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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.0 02 Jul-08  Version 8.32
5    ------------
7    1.  Improved JIT compiler optimizations for first character search and single
8        character iterators.
10    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
11        Patch by Daniel Richard G.
13    3.  Single character iterator optimizations in the JIT compiler.
15    4.  Improved JIT compiler optimizations for character ranges.
17    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
18        Reported by Giuseppe D'Angelo.
20    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
21        of a line, was being set incorrectly in cases where .* appeared inside
22        atomic brackets at the start of a pattern, or where there was a subsequent
23        *PRUNE or *SKIP.
25    7.  Improved instruction cache flush for POWER/PowerPC.
26        Patch by Daniel Richard G.
28    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
29        grep:
31        (a) There is now no limit to the number of patterns to be matched.
33        (b) An error is given if a pattern is too long.
35        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
36            are now supported.
38        (d) --exclude-from and --include-from (multiple use) have been added.
40        (e) Exclusions and inclusions now apply to all files and directories, not
41            just to those obtained from scanning a directory recursively.
43        (f) Multiple uses of -f and --file-list are now supported.
45        (g) In a Windows environment, the default for -d has been changed from
46            "read" (the GNU grep default) to "skip", because otherwise the presence
47            of a directory in the file list provokes an error.
49        (h) The documentation has been revised and clarified in places.
51    9.  Improve the matching speed of capturing brackets.
53    10. Changed the meaning of \X so that it now matches a Unicode extended
54        grapheme cluster.
56    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
57        out POSIX threads when JIT support is configured.
59    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
61    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
62        structure could go wrong in environments where size_t is not the same size
63        as int.
65    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
66        set.
68    15. The EBCDIC support had decayed; later updates to the code had included
69        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
70        general tidy up of EBCDIC-related issues, and the documentation was also
71        not quite right. There is now a test that can be run on ASCII systems to
72        check some of the EBCDIC-related things (but is it not a full test).
74    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
75        in a small tidy to the code.
79    Version 8.31 06-July-2012
80    -------------------------
82    1.  Fixing a wrong JIT test case and some compiler warnings.
84    2.  Removed a bashism from the RunTest script.
86    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
87        to unsigned type, result still unsigned" that was given by an MS compiler
88        on encountering the code "-sizeof(xxx)".
90    4.  Partial matching support is added to the JIT compiler.
92    5.  Fixed several bugs concerned with partial matching of items that consist
93        of more than one character:
95        (a) /^(..)\1/ did not partially match "aba" because checking references was
96            done on an "all or nothing" basis. This also applied to repeated
97            references.
99        (b) \R did not give a hard partial match if \r was found at the end of the
100            subject.
102        (c) \X did not give a hard partial match after matching one or more
103            characters at the end of the subject.
105        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
106            a partial match for the string "\r".
108        (e) When newline was set to CRLF, the metacharacter "." did not recognize
109            a partial match for a CR character at the end of the subject string.
111    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
112        running pcretest, the text "(JIT)" added to the output whenever JIT is
113        actually used to run the match.
115    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
116        or /S+[+] with a digit between 1 and 7.
118    8.  OP_NOT now supports any UTF character not just single-byte ones.
120    9.  (*MARK) control verb is now supported by the JIT compiler.
122    10. The command "./RunTest list" lists the available tests without actually
123        running any of them. (Because I keep forgetting what they all are.)
127    12. Applied a (slightly modified) user-supplied patch that improves performance
128        when the heap is used for recursion (compiled with --disable-stack-for-
129        recursion). Instead of malloc and free for each heap frame each time a
130        logical recursion happens, frames are retained on a chain and re-used where
131        possible. This sometimes gives as much as 30% improvement.
133    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
134        call.
136    14. As documented, (*COMMIT) is now confined to within a positive assertion.
138    15. It is now possible to link pcretest with libedit as an alternative to
139        libreadline.
141    16. (*COMMIT) control verb is now supported by the JIT compiler.
143    17. The Unicode data tables have been updated to Unicode 6.1.0.
145    18. Added --file-list option to pcregrep.
147    19. Added binary file support to pcregrep, including the -a, --binary-files,
148        -I, and --text options.
150    20. The madvise function is renamed for posix_madvise for QNX compatibility
151        reasons. Fixed by Giuseppe D'Angelo.
153    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
155    22. Changed the option for creating symbolic links for 16-bit man pages from
156        -s to -sf so that re-installing does not cause issues.
158    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
160    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
161        matches in certain environments (the workspace was not being correctly
162        retained). Also added to pcre_dfa_exec() a simple plausibility check on
163        some of the workspace data at the beginning of a restart.
165    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
166        was not doing so when it should - probably a typo introduced by SVN 528
167        (change 8.10/14).
169    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
170        \w+ when the character tables indicated that \x{c4} was a word character.
171        There were several related cases, all because the tests for doing a table
172        lookup were testing for characters less than 127 instead of 255.
174    27. If a pattern contains capturing parentheses that are not used in a match,
175        their slots in the ovector are set to -1. For those that are higher than
176        any matched groups, this happens at the end of processing. In the case when
177        there were back references that the ovector was too small to contain
178        (causing temporary malloc'd memory to be used during matching), and the
179        highest capturing number was not used, memory off the end of the ovector
180        was incorrectly being set to -1. (It was using the size of the temporary
181        memory instead of the true size.)
183    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
184        ovector size, it uses memory at the end of the block that it has got.
186    29. Check for an overlong MARK name and give an error at compile time. The
187        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
189    30. JIT compiler update.
191    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
192        Rill for the patch.
194    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
196    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
198    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
199        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
200        was enabled.
202    35. Improve JIT code generation for greedy plus quantifier.
204    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
205        1 to "aa" instead of to an empty string. The bug affected repeated groups
206        that could potentially match an empty string.
208    37. Optimizing single character iterators in JIT.
210    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
211        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
212        codepoints that are too big for the mode are faulted, and in a UTF mode,
213        disallowed codepoints are also faulted.
