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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  Version 8.11 10-Oct-2010
5    ------------------------
6    
7    1.  (*THEN) was not working properly if there were untried alternatives prior
8        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
9        backtracked to try for "b" instead of moving to the next alternative branch
10        at the same level (in this case, to look for "c"). The Perl documentation
11        is clear that when (*THEN) is backtracked onto, it goes to the "next
12        alternative in the innermost enclosing group".
13    
14    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
15        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
16        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
17        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
18        (*THEN).
19    
20    3.  If \s appeared in a character class, it removed the VT character from
21        the class, even if it had been included by some previous item, for example
22        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
23        of \s, but is part of the POSIX "space" class.)
24    
25    4.  A partial match never returns an empty string (because you can always
26        match an empty string at the end of the subject); however the checking for
27        an empty string was starting at the "start of match" point. This has been
28        changed to the "earliest inspected character" point, because the returned
29        data for a partial match starts at this character. This means that, for
30        example, /(?<=abc)def/ gives a partial match for the subject "abc"
31        (previously it gave "no match").
32    
33    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
34        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
35        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
36        has an implication that the given string is incomplete (because a partial
37        match is preferred over a full match). For this reason, these items now
38        give a partial match in this situation. [Aside: previously, the one case
39        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
40        match rather than a full match, which was wrong by the old rules, but is
41        now correct.]
42    
43    6.  There was a bug in the handling of #-introduced comments, recognized when
44        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
45        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
46        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
47        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
48        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
49        places in pcre_compile().
50    
51    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
52        comments when looking ahead for named forward references to subpatterns,
53        the only newline sequence it recognized was NL. It now handles newlines
54        according to the set newline convention.
55    
56    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
57        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
58        cater for a lack of strerror(). These oversights have been fixed.
59    
60    9.  Added --match-limit and --recursion-limit to pcregrep.
61    
62    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
63    
64    11. When the -o option was used, pcregrep was setting a return code of 1, even
65        when matches were found, and --line-buffered was not being honoured.
66    
67    12. Added an optional parentheses number to the -o and --only-matching options
68        of pcregrep.
69    
70    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
71        can match an empty string. The code to do it in pcretest and pcredemo
72        needed fixing:
73    
74        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
75            only one byte after an empty string match just before CRLF (this case
76            just got forgotten; "any" and "anycrlf" were OK).
77    
78        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
79            mode when an empty string match preceded an ASCII character followed by
80            a non-ASCII character. (The code for advancing by one character rather
81            than one byte was nonsense.)
82    
83        (c) The pcredemo.c sample program did not have any code at all to handle
84            the cases when CRLF is a valid newline sequence.
85    
86    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
87        as a starting offset was within the subject string. There is now a new
88        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
89        negative or greater than the length of the string. In order to test this,
90        pcretest is extended to allow the setting of negative starting offsets.
91    
92    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
93        starting offset points to the beginning of a UTF-8 character was
94        unnecessarily clumsy. I tidied it up.
95    
96    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
97        bad UTF-8 sequence and one that is incomplete.
98    
99    17. Nobody had reported that the --include_dir option, which was added in
100        release 7.7 should have been called --include-dir (hyphen, not underscore)
101        for compatibility with GNU grep. I have changed it to --include-dir, but
102        left --include_dir as an undocumented synonym, and the same for
103        --exclude-dir, though that is not available in GNU grep, at least as of
104        release 2.5.4.
105    
106    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
107        characters from a string of bytes) have been redefined so as not to use
108        loops, in order to improve performance in some environments. At the same
109        time, I abstracted some of the common code into auxiliary macros to save
110        repetition (this should not affect the compiled code).
111    
112    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
113        compile-time error is now given if \c is not followed by an ASCII
114        character, that is, a byte less than 128. (In EBCDIC mode, the code is
115        different, and any byte value is allowed.)
116    
117    
118    Version 8.10 25-Jun-2010
119    ------------------------
120    
121    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
122        THEN.
123    
124    2.  (*ACCEPT) was not working when inside an atomic group.
125    
126    3.  Inside a character class, \B is treated as a literal by default, but
127        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
128        causes the error). The code is unchanged, but I tidied the documentation.
129    
130    4.  Inside a character class, PCRE always treated \R and \X as literals,
131        whereas Perl faults them if its -w option is set. I have changed PCRE so
132        that it faults them when PCRE_EXTRA is set.
133    
134    5.  Added support for \N, which always matches any character other than
135        newline. (It is the same as "." when PCRE_DOTALL is not set.)
136    
137    6.  When compiling pcregrep with newer versions of gcc which may have
138        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
139        declared with attribute warn_unused_result" were given. Just casting the
140        result to (void) does not stop the warnings; a more elaborate fudge is
141        needed. I've used a macro to implement this.
142    
143    7.  Minor change to pcretest.c to avoid a compiler warning.
144    
145    8.  Added four artifical Unicode properties to help with an option to make
146        \s etc use properties (see next item). The new properties are: Xan
147        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
148    
149    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
150        use Unicode properties. (*UCP) at the start of a pattern can be used to set
151        this option. Modified pcretest to add /W to test this facility. Added
152        REG_UCP to make it available via the POSIX interface.
153    
154    10. Added --line-buffered to pcregrep.
155    
156    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
157        studied, and the match started with a letter with a code point greater than
158        127 whose first byte was different to the first byte of the other case of
159        the letter, the other case of this starting letter was not recognized
160        (#976).
161    
162    12. If a pattern that was studied started with a repeated Unicode property
163        test, for example, \p{Nd}+, there was the theoretical possibility of
164        setting up an incorrect bitmap of starting bytes, but fortunately it could
165        not have actually happened in practice until change 8 above was made (it
166        added property types that matched character-matching opcodes).
167    
168    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
169        possible starting bytes for non-anchored patterns.
170    
171    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
172        \R, and also a number of cases that involve Unicode properties, both
173        explicit and implicit when PCRE_UCP is set.
174    
175    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
176        input, it could crash or give wrong results if characters with values
177        greater than 0xc0 were present in the subject string. (Detail: it assumed
178        UTF-8 input when processing these items.)
179    
180    16. Added a lot of (int) casts to avoid compiler warnings in systems where
181        size_t is 64-bit (#991).
