version as implemented for Ad
741        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
742        stage table and inline lookup instead of a function, giving speed ups of 2
743        to 5 times on some simple patterns that I tested. Permission was given to
744        distribute the MultiStage2.py script that generates the tables (it's not in
745        the tarball, but is in the Subversion repository).
746    
747    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
748        scripts.
749    
750    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
751        a group with a zero qualifier. The result of the study could be incorrect,
752        or the function might crash, depending on the pattern.
753    
754    4.  Caseless matching was not working for non-ASCII characters in back
755        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
756        It now works when Unicode Property Support is available.
757    
758    5.  In pcretest, an escape such as \x{de} in the data was always generating
759        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
760        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
761        truncation.
762    
763    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
764    
765    7.  Added two (int) casts to pcregrep when printing the difference of two
766        pointers, in case they are 64-bit values.
767    
768    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
769        test 2 if it fails.
770    
771    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
772        and a #define of that name to empty if it is not externally set. This is to
773        allow users of MSVC to set it if necessary.
774    
775    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
776        the convenience functions in the pcre_get.c source file.
777    
778    11. An option change at the start of a pattern that had top-level alternatives
779        could cause overwriting and/or a crash. This command provoked a crash in
780        some environments:
781    
782          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
783    
784        This potential security problem was recorded as CVE-2008-2371.
785    
786    12. For a pattern where the match had to start at the beginning or immediately
787        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
788        pcre_dfa_exec() could read past the end of the passed subject if there was
789        no match. To help with detecting such bugs (e.g. with valgrind), I modified
790        pcretest so that it places the subject at the end of its malloc-ed buffer.
791    
792    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
793        exec() might read past the end of the data buffer in UTF-8 mode.
794    
795    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
796        the data contained the byte 0x85 as part of a UTF-8 character within its
797        first line. This applied both to normal and DFA matching.
798    
799    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
800        /^[^d]*?$/8 failed to match "abc".
801    
802    16. Added a missing copyright notice to pcrecpp_internal.h.
803    
804    17. Make it more clear in the documentation that values returned from
805        pcre_exec() in ovector are byte offsets, not character counts.
806    
807    18. Tidied a few places to stop certain compilers from issuing warnings.
808    
809    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
810        supplied by Stefan Weber. I made a further small update for 7.8 because
811        there is a change of source arrangements: the pcre_searchfuncs.c module is
812        replaced by pcre_ucd.c.
813    
814    
815    Version 7.7 07-May-08
816    ---------------------
817    
818    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
819        a string to a long long, pretend we don't even have a long long." This is
820        done by checking for the strtoq, strtoll, and _strtoi64 functions.
821    
822    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
823        pre-7.6 versions, which defined a global no_arg variable instead of putting
824        it in the RE class. (See also #8 below.)
825    
826    3.  Remove a line of dead code, identified by coverity and reported by Nuno
827        Lopes.
828    
829    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
830    
831        (1) The include/exclude patterns were being applied to the whole pathnames
832            of files, instead of just to the final components.
833    
834        (2) If there was more than one level of directory, the subdirectories were
835            skipped unless they satisfied the include/exclude conditions. This is
836            inconsistent with GNU grep (and could even be seen as contrary to the
837            pcregrep specification - which I improved to make it absolutely clear).
838            The action now is always to scan all levels of directory, and just
839            apply the include/exclude patterns to regular files.
840    
841    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
842        --exclude_dir in the tests to avoid scanning .svn directories.
843    
844    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
845        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
846        doesn't support NULs in patterns.
847    
848    7.  Added some missing "const"s to declarations of static tables in
849        pcre_compile.c and pcre_dfa_exec.c.
850    
851    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
852        caused by fix #2  above. (Subsequently also a second patch to fix the
853        first patch. And a third patch - this was a messy problem.)
854    
855    9.  Applied Craig's patch to remove the use of push_back().
856    
857    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
858        matching function regexec().
859    
860    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
861        which, however, unlike Perl's \g{...}, are subroutine calls, not back
862        references. PCRE supports relative numbers with this syntax (I don't think
863        Oniguruma does).
864    
865    12. Previously, a group with a zero repeat such as (...){0} was completely
866        omitted from the compiled regex. However, this means that if the group
867        was called as a subroutine from elsewhere in the pattern, things went wrong
868        (an internal error was given). Such groups are now left in the compiled
869        pattern, with a new opcode that causes them to be skipped at execution
870        time.
871    
872    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
873        to the way PCRE behaves:
874    
875        (a) A lone ] character is dis-allowed (Perl treats it as data).
876    
877        (b) A back reference to an unmatched subpattern matches an empty string
878            (Perl fails the current match path).
879    
880        (c) A data ] in a character class must be notated as \] because if the
881            first data character in a class is ], it defines an empty class. (In
882            Perl it is not possible to have an empty class.) The empty class []
883            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
884            The negative empty class [^] matches any one character, independently
885            of the DOTALL setting.
886    
887    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
888        non-existent subpattern following a character class starting with ']' and
889        containing () gave an internal compiling error instead of "reference to
890        non-existent subpattern". Fortunately, when the pattern did exist, the
891        compiled code was correct. (When scanning forwards to check for the
892        existencd of the subpattern, it was treating the data ']' as terminating
893        the class, so got the count wrong. When actually compiling, the reference
894        was subsequently set up correctly.)
895    
896    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
897        it was being rejected as not supported by pcre_dfa_exec(), even though
898        other assertions are supported. I have made pcre_dfa_exec() support
899        (*FAIL).
900    
901    16. The implementation of 13c above involved the invention of a new opcode,
902        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
903        cannot be changed at match time, I realized I could make a small
904        improvement to matching performance by compiling OP_ALLANY instead of
905        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
906        on the OP_ANY path.
907    
908    17. Compiling pcretest on Windows with readline support failed without the
909        following two fixes: (1) Make the unistd.h include conditional on
910        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
911    
912    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
913        ncurses library to be included for pcretest when ReadLine support is
914        requested, but also to allow for it to be overridden. This patch came from
915        Daniel Bergström.
916    
917    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
918        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
919        any errors with the current Unicode tables. Thanks to Peter Kankowski for
920        spotting this.
921    
922    
923    Version 7.6 28-Jan-08
924    ---------------------
925    
926    1.  A character class containing a very large number of characters with
927        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
928        overflow.
929    
930    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
931        HAVE_LONG_LONG is not defined.
932    
933    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
934        bring them up to date and include new features. This patch includes:
935    
936        - Fixed PH's badly added libz and libbz2 support.
937        - Fixed a problem with static linking.
938        - Added pcredemo. [But later removed - see 7 below.]
939        - Fixed dftables problem and added an option.
940        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
941            HAVE_LONG_LONG.
942        - Added readline support for pcretest.
943        - Added an listing of the option settings after cmake has run.
944    
945    4.  A user submitted a patch to Makefile that makes it easy to create
946        "pcre.dll" under mingw when using Configure/Make. I added stuff to
947        Makefile.am that cause it to include this special target, without
948        affecting anything else. Note that the same mingw target plus all
949        the other distribution libraries and programs are now supported
950        when configuring with CMake (see 6 below) instead of with
951        Configure/Make.
952    
953    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
954        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
955        exported in the Windows port". It has not yet been confirmed that the patch
956        solves the problem, but it does no harm.
957    
958    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
959        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
960        with CMake, and also correct the comment about stack recursion.
961    
962    7.  Remove the automatic building of pcredemo from the ./configure system and
963        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
964        of a program that users should build themselves after PCRE is installed, so
965        building it automatically is not really right. What is more, it gave
966        trouble in some build environments.
967    
968    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
969    
970    
971    Version 7.5 10-Jan-08
972    ---------------------
973    
974    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
975        values in parens when parsing an RE using the C++ wrapper."
976    
977    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
978        Characters greater than 255 were excluded from the class instead of being
979        included.
980    
981    3.  The same bug as (2) above applied to negated POSIX classes such as
982        [:^space:].
983    
984    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
985        defined or documented. It seems to have been a typo for PCRE_STATIC, so
986        I have changed it.
987    
988    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
989        first named subpattern) and a construct such as (?&a) would reference the
990        first named subpattern whose name started with "a" (in other words, the
991        length check was missing). Both these problems are fixed. "Subpattern name
992        expected" is now given for (?&) (a zero-length name), and this patch also
993        makes it give the same error for \k'' (previously it complained that that
994        was a reference to a non-existent subpattern).
995    
996    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
997        this is right because (?- can be followed by option settings as well as by
998        digits. I have, however, made the messages clearer.
999    
1000    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1001        than the number used in the conditional) now cause a compile-time error.
1002        This is actually not compatible with Perl, which accepts such patterns, but
1003        treats the conditional as always being FALSE (as PCRE used to), but it
1004        seems to me that giving a diagnostic is better.
1005    
1006    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1007        and messages.
1008    
1009    9.  Fix two occurrences of "backslash" in comments that should have been
1010        "backspace".
1011    
1012    10. Remove two redundant lines of code that can never be obeyed (their function
1013        was moved elsewhere).
1014    
1015    11. The program that makes PCRE's Unicode character property table had a bug
1016        which caused it to generate incorrect table entries for sequences of
1017        characters that have the same character type, but are in different scripts.
1018        It amalgamated them into a single range, with the script of the first of
1019        them. In other words, some characters were in the wrong script. There were
1020        thirteen such cases, affecting characters in the following ranges:
1021    
1022          U+002b0 - U+002c1
1023          U+0060c - U+0060d
1024          U+0061e - U+00612
1025          U+0064b - U+0065e
1026          U+0074d - U+0076d
1027          U+01800 - U+01805
1028          U+01d00 - U+01d77
1029          U+01d9b - U+01dbf
1030          U+0200b - U+0200f
1031          U+030fc - U+030fe
1032          U+03260 - U+0327f
1033          U+0fb46 - U+0fbb1
1034          U+10450 - U+1049d
1035    
1036    12. The -o option (show only the matching part of a line) for pcregrep was not
1037        compatible with GNU grep in that, if there was more than one match in a
1038        line, it showed only the first of them. It now behaves in the same way as
1039        GNU grep.
1040    
1041    13. If the -o and -v options were combined for pcregrep, it printed a blank
1042        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1043        does the same. The return code can be used to tell if there were any
1044        non-matching lines.
1045    
1046    14. Added --file-offsets and --line-offsets to pcregrep.
1047    
1048    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1049        infinitely looping recursion. The bug was that positive lookaheads were not
1050        being skipped when checking for a possible empty match (negative lookaheads
1051        and both kinds of lookbehind were skipped).
1052    
1053    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1054        inclusion of <windows.h> to before rather than after the definition of
1055        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1056    
1057    17. Specifying a possessive quantifier with a specific limit for a Unicode
1058        character property caused pcre_compile() to compile bad code, which led at
1059        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1060        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1061        caused the error; without that there was no problem.
1062    
1063    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1064    
1065    19. Added --enable-pcretest-libreadline.
1066    
1067    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1068        RE::GlobalReplace(). As a result, the number of replacements returned was
1069        double what it should be. I removed one of the increments, but Craig sent a
1070        later patch that removed the other one (the right fix) and added unit tests
1071        that check the return values (which was not done before).
1072    
1073    21. Several CMake things:
1074    
1075        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1076            the names libpcre and libpcreposix, not just pcre and pcreposix.
1077    
1078        (2) The above change means that pcretest and pcregrep are now correctly
1079            linked with the newly-built libraries, not previously installed ones.
1080    
1081        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1082    
1083    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1084        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1085        UTF-8 newline character). The key issue is that the pattern starts .*;
1086        this means that the match must be either at the beginning, or after a
1087        newline. The bug was in the code for advancing after a failed match and
1088        checking that the new position followed a newline. It was not taking
1089        account of UTF-8 characters correctly.
1090    
1091    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1092        character classes. PCRE was not treating the sequence [:...:] as a
1093        character class unless the ... were all letters. Perl, however, seems to
1094        allow any characters between [: and :], though of course it rejects as
1095        unknown any "names" that contain non-letters, because all the known class
1096        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1097        for example, whereas PCRE did not - it did not recognize a POSIX character
1098        class. This seemed a bit dangerous, so the code has been changed to be
1099        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1100        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1101        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1102        Perl does, and where it didn't before.
1103    
1104    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1105        Windows environments %n is disabled by default.
1106    
1107    
1108    Version 7.4 21-Sep-07
1109    ---------------------
1110    
1111    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1112        means that a class such as [\s] counted as "explicit reference to CR or
1113        LF". That isn't really right - the whole point of the change was to try to
1114        help when there was an actual mention of one of the two characters. So now
1115        the change happens only if \r or \n (or a literal CR or LF) character is
1116        encountered.
1117    
1118    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1119        of both had grown to the point where there were only 3 bits left.
1120        Fortunately, there was spare space in the data structure, and so I have
1121        moved the internal flags into a new 16-bit field to free up more option
1122        bits.
1123    
1124    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1125        but did not set the internal JCHANGED flag - either of these is enough to
1126        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1127        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1128        start sets both bits.
1129    
1130    4.  Added options (at build time, compile time, exec time) to change \R from
1131        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1132    
1133    5.  doc/pcresyntax.html was missing from the distribution.
1134    
1135    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1136        compatibility, even though it is no longer used.