215    39. If PCRE was compiled with UTF support, in three places in the DFA
216        matcher there was code that should only have been obeyed in UTF mode, but
217        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
218        processing when bytes with values greater than 127 were present. In 16-bit
219        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
220        both cases the values are those that cannot be the first data item in a UTF
221        character. The three items that might have provoked this were recursions,
222        possessively repeated groups, and atomic groups.
224    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
225        and pcregrep, because some OS require shared objects to be explicitly
226        passed to ld, causing the link step to fail if they are not.
228    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
229        mode, patterns that started with \h* or \R* might be incorrectly matched.
232    Version 8.30 04-February-2012
233    -----------------------------
235    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
236        name is defined in ctype.h.
238    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
239        only in quite long subpatterns.
241    3.  Removed the function pcre_info(), which has been obsolete and deprecated
242        since it was replaced by pcre_fullinfo() in February 2000.
244    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
245        match a (*MARK), and the match failed at the start of the subject, a
246        reference to memory before the start of the subject could occur. This bug
247        was introduced by fix 17 of release 8.21.
249    5.  A reference to an unset group with zero minimum repetition was giving
250        totally wrong answers (in non-JavaScript-compatibility mode). For example,
251        /(another)?(\1?)test/ matched against "hello world test". This bug was
252        introduced in release 8.13.
254    6.  Add support for 16-bit character strings (a large amount of work involving
255        many changes and refactorings).
257    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
258        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
259        from a file.
261    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
262        rounding is not applied in this particular case).
264    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
265        if they appear, or are escaped, in patterns.
267    10. Get rid of a number of -Wunused-but-set-variable warnings.
269    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
270        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
271        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
272        also returns the mark "x". This bug applied to capturing parentheses,
273        non-capturing parentheses, and atomic parentheses. It also applied to some
274        assertions.
276    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
277        information out of configure.ac instead of relying on pcre.h.generic, which
278        is not stored in the repository.
280    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
281        -lreadline.
283    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
285    15. Applied Graycode's patch to put the top-level frame on the stack rather
286        than the heap when not using the stack for recursion. This gives a
287        performance improvement in many cases when recursion is not deep.
289    16. Experimental code added to "pcretest -C" to output the stack frame size.
292    Version 8.21 12-Dec-2011
293    ------------------------
295    1.  Updating the JIT compiler.
297    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
298        are added as well.
300    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
301        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
302        calling _pcre_jit_exec. Some extra comments are added.
304    4.  (*MARK) settings inside atomic groups that do not contain any capturing
305        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
306        was introduced by change 18 for 8.20.
308    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
309        ECMA-262 standard.
311    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
312        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
313        This bug was probably introduced by change 9 of 8.13.
315    7.  While fixing 6 above, I noticed that a number of other items were being
316        incorrectly rejected as "not fixed length". This arose partly because newer
317        opcodes had not been added to the fixed-length checking code. I have (a)
318        corrected the bug and added tests for these items, and (b) arranged for an
319        error to occur if an unknown opcode is encountered while checking for fixed
320        length instead of just assuming "not fixed length". The items that were
321        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
322        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
323        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
325    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
326        being incorrectly compiled and would have given unpredicatble results.
328    9.  A possessively repeated subpattern with minimum repeat count greater than
329        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
330        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
331        the first (A) could occur when it should not.
333    10. Add a cast and remove a redundant test from the code.
335    11. JIT should use pcre_malloc/pcre_free for allocation.
337    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
338        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
339        is anything other than /usr, -L is still shown).
341    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
343    14. Perl does not support \N without a following name in a [] class; PCRE now
344        also gives an error.
346    15. If a forward reference was repeated with an upper limit of around 2000,
347        it caused the error "internal error: overran compiling workspace". The
348        maximum number of forward references (including repeats) was limited by the
349        internal workspace, and dependent on the LINK_SIZE. The code has been
350        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
351        the default depends on LINK_SIZE. There is a new upper limit (for safety)
352        of around 200,000 forward references. While doing this, I also speeded up
353        the filling in of repeated forward references.
355    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
356        incorrectly expecting the subject to contain another "a" after the start.
358    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
359        in the match, the SKIP should be ignored. This was not happening; instead
360        the SKIP was being treated as NOMATCH. For patterns such as
361        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
362        tested.
364    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
365        now much more compatible with Perl, in particular in cases where the result
366        is a non-match for a non-anchored pattern. For example, if
367        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
368        "m", where previously it did not return a name. A side effect of this
369        change is that for partial matches, the last encountered mark name is
370        returned, as for non matches. A number of tests that were previously not
371        Perl-compatible have been moved into the Perl-compatible test files. The
372        refactoring has had the pleasing side effect of removing one argument from
373        the match() function, thus reducing its stack requirements.
375    19. If the /S+ option was used in pcretest to study a pattern using JIT,
376        subsequent uses of /S (without +) incorrectly behaved like /S+.
378    21. Retrieve executable code size support for the JIT compiler and fixing
379        some warnings.
381    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
382        not work when the shorter character appeared right at the end of the
383        subject string.
385    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
386        systems.
388    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
389        output it when the /M option is used in pcretest.
391    25. The CheckMan script was not being included in the distribution. Also, added
392        an explicit "perl" to run Perl scripts from the PrepareRelease script
393        because this is reportedly needed in Windows.
395    26. If study data was being save in a file and studying had not found a set of
396        "starts with" bytes for the pattern, the data written to the file (though
397        never used) was taken from uninitialized memory and so caused valgrind to
398        complain.
400    27. Updated RunTest.bat as provided by Sheri Pierce.
402    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
404    29. Computation of memory usage for the table of capturing group names was
405        giving an unnecessarily large value.
408    Version 8.20 21-Oct-2011
409    ------------------------
411    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
412        a POSIX class. After further experiments with Perl, which convinced me that
413        Perl has bugs and confusions, a closing square bracket is no longer allowed
414        in a POSIX name. This bug also affected patterns with classes that started
415        with full stops.
417    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
418        captured substring, but while checking the failing first alternative,
419        substring 1 is temporarily captured. If the output vector supplied to
420        pcre_exec() was not big enough for this capture, the yield of the function
421        was still zero ("insufficient space for captured substrings"). This cannot
422        be totally fixed without adding another stack variable, which seems a lot
423        of expense for a edge case. However, I have improved the situation in cases
424        such as /(a)(b)x|abc/ matched against "abc", where the return code
425        indicates that fewer than the maximum number of slots in the ovector have
426        been set.