182    
183    17. Added a check for running out of memory when PCRE is compiled with
184        --disable-stack-for-recursion (#990).
185    
186    18. If the last data line in a file for pcretest does not have a newline on
187        the end, a newline was missing in the output.
188    
189    19. The default pcre_chartables.c file recognizes only ASCII characters (values
190        less than 128) in its various bitmaps. However, there is a facility for
191        generating tables according to the current locale when PCRE is compiled. It
192        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
193        characters, are recognized by isspace() and therefore were getting set in
194        these tables, and indeed these tables seem to approximate to ISO 8859. This
195        caused a problem in UTF-8 mode when pcre_study() was used to create a list
196        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
197        which of course cannot start UTF-8 characters. I have changed the code so
198        that only real ASCII characters (less than 128) and the correct starting
199        bytes for UTF-8 encodings are set for characters greater than 127 when in
200        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
201        altogether.)
202    
203    20. Added the /T option to pcretest so as to be able to run tests with non-
204        standard character tables, thus making it possible to include the tests
205        used for 19 above in the standard set of tests.
206    
207    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
208        reference to a subpattern the other side of a comment that contains an
209        opening parenthesis caused either an internal compiling error, or a
210        reference to the wrong subpattern.
211    
212    
213    Version 8.02 19-Mar-2010
214    ------------------------
215    
216    1.  The Unicode data tables have been updated to Unicode 5.2.0.
217    
218    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
219        configured.
220    
221    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
222        original author of that file, following a query about its status.
223    
224    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
225        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
226    
227    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
228        quantifier applied to a forward-referencing subroutine call, could compile
229        incorrect code or give the error "internal error: previously-checked
230        referenced subpattern not found".
231    
232    6.  Both MS Visual Studio and Symbian OS have problems with initializing
233        variables to point to external functions. For these systems, therefore,
234        pcre_malloc etc. are now initialized to local functions that call the
235        relevant global functions.
236    
237    7.  There were two entries missing in the vectors called coptable and poptable
238        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
239        I've fixed the data, and added a kludgy way of testing at compile time that
240        the lengths are correct (equal to the number of opcodes).
241    
242    8.  Following on from 7, I added a similar kludge to check the length of the
243        eint vector in pcreposix.c.
244    
245    9.  Error texts for pcre_compile() are held as one long string to avoid too
246        much relocation at load time. To find a text, the string is searched,
247        counting zeros. There was no check for running off the end of the string,
248        which could happen if a new error number was added without updating the
249        string.
250    
251    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
252    
253    11. \K was not working if it appeared in an atomic group or in a group that
254        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
255        \K is "not well defined" if used in an assertion. PCRE now accepts it if
256        the assertion is positive, but not if it is negative.
257    
258    12. Change 11 fortuitously reduced the size of the stack frame used in the
259        "match()" function of pcre_exec.c by one pointer. Forthcoming
260        implementation of support for (*MARK) will need an extra pointer on the
261        stack; I have reserved it now, so that the stack frame size does not
262        decrease.
263    
264    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
265        item in branch that calls a recursion is a subroutine call - as in the
266        second branch in the above example - was incorrectly given the compile-
267        time error "recursive call could loop indefinitely" because pcre_compile()
268        was not correctly checking the subroutine for matching a non-empty string.
269    
270    14. The checks for overrunning compiling workspace could trigger after an
271        overrun had occurred. This is a "should never occur" error, but it can be
272        triggered by pathological patterns such as hundreds of nested parentheses.
273        The checks now trigger 100 bytes before the end of the workspace.
274    
275    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
276    
277    
278    Version 8.01 19-Jan-2010
279    ------------------------
280    
281    1.  If a pattern contained a conditional subpattern with only one branch (in
282        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
283        computed the wrong minimum data length (which is of course zero for such
284        subpatterns). This could cause incorrect "no match" results.
285    
286    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
287        the pattern is reset in the first branch, pcre_compile() failed with
288        "internal error: code overflow at offset...". This happened only when
289        the reset was to the original external option setting. (An optimization
290        abstracts leading options settings into an external setting, which was the
291        cause of this.)
292    
293    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
294        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
295        assertion pattern did not match (meaning that the assertion was true), it
296        was incorrectly treated as false if the SKIP had been reached during the
297        matching. This also applied to assertions used as conditions.
298    
299    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
300        assertion subpattern, including such a pattern used as a condition,
301        unpredictable results occurred, instead of the error return
302        PCRE_ERROR_DFA_UITEM.
303    
304    5.  The C++ GlobalReplace function was not working like Perl for the special
305        situation when an empty string is matched. It now does the fancy magic
306        stuff that is necessary.
307    
308    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
309        removed. (These were left over from very, very early versions of PCRE.)
310    
311    7.  Some cosmetic changes to the code to make life easier when compiling it
312        as part of something else:
313    
314        (a) Change DEBUG to PCRE_DEBUG.
315    
316        (b) In pcre_compile(), rename the member of the "branch_chain" structure
317            called "current" as "current_branch", to prevent a collision with the
318            Linux macro when compiled as a kernel module.
319    
320        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
321            prevent a collision with the Linux macro when compiled as a kernel
322            module.
323    
324    8.  In pcre_compile() there are some checks for integer overflows that used to
325        cast potentially large values to (double). This has been changed to that
326        when building, a check for int64_t is made, and if it is found, it is used
327        instead, thus avoiding the use of floating point arithmetic. (There is no
328        other use of FP in PCRE.) If int64_t is not found, the fallback is to
329        double.
330    
331    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
332        2005 (difference between two addresses compared to an unsigned value).
333    
334    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
335        custom one, because of the following reported problem in Windows:
336    
337          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
338              under Win32.
339          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
340              therefore missing the function definition.
341          - The compiler thus generates a "C" signature for the test function.
342          - The linker fails to find the "C" function.
343          - PCRE fails to configure if asked to do so against libbz2.
344    
345    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
346        messages were output:
347    
348          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
349          rerunning libtoolize, to keep the correct libtool macros in-tree.
350          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
351    
352        I have done both of these things.
353    
354    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
355        most of the time, it *can* run out if it is given a pattern that contains a
356        runaway infinite recursion. I updated the discussion in the pcrestack man
357        page.