1137    
1138    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1139        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1140        windows.h file is present (where different names are used). [This was
1141        reversed later after testing - see 16 below.]
1142    
1143    8.  Changed all #include <config.h> to #include "config.h". There were also
1144        some further <pcre.h> cases that I changed to "pcre.h".
1145    
1146    9.  When pcregrep was used with the --colour option, it missed the line ending
1147        sequence off the lines that it output.
1148    
1149    10. It was pointed out to me that arrays of string pointers cause lots of
1150        relocations when a shared library is dynamically loaded. A technique of
1151        using a single long string with a table of offsets can drastically reduce
1152        these. I have refactored PCRE in four places to do this. The result is
1153        dramatic:
1154    
1155          Originally:                          290
1156          After changing UCP table:            187
1157          After changing error message table:   43
1158          After changing table of "verbs"       36
1159          After changing table of Posix names   22
1160    
1161        Thanks to the folks working on Gregex for glib for this insight.
1162    
1163    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1164        unicode-properties was also set.
1165    
1166    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1167    
1168    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1169        checked only for CRLF.
1170    
1171    14. Added casts to pcretest.c to avoid compiler warnings.
1172    
1173    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1174    
1175    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1176        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1177        entirely. This removes changes made in 7 above.
1178    
1179    17. The CMake files have been updated, and there is now more information about
1180        building with CMake in the NON-UNIX-USE document.
1181    
1182    
1183    Version 7.3 28-Aug-07
1184    ---------------------
1185    
1186     1. In the rejigging of the build system that eventually resulted in 7.1, the
1187        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1188        brackets there is not right, since it causes compilers to look for an
1189        installed pcre.h, not the version that is in the source that is being
1190        compiled (which of course may be different). I have changed it back to:
1191    
1192          #include "pcre.h"
1193    
1194        I have a vague recollection that the change was concerned with compiling in
1195        different directories, but in the new build system, that is taken care of
1196        by the VPATH setting the Makefile.
1197    
1198     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1199        when the subject happened to end in the byte 0x85 (e.g. if the last
1200        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1201        characters but of course it shouldn't be taken as a newline when it is part
1202        of another character. The bug was that, for an unlimited repeat of . in
1203        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1204        characters when looking for a newline.
1205    
1206     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1207    
1208     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1209        in debug output.
1210    
1211     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1212        long printing in the pcrecpp unittest when running under MinGW.
1213    
1214     6. ESC_K was left out of the EBCDIC table.
1215    
1216     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1217        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1218        limit also applies to "virtual nesting" when a pattern is recursive, and in
1219        this case 1000 isn't so big. I have been able to remove this limit at the
1220        expense of backing off one optimization in certain circumstances. Normally,
1221        when pcre_exec() would call its internal match() function recursively and
1222        immediately return the result unconditionally, it uses a "tail recursion"
1223        feature to save stack. However, when a subpattern that can match an empty
1224        string has an unlimited repetition quantifier, it no longer makes this
1225        optimization. That gives it a stack frame in which to save the data for
1226        checking that an empty string has been matched. Previously this was taken
1227        from the 1000-entry workspace that had been reserved. So now there is no
1228        explicit limit, but more stack is used.
1229    
1230     8. Applied Daniel's patches to solve problems with the import/export magic
1231        syntax that is required for Windows, and which was going wrong for the
1232        pcreposix and pcrecpp parts of the library. These were overlooked when this
1233        problem was solved for the main library.
1234    
1235     9. There were some crude static tests to avoid integer overflow when computing
1236        the size of patterns that contain repeated groups with explicit upper
1237        limits. As the maximum quantifier is 65535, the maximum group length was
1238        set at 30,000 so that the product of these two numbers did not overflow a
1239        32-bit integer. However, it turns out that people want to use groups that
1240        are longer than 30,000 bytes (though not repeat them that many times).
1241        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1242        made it possible to implement the integer overflow checks in a much more
1243        dynamic way, which I have now done. The artificial limitation on group
1244        length has been removed - we now have only the limit on the total length of
1245        the compiled pattern, which depends on the LINK_SIZE setting.
1246    
1247    10. Fixed a bug in the documentation for get/copy named substring when
1248        duplicate names are permitted. If none of the named substrings are set, the
1249        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1250        empty string.
1251    
1252    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1253        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1254        because the ] is interpreted as the first data character and the
1255        terminating ] is not found. PCRE has been made compatible with Perl in this
1256        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1257        cause memory overwriting.
1258    
1259    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1260        string has been matched (to stop an infinite loop). It was not recognizing
1261        a conditional subpattern that could match an empty string if that
1262        subpattern was within another subpattern. For example, it looped when
1263        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1264        condition was not nested. This bug has been fixed.
1265    
1266    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1267        past the start of the subject in the presence of bytes with the top bit
1268        set, for example "\x8aBCD".
1269    
1270    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1271        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1272    
1273    14. Optimized (?!) to (*FAIL).
1274    
1275    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1276        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1277        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1278        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1279        does: it's just the validity check that is more restrictive.
1280    
1281    16. Inserted checks for integer overflows during escape sequence (backslash)
1282        processing, and also fixed erroneous offset values for syntax errors during
1283        backslash processing.
1284    
1285    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1286        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1287    
1288    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1289        caused an overrun.
1290    
1291    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1292        something other than just ASCII characters) inside a group that had an
1293        unlimited repeat caused a loop at compile time (while checking to see
1294        whether the group could match an empty string).
1295    
1296    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1297        [\P{Any}] did so. (Error in the code for printing property names.)
1298    
1299    21. An orphan \E inside a character class could cause a crash.
1300    
1301    22. A repeated capturing bracket such as (A)? could cause a wild memory
1302        reference during compilation.
1303    
1304    23. There are several functions in pcre_compile() that scan along a compiled
1305        expression for various reasons (e.g. to see if it's fixed length for look
1306        behind). There were bugs in these functions when a repeated \p or \P was
1307        present in the pattern. These operators have additional parameters compared
1308        with \d, etc, and these were not being taken into account when moving along
1309        the compiled data. Specifically:
1310    
1311        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1312            length.
1313    
1314        (b) An item such as \pL+ within a repeated group could cause crashes or
1315            loops.
1316    
1317        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1318            "reference to non-existent subpattern" error.
1319    
1320        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1321    
1322    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1323        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1324    
1325    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1326    
1327    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1328        character were causing crashes (broken optimization).
1329    
1330    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1331        \p or \P) caused a compile-time loop.
1332    
1333    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1334        break. For example, the unstudied pattern [\r\n]A does not match the string
1335        "\r\nA" because change 7.0/46 below moves the current point on by two
1336        characters after failing to match at the start. However, the pattern \nA
1337        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1338        the same is true. There doesn't seem any very clean way out of this, but
1339        what I have chosen to do makes the common cases work: PCRE now takes note
1340        of whether there can be an explicit match for \r or \n anywhere in the
1341        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1342        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1343        pattern has explicit CR or LF references.
1344    
1345    29. Added (*CR) etc for changing newline setting at start of pattern.
1346    
1347    
1348    Version 7.2 19-Jun-07
1349    ---------------------
1350    
1351     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1352        which is apparently normally available under Windows.
1353    
1354     2. Re-jig the pcregrep tests with different newline settings in an attempt
1355        to make them independent of the local environment's newline setting.
1356    
1357     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1358    
1359     4. Some of the "internals" tests were previously cut out when the link size
1360        was not 2, because the output contained actual offsets. The recent new
1361        "Z" feature of pcretest means that these can be cut out, making the tests
1362        usable with all link sizes.
1363    
1364     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1365        stack recursion. This gives a massive performance boost under BSD, but just
1366        a small improvement under Linux. However, it saves one field in the frame
1367        in all cases.
1368    
1369     6. Added more features from the forthcoming Perl 5.10:
1370    
1371        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1372            recursion call. It refers to the nth most recently opened parentheses.
1373    
1374        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1375            to be opened parentheses.
1376    
1377        (c) Conditions that refer to capturing parentheses can be specified
1378            relatively, for example, (?(-2)... or (?(+3)...
1379    
1380        (d) \K resets the start of the current match so that everything before
1381            is not part of it.
1382    
1383        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1384    
1385        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1386            reference syntax.
1387    
1388        (g) (?| introduces a group in which the numbering of parentheses in each
1389            alternative starts with the same number.
1390    
1391        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1392    
1393     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1394        PCRE_INFO_JCHANGED.
1395    
1396     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1397        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1398        for detecting groups that can match an empty string.
1399    
1400     9. A pattern with a very large number of alternatives (more than several
1401        hundred) was running out of internal workspace during the pre-compile
1402        phase, where pcre_compile() figures out how much memory will be needed. A
1403        bit of new cunning has reduced the workspace needed for groups with
1404        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1405        workspace instead of running out of the 4096 that are available.
1406    
1407    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1408    
1409    11. Applied patch from Google to remove an optimization that didn't quite work.
1410        The report of the bug said:
1411    
1412          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1413          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1414          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1415    
1416    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1417        it matched the wrong number of bytes.
1418    
1419    
1420    Version 7.1 24-Apr-07
1421    ---------------------
1422    
1423     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1424        that is more "standard", making use of automake and other Autotools. There
1425        is some re-arrangement of the files and adjustment of comments consequent
1426        on this.
1427    
1428     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1429        for recursive directory scanning broke on some systems because the files
1430        are not scanned in any specific order and on different systems the order
1431        was different. A call to "sort" has been inserted into RunGrepTest for the
1432        approprate test as a short-term fix. In the longer term there may be an
1433        alternative.
1434    
1435     3. I had an email from Eric Raymond about problems translating some of PCRE's
1436        man pages to HTML (despite the fact that I distribute HTML pages, some
1437        people do their own conversions for various reasons). The problems
1438        concerned the use of low-level troff macros .br and .in. I have therefore
1439        removed all such uses from the man pages (some were redundant, some could
1440        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1441        HTML has been updated to handle .nf/.fi and to complain if it encounters
1442        .br or .in.
1443    
1444     4. Updated comments in configure.ac that get placed in config.h.in and also
1445        arranged for config.h to be included in the distribution, with the name
1446        config.h.generic, for the benefit of those who have to compile without
1447        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1448    
1449     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1450        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1451        makevp.bat for the current PCRE, using the additional files
1452        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1453    
1454     6. A Windows user reported a minor discrepancy with test 2, which turned out
1455        to be caused by a trailing space on an input line that had got lost in his
1456        copy. The trailing space was an accident, so I've just removed it.
1457    
1458     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1459        that is needed.
1460    
1461     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1462        as "const" (a) because they are and (b) because it helps the PHP
1463        maintainers who have recently made a script to detect big data structures
1464        in the php code that should be moved to the .rodata section. I remembered
1465        to update Builducptable as well, so it won't revert if ucptable.h is ever
1466        re-created.
1467    
1468     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1469        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1470        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1471        support is not required. This saves 1.5-2K of code, which is important in
1472        some applications.
1473    
1474        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1475        so as not to refer to the tables, even though these functions will never be
1476        called when UTF-8 support is disabled. Otherwise there are problems with a
1477        shared library.
1478    
1479    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1480    
1481        (a) It was defining its arguments as char * instead of void *.
1482    
1483        (b) It was assuming that all moves were upwards in memory; this was true
1484            a long time ago when I wrote it, but is no longer the case.
1485    
1486        The emulated memove() is provided for those environments that have neither
1487        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1488        is clearly not the case, as these two bugs were recently reported.
1489    
1490    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1491        and Detrail to create the HTML documentation, the .txt form of the man
1492        pages, and it removes trailing spaces from listed files. It also creates
1493        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1494        case, it wraps all the #defines with #ifndefs. This script should be run
1495        before "make dist".
1496    
1497    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1498        with Unicode property support.
1499    
1500        (a) For a maximizing quantifier, if the two different cases of the
1501            character were of different lengths in their UTF-8 codings (there are
1502            some cases like this - I found 11), and the matching function had to
1503            back up over a mixture of the two cases, it incorrectly assumed they
1504            were both the same length.
1505    
1506        (b) When PCRE was configured to use the heap rather than the stack for
1507            recursion during matching, it was not correctly preserving the data for
1508            the other case of a UTF-8 character when checking ahead for a match
1509            while processing a minimizing repeat. If the check also involved
1510            matching a wide character, but failed, corruption could cause an
1511            erroneous result when trying to check for a repeat of the original
1512            character.
1513    
1514    13. Some tidying changes to the testing mechanism:
1515    
1516        (a) The RunTest script now detects the internal link size and whether there
1517            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1518            values substituted by "configure". (The RunGrepTest script already did
1519            this for UTF-8.) The configure.ac script no longer substitutes the
1520            relevant variables.
1521    
1522        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1523            with length and offset values. This means that the output is different
1524            for different internal link sizes. Test 2 is skipped for link sizes
1525            other than 2 because of this, bypassing the problem. Unfortunately,
1526            there was also a test in test 3 (the locale tests) that used /B and
1527            failed for link sizes other than 2. Rather than cut the whole test out,
1528            I have added a new /Z option to pcretest that replaces the length and
1529            offset values with spaces. This is now used to make test 3 independent
1530            of link size. (Test 2 will be tidied up later.)
1531    
1532    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1533        segmentation fault instead of returning the appropriate error message.