428    3.  Related to (2) above: when there are more back references in a pattern than
429        slots in the output vector, pcre_exec() uses temporary memory during
430        matching, and copies in the captures as far as possible afterwards. It was
431        using the entire output vector, but this conflicts with the specification
432        that only 2/3 is used for passing back captured substrings. Now it uses
433        only the first 2/3, for compatibility. This is, of course, another edge
434        case.
436    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
437        main code base, and can be used by building with --enable-jit. When this is
438        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
439        runtime --no-jit option is given.
441    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
442        ovector, the return from the function was zero, implying that there were
443        other matches that did not fit. The correct "exactly full" value is now
444        returned.
446    6.  If a subpattern that was called recursively or as a subroutine contained
447        (*PRUNE) or any other control that caused it to give a non-standard return,
448        invalid errors such as "Error -26 (nested recursion at the same subject
449        position)" or even infinite loops could occur.
451    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
452        computing the minimum length on reaching *ACCEPT, and so ended up with the
453        wrong value of 1 rather than 0. Further investigation indicates that
454        computing a minimum subject length in the presence of *ACCEPT is difficult
455        (think back references, subroutine calls), and so I have changed the code
456        so that no minimum is registered for a pattern that contains *ACCEPT.
458    8.  If (*THEN) was present in the first (true) branch of a conditional group,
459        it was not handled as intended. [But see 16 below.]
461    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
462        Sheri Pierce.
464    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
465        the first byte in a match must be "a".
467    11. Change 17 for 8.13 increased the recursion depth for patterns like
468        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
469        pattern contains any instances of (*THEN). If it does not, the old
470        optimizations are restored. It would be nice to do this on a per-group
471        basis, but at the moment that is not feasible.
473    12. In some environments, the output of pcretest -C is CRLF terminated. This
474        broke RunTest's code that checks for the link size. A single white space
475        character after the value is now allowed for.
477    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
478        For "fr", it uses the Windows-specific input and output files.
480    14. If (*THEN) appeared in a group that was called recursively or as a
481        subroutine, it did not work as intended. [But see next item.]
483    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
484        pattern fragments (but not containing any | characters). If A and B are
485        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
486        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
487        D. In other words, Perl considers parentheses that do not contain any |
488        characters to be part of a surrounding alternative, whereas PCRE was
489        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
490        differently. PCRE now behaves in the same way as Perl, except in the case
491        of subroutine/recursion calls such as (?1) which have in any case always
492        been different (but PCRE had them first :-).
494    16. Related to 15 above: Perl does not treat the | in a conditional group as
495        creating alternatives. Such a group is treated in the same way as an
496        ordinary group without any | characters when processing (*THEN). PCRE has
497        been changed to match Perl's behaviour.
499    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
500        RunGrepTest script failed.
502    18. Change 22 for version 13 caused atomic groups to use more stack. This is
503        inevitable for groups that contain captures, but it can lead to a lot of
504        stack use in large patterns. The old behaviour has been restored for atomic
505        groups that do not contain any capturing parentheses.
507    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
508        suppress the check for a minimum subject length at run time. (If it was
509        given to pcre_exec() or pcre_dfa_exec() it did work.)
511    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
512        fail to work when decoding hex characters in data strings in EBCDIC
513        environments.
515    21. It appears that in at least one Mac OS environment, the isxdigit() function
516        is implemented as a macro that evaluates to its argument more than once,
517        contravening the C 90 Standard (I haven't checked a later standard). There
518        was an instance in pcretest which caused it to go wrong when processing
519        \x{...} escapes in subject strings. The has been rewritten to avoid using
520        things like p++ in the argument of isxdigit().
523    Version 8.13 16-Aug-2011
524    ------------------------
526    1.  The Unicode data tables have been updated to Unicode 6.0.0.
528    2.  Two minor typos in pcre_internal.h have been fixed.
530    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
531        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
532        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
534    4.  There were a number of related bugs in the code for matching backrefences
535        caselessly in UTF-8 mode when codes for the characters concerned were
536        different numbers of bytes. For example, U+023A and U+2C65 are an upper
537        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
538        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
539        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
540        2-byte code at the end of the subject (it thought there wasn't enough data
541        left).
543    5.  Comprehensive information about what went wrong is now returned by
544        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
545        as the output vector has at least 2 elements. The offset of the start of
546        the failing character and a reason code are placed in the vector.
548    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
549        now returned is for the first byte of the failing character, instead of the
550        last byte inspected. This is an incompatible change, but I hope it is small
551        enough not to be a problem. It makes the returned offset consistent with
552        pcre_exec() and pcre_dfa_exec().
554    7.  pcretest now gives a text phrase as well as the error number when
555        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
556        failure, the offset and reason code are output.
558    8.  When \R was used with a maximizing quantifier it failed to skip backwards
559        over a \r\n pair if the subsequent match failed. Instead, it just skipped
560        back over a single character (\n). This seems wrong (because it treated the
561        two characters as a single entity when going forwards), conflicts with the
562        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
563        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
564        has been changed.
566    9.  Some internal refactoring has changed the processing so that the handling
567        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
568        time (the PCRE_DOTALL option was changed this way some time ago: version
569        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
570        which was always a bit of a fudge. It also means that there is one less
571        argument for the match() function, which reduces its stack requirements
572        slightly. This change also fixes an incompatibility with Perl: the pattern
573        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
575    10. More internal refactoring has drastically reduced the number of recursive
576        calls to match() for possessively repeated groups such as (abc)++ when
577        using pcre_exec().
579    11. While implementing 10, a number of bugs in the handling of groups were
580        discovered and fixed:
582        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
583        (a|)*(?1) gave a compile-time internal error.
584        ((a|)+)+  did not notice that the outer group could match an empty string.
585        (^a|^)+   was not marked as anchored.
586        (.*a|.*)+ was not marked as matching at start or after a newline.
588    12. Yet more internal refactoring has removed another argument from the match()
589        function. Special calls to this function are now indicated by setting a
590        value in a variable in the "match data" data block.