358    
359    13. Now that we have gone to the x.xx style of version numbers, the minor
360        version may start with zero. Using 08 or 09 is a bad idea because users
361        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
362        interpreted as invalid octal numbers. I've updated the previous comment in
363        configure.ac, and also added a check that gives an error if 08 or 09 are
364        used.
365    
366    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
367        causing partial matching to fail when the end of the subject matched \W
368        in a UTF-8 pattern where \W was quantified with a minimum of 3.
369    
370    15. There were some discrepancies between the declarations in pcre_internal.h
371        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
372        their definitions. The declarations used "const uschar *" and the
373        definitions used USPTR. Even though USPTR is normally defined as "const
374        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
375        reported that: "This difference in casting confuses some C++ compilers, for
376        example, SunCC recognizes above declarations as different functions and
377        generates broken code for hbpcre." I have changed the declarations to use
378        USPTR.
379    
380    16. GNU libtool is named differently on some systems. The autogen.sh script now
381        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
382        (FreeBSD).
383    
384    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
385        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
386        comment: "Figure out how to create a longlong from a string: strtoll and
387        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
388        instance, but it only takes 2 args instead of 3!"
389    
390    18. A subtle bug concerned with back references has been fixed by a change of
391        specification, with a corresponding code fix. A pattern such as
392        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
393        refers, was giving matches when it shouldn't. For example, xa=xaaa would
394        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
395        same bug. Such groups have to be quantified to be useful, or contained
396        inside another quantified group. (If there's no repetition, the reference
397        can never match.) The problem arises because, having left the group and
398        moved on to the rest of the pattern, a later failure that backtracks into
399        the group uses the captured value from the final iteration of the group
400        rather than the correct earlier one. I have fixed this in PCRE by forcing
401        any group that contains a reference to itself to be an atomic group; that
402        is, there cannot be any backtracking into it once it has completed. This is
403        similar to recursive and subroutine calls.
404    
405    
406    Version 8.00 19-Oct-09
407    ----------------------
408    
409    1.  The table for translating pcre_compile() error codes into POSIX error codes
410        was out-of-date, and there was no check on the pcre_compile() error code
411        being within the table. This could lead to an OK return being given in
412        error.
413    
414    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
415        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
416        in a Windows environment.
417    
418    3.  The pcregrep --count option prints the count for each file even when it is
419        zero, as does GNU grep. However, pcregrep was also printing all files when
420        --files-with-matches was added. Now, when both options are given, it prints
421        counts only for those files that have at least one match. (GNU grep just
422        prints the file name in this circumstance, but including the count seems
423        more useful - otherwise, why use --count?) Also ensured that the
424        combination -clh just lists non-zero counts, with no names.
425    
426    4.  The long form of the pcregrep -F option was incorrectly implemented as
427        --fixed_strings instead of --fixed-strings. This is an incompatible change,
428        but it seems right to fix it, and I didn't think it was worth preserving
429        the old behaviour.
430    
431    5.  The command line items --regex=pattern and --regexp=pattern were not
432        recognized by pcregrep, which required --regex pattern or --regexp pattern
433        (with a space rather than an '='). The man page documented the '=' forms,
434        which are compatible with GNU grep; these now work.
435    
436    6.  No libpcreposix.pc file was created for pkg-config; there was just
437        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
438    
439    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
440        when UCP support is not needed, by modifying the Python script that
441        generates it from Unicode data files. This should not matter if the module
442        is correctly used as a library, but I received one complaint about 50K of
443        unwanted data. My guess is that the person linked everything into his
444        program rather than using a library. Anyway, it does no harm.
445    
446    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
447        was a minimum greater than 1 for a wide character in a possessive
448        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
449        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
450        character. Chaos in the form of incorrect output or a compiling loop could
451        result.
452    
453    9.  The restrictions on what a pattern can contain when partial matching is
454        requested for pcre_exec() have been removed. All patterns can now be
455        partially matched by this function. In addition, if there are at least two
456        slots in the offset vector, the offset of the earliest inspected character
457        for the match and the offset of the end of the subject are set in them when
458        PCRE_ERROR_PARTIAL is returned.
459    
460    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
461        synonymous with PCRE_PARTIAL, for backwards compatibility, and
462        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
463        and may be more useful for multi-segment matching.
464    
465    11. Partial matching with pcre_exec() is now more intuitive. A partial match
466        used to be given if ever the end of the subject was reached; now it is
467        given only if matching could not proceed because another character was
468        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
469        string "Z", which now yields "no match" instead of "partial match". In the
470        case of pcre_dfa_exec(), "no match" is given if every matching path for the
471        final character ended with (*FAIL).
472    
473    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
474        if the pattern had a "must contain" character that was already found in the
475        earlier partial match, unless partial matching was again requested. For
476        example, with the pattern /dog.(body)?/, the "must contain" character is
477        "g". If the first part-match was for the string "dog", restarting with
478        "sbody" failed. This bug has been fixed.
479    
480    13. The string returned by pcre_dfa_exec() after a partial match has been
481        changed so that it starts at the first inspected character rather than the
482        first character of the match. This makes a difference only if the pattern
483        starts with a lookbehind assertion or \b or \B (\K is not supported by
484        pcre_dfa_exec()). It's an incompatible change, but it makes the two
485        matching functions compatible, and I think it's the right thing to do.
486    
487    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
488        so that the demonstration program is easily available in environments where
489        PCRE has not been installed from source.
490    
491    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
492        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
493        library.
494    
495    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
496        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
497        is not the first non-POSIX option to be added. Clearly some people find
498        these options useful.
499    
500    17. If a caller to the POSIX matching function regexec() passes a non-zero
501        value for nmatch with a NULL value for pmatch, the value of
502        nmatch is forced to zero.
503    
504    18. RunGrepTest did not have a test for the availability of the -u option of
505        the diff command, as RunTest does. It now checks in the same way as
506        RunTest, and also checks for the -b option.
507    
508    19. If an odd number of negated classes containing just a single character
509        interposed, within parentheses, between a forward reference to a named
510        subpattern and the definition of the subpattern, compilation crashed with
511        an internal error, complaining that it could not find the referenced
512        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
513        [The bug was that it was starting one character too far in when skipping
514        over the character class, thus treating the ] as data rather than
515        terminating the class. This meant it could skip too much.]