1534    
1535    15. In multiline mode when the newline sequence was set to "any", the pattern
1536        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1537        This doesn't seem right; it now treats the CRLF combination as the line
1538        ending, and so does not match in that case. It's only a pattern such as ^$
1539        that would hit this one: something like ^ABC$ would have failed after \r
1540        and then tried again after \r\n.
1541    
1542    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1543        in an attempt to make files that differ only in their line terminators
1544        compare equal. This works on Linux.
1545    
1546    17. Under certain error circumstances pcregrep might try to free random memory
1547        as it exited. This is now fixed, thanks to valgrind.
1548    
1549    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1550        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1551        was because its rules for how to advance for /g after matching an empty
1552        string at the end of a line did not allow for this case. They now check for
1553        it specially.
1554    
1555    20. pcretest is supposed to handle patterns and data of any length, by
1556        extending its buffers when necessary. It was getting this wrong when the
1557        buffer for a data line had to be extended.
1558    
1559    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1560        CRLF as a newline sequence.
1561    
1562    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1563        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1564        I have nevertheless tidied it up.
1565    
1566    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1567    
1568    24. Added a man page for pcre-config.
1569    
1570    
1571    Version 7.0 19-Dec-06
1572    ---------------------
1573    
1574     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1575        moving to gcc 4.1.1.
1576    
1577     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1578        sys/time.h, which is documented as needed for this function. It doesn't
1579        seem to matter on Linux, but it showed up on some releases of OS X.
1580    
1581     3. It seems that there are systems where bytes whose values are greater than
1582        127 match isprint() in the "C" locale. The "C" locale should be the
1583        default when a C program starts up. In most systems, only ASCII printing
1584        characters match isprint(). This difference caused the output from pcretest
1585        to vary, making some of the tests fail. I have changed pcretest so that:
1586    
1587        (a) When it is outputting text in the compiled version of a pattern, bytes
1588            other than 32-126 are always shown as hex escapes.
1589    
1590        (b) When it is outputting text that is a matched part of a subject string,
1591            it does the same, unless a different locale has been set for the match
1592            (using the /L modifier). In this case, it uses isprint() to decide.
1593    
1594     4. Fixed a major bug that caused incorrect computation of the amount of memory
1595        required for a compiled pattern when options that changed within the
1596        pattern affected the logic of the preliminary scan that determines the
1597        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1598        that the computed length was too small. The symptoms of this bug were
1599        either the PCRE error "internal error: code overflow" from pcre_compile(),
1600        or a glibc crash with a message such as "pcretest: free(): invalid next
1601        size (fast)". Examples of patterns that provoked this bug (shown in
1602        pcretest format) are:
1603    
1604          /(?-x: )/x
1605          /(?x)(?-x: \s*#\s*)/
1606          /((?i)[\x{c0}])/8
1607          /(?i:[\x{c0}])/8
1608    
1609        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1610        is now done differently.
1611    
1612     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1613        wrapper classes; (b) implement a new function in the C++ scanner that is
1614        more efficient than the old way of doing things because it avoids levels of
1615        recursion in the regex matching; (c) add a paragraph to the documentation
1616        for the FullMatch() function.
1617    
1618     6. The escape sequence \n was being treated as whatever was defined as
1619        "newline". Not only was this contrary to the documentation, which states
1620        that \n is character 10 (hex 0A), but it also went horribly wrong when
1621        "newline" was defined as CRLF. This has been fixed.
1622    
1623     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1624        was being set to -1 for the "end of line" case (supposedly a value that no
1625        character can have). Though this value is never used (the check for end of
1626        line is "zero bytes in current character"), it caused compiler complaints.
1627        I've changed it to 0xffffffff.
1628    
1629     8. In pcre_version.c, the version string was being built by a sequence of
1630        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1631        string (as it is for production releases) called a macro with an empty
1632        argument. The C standard says the result of this is undefined. The gcc
1633        compiler treats it as an empty string (which was what was wanted) but it is
1634        reported that Visual C gives an error. The source has been hacked around to
1635        avoid this problem.
1636    
1637     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1638        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1639        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1640        of them did).
1641    
1642    10. Originally, pcretest opened its input and output without "b"; then I was
1643        told that "b" was needed in some environments, so it was added for release
1644        5.0 to both the input and output. (It makes no difference on Unix-like
1645        systems.) Later I was told that it is wrong for the input on Windows. I've
1646        now abstracted the modes into two macros, to make it easier to fiddle with
1647        them, and removed "b" from the input mode under Windows.
1648    
1649    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1650    
1651    12. Added -help and --help to pcretest as an official way of being reminded
1652        of the options.
1653    
1654    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1655        and pcrecpp.cc because they annoy compilers at high warning levels.
1656    
1657    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1658    
1659    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1660        scripts are not C programs :-) and which was not noticed because it works
1661        on Linux.
1662    
1663    16. pcretest is supposed to handle any length of pattern and data line (as one
1664        line or as a continued sequence of lines) by extending its input buffer if
1665        necessary. This feature was broken for very long pattern lines, leading to
1666        a string of junk being passed to pcre_compile() if the pattern was longer
1667        than about 50K.
1668    
1669    17. I have done a major re-factoring of the way pcre_compile() computes the
1670        amount of memory needed for a compiled pattern. Previously, there was code
1671        that made a preliminary scan of the pattern in order to do this. That was
1672        OK when PCRE was new, but as the facilities have expanded, it has become
1673        harder and harder to keep it in step with the real compile phase, and there
1674        have been a number of bugs (see for example, 4 above). I have now found a
1675        cunning way of running the real compile function in a "fake" mode that
1676        enables it to compute how much memory it would need, while actually only
1677        ever using a few hundred bytes of working memory and without too many
1678        tests of the mode. This should make future maintenance and development
1679        easier. A side effect of this work is that the limit of 200 on the nesting
1680        depth of parentheses has been removed (though this was never a serious
1681        limitation, I suspect). However, there is a downside: pcre_compile() now
1682        runs more slowly than before (30% or more, depending on the pattern). I
1683        hope this isn't a big issue. There is no effect on runtime performance.
1684    
1685    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1686        newline (only possible for the last line of a file) and it was a
1687        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1688    
1689    19. Added additional timing features to pcretest. (1) The -tm option now times
1690        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1691        separate command line item, by a number that specifies the number of
1692        repeats to use when timing. The default is 50000; this gives better
1693        precision, but takes uncomfortably long for very large patterns.
1694    
1695    20. Extended pcre_study() to be more clever in cases where a branch of a
1696        subpattern has no definite first character. For example, (a*|b*)[cd] would
1697        previously give no result from pcre_study(). Now it recognizes that the
1698        first character must be a, b, c, or d.
1699    
1700    21. There was an incorrect error "recursive call could loop indefinitely" if
1701        a subpattern (or the entire pattern) that was being tested for matching an
1702        empty string contained only one non-empty item after a nested subpattern.
1703        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1704        incorrectly, because the \d was being skipped in the check.
1705    
1706    22. The pcretest program now has a new pattern option /B and a command line
1707        option -b, which is equivalent to adding /B to every pattern. This causes
1708        it to show the compiled bytecode, without the additional information that
1709        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1710        is the same as /B/I).
1711    
1712    23. A new optimization is now able automatically to treat some sequences such
1713        as a*b as a*+b. More specifically, if something simple (such as a character
1714        or a simple class like \d) has an unlimited quantifier, and is followed by
1715        something that cannot possibly match the quantified thing, the quantifier
1716        is automatically "possessified".
1717    
1718    24. A recursive reference to a subpattern whose number was greater than 39
1719        went wrong under certain circumstances in UTF-8 mode. This bug could also
1720        have affected the operation of pcre_study().
1721    
1722    25. Realized that a little bit of performance could be had by replacing
1723        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1724    
1725    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1726    
1727    27. Possessive quantifiers such as a++ were previously implemented by turning
1728        them into atomic groups such as ($>a+). Now they have their own opcodes,
1729        which improves performance. This includes the automatically created ones
1730        from 23 above.
1731    
1732    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1733        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1734        the first matched character to be a colon. This applied both to named and
1735        numbered groups.
1736    
1737    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1738    
1739    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1740        building PCRE on Windows easier, so I have included it in the distribution.
1741    
1742    31. There is now a check in pcretest against a ridiculously large number being
1743        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1744        loop, the loop is abandoned.
1745    
1746    32. Forward references to subpatterns in conditions such as (?(2)...) where
1747        subpattern 2 is defined later cause pcre_compile() to search forwards in
1748        the pattern for the relevant set of parentheses. This search went wrong
1749        when there were unescaped parentheses in a character class, parentheses
1750        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1751    
1752    33. "Subroutine" calls and backreferences were previously restricted to
1753        referencing subpatterns earlier in the regex. This restriction has now
1754        been removed.
1755    
1756    34. Added a number of extra features that are going to be in Perl 5.10. On the
1757        whole, these are just syntactic alternatives for features that PCRE had
1758        previously implemented using the Python syntax or my own invention. The
1759        other formats are all retained for compatibility.
1760    
1761        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1762            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1763            also .NET compatible.
1764    
1765        (b) A recursion or subroutine call to a named group can now be defined as
1766            (?&name) as well as (?P>name).
1767    
1768        (c) A backreference to a named group can now be defined as \k<name> or
1769            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1770            5.10, are also .NET compatible.
1771    
1772        (d) A conditional reference to a named group can now use the syntax
1773            (?(<name>) or (?('name') as well as (?(name).
1774    
1775        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1776            groups (named and numbered) that are never evaluated inline, but can be
1777            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1778            is always false. There may be only one alternative in such a group.
1779    
1780        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1781            as the simple (?(R). The condition is true only if the most recent
1782            recursion is that of the given number or name. It does not search out
1783            through the entire recursion stack.
1784    
1785        (g) The escape \gN or \g{N} has been added, where N is a positive or
1786            negative number, specifying an absolute or relative reference.
1787    
1788    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1789        some "unreachable code" warnings.
1790    
1791    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1792        things, this adds five new scripts.
1793    
1794    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1795        There were also incompatibilities regarding the handling of \Q..\E inside
1796        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1797        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1798    
1799    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1800        matches an empty string, and forcibly breaks the loop. There were bugs in
1801        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1802        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1803        separate and independent bugs (that affected different cases) have been
1804        fixed.
1805    
1806    39. Refactored the code to abolish the use of different opcodes for small
1807        capturing bracket numbers. This is a tidy that I avoided doing when I
1808        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1809        The new approach is not only tidier, it makes it possible to reduce the
1810        memory needed to fix the previous bug (38).
1811    
1812    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1813        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1814        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1815        mode.
1816    
1817    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1818        report.
1819    
1820    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1821        copy construction and assignment in the C++ wrapper.
1822    
1823    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1824        couple of bugs that could have given wrong results in the "--newline=crlf"
1825        case.
1826    
1827    44. Added a number of casts and did some reorganization of signed/unsigned int
1828        variables following suggestions from Dair Grant. Also renamed the variable
1829        "this" as "item" because it is a C++ keyword.
1830    
1831    45. Arranged for dftables to add
1832    
1833          #include "pcre_internal.h"
1834    
1835        to pcre_chartables.c because without it, gcc 4.x may remove the array
1836        definition from the final binary if PCRE is built into a static library and
1837        dead code stripping is activated.
1838    
1839    46. For an unanchored pattern, if a match attempt fails at the start of a
1840        newline sequence, and the newline setting is CRLF or ANY, and the next two
1841        characters are CRLF, advance by two characters instead of one.
1842    
1843    
1844    Version 6.7 04-Jul-06
1845    ---------------------
1846    
1847     1. In order to handle tests when input lines are enormously long, pcretest has
1848        been re-factored so that it automatically extends its buffers when
1849        necessary. The code is crude, but this _is_ just a test program. The
1850        default size has been increased from 32K to 50K.
1851    
1852     2. The code in pcre_study() was using the value of the re argument before
1853        testing it for NULL. (Of course, in any sensible call of the function, it
1854        won't be NULL.)
1855    
1856     3. The memmove() emulation function in pcre_internal.h, which is used on
1857        systems that lack both memmove() and bcopy() - that is, hardly ever -
1858        was missing a "static" storage class specifier.
1859    
1860     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1861        containing an extended class (one that cannot be represented by a bitmap
1862        because it contains high-valued characters or Unicode property items, e.g.
1863        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1864        pattern, but PCRE should not loop if you do not (it no longer does).
1865        [Detail: two cases were found: (a) a repeated subpattern containing an
1866        extended class; (b) a recursive reference to a subpattern that followed a
1867        previous extended class. It wasn't skipping over the extended class
1868        correctly when UTF-8 mode was not set.]
1869    
1870     5. A negated single-character class was not being recognized as fixed-length
1871        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1872        compile error "lookbehind assertion is not fixed length".
1873    
1874     6. The RunPerlTest auxiliary script was showing an unexpected difference
1875        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1876        write a Perl script that can interpret lines of an input file either as
1877        byte characters or as UTF-8, which is what "perltest" was being required to
1878        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1879        can't do is switch easily at run time between having the "use utf8;" pragma
1880        or not. In the end, I fudged it by using the RunPerlTest script to insert
1881        "use utf8;" explicitly for the UTF-8 tests.