592    13. Be more explicit in pcre_study() instead of relying on "default" for
593        opcodes that mean there is no starting character; this means that when new
594        ones are added and accidentally left out of pcre_study(), testing should
595        pick them up.
597    14. The -s option of pcretest has been documented for ages as being an old
598        synonym of -m (show memory usage). I have changed it to mean "force study
599        for every regex", that is, assume /S for every regex. This is similar to -i
600        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
601        using it. It makes it easier to run collections of tests with and without
602        study enabled, and thereby test pcre_study() more easily. All the standard
603        tests are now run with and without -s (but some patterns can be marked as
604        "never study" - see 20 below).
606    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
607        restoration of the capturing data to the outer values was not happening
608        correctly.
610    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
611        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
612        pattern had matched an empty string, and so incorrectly returned a no
613        match.
615    17. There was optimizing code for the last branch of non-capturing parentheses,
616        and also for the obeyed branch of a conditional subexpression, which used
617        tail recursion to cut down on stack usage. Unfortunately, now that there is
618        the possibility of (*THEN) occurring in these branches, tail recursion is
619        no longer possible because the return has to be checked for (*THEN). These
620        two optimizations have therefore been removed. [But see 8.20/11 above.]
622    18. If a pattern containing \R was studied, it was assumed that \R always
623        matched two bytes, thus causing the minimum subject length to be
624        incorrectly computed because \R can also match just one byte.
626    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
627        was incorrectly computed.
629    20. If /S is present twice on a test pattern in pcretest input, it now
630        *disables* studying, thereby overriding the use of -s on the command line
631        (see 14 above). This is necessary for one or two tests to keep the output
632        identical in both cases.
634    21. When (*ACCEPT) was used in an assertion that matched an empty string and
635        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
637    22. When an atomic group that contained a capturing parenthesis was
638        successfully matched, but the branch in which it appeared failed, the
639        capturing was not being forgotten if a higher numbered group was later
640        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
641        group 1 to "a", when in fact it should be unset. This applied to multi-
642        branched capturing and non-capturing groups, repeated or not, and also to
643        positive assertions (capturing in negative assertions does not happen
644        in PCRE) and also to nested atomic groups.
646    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
647        subject after a captured substring, to make it easier to tell which of a
648        number of identical substrings has been captured.
650    24. The way atomic groups are processed by pcre_exec() has been changed so that
651        if they are repeated, backtracking one repetition now resets captured
652        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
653        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
654        "aaa". Previously, it would have been "a". As part of this code
655        refactoring, the way recursive calls are handled has also been changed.
657    25. If an assertion condition captured any substrings, they were not passed
658        back unless some other capturing happened later. For example, if
659        (?(?=(a))a) was matched against "a", no capturing was returned.
661    26. When studying a pattern that contained subroutine calls or assertions,
662        the code for finding the minimum length of a possible match was handling
663        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
664        group 1 called group 2 while simultaneously a separate group 2 called group
665        1). A stack overflow occurred in this case. I have fixed this by limiting
666        the recursion depth to 10.
668    27. Updated RunTest.bat in the distribution to the version supplied by Tom
669        Fortmann. This supports explicit test numbers on the command line, and has
670        argument validation and error reporting.
672    28. An instance of \X with an unlimited repeat could fail if at any point the
673        first character it looked at was a mark character.
675    29. Some minor code refactoring concerning Unicode properties and scripts
676        should reduce the stack requirement of match() slightly.
678    30. Added the '=' option to pcretest to check the setting of unused capturing
679        slots at the end of the pattern, which are documented as being -1, but are
680        not included in the return count.
682    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
683        compiled something random. Now it gives a compile-time error (as does
684        Perl).
686    32. A *MARK encountered during the processing of a positive assertion is now
687        recorded and passed back (compatible with Perl).
689    33. If --only-matching or --colour was set on a pcregrep call whose pattern
690        had alternative anchored branches, the search for a second match in a line
691        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
692        matched the line "0102" twice. The same bug affected patterns that started
693        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
694        twice.
696    34. Previously, PCRE did not allow quantification of assertions. However, Perl
697        does, and because of capturing effects, quantifying parenthesized
698        assertions may at times be useful. Quantifiers are now allowed for
699        parenthesized assertions.
701    35. A minor code tidy in pcre_compile() when checking options for \R usage.
703    36. \g was being checked for fancy things in a character class, when it should
704        just be a literal "g".
706    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
707        appearance of a nested POSIX class supersedes an apparent external class.
708        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
709        unescaped square brackets may also appear as part of class names. For
710        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
711        more like Perl. (But see 8.20/1 above.)
713    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
714        was because it thought it was \N{name}, which is not supported).
716    39. Add minix to OS list not supporting the -S option in pcretest.
718    40. PCRE tries to detect cases of infinite recursion at compile time, but it
719        cannot analyze patterns in sufficient detail to catch mutual recursions
720        such as ((?1))((?2)). There is now a runtime test that gives an error if a
721        subgroup is called recursively as a subpattern for a second time at the
722        same position in the subject string. In previous releases this might have
723        been caught by the recursion limit, or it might have run out of stack.
725    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
726        happen only once. PCRE was, however incorrectly giving a compile time error
727        "recursive call could loop indefinitely" because it cannot analyze the
728        pattern in sufficient detail. The compile time test no longer happens when
729        PCRE is compiling a conditional subpattern, but actual runaway loops are
730        now caught at runtime (see 40 above).
732    42. It seems that Perl allows any characters other than a closing parenthesis
733        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
734        has been changed to be the same.
736    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
737        as not to get warnings when autogen.sh is called. Also changed
738        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
740    44. To help people who use pcregrep to scan files containing exceedingly long
741        lines, the following changes have been made:
743        (a) The default value of the buffer size parameter has been increased from
744            8K to 20K. (The actual buffer used is three times this size.)
746        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
747            PCRE is built.
749        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
750            to be set at run time.
752        (d) Numerical values in pcregrep options can be followed by K or M, for
753            example --buffer-size=50K.
755        (e) If a line being scanned overflows pcregrep's buffer, an error is now
756            given and the return code is set to 2.