516    
517    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
518        /g option in pcretest when the pattern contains \K, which makes it possible
519        to have an empty string match not at the start, even when the pattern is
520        anchored. Updated pcretest and pcredemo to use this option.
521    
522    21. If the maximum number of capturing subpatterns in a recursion was greater
523        than the maximum at the outer level, the higher number was returned, but
524        with unset values at the outer level. The correct (outer level) value is
525        now given.
526    
527    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
528        PCRE did not set those parentheses (unlike Perl). I have now found a way to
529        make it do so. The string so far is captured, making this feature
530        compatible with Perl.
531    
532    23. The tests have been re-organized, adding tests 11 and 12, to make it
533        possible to check the Perl 5.10 features against Perl 5.10.
534    
535    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
536        pattern matches a fixed length string. PCRE did not allow this; now it
537        does. Neither allows recursion.
538    
539    25. I finally figured out how to implement a request to provide the minimum
540        length of subject string that was needed in order to match a given pattern.
541        (It was back references and recursion that I had previously got hung up
542        on.) This code has now been added to pcre_study(); it finds a lower bound
543        to the length of subject needed. It is not necessarily the greatest lower
544        bound, but using it to avoid searching strings that are too short does give
545        some useful speed-ups. The value is available to calling programs via
546        pcre_fullinfo().
547    
548    26. While implementing 25, I discovered to my embarrassment that pcretest had
549        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
550        study optimizations had never been tested with that matching function.
551        Oops. What is worse, even when it was passed study data, there was a bug in
552        pcre_dfa_exec() that meant it never actually used it. Double oops. There
553        were also very few tests of studied patterns with pcre_dfa_exec().
554    
555    27. If (?| is used to create subpatterns with duplicate numbers, they are now
556        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
557        on the other side of the coin, they are no longer allowed to have different
558        names, because these cannot be distinguished in PCRE, and this has caused
559        confusion. (This is a difference from Perl.)
560    
561    28. When duplicate subpattern names are present (necessarily with different
562        numbers, as required by 27 above), and a test is made by name in a
563        conditional pattern, either for a subpattern having been matched, or for
564        recursion in such a pattern, all the associated numbered subpatterns are
565        tested, and the overall condition is true if the condition is true for any
566        one of them. This is the way Perl works, and is also more like the way
567        testing by number works.
568    
569    
570    Version 7.9 11-Apr-09
571    ---------------------
572    
573    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
574        (pcretest), all targets were linked against these libraries. This included
575        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
576        libraries. This caused unwanted dependencies to be created. This problem
577        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
578        pcretest is linked with readline.
579    
580    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
581        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
582        moved outside it again, because FALSE and TRUE are already defined in AIX,
583        but BOOL is not.
584    
585    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
586        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
587    
588    4.  The pcregrep documentation said spaces were inserted as well as colons (or
589        hyphens) following file names and line numbers when outputting matching
590        lines. This is not true; no spaces are inserted. I have also clarified the
591        wording for the --colour (or --color) option.
592    
593    5.  In pcregrep, when --colour was used with -o, the list of matching strings
594        was not coloured; this is different to GNU grep, so I have changed it to be
595        the same.
596    
597    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
598        each matching line was coloured. Now it goes on to look for further matches
599        of any of the test patterns, which is the same behaviour as GNU grep.
600    
601    7.  A pattern that could match an empty string could cause pcregrep to loop; it
602        doesn't make sense to accept an empty string match in pcregrep, so I have
603        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
604        seems to be how GNU grep behaves.
605    
606    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
607        start or after a newline", because the conditional assertion was not being
608        correctly handled. The rule now is that both the assertion and what follows
609        in the first alternative must satisfy the test.
610    
611    9.  If auto-callout was enabled in a pattern with a conditional group whose
612        condition was an assertion, PCRE could crash during matching, both with
613        pcre_exec() and pcre_dfa_exec().
614    
615    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
616        used for matching.
617    
618    11. Unicode property support in character classes was not working for
619        characters (bytes) greater than 127 when not in UTF-8 mode.
620    
621    12. Added the -M command line option to pcretest.
622    
623    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
624    
625    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
626    
627    16. Added comments and documentation about mis-use of no_arg in the C++
628        wrapper.
629    
630    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
631        from Martin Jerabek that uses macro names for all relevant character and
632        string constants.
633    
634    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
635        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
636        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
637        these, but not everybody uses configure.
638    
639    19. A conditional group that had only one branch was not being correctly
640        recognized as an item that could match an empty string. This meant that an
641        enclosing group might also not be so recognized, causing infinite looping
642        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
643        with the subject "ab", where knowledge that the repeated group can match
644        nothing is needed in order to break the loop.
645    
646    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
647        exec(), but without supplying a callout function, matching went wrong.
648    
649    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
650        leak if the size of the offset vector was greater than 30. When the vector
651        is smaller, the saved offsets during recursion go onto a local stack
652        vector, but for larger vectors malloc() is used. It was failing to free
653        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
654        error, in fact).
655    
656    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
657        heapframe that is used only when UTF-8 support is enabled. This caused no
658        problem, but was untidy.
659    
660    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
661        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
662        included within another project.
663    
664    24. Steven Van Ingelgem's patches to add more options to the CMake support,
665        slightly modified by me:
666    
667          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
668              not building pcregrep.
669    
670          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
671              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
672    
673    25. Forward references, both numeric and by name, in patterns that made use of
674        duplicate group numbers, could behave incorrectly or give incorrect errors,
675        because when scanning forward to find the reference group, PCRE was not
676        taking into account the duplicate group numbers. A pattern such as
677        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
678    
679    26. Changed a few more instances of "const unsigned char *" to USPTR, making
680        the feature of a custom pointer more persuasive (as requested by a user).
681    
682    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
683        pcretest.c, inside #ifndefs, because it seems they are sometimes already
684        pre-defined.
685    
686    28. Added support for (*UTF8) at the start of a pattern.
687    
688    29. Arrange for flags added by the "release type" setting in CMake to be shown
689        in the configuration summary.