1882    
1883     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1884        the end of the subject string, contrary to the documentation and to what
1885        Perl does. This was true of both matching functions. Now it matches only at
1886        the start of the subject and immediately after *internal* newlines.
1887    
1888     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1889        a pointer to an int instead of a pointer to an unsigned long int. This
1890        caused problems on 64-bit systems.
1891    
1892     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1893        instance of the 'standard' template library not being so standard".
1894    
1895    10. There was no check on the number of named subpatterns nor the maximum
1896        length of a subpattern name. The product of these values is used to compute
1897        the size of the memory block for a compiled pattern. By supplying a very
1898        long subpattern name and a large number of named subpatterns, the size
1899        computation could be caused to overflow. This is now prevented by limiting
1900        the length of names to 32 characters, and the number of named subpatterns
1901        to 10,000.
1902    
1903    11. Subpatterns that are repeated with specific counts have to be replicated in
1904        the compiled pattern. The size of memory for this was computed from the
1905        length of the subpattern and the repeat count. The latter is limited to
1906        65535, but there was no limit on the former, meaning that integer overflow
1907        could in principle occur. The compiled length of a repeated subpattern is
1908        now limited to 30,000 bytes in order to prevent this.
1909    
1910    12. Added the optional facility to have named substrings with the same name.
1911    
1912    13. Added the ability to use a named substring as a condition, using the
1913        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1914        are numbers (not recommended). Forward references are permitted.
1915    
1916    14. Added forward references in named backreferences (if you see what I mean).
1917    
1918    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1919        pattern could run off the end of the subject. For example, the pattern
1920        "(?s)(.{1,5})"8 did this with the subject "ab".
1921    
1922    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1923        PCRE_CASELESS was set when matching characters that were quantified with ?
1924        or *.
1925    
1926    17. A character class other than a single negated character that had a minimum
1927        but no maximum quantifier - for example [ab]{6,} - was not handled
1928        correctly by pce_dfa_exec(). It would match only one character.
1929    
1930    18. A valid (though odd) pattern that looked like a POSIX character
1931        class but used an invalid character after [ (for example [[,abc,]]) caused
1932        pcre_compile() to give the error "Failed: internal error: code overflow" or
1933        in some cases to crash with a glibc free() error. This could even happen if
1934        the pattern terminated after [[ but there just happened to be a sequence of
1935        letters, a binary zero, and a closing ] in the memory that followed.
1936    
1937    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1938        over the years. Originally (before any Unicode support), just the bottom 8
1939        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1940        output from "man perlunicode" includes this:
1941    
1942          The regular expression compiler produces polymorphic opcodes.  That
1943          is, the pattern adapts to the data and automatically switches to
1944          the Unicode character scheme when presented with Unicode data--or
1945          instead uses a traditional byte scheme when presented with byte
1946          data.
1947    
1948        Sadly, a wide octal escape does not cause a switch, and in a string with
1949        no other multibyte characters, these octal escapes are treated as before.
1950        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1951        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1952        Unicode string.
1953    
1954        I have not perpetrated such confusion in PCRE. Up till now, it took just
1955        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1956        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1957        translate to the appropriate multibyte character.
1958    
1959    29. Applied some refactoring to reduce the number of warnings from Microsoft
1960        and Borland compilers. This has included removing the fudge introduced
1961        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1962        a warning about an unused variable.
1963    
1964    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1965        characters since release 4.0, because Perl (from release 5.004) does not.
1966        [Or at least, is documented not to: some releases seem to be in conflict
1967        with the documentation.] However, when a pattern was studied with
1968        pcre_study() and all its branches started with \s, PCRE still included VT
1969        as a possible starting character. Of course, this did no harm; it just
1970        caused an unnecessary match attempt.
1971    
1972    22. Removed a now-redundant internal flag bit that recorded the fact that case
1973        dependency changed within the pattern. This was once needed for "required
1974        byte" processing, but is no longer used. This recovers a now-scarce options
1975        bit. Also moved the least significant internal flag bit to the most-
1976        significant bit of the word, which was not previously used (hangover from
1977        the days when it was an int rather than a uint) to free up another bit for
1978        the future.
1979    
1980    23. Added support for CRLF line endings as well as CR and LF. As well as the
1981        default being selectable at build time, it can now be changed at runtime
1982        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1983        specify that it is scanning data with non-default line endings.
1984    
1985    24. Changed the definition of CXXLINK to make it agree with the definition of
1986        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1987    
1988    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1989        recursions. This makes a big different to stack usage for some patterns.
1990    
1991    26. If a subpattern containing a named recursion or subroutine reference such
1992        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1993        the space required for the compiled pattern went wrong and gave too small a
1994        value. Depending on the environment, this could lead to "Failed: internal
1995        error: code overflow at offset 49" or "glibc detected double free or
1996        corruption" errors.
1997    
1998    27. Applied patches from Google (a) to support the new newline modes and (b) to
1999        advance over multibyte UTF-8 characters in GlobalReplace.
2000    
2001    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2002        difference for some implementation of PCRE in some Windows version.
2003    
2004    29. Added some extra testing facilities to pcretest:
2005    
2006        \q<number>   in a data line sets the "match limit" value
2007        \Q<number>   in a data line sets the "match recursion limt" value
2008        -S <number>  sets the stack size, where <number> is in megabytes
2009    
2010        The -S option isn't available for Windows.
2011    
2012    
2013    Version 6.6 06-Feb-06
2014    ---------------------
2015    
2016     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2017        in pcreposix.h. I have copied the definition from pcre.h.
2018    
2019     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2020        because pcre.h is no longer a built file.
2021    
2022     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2023        not normally included in the compiled code.
2024    
2025    
2026    Version 6.5 01-Feb-06
2027    ---------------------
2028    
2029     1. When using the partial match feature with pcre_dfa_exec(), it was not
2030        anchoring the second and subsequent partial matches at the new starting
2031        point. This could lead to incorrect results. For example, with the pattern
2032        /1234/, partially matching against "123" and then "a4" gave a match.
2033    
2034     2. Changes to pcregrep:
2035    
2036        (a) All non-match returns from pcre_exec() were being treated as failures
2037            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2038            error message is output. Some extra information is given for the
2039            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2040            probably the only errors that are likely to be caused by users (by
2041            specifying a regex that has nested indefinite repeats, for instance).
2042            If there are more than 20 of these errors, pcregrep is abandoned.
2043    
2044        (b) A binary zero was treated as data while matching, but terminated the
2045            output line if it was written out. This has been fixed: binary zeroes
2046            are now no different to any other data bytes.
2047    
2048        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2049            used to set a locale for matching. The --locale=xxxx long option has
2050            been added (no short equivalent) to specify a locale explicitly on the
2051            pcregrep command, overriding the environment variables.
2052    
2053        (d) When -B was used with -n, some line numbers in the output were one less
2054            than they should have been.
2055    
2056        (e) Added the -o (--only-matching) option.
2057    
2058        (f) If -A or -C was used with -c (count only), some lines of context were
2059            accidentally printed for the final match.
2060    
2061        (g) Added the -H (--with-filename) option.
2062    
2063        (h) The combination of options -rh failed to suppress file names for files
2064            that were found from directory arguments.
2065    
2066        (i) Added the -D (--devices) and -d (--directories) options.
2067    
2068        (j) Added the -F (--fixed-strings) option.
2069    
2070        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2071    
2072        (l) Added the --colo(u)r option.
2073    
2074        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2075            is not present by default.
2076    
2077     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2078        items such as (?R) or (?1), when the recursion could match a number of
2079        alternatives. If it matched one of the alternatives, but subsequently,
2080        outside the recursion, there was a failure, the code tried to back up into
2081        the recursion. However, because of the way PCRE is implemented, this is not
2082        possible, and the result was an incorrect result from the match.
2083    
2084        In order to prevent this happening, the specification of recursion has
2085        been changed so that all such subpatterns are automatically treated as
2086        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2087    
2088     4. I had overlooked the fact that, in some locales, there are characters for
2089        which isalpha() is true but neither isupper() nor islower() are true. In
2090        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2091        and ordfeminine) are like this. This affected the treatment of \w and \W
2092        when they appeared in character classes, but not when they appeared outside
2093        a character class. The bit map for "word" characters is now created
2094        separately from the results of isalnum() instead of just taking it from the
2095        upper, lower, and digit maps. (Plus the underscore character, of course.)
2096    
2097     5. The above bug also affected the handling of POSIX character classes such as
2098        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2099        permanent tables. Instead, the bit maps for such a class were previously
2100        created as the appropriate unions of the upper, lower, and digit bitmaps.
2101        Now they are created by subtraction from the [[:word:]] class, which has
2102        its own bitmap.
2103    
2104     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2105        It is created by subtracting the vertical space characters (\x09, \x0a,
2106        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2107        subtraction was done in the overall bitmap for a character class, meaning
2108        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2109        be recognized. This bug has been fixed.
2110    
2111     7. Patches from the folks at Google:
2112    
2113          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2114          real life, but is still worth protecting against".
2115    
2116          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2117          regular expressions".
2118    
2119          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2120          have it.
2121    
2122          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2123          "configure" and the latter not, in order to fix a problem somebody had
2124          with compiling the Arg class on HP-UX.
2125    
2126          (e) Improve the error-handling of the C++ wrapper a little bit.
2127    
2128          (f) New tests for checking recursion limiting.
2129    
2130     8. The pcre_memmove() function, which is used only if the environment does not
2131        have a standard memmove() function (and is therefore rarely compiled),
2132        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2133        returning a result (though PCRE never actually uses the result).
2134    
2135     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2136        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2137        returned instead of calling malloc() with an overflowing number that would
2138        most likely cause subsequent chaos.
2139    
2140    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2141    
2142    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2143        with this option is matched, the nmatch and pmatch options of regexec() are
2144        ignored.
2145    
2146    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2147        provided in case anyone wants to the the POSIX interface with UTF-8
2148        strings.
2149    
2150    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2151        C++ linking (needed for some HP-UX environments).
2152    
2153    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2154        (unused parameter) and in the pcre_printint() function (omitted "default"
2155        switch label when the default is to do nothing).
2156    
2157    15. Added some code to make it possible, when PCRE is compiled as a C++
2158        library, to replace subject pointers for pcre_exec() with a smart pointer
2159        class, thus making it possible to process discontinuous strings.
2160    
2161    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2162        much the same function. They were added by different people who were trying
2163        to make PCRE easy to compile on non-Unix systems. It has been suggested
2164        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2165        for compiling on Windows systems. I have therefore replaced it with
2166        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2167        defaults to "extern" for C or "extern C" for C++, which works fine on
2168        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2169        SCOPE with something explicit in config.h. In addition:
2170    
2171        (a) pcreposix.h still had just "extern" instead of either of these macros;
2172            I have replaced it with PCRE_DATA_SCOPE.
2173    
2174        (b) Functions such as _pcre_xclass(), which are internal to the library,
2175            but external in the C sense, all had PCRE_EXPORT in their definitions.
2176            This is apparently wrong for the Windows case, so I have removed it.
2177            (It makes no difference on Unix-like systems.)
2178    
2179    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2180        of recursive calls to match(). This is different to MATCH_LIMIT because
2181        that limits the total number of calls to match(), not all of which increase
2182        the depth of recursion. Limiting the recursion depth limits the amount of
2183        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2184        when PCRE is compiled, and changed at run time. A patch from Google adds
2185        this functionality to the C++ interface.
2186    
2187    18. Changes to the handling of Unicode character properties:
2188    
2189        (a) Updated the table to Unicode 4.1.0.
2190    
2191        (b) Recognize characters that are not in the table as "Cn" (undefined).
2192    
2193        (c) I revised the way the table is implemented to a much improved format
2194            which includes recognition of ranges. It now supports the ranges that
2195            are defined in UnicodeData.txt, and it also amalgamates other
2196            characters into ranges. This has reduced the number of entries in the
2197            table from around 16,000 to around 3,000, thus reducing its size
2198            considerably. I realized I did not need to use a tree structure after
2199            all - a binary chop search is just as efficient. Having reduced the
2200            number of entries, I extended their size from 6 bytes to 8 bytes to
2201            allow for more data.
2202    
2203        (d) Added support for Unicode script names via properties such as \p{Han}.
2204    
2205    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2206        matching that character.
2207    
2208    20. When matching a repeated Unicode property with a minimum greater than zero,
2209        (for example \pL{2,}), PCRE could look past the end of the subject if it
2210        reached it while seeking the minimum number of characters. This could
2211        happen only if some of the characters were more than one byte long, because
2212        there is a check for at least the minimum number of bytes.
2213    
2214    21. Refactored the implementation of \p and \P so as to be more general, to
2215        allow for more different types of property in future. This has changed the
2216        compiled form incompatibly. Anybody with saved compiled patterns that use
2217        \p or \P will have to recompile them.
2218    
2219    22. Added "Any" and "L&" to the supported property types.
2220    
2221    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2222        but give a compile time error if the value is greater than 0xff.
2223    
2224    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2225        accidentally not being installed or uninstalled.
2226    
2227    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2228        made were to insert the current release number. This seemed silly, because
2229        it made things harder for people building PCRE on systems that don't run
2230        "configure". I have turned pcre.h into a distributed file, no longer built
2231        by "configure", with the version identification directly included. There is
2232        no longer a pcre.h.in file.