758    45. Add a pointer to the latest mark to the callout data block.
760    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
761        partial match of an empty string instead of no match. This was specific to
762        the use of ".".
764    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
765        complete match instead of a partial match. This bug was dependent on both
766        the PCRE_UTF8 and PCRE_DOTALL options being set.
768    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
769        starting byte set, because \b was not being ignored.
772    Version 8.12 15-Jan-2011
773    ------------------------
775    1.  Fixed some typos in the markup of the man pages, and wrote a script that
776        checks for such things as part of the documentation building process.
778    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
779        --match-limit and --recursion-limit options (added for 8.11). In
780        particular, this made one of the standard tests fail. (The integer value
781        went into the wrong half of a long int.)
783    3.  If the --colour option was given to pcregrep with -v (invert match), it
784        did strange things, either producing crazy output, or crashing. It should,
785        of course, ignore a request for colour when reporting lines that do not
786        match.
788    4.  Another pcregrep bug caused similar problems if --colour was specified with
789        -M (multiline) and the pattern match finished with a line ending.
791    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
792        matched in multiline mode, the following line was shown as part of the
793        match. This seems wrong, so I have changed it.
795    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
796        the check for further matches in the same line (so they could be coloured)
797        to overrun the end of the current line. If another match was found, it was
798        incorrectly shown (and then shown again when found in the next line).
800    7.  If pcregrep was compiled under Windows, there was a reference to the
801        function pcregrep_exit() before it was defined. I am assuming this was
802        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
803        reported by a user. I've moved the definition above the reference.
806    Version 8.11 10-Dec-2010
807    ------------------------
809    1.  (*THEN) was not working properly if there were untried alternatives prior
810        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
811        backtracked to try for "b" instead of moving to the next alternative branch
812        at the same level (in this case, to look for "c"). The Perl documentation
813        is clear that when (*THEN) is backtracked onto, it goes to the "next
814        alternative in the innermost enclosing group".
816    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
817        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
818        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
819        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
820        (*THEN).
822    3.  If \s appeared in a character class, it removed the VT character from
823        the class, even if it had been included by some previous item, for example
824        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
825        of \s, but is part of the POSIX "space" class.)
827    4.  A partial match never returns an empty string (because you can always
828        match an empty string at the end of the subject); however the checking for
829        an empty string was starting at the "start of match" point. This has been
830        changed to the "earliest inspected character" point, because the returned
831        data for a partial match starts at this character. This means that, for
832        example, /(?<=abc)def/ gives a partial match for the subject "abc"
833        (previously it gave "no match").
835    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
836        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
837        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
838        has an implication that the given string is incomplete (because a partial
839        match is preferred over a full match). For this reason, these items now
840        give a partial match in this situation. [Aside: previously, the one case
841        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
842        match rather than a full match, which was wrong by the old rules, but is
843        now correct.]
845    6.  There was a bug in the handling of #-introduced comments, recognized when
846        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
847        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
848        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
849        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
850        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
851        places in pcre_compile().
853    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
854        comments when looking ahead for named forward references to subpatterns,
855        the only newline sequence it recognized was NL. It now handles newlines
856        according to the set newline convention.
858    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
859        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
860        cater for a lack of strerror(). These oversights have been fixed.
862    9.  Added --match-limit and --recursion-limit to pcregrep.
864    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
866    11. When the -o option was used, pcregrep was setting a return code of 1, even
867        when matches were found, and --line-buffered was not being honoured.
869    12. Added an optional parentheses number to the -o and --only-matching options
870        of pcregrep.
872    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
873        can match an empty string. The code to do it in pcretest and pcredemo
874        needed fixing:
876        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
877            only one byte after an empty string match just before CRLF (this case
878            just got forgotten; "any" and "anycrlf" were OK).
880        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
881            mode when an empty string match preceded an ASCII character followed by
882            a non-ASCII character. (The code for advancing by one character rather
883            than one byte was nonsense.)
885        (c) The pcredemo.c sample program did not have any code at all to handle
886            the cases when CRLF is a valid newline sequence.
888    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
889        as a starting offset was within the subject string. There is now a new
890        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
891        negative or greater than the length of the string. In order to test this,
892        pcretest is extended to allow the setting of negative starting offsets.
894    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
895        starting offset points to the beginning of a UTF-8 character was
896        unnecessarily clumsy. I tidied it up.
898    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
899        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
901    17. Nobody had reported that the --include_dir option, which was added in
902        release 7.7 should have been called --include-dir (hyphen, not underscore)
903        for compatibility with GNU grep. I have changed it to --include-dir, but
904        left --include_dir as an undocumented synonym, and the same for
905        --exclude-dir, though that is not available in GNU grep, at least as of
906        release 2.5.4.
908    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
909        characters from a string of bytes) have been redefined so as not to use
910        loops, in order to improve performance in some environments. At the same
911        time, I abstracted some of the common code into auxiliary macros to save
912        repetition (this should not affect the compiled code).
914    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
915        compile-time error is now given if \c is not followed by an ASCII
916        character, that is, a byte less than 128. (In EBCDIC mode, the code is
917        different, and any byte value is allowed.)
919    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
920        START_OPTIMIZE option, which is now allowed at compile time - but just
921        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
922        to pcregrep and other applications that have no direct access to PCRE
923        options. The new /Y option in pcretest sets this option when calling
924        pcre_compile().
926    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
927        back references. Groups containing recursive back references were forced to
928        be atomic by that change, but in the case of named groups, the amount of
929        memory required was incorrectly computed, leading to "Failed: internal
930        error: code overflow". This has been fixed.
932    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
933        pcretest.c, to avoid build problems in some Borland environments.
936    Version 8.10 25-Jun-2010
937    ------------------------
939    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
940        THEN.
942    2.  (*ACCEPT) was not working when inside an atomic group.
944    3.  Inside a character class, \B is treated as a literal by default, but
945        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
946        causes the error). The code is unchanged, but I tidied the documentation.
948    4.  Inside a character class, PCRE always treated \R and \X as literals,
949        whereas Perl faults them if its -w option is set. I have changed PCRE so
950        that it faults them when PCRE_EXTRA is set.