690    
691    
692    Version 7.8 05-Sep-08
693    ---------------------
694    
695    1.  Replaced UCP searching code with optimized version as implemented for Ad
696        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
697        stage table and inline lookup instead of a function, giving speed ups of 2
698        to 5 times on some simple patterns that I tested. Permission was given to
699        distribute the MultiStage2.py script that generates the tables (it's not in
700        the tarball, but is in the Subversion repository).
701    
702    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
703        scripts.
704    
705    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
706        a group with a zero qualifier. The result of the study could be incorrect,
707        or the function might crash, depending on the pattern.
708    
709    4.  Caseless matching was not working for non-ASCII characters in back
710        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
711        It now works when Unicode Property Support is available.
712    
713    5.  In pcretest, an escape such as \x{de} in the data was always generating
714        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
715        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
716        truncation.
717    
718    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
719    
720    7.  Added two (int) casts to pcregrep when printing the difference of two
721        pointers, in case they are 64-bit values.
722    
723    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
724        test 2 if it fails.
725    
726    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
727        and a #define of that name to empty if it is not externally set. This is to
728        allow users of MSVC to set it if necessary.
729    
730    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
731        the convenience functions in the pcre_get.c source file.
732    
733    11. An option change at the start of a pattern that had top-level alternatives
734        could cause overwriting and/or a crash. This command provoked a crash in
735        some environments:
736    
737          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
738    
739        This potential security problem was recorded as CVE-2008-2371.
740    
741    12. For a pattern where the match had to start at the beginning or immediately
742        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
743        pcre_dfa_exec() could read past the end of the passed subject if there was
744        no match. To help with detecting such bugs (e.g. with valgrind), I modified
745        pcretest so that it places the subject at the end of its malloc-ed buffer.
746    
747    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
748        exec() might read past the end of the data buffer in UTF-8 mode.
749    
750    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
751        the data contained the byte 0x85 as part of a UTF-8 character within its
752        first line. This applied both to normal and DFA matching.
753    
754    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
755        /^[^d]*?$/8 failed to match "abc".
756    
757    16. Added a missing copyright notice to pcrecpp_internal.h.
758    
759    17. Make it more clear in the documentation that values returned from
760        pcre_exec() in ovector are byte offsets, not character counts.
761    
762    18. Tidied a few places to stop certain compilers from issuing warnings.
763    
764    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
765        supplied by Stefan Weber. I made a further small update for 7.8 because
766        there is a change of source arrangements: the pcre_searchfuncs.c module is
767        replaced by pcre_ucd.c.
768    
769    
770    Version 7.7 07-May-08
771    ---------------------
772    
773    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
774        a string to a long long, pretend we don't even have a long long." This is
775        done by checking for the strtoq, strtoll, and _strtoi64 functions.
776    
777    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
778        pre-7.6 versions, which defined a global no_arg variable instead of putting
779        it in the RE class. (See also #8 below.)
780    
781    3.  Remove a line of dead code, identified by coverity and reported by Nuno
782        Lopes.
783    
784    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
785    
786        (1) The include/exclude patterns were being applied to the whole pathnames
787            of files, instead of just to the final components.
788    
789        (2) If there was more than one level of directory, the subdirectories were
790            skipped unless they satisfied the include/exclude conditions. This is
791            inconsistent with GNU grep (and could even be seen as contrary to the
792            pcregrep specification - which I improved to make it absolutely clear).
793            The action now is always to scan all levels of directory, and just
794            apply the include/exclude patterns to regular files.
795    
796    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
797        --exclude_dir in the tests to avoid scanning .svn directories.
798    
799    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
800        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
801        doesn't support NULs in patterns.
802    
803    7.  Added some missing "const"s to declarations of static tables in
804        pcre_compile.c and pcre_dfa_exec.c.
805    
806    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
807        caused by fix #2  above. (Subsequently also a second patch to fix the
808        first patch. And a third patch - this was a messy problem.)
809    
810    9.  Applied Craig's patch to remove the use of push_back().
811    
812    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
813        matching function regexec().
814    
815    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
816        which, however, unlike Perl's \g{...}, are subroutine calls, not back
817        references. PCRE supports relative numbers with this syntax (I don't think
818        Oniguruma does).
819    
820    12. Previously, a group with a zero repeat such as (...){0} was completely
821        omitted from the compiled regex. However, this means that if the group
822        was called as a subroutine from elsewhere in the pattern, things went wrong
823        (an internal error was given). Such groups are now left in the compiled
824        pattern, with a new opcode that causes them to be skipped at execution
825        time.
826    
827    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
828        to the way PCRE behaves:
829    
830        (a) A lone ] character is dis-allowed (Perl treats it as data).
831    
832        (b) A back reference to an unmatched subpattern matches an empty string
833            (Perl fails the current match path).
834    
835        (c) A data ] in a character class must be notated as \] because if the
836            first data character in a class is ], it defines an empty class. (In
837            Perl it is not possible to have an empty class.) The empty class []
838            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
839            The negative empty class [^] matches any one character, independently
840            of the DOTALL setting.
841    
842    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
843        non-existent subpattern following a character class starting with ']' and
844        containing () gave an internal compiling error instead of "reference to
845        non-existent subpattern". Fortunately, when the pattern did exist, the
846        compiled code was correct. (When scanning forwards to check for the
847        existencd of the subpattern, it was treating the data ']' as terminating
848        the class, so got the count wrong. When actually compiling, the reference
849        was subsequently set up correctly.)
850    
851    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
852        it was being rejected as not supported by pcre_dfa_exec(), even though
853        other assertions are supported. I have made pcre_dfa_exec() support
854        (*FAIL).
855    
856    16. The implementation of 13c above involved the invention of a new opcode,
857        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
858        cannot be changed at match time, I realized I could make a small
859        improvement to matching performance by compiling OP_ALLANY instead of
860        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
861        on the OP_ANY path.
862    
863    17. Compiling pcretest on Windows with readline support failed without the
864        following two fixes: (1) Make the unistd.h include conditional on
865        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
866    
867    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
868        ncurses library to be included for pcretest when ReadLine support is
869        requested, but also to allow for it to be overridden. This patch came from
870        Daniel Bergström.
871    
872    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
873        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
874        any errors with the current Unicode tables. Thanks to Peter Kankowski for
875        spotting this.