2233    
2234        However, this change necessitated a change to the pcre-config script as
2235        well. It is built from pcre-config.in, and one of the substitutions was the
2236        release number. I have updated configure.ac so that ./configure now finds
2237        the release number by grepping pcre.h.
2238    
2239    26. Added the ability to run the tests under valgrind.
2240    
2241    
2242    Version 6.4 05-Sep-05
2243    ---------------------
2244    
2245     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2246        "--" to be printed when multiple files were scanned, even when none of the
2247        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2248        consider it to be a bug, and have restored the previous behaviour.
2249    
2250     2. A couple of code tidies to get rid of compiler warnings.
2251    
2252     3. The pcretest program used to cheat by referring to symbols in the library
2253        whose names begin with _pcre_. These are internal symbols that are not
2254        really supposed to be visible externally, and in some environments it is
2255        possible to suppress them. The cheating is now confined to including
2256        certain files from the library's source, which is a bit cleaner.
2257    
2258     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2259        file's purpose clearer.
2260    
2261     5. Reorganized pcre_ucp_findchar().
2262    
2263    
2264    Version 6.3 15-Aug-05
2265    ---------------------
2266    
2267     1. The file libpcre.pc.in did not have general read permission in the tarball.
2268    
2269     2. There were some problems when building without C++ support:
2270    
2271        (a) If C++ support was not built, "make install" and "make test" still
2272            tried to test it.
2273    
2274        (b) There were problems when the value of CXX was explicitly set. Some
2275            changes have been made to try to fix these, and ...
2276    
2277        (c) --disable-cpp can now be used to explicitly disable C++ support.
2278    
2279        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2280            backslash in a target when C++ was disabled. This confuses some
2281            versions of "make", apparently. Using an intermediate variable solves
2282            this. (Same for CPP_LOBJ.)
2283    
2284     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2285        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2286        necessary on certain architectures.
2287    
2288     4. Added a setting of -export-symbols-regex to the link command to remove
2289        those symbols that are exported in the C sense, but actually are local
2290        within the library, and not documented. Their names all begin with
2291        "_pcre_". This is not a perfect job, because (a) we have to except some
2292        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2293        available (and never for static libraries). I have made a note to try to
2294        find a way round (a) in the future.
2295    
2296    
2297    Version 6.2 01-Aug-05
2298    ---------------------
2299    
2300     1. There was no test for integer overflow of quantifier values. A construction
2301        such as {1111111111111111} would give undefined results. What is worse, if
2302        a minimum quantifier for a parenthesized subpattern overflowed and became
2303        negative, the calculation of the memory size went wrong. This could have
2304        led to memory overwriting.
2305    
2306     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2307    
2308     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2309        operating environments where this matters.
2310    
2311     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2312        PCRE options from within the C++ wrapper.
2313    
2314     5. Named capturing subpatterns were not being correctly counted when a pattern
2315        was compiled. This caused two problems: (a) If there were more than 100
2316        such subpatterns, the calculation of the memory needed for the whole
2317        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2318        back references of the form \12, where the number was greater than 9, were
2319        not recognized as back references, even though there were sufficient
2320        previous subpatterns.
2321    
2322     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2323        versions of gcc, e.g. 2.95.4.
2324    
2325    
2326    Version 6.1 21-Jun-05
2327    ---------------------
2328    
2329     1. There was one reference to the variable "posix" in pcretest.c that was not
2330        surrounded by "#if !defined NOPOSIX".
2331    
2332     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2333        the cross-check on the old pcre_info() function, for the benefit of the
2334        cut-down version of PCRE that is currently imported into Exim.
2335    
2336     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2337        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2338        patterns that start (?i) but I don't think that matters. The use of (?i) is
2339        just an example; this all applies to the other options as well.
2340    
2341     4. Since libtool seems to echo the compile commands it is issuing, the output
2342        from "make" can be reduced a bit by putting "@" in front of each libtool
2343        compile command.
2344    
2345     5. Patch from the folks at Google for configure.in to be a bit more thorough
2346        in checking for a suitable C++ installation before trying to compile the
2347        C++ stuff. This should fix a reported problem when a compiler was present,
2348        but no suitable headers.
2349    
2350     6. The man pages all had just "PCRE" as their title. I have changed them to
2351        be the relevant file name. I have also arranged that these names are
2352        retained in the file doc/pcre.txt, which is a concatenation in text format
2353        of all the man pages except the little individual ones for each function.
2354    
2355     7. The NON-UNIX-USE file had not been updated for the different set of source
2356        files that come with release 6. I also added a few comments about the C++
2357        wrapper.
2358    
2359    
2360    Version 6.0 07-Jun-05
2361    ---------------------
2362    
2363     1. Some minor internal re-organization to help with my DFA experiments.
2364    
2365     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2366        didn't matter for the library itself when fully configured, but did matter
2367        when compiling without UCP support, or within Exim, where the ucp files are
2368        not imported.
2369    
2370     3. Refactoring of the library code to split up the various functions into
2371        different source modules. The addition of the new DFA matching code (see
2372        below) to a single monolithic source would have made it really too
2373        unwieldy, quite apart from causing all the code to be include in a
2374        statically linked application, when only some functions are used. This is
2375        relevant even without the DFA addition now that patterns can be compiled in
2376        one application and matched in another.
2377    
2378        The downside of splitting up is that there have to be some external
2379        functions and data tables that are used internally in different modules of
2380        the library but which are not part of the API. These have all had their
2381        names changed to start with "_pcre_" so that they are unlikely to clash
2382        with other external names.
2383    
2384     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2385        a different (DFA) algorithm. Although it is slower than the original
2386        function, it does have some advantages for certain types of matching
2387        problem.
2388    
2389     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2390        including restarting after a partial match.
2391    
2392     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2393        defined when compiling for Windows was sent to me. I have put it into the
2394        code, though I have no means of testing or verifying it.
2395    
2396     7. Added the pcre_refcount() auxiliary function.
2397    
2398     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2399        match before or at the first newline in the subject string. In pcretest,
2400        the /f option on a pattern can be used to set this.
2401    
2402     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2403        would behave wrongly. This has been present in PCRE since release 4.0.
2404    
2405    10. A number of changes to the pcregrep command:
2406    
2407        (a) Refactored how -x works; insert ^(...)$ instead of setting
2408            PCRE_ANCHORED and checking the length, in preparation for adding
2409            something similar for -w.
2410    
2411        (b) Added the -w (match as a word) option.
2412    
2413        (c) Refactored the way lines are read and buffered so as to have more
2414            than one at a time available.
2415    
2416        (d) Implemented a pcregrep test script.
2417    
2418        (e) Added the -M (multiline match) option. This allows patterns to match
2419            over several lines of the subject. The buffering ensures that at least
2420            8K, or the rest of the document (whichever is the shorter) is available
2421            for matching (and similarly the previous 8K for lookbehind assertions).
2422    
2423        (f) Changed the --help output so that it now says
2424    
2425              -w, --word-regex(p)
2426    
2427            instead of two lines, one with "regex" and the other with "regexp"
2428            because that confused at least one person since the short forms are the
2429            same. (This required a bit of code, as the output is generated
2430            automatically from a table. It wasn't just a text change.)
2431    
2432        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2433            option but starts with a hyphen. Could be a pattern or a path name
2434            starting with a hyphen, for instance.
2435    
2436        (h) "-" can be given as a file name to represent stdin.
2437    
2438        (i) When file names are being printed, "(standard input)" is used for
2439            the standard input, for compatibility with GNU grep. Previously
2440            "<stdin>" was used.
2441    
2442        (j) The option --label=xxx can be used to supply a name to be used for
2443            stdin when file names are being printed. There is no short form.
2444    
2445        (k) Re-factored the options decoding logic because we are going to add
2446            two more options that take data. Such options can now be given in four
2447            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2448    
2449        (l) Added the -A, -B, and -C options for requesting that lines of context
2450            around matches be printed.
2451    
2452        (m) Added the -L option to print the names of files that do not contain
2453            any matching lines, that is, the complement of -l.
2454    
2455        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2456            continue to scan other files.
2457    
2458        (o) The -s option was incorrectly implemented. For compatibility with other
2459            greps, it now suppresses the error message for a non-existent or non-
2460            accessible file (but not the return code). There is a new option called
2461            -q that suppresses the output of matching lines, which was what -s was
2462            previously doing.
2463    
2464        (p) Added --include and --exclude options to specify files for inclusion
2465            and exclusion when recursing.
2466    
2467    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2468        Hopefully, it now does.
2469    
2470    12. Missing cast in pcre_study().
2471    
2472    13. Added an "uninstall" target to the makefile.
2473    
2474    14. Replaced "extern" in the function prototypes in Makefile.in with
2475        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2476        world, but is set differently for Windows.
2477    
2478    15. Added a second compiling function called pcre_compile2(). The only
2479        difference is that it has an extra argument, which is a pointer to an
2480        integer error code. When there is a compile-time failure, this is set
2481        non-zero, in addition to the error test pointer being set to point to an
2482        error message. The new argument may be NULL if no error number is required
2483        (but then you may as well call pcre_compile(), which is now just a
2484        wrapper). This facility is provided because some applications need a
2485        numeric error indication, but it has also enabled me to tidy up the way
2486        compile-time errors are handled in the POSIX wrapper.
2487    
2488    16. Added VPATH=.libs to the makefile; this should help when building with one
2489        prefix path and installing with another. (Or so I'm told by someone who
2490        knows more about this stuff than I do.)
2491    
2492    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2493        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2494        match everything, including newlines. This is not POSIX-compatible, but
2495        somebody wanted the feature. From pcretest it can be activated by using
2496        both the P and the s flags.
2497    
2498    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2499    
2500    19. libpcre.pc was being incorrectly installed as executable.
2501    
2502    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2503        it now also looks for '\r' so that it will work unmodified on Windows.
2504    
2505    21. Added Google's contributed C++ wrapper to the distribution.
2506    
2507    22. Added some untidy missing memory free() calls in pcretest, to keep
2508        Electric Fence happy when testing.
2509    
2510    
2511    
2512    Version 5.0 13-Sep-04
2513    ---------------------
2514    
2515     1. Internal change: literal characters are no longer packed up into items
2516        containing multiple characters in a single byte-string. Each character
2517        is now matched using a separate opcode. However, there may be more than one
2518        byte in the character in UTF-8 mode.
2519    
2520     2. The pcre_callout_block structure has two new fields: pattern_position and
2521        next_item_length. These contain the offset in the pattern to the next match
2522        item, and its length, respectively.
2523    
2524     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2525        insertion of callouts before each pattern item. Added the /C option to
2526        pcretest to make use of this.
2527    
2528     4. On the advice of a Windows user, the lines
2529    
2530          #if defined(_WIN32) || defined(WIN32)
2531          _setmode( _fileno( stdout ), 0x8000 );
2532          #endif  /* defined(_WIN32) || defined(WIN32) */
2533    
2534        have been added to the source of pcretest. This apparently does useful
2535        magic in relation to line terminators.
2536    
2537     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2538        for the benefit of those environments where the "b" makes a difference.
2539    
2540     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2541        to know about it. I have put a hack into configure.in that adds in code
2542        to set GCC=yes if CC=icc. This seems to end up at a point in the
2543        generated configure script that is early enough to affect the setting of
2544        compiler options, which is what is needed, but I have no means of testing
2545        whether it really works. (The user who reported this had patched the
2546        generated configure script, which of course I cannot do.)
2547    
2548        LATER: After change 22 below (new libtool files), the configure script
2549        seems to know about icc (and also ecc). Therefore, I have commented out
2550        this hack in configure.in.
2551    
2552     7. Added support for pkg-config (2 patches were sent in).
2553    
2554     8. Negated POSIX character classes that used a combination of internal tables
2555        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2556        [[:^ascii]]. Typically, they would match almost any characters. The other
2557        POSIX classes were not broken in this way.
2558    
2559     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2560        to find the match, as PCRE was deluded into thinking that the match had to
2561        start at the start point or following a newline. The same bug applied to
2562        patterns with negative forward assertions or any backward assertions
2563        preceding ".*" at the start, unless the pattern required a fixed first
2564        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2565    
2566    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2567        starting at the last subject character, bytes beyond the end of the subject
2568        string were read.
2569    
2570    11. Renamed the variable "class" as "classbits" to make life easier for C++
2571        users. (Previously there was a macro definition, but it apparently wasn't
2572        enough.)
2573    
2574    12. Added the new field "tables" to the extra data so that tables can be passed
2575        in at exec time, or the internal tables can be re-selected. This allows
2576        a compiled regex to be saved and re-used at a later time by a different
2577        program that might have everything at different addresses.
2578    
2579    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2580        -R library as well as a -L library.
2581    
2582    14. The debugging options of pcretest (-d on the command line or D on a
2583        pattern) showed incorrect output for anything following an extended class
2584        that contained multibyte characters and which was followed by a quantifier.
2585    
2586    15. Added optional support for general category Unicode character properties
2587        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2588        support. It adds about 90K to the size of the library. The meanings of the
2589        inbuilt class escapes such as \d and \s have NOT been changed.
2590    
2591    16. Updated pcredemo.c to include calls to free() to release the memory for the
2592        compiled pattern.