952    5.  Added support for \N, which always matches any character other than
953        newline. (It is the same as "." when PCRE_DOTALL is not set.)
955    6.  When compiling pcregrep with newer versions of gcc which may have
956        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
957        declared with attribute warn_unused_result" were given. Just casting the
958        result to (void) does not stop the warnings; a more elaborate fudge is
959        needed. I've used a macro to implement this.
961    7.  Minor change to pcretest.c to avoid a compiler warning.
963    8.  Added four artifical Unicode properties to help with an option to make
964        \s etc use properties (see next item). The new properties are: Xan
965        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
967    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
968        use Unicode properties. (*UCP) at the start of a pattern can be used to set
969        this option. Modified pcretest to add /W to test this facility. Added
970        REG_UCP to make it available via the POSIX interface.
972    10. Added --line-buffered to pcregrep.
974    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
975        studied, and the match started with a letter with a code point greater than
976        127 whose first byte was different to the first byte of the other case of
977        the letter, the other case of this starting letter was not recognized
978        (#976).
980    12. If a pattern that was studied started with a repeated Unicode property
981        test, for example, \p{Nd}+, there was the theoretical possibility of
982        setting up an incorrect bitmap of starting bytes, but fortunately it could
983        not have actually happened in practice until change 8 above was made (it
984        added property types that matched character-matching opcodes).
986    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
987        possible starting bytes for non-anchored patterns.
989    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
990        \R, and also a number of cases that involve Unicode properties, both
991        explicit and implicit when PCRE_UCP is set.
993    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
994        input, it could crash or give wrong results if characters with values
995        greater than 0xc0 were present in the subject string. (Detail: it assumed
996        UTF-8 input when processing these items.)
998    16. Added a lot of (int) casts to avoid compiler warnings in systems where
999        size_t is 64-bit (#991).
1001    17. Added a check for running out of memory when PCRE is compiled with
1002        --disable-stack-for-recursion (#990).
1004    18. If the last data line in a file for pcretest does not have a newline on
1005        the end, a newline was missing in the output.
1007    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1008        less than 128) in its various bitmaps. However, there is a facility for
1009        generating tables according to the current locale when PCRE is compiled. It
1010        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1011        characters, are recognized by isspace() and therefore were getting set in
1012        these tables, and indeed these tables seem to approximate to ISO 8859. This
1013        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1014        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1015        which of course cannot start UTF-8 characters. I have changed the code so
1016        that only real ASCII characters (less than 128) and the correct starting
1017        bytes for UTF-8 encodings are set for characters greater than 127 when in
1018        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1019        altogether.)
1021    20. Added the /T option to pcretest so as to be able to run tests with non-
1022        standard character tables, thus making it possible to include the tests
1023        used for 19 above in the standard set of tests.
1025    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1026        reference to a subpattern the other side of a comment that contains an
1027        opening parenthesis caused either an internal compiling error, or a
1028        reference to the wrong subpattern.
1031    Version 8.02 19-Mar-2010
1032    ------------------------
1034    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1036    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1037        configured.
1039    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1040        original author of that file, following a query about its status.
1042    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1043        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1045    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1046        quantifier applied to a forward-referencing subroutine call, could compile
1047        incorrect code or give the error "internal error: previously-checked
1048        referenced subpattern not found".
1050    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1051        variables to point to external functions. For these systems, therefore,
1052        pcre_malloc etc. are now initialized to local functions that call the
1053        relevant global functions.
1055    7.  There were two entries missing in the vectors called coptable and poptable
1056        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1057        I've fixed the data, and added a kludgy way of testing at compile time that
1058        the lengths are correct (equal to the number of opcodes).
1060    8.  Following on from 7, I added a similar kludge to check the length of the
1061        eint vector in pcreposix.c.
1063    9.  Error texts for pcre_compile() are held as one long string to avoid too
1064        much relocation at load time. To find a text, the string is searched,
1065        counting zeros. There was no check for running off the end of the string,
1066        which could happen if a new error number was added without updating the
1067        string.
1069    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1071    11. \K was not working if it appeared in an atomic group or in a group that
1072        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1073        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1074        the assertion is positive, but not if it is negative.
1076    12. Change 11 fortuitously reduced the size of the stack frame used in the
1077        "match()" function of pcre_exec.c by one pointer. Forthcoming
1078        implementation of support for (*MARK) will need an extra pointer on the
1079        stack; I have reserved it now, so that the stack frame size does not
1080        decrease.
1082    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1083        item in branch that calls a recursion is a subroutine call - as in the
1084        second branch in the above example - was incorrectly given the compile-
1085        time error "recursive call could loop indefinitely" because pcre_compile()
1086        was not correctly checking the subroutine for matching a non-empty string.
1088    14. The checks for overrunning compiling workspace could trigger after an
1089        overrun had occurred. This is a "should never occur" error, but it can be
1090        triggered by pathological patterns such as hundreds of nested parentheses.
1091        The checks now trigger 100 bytes before the end of the workspace.
1093    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1096    Version 8.01 19-Jan-2010
1097    ------------------------
1099    1.  If a pattern contained a conditional subpattern with only one branch (in
1100        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1101        computed the wrong minimum data length (which is of course zero for such
1102        subpatterns). This could cause incorrect "no match" results.
1104    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1105        the pattern is reset in the first branch, pcre_compile() failed with
1106        "internal error: code overflow at offset...". This happened only when
1107        the reset was to the original external option setting. (An optimization
1108        abstracts leading options settings into an external setting, which was the
1109        cause of this.)
1111    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1112        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1113        assertion pattern did not match (meaning that the assertion was true), it
1114        was incorrectly treated as false if the SKIP had been reached during the
1115        matching. This also applied to assertions used as conditions.
1117    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1118        assertion subpattern, including such a pattern used as a condition,
1119        unpredictable results occurred, instead of the error return
1122    5.  The C++ GlobalReplace function was not working like Perl for the special
1123        situation when an empty string is matched. It now does the fancy magic
1124        stuff that is necessary.
1126    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1127        removed. (These were left over from very, very early versions of PCRE.)