876    
877    
878    Version 7.6 28-Jan-08
879    ---------------------
880    
881    1.  A character class containing a very large number of characters with
882        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
883        overflow.
884    
885    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
886        HAVE_LONG_LONG is not defined.
887    
888    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
889        bring them up to date and include new features. This patch includes:
890    
891        - Fixed PH's badly added libz and libbz2 support.
892        - Fixed a problem with static linking.
893        - Added pcredemo. [But later removed - see 7 below.]
894        - Fixed dftables problem and added an option.
895        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
896            HAVE_LONG_LONG.
897        - Added readline support for pcretest.
898        - Added an listing of the option settings after cmake has run.
899    
900    4.  A user submitted a patch to Makefile that makes it easy to create
901        "pcre.dll" under mingw when using Configure/Make. I added stuff to
902        Makefile.am that cause it to include this special target, without
903        affecting anything else. Note that the same mingw target plus all
904        the other distribution libraries and programs are now supported
905        when configuring with CMake (see 6 below) instead of with
906        Configure/Make.
907    
908    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
909        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
910        exported in the Windows port". It has not yet been confirmed that the patch
911        solves the problem, but it does no harm.
912    
913    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
914        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
915        with CMake, and also correct the comment about stack recursion.
916    
917    7.  Remove the automatic building of pcredemo from the ./configure system and
918        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
919        of a program that users should build themselves after PCRE is installed, so
920        building it automatically is not really right. What is more, it gave
921        trouble in some build environments.
922    
923    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
924    
925    
926    Version 7.5 10-Jan-08
927    ---------------------
928    
929    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
930        values in parens when parsing an RE using the C++ wrapper."
931    
932    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
933        Characters greater than 255 were excluded from the class instead of being
934        included.
935    
936    3.  The same bug as (2) above applied to negated POSIX classes such as
937        [:^space:].
938    
939    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
940        defined or documented. It seems to have been a typo for PCRE_STATIC, so
941        I have changed it.
942    
943    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
944        first named subpattern) and a construct such as (?&a) would reference the
945        first named subpattern whose name started with "a" (in other words, the
946        length check was missing). Both these problems are fixed. "Subpattern name
947        expected" is now given for (?&) (a zero-length name), and this patch also
948        makes it give the same error for \k'' (previously it complained that that
949        was a reference to a non-existent subpattern).
950    
951    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
952        this is right because (?- can be followed by option settings as well as by
953        digits. I have, however, made the messages clearer.
954    
955    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
956        than the number used in the conditional) now cause a compile-time error.
957        This is actually not compatible with Perl, which accepts such patterns, but
958        treats the conditional as always being FALSE (as PCRE used to), but it
959        seems to me that giving a diagnostic is better.
960    
961    8.  Change "alphameric" to the more common word "alphanumeric" in comments
962        and messages.
963    
964    9.  Fix two occurrences of "backslash" in comments that should have been
965        "backspace".
966    
967    10. Remove two redundant lines of code that can never be obeyed (their function
968        was moved elsewhere).
969    
970    11. The program that makes PCRE's Unicode character property table had a bug
971        which caused it to generate incorrect table entries for sequences of
972        characters that have the same character type, but are in different scripts.
973        It amalgamated them into a single range, with the script of the first of
974        them. In other words, some characters were in the wrong script. There were
975        thirteen such cases, affecting characters in the following ranges:
976    
977          U+002b0 - U+002c1
978          U+0060c - U+0060d
979          U+0061e - U+00612
980          U+0064b - U+0065e
981          U+0074d - U+0076d
982          U+01800 - U+01805
983          U+01d00 - U+01d77
984          U+01d9b - U+01dbf
985          U+0200b - U+0200f
986          U+030fc - U+030fe
987          U+03260 - U+0327f
988          U+0fb46 - U+0fbb1
989          U+10450 - U+1049d
990    
991    12. The -o option (show only the matching part of a line) for pcregrep was not
992        compatible with GNU grep in that, if there was more than one match in a
993        line, it showed only the first of them. It now behaves in the same way as
994        GNU grep.
995    
996    13. If the -o and -v options were combined for pcregrep, it printed a blank
997        line for every non-matching line. GNU grep prints nothing, and pcregrep now
998        does the same. The return code can be used to tell if there were any
999        non-matching lines.
1000    
1001    14. Added --file-offsets and --line-offsets to pcregrep.
1002    
1003    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1004        infinitely looping recursion. The bug was that positive lookaheads were not
1005        being skipped when checking for a possible empty match (negative lookaheads
1006        and both kinds of lookbehind were skipped).
1007    
1008    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1009        inclusion of <windows.h> to before rather than after the definition of
1010        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1011    
1012    17. Specifying a possessive quantifier with a specific limit for a Unicode
1013        character property caused pcre_compile() to compile bad code, which led at
1014        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1015        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1016        caused the error; without that there was no problem.
1017    
1018    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1019    
1020    19. Added --enable-pcretest-libreadline.
1021    
1022    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1023        RE::GlobalReplace(). As a result, the number of replacements returned was
1024        double what it should be. I removed one of the increments, but Craig sent a
1025        later patch that removed the other one (the right fix) and added unit tests
1026        that check the return values (which was not done before).
1027    
1028    21. Several CMake things:
1029    
1030        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1031            the names libpcre and libpcreposix, not just pcre and pcreposix.
1032    
1033        (2) The above change means that pcretest and pcregrep are now correctly
1034            linked with the newly-built libraries, not previously installed ones.
1035    
1036        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1037    
1038    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1039        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1040        UTF-8 newline character). The key issue is that the pattern starts .*;
1041        this means that the match must be either at the beginning, or after a
1042        newline. The bug was in the code for advancing after a failed match and
1043        checking that the new position followed a newline. It was not taking
1044        account of UTF-8 characters correctly.
1045    
1046    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1047        character classes. PCRE was not treating the sequence [:...:] as a
1048        character class unless the ... were all letters. Perl, however, seems to
1049        allow any characters between [: and :], though of course it rejects as
1050        unknown any "names" that contain non-letters, because all the known class
1051        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1052        for example, whereas PCRE did not - it did not recognize a POSIX character
1053        class. This seemed a bit dangerous, so the code has been changed to be
1054        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1055        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1056        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1057        Perl does, and where it didn't before.