2593    
2594    17. The generated file chartables.c was being created in the source directory
2595        instead of in the building directory. This caused the build to fail if the
2596        source directory was different from the building directory, and was
2597        read-only.
2598    
2599    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2600        file. No doubt somebody will tell me if they don't make sense... Also added
2601        Dan Mooney's comments about building on OpenVMS.
2602    
2603    19. Added support for partial matching via the PCRE_PARTIAL option for
2604        pcre_exec() and the \P data escape in pcretest.
2605    
2606    20. Extended pcretest with 3 new pattern features:
2607    
2608        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2609              write the compiled pattern to the file whose name is "rest-of-line".
2610              This is a straight binary dump of the data, with the saved pointer to
2611              the character tables forced to be NULL. The study data, if any, is
2612              written too. After writing, pcretest reads a new pattern.
2613    
2614        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2615              compiled pattern from the given file. There must not be any
2616              occurrences of "<" in the file name (pretty unlikely); if there are,
2617              pcretest will instead treat the initial "<" as a pattern delimiter.
2618              After reading in the pattern, pcretest goes on to read data lines as
2619              usual.
2620    
2621        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2622              and 16-bit fields in a compiled pattern, to simulate a pattern that
2623              was compiled on a host of opposite endianness.
2624    
2625    21. The pcre-exec() function can now cope with patterns that were compiled on
2626        hosts of opposite endianness, with this restriction:
2627    
2628          As for any compiled expression that is saved and used later, the tables
2629          pointer field cannot be preserved; the extra_data field in the arguments
2630          to pcre_exec() should be used to pass in a tables address if a value
2631          other than the default internal tables were used at compile time.
2632    
2633    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2634        now diagnosed as an error. Previously, most of the time, a negative number
2635        would have been treated as zero, but if in addition "ovector" was passed as
2636        NULL, a crash could occur.
2637    
2638    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2639        new versions from the libtool 1.5 distribution (the last one is a copy of
2640        a file called libtool.m4). This seems to have fixed the need to patch
2641        "configure" to support Darwin 1.3 (which I used to do). However, I still
2642        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2643        workstation).
2644    
2645    24. Changed the PCRE licence to be the more standard "BSD" licence.
2646    
2647    
2648    Version 4.5 01-Dec-03
2649    ---------------------
2650    
2651     1. There has been some re-arrangement of the code for the match() function so
2652        that it can be compiled in a version that does not call itself recursively.
2653        Instead, it keeps those local variables that need separate instances for
2654        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2655        needs to "recurse". Keeping track of where control must go is done by means
2656        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2657        hide most of the details from the main code, and operates only if
2658        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2659        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2660        operating.
2661    
2662        To make it easier for callers to provide specially tailored get/free
2663        functions for this usage, two new functions, pcre_stack_malloc, and
2664        pcre_stack_free, are used. They are always called in strict stacking order,
2665        and the size of block requested is always the same.
2666    
2667        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2668        PCRE has been compiled to use the stack or the heap for recursion. The
2669        -C option of pcretest uses this to show which version is compiled.
2670    
2671        A new data escape \S, is added to pcretest; it causes the amounts of store
2672        obtained and freed by both kinds of malloc/free at match time to be added
2673        to the output.
2674    
2675     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2676        what's available on my current Linux desktop machine.
2677    
2678     3. When matching a UTF-8 string, the test for a valid string at the start has
2679        been extended. If start_offset is not zero, PCRE now checks that it points
2680        to a byte that is the start of a UTF-8 character. If not, it returns
2681        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2682        this is necessary because there may be backward assertions in the pattern.
2683        When matching the same subject several times, it may save resources to use
2684        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2685    
2686     4. The code for checking the validity of UTF-8 strings has been tightened so
2687        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2688        containing "overlong sequences".
2689    
2690     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2691        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2692        should have been "&", but it just so happened that all the cases this let
2693        through by mistake were picked up later in the function.
2694    
2695     6. I had used a variable called "isblank" - this is a C99 function, causing
2696        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2697    
2698     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2699        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2700        so the version is shown; (c) stop "make test" echoing "./RunTest".
2701    
2702     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2703    
2704     9. The prototype for memmove() for systems that don't have it was using
2705        size_t, but the inclusion of the header that defines size_t was later. I've
2706        moved the #includes for the C headers earlier to avoid this.
2707    
2708    10. Added some adjustments to the code to make it easier to compiler on certain
2709        special systems:
2710    
2711          (a) Some "const" qualifiers were missing.
2712          (b) Added the macro EXPORT before all exported functions; by default this
2713              is defined to be empty.
2714          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2715              that it reads its output file name as an argument instead of writing
2716              to the standard output and assuming this can be redirected.
2717    
2718    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2719        class containing characters with values greater than 255, PCRE compilation
2720        went into a loop.
2721    
2722    12. A recursive reference to a subpattern that was within another subpattern
2723        that had a minimum quantifier of zero caused PCRE to crash. For example,
2724        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2725        recursion. If the recursively-called subpattern itself had a zero repeat,
2726        that was OK.
2727    
2728    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2729        buffer into which it was copied (for escape processing) was still set at
2730        1024, so long lines caused crashes.
2731    
2732    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2733        "internal error: code overflow...". This applied to any character class
2734        that was followed by a possessive quantifier.
2735    
2736    15. Modified the Makefile to add libpcre.la as a prerequisite for
2737        libpcreposix.la because I was told this is needed for a parallel build to
2738        work.
2739    
2740    16. If a pattern that contained .* following optional items at the start was
2741        studied, the wrong optimizing data was generated, leading to matching
2742        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2743        matching string must start with a or b or c. The correct conclusion for
2744        this pattern is that a match can start with any character.
2745    
2746    
2747    Version 4.4 13-Aug-03
2748    ---------------------
2749    
2750     1. In UTF-8 mode, a character class containing characters with values between
2751        127 and 255 was not handled correctly if the compiled pattern was studied.
2752        In fixing this, I have also improved the studying algorithm for such
2753        classes (slightly).
2754    
2755     2. Three internal functions had redundant arguments passed to them. Removal
2756        might give a very teeny performance improvement.
2757    
2758     3. Documentation bug: the value of the capture_top field in a callout is *one
2759        more than* the number of the hightest numbered captured substring.
2760    
2761     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2762        in incorrectly linking with a previously installed version. They now link
2763        explicitly with libpcre.la.
2764    
2765     5. configure.in no longer needs to recognize Cygwin specially.
2766    
2767     6. A problem in pcre.in for Windows platforms is fixed.
2768    
2769     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2770        pcretest, it used to include the size of the study block as part of its
2771        output. Unfortunately, the structure contains a field that has a different
2772        size on different hardware architectures. This meant that the tests that
2773        showed this size failed. As the block is currently always of a fixed size,
2774        this information isn't actually particularly useful in pcretest output, so
2775        I have just removed it.
2776    
2777     8. Three pre-processor statements accidentally did not start in column 1.
2778        Sadly, there are *still* compilers around that complain, even though
2779        standard C has not required this for well over a decade. Sigh.
2780    
2781     9. In pcretest, the code for checking callouts passed small integers in the
2782        callout_data field, which is a void * field. However, some picky compilers
2783        complained about the casts involved for this on 64-bit systems. Now
2784        pcretest passes the address of the small integer instead, which should get
2785        rid of the warnings.
2786    
2787    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2788        both compile and run time, and gives an error if an invalid UTF-8 sequence
2789        is found. There is a option for disabling this check in cases where the
2790        string is known to be correct and/or the maximum performance is wanted.
2791    
2792    11. In response to a bug report, I changed one line in Makefile.in from
2793    
2794            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2795        to
2796            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2797    
2798        to look similar to other lines, but I have no way of telling whether this
2799        is the right thing to do, as I do not use Windows. No doubt I'll get told
2800        if it's wrong...
2801    
2802    
2803    Version 4.3 21-May-03
2804    ---------------------
2805    
2806    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2807       Makefile.
2808    
2809    2. Some refactoring to improve the quality of the code:
2810    
2811       (i)   The utf8_table... variables are now declared "const".
2812    
2813       (ii)  The code for \cx, which used the "case flipping" table to upper case
2814             lower case letters, now just substracts 32. This is ASCII-specific,
2815             but the whole concept of \cx is ASCII-specific, so it seems
2816             reasonable.
2817    
2818       (iii) PCRE was using its character types table to recognize decimal and
2819             hexadecimal digits in the pattern. This is silly, because it handles
2820             only 0-9, a-f, and A-F, but the character types table is locale-
2821             specific, which means strange things might happen. A private
2822             table is now used for this - though it costs 256 bytes, a table is
2823             much faster than multiple explicit tests. Of course, the standard
2824             character types table is still used for matching digits in subject
2825             strings against \d.
2826    
2827       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2828             ending in _t are). So I've renamed it as ESC_tee.
2829    
2830    3. The first argument for regexec() in the POSIX wrapper should have been
2831       defined as "const".
2832    
2833    4. Changed pcretest to use malloc() for its buffers so that they can be
2834       Electric Fenced for debugging.
2835    
2836    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2837       to read one or more bytes before the start of the subject string. Often this
2838       had no effect on PCRE's behaviour, but in some circumstances it could
2839       provoke a segmentation fault.
2840    
2841    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2842       to try to read one or more bytes before the start of the subject string.
2843    
2844    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2845       UTF-8 support could misbehave in various ways if the subject string
2846       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2847       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2848       back over UTF-8 characters.)
2849    
2850    
2851    Version 4.2 14-Apr-03
2852    ---------------------
2853    
2854    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2855    
2856    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2857         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2858         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2859         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2860         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2861           and BUILD_EXEEXT
2862         Note: automatic setting of the BUILD variables is not yet working
2863         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2864           compile-time but not at link-time
2865         [LINK]: use for linking executables only
2866         make different versions for Windows and non-Windows
2867         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2868           libraries
2869         [LINK_FOR_BUILD]: new variable
2870         [OBJEXT]: use throughout
2871         [EXEEXT]: use throughout
2872         <winshared>: new target
2873         <wininstall>: new target
2874         <dftables.o>: use native compiler
2875         <dftables>: use native linker
2876         <install>: handle Windows platform correctly
2877         <clean>: ditto
2878         <check>: ditto
2879         copy DLL to top builddir before testing
2880    
2881       As part of these changes, -no-undefined was removed again. This was reported
2882       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2883       in any case.
2884    
2885    3. Some tidies to get rid of compiler warnings:
2886    
2887       . In the match_data structure, match_limit was an unsigned long int, whereas
2888         match_call_count was an int. I've made them both unsigned long ints.
2889    
2890       . In pcretest the fact that a const uschar * doesn't automatically cast to
2891         a void * provoked a warning.
2892    
2893       . Turning on some more compiler warnings threw up some "shadow" variables
2894         and a few more missing casts.
2895    
2896    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2897       option, a class that contained a single character with a value between 128
2898       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2899    
2900    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2901       option, a class that contained several characters, but with at least one
2902       whose value was between 128 and 255 caused PCRE to crash.
2903    
2904    
2905    Version 4.1 12-Mar-03
2906    ---------------------
2907    
2908    1. Compiling with gcc -pedantic found a couple of places where casts were
2909    needed, and a string in dftables.c that was longer than standard compilers are
2910    required to support.
2911    
2912    2. Compiling with Sun's compiler found a few more places where the code could
2913    be tidied up in order to avoid warnings.
2914    
2915    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2916    first of these names is deprecated in the latest Autoconf in favour of the name
2917    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2918    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2919    analogy I have changed it to CFLAGS_FOR_BUILD.
2920    
2921    4. Added -no-undefined to the linking command in the Makefile, because this is
2922    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2923    linking step for the pcreposix library.
2924    
2925    5. PCRE was failing to diagnose the case of two named groups with the same
2926    name.
2927    
2928    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2929    literal character that is needed in the subject for a match, and scans along to
2930    ensure that it is present before embarking on the full matching process. This
2931    saves time in cases of nested unlimited repeats that are never going to match.
2932    Problem: the scan can take a lot of time if the subject is very long (e.g.
2933    megabytes), thus penalizing straightforward matches. It is now done only if the
2934    amount of subject to be scanned is less than 1000 bytes.
2935    
2936    7. A lesser problem with the same optimization is that it was recording the
2937    first character of an anchored pattern as "needed", thus provoking a search
2938    right along the subject, even when the first match of the pattern was going to
2939    fail. The "needed" character is now not set for anchored patterns, unless it
2940    follows something in the pattern that is of non-fixed length. Thus, it still
2941    fulfils its original purpose of finding quick non-matches in cases of nested
2942    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2943    
2944    
2945    Version 4.0 17-Feb-03
2946    ---------------------
2947    
2948    1. If a comment in an extended regex that started immediately after a meta-item
2949    extended to the end of string, PCRE compiled incorrect data. This could lead to
2950    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2951    
2952    2. Moved to autoconf 2.53 and libtool 1.4.2.
2953    
2954    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2955    the special perltest8 script is no longer needed - all the tests can be run
2956    from a single perltest script.
2957    
2958    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2959    by \s. It has now been removed in PCRE. This means it isn't recognized as
2960    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2961    class [:space:] *does* include VT, thereby creating a mess.
2962    
2963    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2964    space and tab.
2965    
2966    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2967    its new features into the main test script, reducing the number of scripts.