1129    7.  Some cosmetic changes to the code to make life easier when compiling it
1130        as part of something else:
1132        (a) Change DEBUG to PCRE_DEBUG.
1134        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1135            called "current" as "current_branch", to prevent a collision with the
1136            Linux macro when compiled as a kernel module.
1138        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1139            prevent a collision with the Linux macro when compiled as a kernel
1140            module.
1142    8.  In pcre_compile() there are some checks for integer overflows that used to
1143        cast potentially large values to (double). This has been changed to that
1144        when building, a check for int64_t is made, and if it is found, it is used
1145        instead, thus avoiding the use of floating point arithmetic. (There is no
1146        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1147        double.
1149    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1150        2005 (difference between two addresses compared to an unsigned value).
1152    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1153        custom one, because of the following reported problem in Windows:
1155          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1156              under Win32.
1157          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1158              therefore missing the function definition.
1159          - The compiler thus generates a "C" signature for the test function.
1160          - The linker fails to find the "C" function.
1161          - PCRE fails to configure if asked to do so against libbz2.
1163    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1164        messages were output:
1166          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1167          rerunning libtoolize, to keep the correct libtool macros in-tree.
1168          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1170        I have done both of these things.
1172    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1173        most of the time, it *can* run out if it is given a pattern that contains a
1174        runaway infinite recursion. I updated the discussion in the pcrestack man
1175        page.
1177    13. Now that we have gone to the x.xx style of version numbers, the minor
1178        version may start with zero. Using 08 or 09 is a bad idea because users
1179        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1180        interpreted as invalid octal numbers. I've updated the previous comment in
1181        configure.ac, and also added a check that gives an error if 08 or 09 are
1182        used.
1184    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1185        causing partial matching to fail when the end of the subject matched \W
1186        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1188    15. There were some discrepancies between the declarations in pcre_internal.h
1189        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1190        their definitions. The declarations used "const uschar *" and the
1191        definitions used USPTR. Even though USPTR is normally defined as "const
1192        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1193        reported that: "This difference in casting confuses some C++ compilers, for
1194        example, SunCC recognizes above declarations as different functions and
1195        generates broken code for hbpcre." I have changed the declarations to use
1196        USPTR.
1198    16. GNU libtool is named differently on some systems. The autogen.sh script now
1199        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1200        (FreeBSD).
1202    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1203        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1204        comment: "Figure out how to create a longlong from a string: strtoll and
1205        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1206        instance, but it only takes 2 args instead of 3!"
1208    18. A subtle bug concerned with back references has been fixed by a change of
1209        specification, with a corresponding code fix. A pattern such as
1210        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1211        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1212        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1213        same bug. Such groups have to be quantified to be useful, or contained
1214        inside another quantified group. (If there's no repetition, the reference
1215        can never match.) The problem arises because, having left the group and
1216        moved on to the rest of the pattern, a later failure that backtracks into
1217        the group uses the captured value from the final iteration of the group
1218        rather than the correct earlier one. I have fixed this in PCRE by forcing
1219        any group that contains a reference to itself to be an atomic group; that
1220        is, there cannot be any backtracking into it once it has completed. This is
1221        similar to recursive and subroutine calls.
1224    Version 8.00 19-Oct-09
1225    ----------------------
1227    1.  The table for translating pcre_compile() error codes into POSIX error codes
1228        was out-of-date, and there was no check on the pcre_compile() error code
1229        being within the table. This could lead to an OK return being given in
1230        error.
1232    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1233        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1234        in a Windows environment.
1236    3.  The pcregrep --count option prints the count for each file even when it is
1237        zero, as does GNU grep. However, pcregrep was also printing all files when
1238        --files-with-matches was added. Now, when both options are given, it prints
1239        counts only for those files that have at least one match. (GNU grep just
1240        prints the file name in this circumstance, but including the count seems
1241        more useful - otherwise, why use --count?) Also ensured that the
1242        combination -clh just lists non-zero counts, with no names.
1244    4.  The long form of the pcregrep -F option was incorrectly implemented as
1245        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1246        but it seems right to fix it, and I didn't think it was worth preserving
1247        the old behaviour.
1249    5.  The command line items --regex=pattern and --regexp=pattern were not
1250        recognized by pcregrep, which required --regex pattern or --regexp pattern
1251        (with a space rather than an '='). The man page documented the '=' forms,
1252        which are compatible with GNU grep; these now work.
1254    6.  No libpcreposix.pc file was created for pkg-config; there was just
1255        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1257    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1258        when UCP support is not needed, by modifying the Python script that
1259        generates it from Unicode data files. This should not matter if the module
1260        is correctly used as a library, but I received one complaint about 50K of
1261        unwanted data. My guess is that the person linked everything into his
1262        program rather than using a library. Anyway, it does no harm.
1264    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1265        was a minimum greater than 1 for a wide character in a possessive
1266        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1267        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1268        character. Chaos in the form of incorrect output or a compiling loop could
1269        result.
1271    9.  The restrictions on what a pattern can contain when partial matching is
1272        requested for pcre_exec() have been removed. All patterns can now be
1273        partially matched by this function. In addition, if there are at least two
1274        slots in the offset vector, the offset of the earliest inspected character
1275        for the match and the offset of the end of the subject are set in them when
1276        PCRE_ERROR_PARTIAL is returned.
1278    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1279        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1280        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1281        and may be more useful for multi-segment matching.
1283    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1284        used to be given if ever the end of the subject was reached; now it is
1285        given only if matching could not proceed because another character was
1286        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1287        string "Z", which now yields "no match" instead of "partial match". In the
1288        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1289        final character ended with (*FAIL).
1291    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1292        if the pattern had a "must contain" character that was already found in the
1293        earlier partial match, unless partial matching was again requested. For
1294        example, with the pattern /dog.(body)?/, the "must contain" character is
1295        "g". If the first part-match was for the string "dog", restarting with
1296        "sbody" failed. This bug has been fixed.
1298    13. The string returned by pcre_dfa_exec() after a partial match has been
1299        changed so that it starts at the first inspected character rather than the
1300        first character of the match. This makes a difference only if the pattern
1301        starts with a lookbehind assertion or \b or \B (\K is not supported by
1302        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1303        matching functions compatible, and I think it's the right thing to do.