1058    
1059    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1060        Windows environments %n is disabled by default.
1061    
1062    
1063    Version 7.4 21-Sep-07
1064    ---------------------
1065    
1066    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1067        means that a class such as [\s] counted as "explicit reference to CR or
1068        LF". That isn't really right - the whole point of the change was to try to
1069        help when there was an actual mention of one of the two characters. So now
1070        the change happens only if \r or \n (or a literal CR or LF) character is
1071        encountered.
1072    
1073    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1074        of both had grown to the point where there were only 3 bits left.
1075        Fortunately, there was spare space in the data structure, and so I have
1076        moved the internal flags into a new 16-bit field to free up more option
1077        bits.
1078    
1079    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1080        but did not set the internal JCHANGED flag - either of these is enough to
1081        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1082        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1083        start sets both bits.
1084    
1085    4.  Added options (at build time, compile time, exec time) to change \R from
1086        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1087    
1088    5.  doc/pcresyntax.html was missing from the distribution.
1089    
1090    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1091        compatibility, even though it is no longer used.
1092    
1093    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1094        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1095        windows.h file is present (where different names are used). [This was
1096        reversed later after testing - see 16 below.]
1097    
1098    8.  Changed all #include <config.h> to #include "config.h". There were also
1099        some further <pcre.h> cases that I changed to "pcre.h".
1100    
1101    9.  When pcregrep was used with the --colour option, it missed the line ending
1102        sequence off the lines that it output.
1103    
1104    10. It was pointed out to me that arrays of string pointers cause lots of
1105        relocations when a shared library is dynamically loaded. A technique of
1106        using a single long string with a table of offsets can drastically reduce
1107        these. I have refactored PCRE in four places to do this. The result is
1108        dramatic:
1109    
1110          Originally:                          290
1111          After changing UCP table:            187
1112          After changing error message table:   43
1113          After changing table of "verbs"       36
1114          After changing table of Posix names   22
1115    
1116        Thanks to the folks working on Gregex for glib for this insight.
1117    
1118    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1119        unicode-properties was also set.
1120    
1121    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1122    
1123    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1124        checked only for CRLF.
1125    
1126    14. Added casts to pcretest.c to avoid compiler warnings.
1127    
1128    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1129    
1130    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1131        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1132        entirely. This removes changes made in 7 above.
1133    
1134    17. The CMake files have been updated, and there is now more information about
1135        building with CMake in the NON-UNIX-USE document.
1136    
1137    
1138    Version 7.3 28-Aug-07
1139    ---------------------
1140    
1141     1. In the rejigging of the build system that eventually resulted in 7.1, the
1142        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1143        brackets there is not right, since it causes compilers to look for an
1144        installed pcre.h, not the version that is in the source that is being
1145        compiled (which of course may be different). I have changed it back to:
1146    
1147          #include "pcre.h"
1148    
1149        I have a vague recollection that the change was concerned with compiling in
1150        different directories, but in the new build system, that is taken care of
1151        by the VPATH setting the Makefile.
1152    
1153     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1154        when the subject happened to end in the byte 0x85 (e.g. if the last
1155        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1156        characters but of course it shouldn't be taken as a newline when it is part
1157        of another character. The bug was that, for an unlimited repeat of . in
1158        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1159        characters when looking for a newline.
1160    
1161     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1162    
1163     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1164        in debug output.
1165    
1166     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1167        long printing in the pcrecpp unittest when running under MinGW.
1168    
1169     6. ESC_K was left out of the EBCDIC table.
1170    
1171     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1172        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1173        limit also applies to "virtual nesting" when a pattern is recursive, and in
1174        this case 1000 isn't so big. I have been able to remove this limit at the
1175        expense of backing off one optimization in certain circumstances. Normally,
1176        when pcre_exec() would call its internal match() function recursively and
1177        immediately return the result unconditionally, it uses a "tail recursion"
1178        feature to save stack. However, when a subpattern that can match an empty
1179        string has an unlimited repetition quantifier, it no longer makes this
1180        optimization. That gives it a stack frame in which to save the data for
1181        checking that an empty string has been matched. Previously this was taken
1182        from the 1000-entry workspace that had been reserved. So now there is no
1183        explicit limit, but more stack is used.
1184    
1185     8. Applied Daniel's patches to solve problems with the import/export magic
1186        syntax that is required for Windows, and which was going wrong for the
1187        pcreposix and pcrecpp parts of the library. These were overlooked when this
1188        problem was solved for the main library.
1189    
1190     9. There were some crude static tests to avoid integer overflow when computing
1191        the size of patterns that contain repeated groups with explicit upper
1192        limits. As the maximum quantifier is 65535, the maximum group length was
1193        set at 30,000 so that the product of these two numbers did not overflow a
1194        32-bit integer. However, it turns out that people want to use groups that
1195        are longer than 30,000 bytes (though not repeat them that many times).
1196        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1197        made it possible to implement the integer overflow checks in a much more
1198        dynamic way, which I have now done. The artificial limitation on group
1199        length has been removed - we now have only the limit on the total length of
1200        the compiled pattern, which depends on the LINK_SIZE setting.
1201    
1202    10. Fixed a bug in the documentation for get/copy named substring when
1203        duplicate names are permitted. If none of the named substrings are set, the
1204        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1205        empty string.
1206    
1207    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1208        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1209        because the ] is interpreted as the first data character and the
1210        terminating ] is not found. PCRE has been made compatible with Perl in this
1211        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1212        cause memory overwriting.
1213    
1214    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1215        string has been matched (to stop an infinite loop). It was not recognizing
1216        a conditional subpattern that could match an empty string if that
1217        subpattern was within another subpattern. For example, it looped when
1218        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1219        condition was not nested. This bug has been fixed.
1220    
1221    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1222        past the start of the subject in the presence of bytes with the top bit
1223        set, for example "\x8aBCD".
1224    
1225    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1226        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1227    
1228    14. Optimized (?!) to (*FAIL).
1229    
1230    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1231        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1232        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1233        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1234        does: it's just the validity check that is more restrictive.
1235    
1236    16. Inserted checks for integer overflows during escape sequence (backslash)
1237        processing, and also fixed erroneous offset values for syntax errors during
1238        backslash processing.