2968    
2969    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2970    were backward compatible, and made the (?i) apply to the whole pattern, as if
2971    /i were given. Now it behaves more logically, and applies the option setting
2972    only to what follows. PCRE has been changed to follow suit. However, if it
2973    finds options settings right at the start of the pattern, it extracts them into
2974    the global options, as before. Thus, they show up in the info data.
2975    
2976    8. Added support for the \Q...\E escape sequence. Characters in between are
2977    treated as literals. This is slightly different from Perl in that $ and @ are
2978    also handled as literals inside the quotes. In Perl, they will cause variable
2979    interpolation. Note the following examples:
2980    
2981        Pattern            PCRE matches      Perl matches
2982    
2983        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2984        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2985        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2986    
2987    For compatibility with Perl, \Q...\E sequences are recognized inside character
2988    classes as well as outside them.
2989    
2990    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2991    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2992    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2993    signed/unsigned warnings.
2994    
2995    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2996    option for pcretest, so I've replaced it by a simple function that does just
2997    that job.
2998    
2999    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
3000    "pcregrep -".
3001    
3002    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
3003    Java package. This provides some syntactic sugar for simple cases of what my
3004    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
3005    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
3006    item, you can use this simplified notation. Note that only makes sense with
3007    greedy quantifiers. Consequently, the use of the possessive quantifier forces
3008    greediness, whatever the setting of the PCRE_UNGREEDY option.
3009    
3010    13. A change of greediness default within a pattern was not taking effect at
3011    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
3012    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
3013    was abstracted outside.
3014    
3015    14. PCRE now supports the \G assertion. It is true when the current matching
3016    position is at the start point of the match. This differs from \A when the
3017    starting offset is non-zero. Used with the /g option of pcretest (or similar
3018    code), it works in the same way as it does for Perl's /g option. If all
3019    alternatives of a regex begin with \G, the expression is anchored to the start
3020    match position, and the "anchored" flag is set in the compiled expression.
3021    
3022    15. Some bugs concerning the handling of certain option changes within patterns
3023    have been fixed. These applied to options other than (?ims). For example,
3024    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
3025    been the other way round. Some of this was related to change 7 above.
3026    
3027    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
3028    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
3029    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
3030    POSIX classes only within a class (e.g. /[[:alpha:]]/).
3031    
3032    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
3033    mode. Unlike ".", it always matches newline, whatever the setting of
3034    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
3035    assertions. Perl allows it, but it doesn't (in general) work because it can't
3036    calculate the length of the lookbehind. At least, that's the case for Perl
3037    5.8.0 - I've been told they are going to document that it doesn't work in
3038    future.
3039    
3040    18. Added an error diagnosis for escapes that PCRE does not support: these are
3041    \L, \l, \N, \P, \p, \U, \u, and \X.
3042    
3043    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
3044    reading past the end of the pattern in cases such as /[abcd/.
3045    
3046    20. PCRE was getting more memory than necessary for patterns with classes that
3047    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
3048    
3049    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
3050    compiling PCRE for use with Virtual Pascal.
3051    
3052    22. Small fix to the Makefile to make it work properly if the build is done
3053    outside the source tree.
3054    
3055    23. Added a new extension: a condition to go with recursion. If a conditional
3056    subpattern starts with (?(R) the "true" branch is used if recursion has
3057    happened, whereas the "false" branch is used only at the top level.
3058    
3059    24. When there was a very long string of literal characters (over 255 bytes
3060    without UTF support, over 250 bytes with UTF support), the computation of how
3061    much memory was required could be incorrect, leading to segfaults or other
3062    strange effects.
3063    
3064    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
3065    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
3066    there was a subsequent back reference to those brackets. This meant that, for
3067    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
3068    possible to check for precisely this case. All we can do is abandon the
3069    optimization if .* occurs inside capturing brackets when there are any back
3070    references whatsoever. (See below for a better fix that came later.)
3071    
3072    26. The handling of the optimization for finding the first character of a
3073    non-anchored pattern, and for finding a character that is required later in the
3074    match were failing in some cases. This didn't break the matching; it just
3075    failed to optimize when it could. The way this is done has been re-implemented.
3076    
3077    27. Fixed typo in error message for invalid (?R item (it said "(?p").
3078    
3079    28. Added a new feature that provides some of the functionality that Perl
3080    provides with (?{...}). The facility is termed a "callout". The way it is done
3081    in PCRE is for the caller to provide an optional function, by setting
3082    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
3083    global variable. By default it is unset, which disables all calling out. To get
3084    the function called, the regex must include (?C) at appropriate points. This
3085    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
3086    This provides a means of identifying different callout points. When PCRE
3087    reaches such a point in the regex, if pcre_callout has been set, the external
3088    function is called. It is provided with data in a structure called
3089    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
3090    matching continues; if it returns a non-zero value, the match at the current
3091    point fails. However, backtracking will occur if possible. [This was changed
3092    later and other features added - see item 49 below.]
3093    
3094    29. pcretest is upgraded to test the callout functionality. It provides a
3095    callout function that displays information. By default, it shows the start of
3096    the match and the current position in the text. There are some new data escapes
3097    to vary what happens:
3098    
3099        \C+         in addition, show current contents of captured substrings
3100        \C-         do not supply a callout function
3101        \C!n        return 1 when callout number n is reached
3102        \C!n!m      return 1 when callout number n is reached for the mth time
3103    
3104    30. If pcregrep was called with the -l option and just a single file name, it
3105    output "<stdin>" if a match was found, instead of the file name.
3106    
3107    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
3108    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
3109    pcre_exec(). This saves a malloc/free per call. The default value of
3110    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
3111    when configuring.
3112    
3113    32. The default maximum size of a compiled pattern is 64K. There have been a
3114    few cases of people hitting this limit. The code now uses macros to handle the
3115    storing of links as offsets within the compiled pattern. It defaults to 2-byte
3116    links, but this can be changed to 3 or 4 bytes by --with-link-size when
3117    configuring. Tests 2 and 5 work only with 2-byte links because they output
3118    debugging information about compiled patterns.
3119    
3120    33. Internal code re-arrangements:
3121    
3122    (a) Moved the debugging function for printing out a compiled regex into
3123        its own source file (printint.c) and used #include to pull it into
3124        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
3125        separate copies.
3126    
3127    (b) Defined the list of op-code names for debugging as a macro in
3128        internal.h so that it is next to the definition of the opcodes.
3129    
3130    (c) Defined a table of op-code lengths for simpler skipping along compiled
3131        code. This is again a macro in internal.h so that it is next to the
3132        definition of the opcodes.
3133    
3134    34. Added support for recursive calls to individual subpatterns, along the
3135    lines of Robin Houston's patch (but implemented somewhat differently).
3136    
3137    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
3138    allow it to read and process whole directories in Win32. This code was
3139    contributed by Lionel Fourquaux; it has not been tested by me.
3140    
3141    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
3142    used to name a group. Names consist of alphanumerics and underscores, and must
3143    be unique. Back references use the syntax (?P=name) and recursive calls use
3144    (?P>name) which is a PCRE extension to the Python extension. Groups still have
3145    numbers. The function pcre_fullinfo() can be used after compilation to extract
3146    a name/number map. There are three relevant calls:
3147    
3148      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
3149      PCRE_INFO_NAMECOUNT            yields the number of entries
3150      PCRE_INFO_NAMETABLE            yields a pointer to the map.
3151    
3152    The map is a vector of fixed-size entries. The size of each entry depends on
3153    the length of the longest name used. The first two bytes of each entry are the
3154    group number, most significant byte first. There follows the corresponding
3155    name, zero terminated. The names are in alphabetical order.
3156    
3157    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
3158    case instead of 255. Making it the same both with and without UTF-8 support
3159    means that the same test output works with both.
3160    
3161    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
3162    calling malloc() with a zero argument.
3163    
3164    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
3165    optimization. I've improved things by keeping a bitmap of backreferences with
3166    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
3167    fact referenced, the optimization can be applied. It is unlikely that a
3168    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
3169    the match to follow \n) will appear inside brackets with a number greater than
3170    31, but if it does, any back reference > 31 suppresses the optimization.
3171    
3172    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
3173    of disabling numbered capturing parentheses. Any opening parenthesis that is
3174    not followed by ? behaves as if it were followed by ?: but named parentheses
3175    can still be used for capturing (and they will acquire numbers in the usual
3176    way).
3177    
3178    41. Redesigned the return codes from the match() function into yes/no/error so
3179    that errors can be passed back from deep inside the nested calls. A malloc
3180    failure while inside a recursive subpattern call now causes the
3181    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
3182    
3183    42. It is now possible to set a limit on the number of times the match()
3184    function is called in a call to pcre_exec(). This facility makes it possible to
3185    limit the amount of recursion and backtracking, though not in a directly
3186    obvious way, because the match() function is used in a number of different
3187    circumstances. The count starts from zero for each position in the subject
3188    string (for non-anchored patterns). The default limit is, for compatibility, a
3189    large number, namely 10 000 000. You can change this in two ways:
3190    
3191    (a) When configuring PCRE before making, you can use --with-match-limit=n
3192        to set a default value for the compiled library.
3193    
3194    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
3195        a different value is set. See 45 below.
3196    
3197    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
3198    
3199    43. Added a new function pcre_config(int, void *) to enable run-time extraction
3200    of things that can be changed at compile time. The first argument specifies
3201    what is wanted and the second points to where the information is to be placed.
3202    The current list of available information is:
3203    
3204      PCRE_CONFIG_UTF8
3205    
3206    The output is an integer that is set to one if UTF-8 support is available;
3207    otherwise it is set to zero.
3208    
3209      PCRE_CONFIG_NEWLINE
3210    
3211    The output is an integer that it set to the value of the code that is used for
3212    newline. It is either LF (10) or CR (13).
3213    
3214      PCRE_CONFIG_LINK_SIZE
3215    
3216    The output is an integer that contains the number of bytes used for internal
3217    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
3218    
3219      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
3220    
3221    The output is an integer that contains the threshold above which the POSIX
3222    interface uses malloc() for output vectors. See item 31 above.
3223    
3224      PCRE_CONFIG_MATCH_LIMIT
3225    
3226    The output is an unsigned integer that contains the default limit of the number
3227    of match() calls in a pcre_exec() execution. See 42 above.
3228    
3229    44. pcretest has been upgraded by the addition of the -C option. This causes it
3230    to extract all the available output from the new pcre_config() function, and to
3231    output it. The program then exits immediately.
3232    
3233    45. A need has arisen to pass over additional data with calls to pcre_exec() in
3234    order to support additional features. One way would have been to define
3235    pcre_exec2() (for example) with extra arguments, but this would not have been
3236    extensible, and would also have required all calls to the original function to
3237    be mapped to the new one. Instead, I have chosen to extend the mechanism that
3238    is used for passing in "extra" data from pcre_study().
3239    
3240    The pcre_extra structure is now exposed and defined in pcre.h. It currently
3241    contains the following fields:
3242    
3243      flags         a bitmap indicating which of the following fields are set
3244      study_data    opaque data from pcre_study()
3245      match_limit   a way of specifying a limit on match() calls for a specific
3246                      call to pcre_exec()
3247      callout_data  data for callouts (see 49 below)
3248    
3249    The flag bits are also defined in pcre.h, and are
3250    
3251      PCRE_EXTRA_STUDY_DATA
3252      PCRE_EXTRA_MATCH_LIMIT
3253      PCRE_EXTRA_CALLOUT_DATA
3254    
3255    The pcre_study() function now returns one of these new pcre_extra blocks, with
3256    the actual study data pointed to by the study_data field, and the
3257    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
3258    before. That is, this change is entirely upwards-compatible and requires no
3259    change to existing code.
3260    
3261    If you want to pass in additional data to pcre_exec(), you can either place it
3262    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
3263    block.
3264    
3265    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
3266    data string contains the escape sequence \M, pcretest calls pcre_exec() several
3267    times with different match limits, until it finds the minimum value needed for
3268    pcre_exec() to complete. The value is then output. This can be instructive; for
3269    most simple matches the number is quite small, but for pathological cases it
3270    gets very large very quickly.
3271    
3272    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
3273    returns the size of the data block pointed to by the study_data field in a
3274    pcre_extra block, that is, the value that was passed as the argument to
3275    pcre_malloc() when PCRE was getting memory in which to place the information
3276    created by pcre_study(). The fourth argument should point to a size_t variable.
3277    pcretest has been extended so that this information is shown after a successful
3278    pcre_study() call when information about the compiled regex is being displayed.
3279    
3280    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
3281    because what follows is always an absolute path. (Later: it turns out that this
3282    is more than cosmetic for MinGW, because it doesn't like empty path
3283    components.)
3284    
3285    49. Some changes have been made to the callout feature (see 28 above):
3286    
3287    (i)  A callout function now has three choices for what it returns:
3288    
3289           0  =>  success, carry on matching
3290         > 0  =>  failure at this point, but backtrack if possible
3291         < 0  =>  serious error, return this value from pcre_exec()
3292    
3293         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
3294         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
3295         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
3296         use by callout functions. It will never be used by PCRE itself.
