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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  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   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 135  Version 7.1 12-Mar-07 Line 1551  Version 7.1 12-Mar-07
1551      was because its rules for how to advance for /g after matching an empty      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      string at the end of a line did not allow for this case. They now check for
1553      it specially.      it specially.
1554    
1555  20. pcretest is supposed to handle patterns and data of any length, by  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      extending its buffers when necessary. It was getting this wrong when the
1557      buffer for a data line had to be extended.      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  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1560      CRLF as a newline sequence.      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  Version 7.0 19-Dec-06

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