1239    
1240    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1241        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1242    
1243    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1244        caused an overrun.
1245    
1246    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1247        something other than just ASCII characters) inside a group that had an
1248        unlimited repeat caused a loop at compile time (while checking to see
1249        whether the group could match an empty string).
1250    
1251    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1252        [\P{Any}] did so. (Error in the code for printing property names.)
1253    
1254    21. An orphan \E inside a character class could cause a crash.
1255    
1256    22. A repeated capturing bracket such as (A)? could cause a wild memory
1257        reference during compilation.
1258    
1259    23. There are several functions in pcre_compile() that scan along a compiled
1260        expression for various reasons (e.g. to see if it's fixed length for look
1261        behind). There were bugs in these functions when a repeated \p or \P was
1262        present in the pattern. These operators have additional parameters compared
1263        with \d, etc, and these were not being taken into account when moving along
1264        the compiled data. Specifically:
1265    
1266        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1267            length.
1268    
1269        (b) An item such as \pL+ within a repeated group could cause crashes or
1270            loops.
1271    
1272        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1273            "reference to non-existent subpattern" error.
1274    
1275        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1276    
1277    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1278        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1279    
1280    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1281    
1282    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1283        character were causing crashes (broken optimization).
1284    
1285    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1286        \p or \P) caused a compile-time loop.
1287    
1288    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1289        break. For example, the unstudied pattern [\r\n]A does not match the string
1290        "\r\nA" because change 7.0/46 below moves the current point on by two
1291        characters after failing to match at the start. However, the pattern \nA
1292        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1293        the same is true. There doesn't seem any very clean way out of this, but
1294        what I have chosen to do makes the common cases work: PCRE now takes note
1295        of whether there can be an explicit match for \r or \n anywhere in the
1296        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1297        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1298        pattern has explicit CR or LF references.
1299    
1300    29. Added (*CR) etc for changing newline setting at start of pattern.
1301    
1302    
1303    Version 7.2 19-Jun-07
1304    ---------------------
1305    
1306     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1307        which is apparently normally available under Windows.
1308    
1309     2. Re-jig the pcregrep tests with different newline settings in an attempt
1310        to make them independent of the local environment's newline setting.
1311    
1312     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1313    
1314     4. Some of the "internals" tests were previously cut out when the link size
1315        was not 2, because the output contained actual offsets. The recent new
1316        "Z" feature of pcretest means that these can be cut out, making the tests
1317        usable with all link sizes.
1318    
1319     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1320        stack recursion. This gives a massive performance boost under BSD, but just
1321        a small improvement under Linux. However, it saves one field in the frame
1322        in all cases.
1323    
1324     6. Added more features from the forthcoming Perl 5.10:
1325    
1326        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1327            recursion call. It refers to the nth most recently opened parentheses.
1328    
1329        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1330            to be opened parentheses.
1331    
1332        (c) Conditions that refer to capturing parentheses can be specified
1333            relatively, for example, (?(-2)... or (?(+3)...
1334    
1335        (d) \K resets the start of the current match so that everything before
1336            is not part of it.
1337    
1338        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1339    
1340        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1341            reference syntax.
1342    
1343        (g) (?| introduces a group in which the numbering of parentheses in each
1344            alternative starts with the same number.
1345    
1346        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1347    
1348     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1349        PCRE_INFO_JCHANGED.
1350    
1351     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1352        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1353        for detecting groups that can match an empty string.
1354    
1355     9. A pattern with a very large number of alternatives (more than several
1356        hundred) was running out of internal workspace during the pre-compile
1357        phase, where pcre_compile() figures out how much memory will be needed. A
1358        bit of new cunning has reduced the workspace needed for groups with
1359        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1360        workspace instead of running out of the 4096 that are available.
1361    
1362    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1363    
1364    11. Applied patch from Google to remove an optimization that didn't quite work.
1365        The report of the bug said:
1366    
1367          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1368          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1369          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1370    
1371    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1372        it matched the wrong number of bytes.
1373    
1374    
1375    Version 7.1 24-Apr-07
1376  ---------------------  ---------------------
1377    
1378   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 32  Version 7.1 12-Mar-07 Line 1403  Version 7.1 12-Mar-07
1403    
1404   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1405      Weber: (1) pcre_internal.h was missing some function renames; (2) updated      Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1406      makevp.bat for the current PCRE, using the additional files !compile.txt,      makevp.bat for the current PCRE, using the additional files
1407      !linklib.txt, and pcregexp.pas.      makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1408    
1409   6. A Windows user reported a minor discrepancy with test 2, which turned out   6. A Windows user reported a minor discrepancy with test 2, which turned out
1410      to be caused by a trailing space on an input line that had got lost in his      to be caused by a trailing space on an input line that had got lost in his
# Line 116  Version 7.1 12-Mar-07 Line 1487  Version 7.1 12-Mar-07
1487  14. If erroroffset was passed as NULL to pcre_compile, it provoked a  14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1488      segmentation fault instead of returning the appropriate error message.      segmentation fault instead of returning the appropriate error message.
1489    
1490    15. In multiline mode when the newline sequence was set to "any", the pattern
1491        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1492        This doesn't seem right; it now treats the CRLF combination as the line
1493        ending, and so does not match in that case. It's only a pattern such as ^$
1494        that would hit this one: something like ^ABC$ would have failed after \r
1495        and then tried again after \r\n.
1496    
1497    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1498        in an attempt to make files that differ only in their line terminators
1499        compare equal. This works on Linux.
1500    
1501    17. Under certain error circumstances pcregrep might try to free random memory
1502        as it exited. This is now fixed, thanks to valgrind.
1503    
1504    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1505        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1506        was because its rules for how to advance for /g after matching an empty
1507        string at the end of a line did not allow for this case. They now check for
1508        it specially.
1509    
1510    20. pcretest is supposed to handle patterns and data of any length, by
1511        extending its buffers when necessary. It was getting this wrong when the
1512        buffer for a data line had to be extended.
1513    
1514    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1515        CRLF as a newline sequence.
1516    
1517    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1518        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1519        I have nevertheless tidied it up.
1520    
1521    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1522    
1523    24. Added a man page for pcre-config.
1524    
1525    
1526  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
1527  ---------------------  ---------------------

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