3297    
3298    (ii) The pcre_extra structure (see 45 above) has a void * field called
3299         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
3300         pcre_callout_block structure has a field of the same name. The contents of
3301         the field passed in the pcre_extra structure are passed to the callout
3302         function in the corresponding field in the callout block. This makes it
3303         easier to use the same callout-containing regex from multiple threads. For
3304         testing, the pcretest program has a new data escape
3305    
3306           \C*n        pass the number n (may be negative) as callout_data
3307    
3308         If the callout function in pcretest receives a non-zero value as
3309         callout_data, it returns that value.
3310    
3311    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
3312    there were some redundant $(CFLAGS) in commands that are now specified as
3313    $(LINK), which already includes $(CFLAGS).
3314    
3315    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
3316    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
3317    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
3318    one-byte characters throughout. Note that case-insensitive matching applies
3319    only to characters whose values are less than 256. PCRE doesn't support the
3320    notion of cases for higher-valued characters.
3321    
3322    (i)   A character class whose characters are all within 0-255 is handled as
3323          a bit map, and the map is inverted for negative classes. Previously, a
3324          character > 255 always failed to match such a class; however it should
3325          match if the class was a negative one (e.g. [^ab]). This has been fixed.
3326    
3327    (ii)  A negated character class with a single character < 255 is coded as
3328          "not this character" (OP_NOT). This wasn't working properly when the test
3329          character was multibyte, either singly or repeated.
3330    
3331    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
3332          mode, for example: \x{100}{2,3}.
3333    
3334    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
3335          singly or repeated) now correctly test multibyte characters. However,
3336          PCRE doesn't recognize any characters with values greater than 255 as
3337          digits, spaces, or word characters. Such characters always match \D, \S,
3338          and \W, and never match \d, \s, or \w.
3339    
3340    (v)   Classes may now contain characters and character ranges with values
3341          greater than 255. For example: [ab\x{100}-\x{400}].
3342    
3343    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
3344          PCRE in UTF-8 mode.
3345    
3346    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
3347    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
3348    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
3349    value.)
3350    
3351    53. The single man page has become too large. I have therefore split it up into
3352    a number of separate man pages. These also give rise to individual HTML pages;
3353    these are now put in a separate directory, and there is an index.html page that
3354    lists them all. Some hyperlinking between the pages has been installed.
3355    
3356    54. Added convenience functions for handling named capturing parentheses.
3357    
3358    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3359    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3360    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3361    are faulted.
3362    
3363    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3364    calling configure. These values are used when compiling the dftables.c program
3365    which is run to generate the source of the default character tables. They
3366    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3367    you will need to set these values.
3368    
3369    57. Updated the building process for Windows DLL, as provided by Fred Cox.
3370    
3371    
3372    Version 3.9 02-Jan-02
3373    ---------------------
3374    
3375    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3376    
3377    2. If --disable-static was given, the building process failed when trying to
3378    build pcretest and pcregrep. (For some reason it was using libtool to compile
3379    them, which is not right, as they aren't part of the library.)
3380    
3381    
3382    Version 3.8 18-Dec-01
3383    ---------------------
3384    
3385    1. The experimental UTF-8 code was completely screwed up. It was packing the
3386    bytes in the wrong order. How dumb can you get?
3387    
3388    
3389    Version 3.7 29-Oct-01
3390    ---------------------
3391    
3392    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
3393    This caused pcretest, when used on the test data, to segfault. Unfortunately,
3394    this didn't happen under Solaris 8, where I normally test things.
3395    
3396    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
3397    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
3398    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
3399    this fix an hour or so after the initial 3.7 release.)
3400    
3401    
3402    Version 3.6 23-Oct-01
3403    ---------------------
3404    
3405    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
3406    offsets passed as NULL with zero offset count.
3407    
3408    2. The config.guess and config.sub files had not been updated when I moved to
3409    the latest autoconf.
3410    
3411    
3412    Version 3.5 15-Aug-01
3413    ---------------------
3414    
3415    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
3416    had been forgotten.
3417    
3418    2. By using declared but undefined structures, we can avoid using "void"
3419    definitions in pcre.h while keeping the internal definitions of the structures
3420    private.
3421    
3422    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3423    user point of view, this means that both static and shared libraries are built
3424    by default, but this can be individually controlled. More of the work of
3425    handling this static/shared cases is now inside libtool instead of PCRE's make
3426    file.
3427    
3428    4. The pcretest utility is now installed along with pcregrep because it is
3429    useful for users (to test regexs) and by doing this, it automatically gets
3430    relinked by libtool. The documentation has been turned into a man page, so
3431    there are now .1, .txt, and .html versions in /doc.
3432    
3433    5. Upgrades to pcregrep:
3434       (i)   Added long-form option names like gnu grep.
3435       (ii)  Added --help to list all options with an explanatory phrase.
3436       (iii) Added -r, --recursive to recurse into sub-directories.
3437       (iv)  Added -f, --file to read patterns from a file.
3438    
3439    6. pcre_exec() was referring to its "code" argument before testing that
3440    argument for NULL (and giving an error if it was NULL).
3441    
3442    7. Upgraded Makefile.in to allow for compiling in a different directory from
3443    the source directory.
3444    
3445    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3446    options bits, the pointer it was passed was to an int instead of to an unsigned
3447    long int. This mattered only on 64-bit systems.
3448    
3449    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3450    generated) instead of pcre.in, which it its source. Also made the same change
3451    in several of the .c files.
3452    
3453    10. A new release of gcc defines printf() as a macro, which broke pcretest
3454    because it had an ifdef in the middle of a string argument for printf(). Fixed
3455    by using separate calls to printf().
3456    
3457    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3458    script, to force use of CR or LF instead of \n in the source. On non-Unix
3459    systems, the value can be set in config.h.
3460    
3461    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3462    absolute limit. Changed the text of the error message to make this clear, and
3463    likewise updated the man page.
3464    
3465    13. The limit of 99 on the number of capturing subpatterns has been removed.
3466    The new limit is 65535, which I hope will not be a "real" limit.
3467    
3468    
3469    Version 3.4 22-Aug-00
3470    ---------------------
3471    
3472    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3473    
3474    2. Diagnose condition (?(0) as an error instead of crashing on matching.
3475    
3476    
3477    Version 3.3 01-Aug-00
3478    ---------------------
3479    
3480    1. If an octal character was given, but the value was greater than \377, it
3481    was not getting masked to the least significant bits, as documented. This could
3482    lead to crashes in some systems.
3483    
3484    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3485    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3486    
3487    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3488    These just pass their arguments on to (pcre_free)(), but they are provided
3489    because some uses of PCRE bind it to non-C systems that can call its functions,
3490    but cannot call free() or pcre_free() directly.
3491    
3492    4. Add "make test" as a synonym for "make check". Corrected some comments in
3493    the Makefile.
3494    
3495    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3496    Makefile.
3497    
3498    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3499    command called pgrep for grepping around the active processes.
3500    
3501    7. Added the beginnings of support for UTF-8 character strings.
3502    
3503    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3504    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3505    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3506    out for the ar command.)
3507    
3508    
3509    Version 3.2 12-May-00
3510    ---------------------
3511    
3512    This is purely a bug fixing release.
3513    
3514    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3515    of ZA. This was just one example of several cases that could provoke this bug,
3516    which was introduced by change 9 of version 2.00. The code for breaking
3517    infinite loops after an iteration that matches an empty string was't working
3518    correctly.
3519    
3520    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3521    when matched against abbab (for example). After matching an empty string, it
3522    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3523    caused it to match further down the string than it should.
3524    
3525    3. The code contained an inclusion of sys/types.h. It isn't clear why this
3526    was there because it doesn't seem to be needed, and it causes trouble on some
3527    systems, as it is not a Standard C header. It has been removed.
3528    
3529    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3530    were reported on the Macintosh. The changes were from
3531    
3532      while ((c = *(++ptr)) != 0 && c != '\n');
3533    to
3534      while ((c = *(++ptr)) != 0 && c != '\n') ;
3535    
3536    Totally extraordinary, but if that's what it takes...
3537    
3538    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3539    available. Added HAVE_BCOPY and an autoconf test for it; if neither
3540    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3541    assumes the way PCRE uses memmove() (always moving upwards).
3542    
3543    6. PCRE is being used in one environment where strchr() is not available. There
3544    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3545    faster code anyway.
3546    
3547    
3548    Version 3.1 09-Feb-00
3549    ---------------------
3550    
3551    The only change in this release is the fixing of some bugs in Makefile.in for
3552    the "install" target:
3553    
3554    (1) It was failing to install pcreposix.h.
3555    
3556    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3557    
3558    
3559    Version 3.0 01-Feb-00
3560    ---------------------
3561    
3562    1. Add support for the /+ modifier to perltest (to output $` like it does in
3563    pcretest).
3564    
3565    2. Add support for the /g modifier to perltest.
3566    
3567    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3568    matches null strings.
3569    
3570    4. Fix perltest so that it doesn't do unwanted things when fed an empty
3571    pattern. Perl treats empty patterns specially - it reuses the most recent
3572    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3573    effect.
3574    
3575    5. The POSIX interface was broken in that it was just handing over the POSIX
3576    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3577    required a bigger vector, with some working space on the end. This means that
3578    the POSIX wrapper now has to get and free some memory, and copy the results.
3579    
3580    6. Added some simple autoconf support, placing the test data and the
3581    documentation in separate directories, re-organizing some of the
3582    information files, and making it build pcre-config (a GNU standard). Also added
3583    libtool support for building PCRE as a shared library, which is now the
3584    default.
3585    
3586    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3587    09 are not valid octal constants. Single digits will be used for minor values
3588    less than 10.
3589    
3590    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3591    existing programs that set these in the POSIX interface can use PCRE without
3592    modification.
3593    
3594    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3595    return all that pcre_info() returns, plus additional data. The pcre_info()
3596    function is retained for compatibility, but is considered to be obsolete.
3597    
3598    10. Added experimental recursion feature (?R) to handle one common case that
3599    Perl 5.6 will be able to do with (?p{...}).
3600    
3601    11. Added support for POSIX character classes like [:alpha:], which Perl is
3602    adopting.
3603    
3604    
3605    Version 2.08 31-Aug-99
3606    ----------------------
3607    
3608    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3609    trying to match at the startoffset position, but instead was moving forward to
3610    the next newline as if a previous match had failed.
3611    
3612    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3613    and could get into a loop if a null string was matched other than at the start
3614    of the subject.
3615    
3616    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3617    be distinguished at compile time, and for completeness also added PCRE_DATE.
3618    
3619    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3620    in GnuWin32 environments.
3621    
3622    
3623    Version 2.07 29-Jul-99
3624    ----------------------
3625    
3626    1. The documentation is now supplied in plain text form and HTML as well as in
3627    the form of man page sources.
3628    
3629    2. C++ compilers don't like assigning (void *) values to other pointer types.
3630    In particular this affects malloc(). Although there is no problem in Standard
3631    C, I've put in casts to keep C++ compilers happy.
3632    
3633    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3634    should be (const char *).
3635    
3636    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3637    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3638    However, I haven't made this a standard facility. The documentation doesn't
3639    mention it, and the Makefile doesn't support it.
3640    
3641    5. The Makefile now contains an "install" target, with editable destinations at
3642    the top of the file. The pcretest program is not installed.
3643    
3644    6. pgrep -V now gives the PCRE version number and date.
3645    
3646    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3647    causing the entire string to be ignored, instead of just the last character.
3648    
3649    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3650    non-matching string, it can take a very, very long time, even for strings of
3651    quite modest length, because of the nested recursion. PCRE now does better in
3652    some of these cases. It does this by remembering the last required literal
3653    character in the pattern, and pre-searching the subject to ensure it is present
3654    before running the real match. In other words, it applies a heuristic to detect
3655    some types of certain failure quickly, and in the above example, if presented
3656    with a string that has no trailing " it gives "no match" very quickly.
3657    
3658    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3659    other alternatives are tried instead.
3660    
3661    
3662    Version 2.06 09-Jun-99
3663    ----------------------
3664    
3665    1. Change pcretest's output for amount of store used to show just the code
3666    space, because the remainder (the data block) varies in size between 32-bit and
3667    64-bit systems.
3668    
3669    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3670    start matching at. This allows lookbehinds to work when searching for multiple
3671    occurrences in a string.
3672    
3673    3. Added additional options to pcretest for testing multiple occurrences:
3674    
3675       /+   outputs the rest of the string that follows a match
3676       /g   loops for multiple occurrences, using the new startoffset argument
3677       /G   loops for multiple occurrences by passing an incremented pointer
3678    
3679    4. PCRE wasn't doing the "first character" optimization for patterns starting
3680    with \b or \B, though it was doing it for other lookbehind assertions. That is,
3681    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3682    the letter 'x'. On long subject strings, this gives a significant speed-up.
3683    
3684    
3685    Version 2.05 21-Apr-99
3686    ----------------------
3687    
3688    1. Changed the type of magic_number from int to long int so that it works
3689    properly on 16-bit systems.
3690    
3691    2. Fixed a bug which caused patterns starting with .* not to work correctly
3692    when the subject string contained newline characters. PCRE was assuming
3693    anchoring for such patterns in all cases, which is not correct because .* will
3694    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3695    DOTALL is set at top level; otherwise it knows that patterns starting with .*
3696    must be retried after every newline in the subject.
3697    
3698    
3699  Version 2.04 18-Feb-99  Version 2.04 18-Feb-99
3700  ----------------------  ----------------------

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