1305    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1306        so that the demonstration program is easily available in environments where
1307        PCRE has not been installed from source.
1309    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1310        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1311        library.
1313    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1314        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1315        is not the first non-POSIX option to be added. Clearly some people find
1316        these options useful.
1318    17. If a caller to the POSIX matching function regexec() passes a non-zero
1319        value for nmatch with a NULL value for pmatch, the value of
1320        nmatch is forced to zero.
1322    18. RunGrepTest did not have a test for the availability of the -u option of
1323        the diff command, as RunTest does. It now checks in the same way as
1324        RunTest, and also checks for the -b option.
1326    19. If an odd number of negated classes containing just a single character
1327        interposed, within parentheses, between a forward reference to a named
1328        subpattern and the definition of the subpattern, compilation crashed with
1329        an internal error, complaining that it could not find the referenced
1330        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1331        [The bug was that it was starting one character too far in when skipping
1332        over the character class, thus treating the ] as data rather than
1333        terminating the class. This meant it could skip too much.]
1335    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1336        /g option in pcretest when the pattern contains \K, which makes it possible
1337        to have an empty string match not at the start, even when the pattern is
1338        anchored. Updated pcretest and pcredemo to use this option.
1340    21. If the maximum number of capturing subpatterns in a recursion was greater
1341        than the maximum at the outer level, the higher number was returned, but
1342        with unset values at the outer level. The correct (outer level) value is
1343        now given.
1345    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1346        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1347        make it do so. The string so far is captured, making this feature
1348        compatible with Perl.
1350    23. The tests have been re-organized, adding tests 11 and 12, to make it
1351        possible to check the Perl 5.10 features against Perl 5.10.
1353    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1354        pattern matches a fixed length string. PCRE did not allow this; now it
1355        does. Neither allows recursion.
1357    25. I finally figured out how to implement a request to provide the minimum
1358        length of subject string that was needed in order to match a given pattern.
1359        (It was back references and recursion that I had previously got hung up
1360        on.) This code has now been added to pcre_study(); it finds a lower bound
1361        to the length of subject needed. It is not necessarily the greatest lower
1362        bound, but using it to avoid searching strings that are too short does give
1363        some useful speed-ups. The value is available to calling programs via
1364        pcre_fullinfo().
1366    26. While implementing 25, I discovered to my embarrassment that pcretest had
1367        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1368        study optimizations had never been tested with that matching function.
1369        Oops. What is worse, even when it was passed study data, there was a bug in
1370        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1371        were also very few tests of studied patterns with pcre_dfa_exec().
1373    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1374        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1375        on the other side of the coin, they are no longer allowed to have different
1376        names, because these cannot be distinguished in PCRE, and this has caused
1377        confusion. (This is a difference from Perl.)
1379    28. When duplicate subpattern names are present (necessarily with different
1380        numbers, as required by 27 above), and a test is made by name in a
1381        conditional pattern, either for a subpattern having been matched, or for
1382        recursion in such a pattern, all the associated numbered subpatterns are
1383        tested, and the overall condition is true if the condition is true for any
1384        one of them. This is the way Perl works, and is also more like the way
1385        testing by number works.
1388    Version 7.9 11-Apr-09
1389    ---------------------
1391    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1392        (pcretest), all targets were linked against these libraries. This included
1393        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1394        libraries. This caused unwanted dependencies to be created. This problem
1395        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1396        pcretest is linked with readline.
1398    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1399        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1400        moved outside it again, because FALSE and TRUE are already defined in AIX,
1401        but BOOL is not.
1403    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1404        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1406    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1407        hyphens) following file names and line numbers when outputting matching
1408        lines. This is not true; no spaces are inserted. I have also clarified the
1409        wording for the --colour (or --color) option.
1411    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1412        was not coloured; this is different to GNU grep, so I have changed it to be
1413        the same.
1415    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1416        each matching line was coloured. Now it goes on to look for further matches
1417        of any of the test patterns, which is the same behaviour as GNU grep.
1419    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1420        doesn't make sense to accept an empty string match in pcregrep, so I have
1421        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1422        seems to be how GNU grep behaves.
1424    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1425        start or after a newline", because the conditional assertion was not being
1426        correctly handled. The rule now is that both the assertion and what follows
1427        in the first alternative must satisfy the test.
1429    9.  If auto-callout was enabled in a pattern with a conditional group whose
1430        condition was an assertion, PCRE could crash during matching, both with
1431        pcre_exec() and pcre_dfa_exec().
1433    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1434        used for matching.
1436    11. Unicode property support in character classes was not working for
1437        characters (bytes) greater than 127 when not in UTF-8 mode.
1439    12. Added the -M command line option to pcretest.
1441    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1443    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1445    16. Added comments and documentation about mis-use of no_arg in the C++
1446        wrapper.
1448    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1449        from Martin Jerabek that uses macro names for all relevant character and
1450        string constants.
1452    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1453        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1454        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1455        these, but not everybody uses configure.
1457    19. A conditional group that had only one branch was not being correctly
1458        recognized as an item that could match an empty string. This meant that an
1459        enclosing group might also not be so recognized, causing infinite looping
1460        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1461        with the subject "ab", where knowledge that the repeated group can match
1462        nothing is needed in order to break the loop.
1464    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1465        exec(), but without supplying a callout function, matching went wrong.
1467    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1468        leak if the size of the offset vector was greater than 30. When the vector
1469        is smaller, the saved offsets during recursion go onto a local stack
1470        vector, but for larger vectors malloc() is used. It was failing to free
1471        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1472        error, in fact).
1474    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1475        heapframe that is used only when UTF-8 support is enabled. This caused no
1476        problem, but was untidy.
1478    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1479        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1480        included within another project.
1482    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1483        slightly modified by me:
1485          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1486              not building pcregrep.
1488          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1489              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1491    25. Forward references, both numeric and by name, in patterns that made use of
1492        duplicate group numbers, could behave incorrectly or give incorrect errors,
1493        because when scanning forward to find the reference group, PCRE was not
1494        taking into account the duplicate group numbers. A pattern such as
1495        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1497    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1498        the feature of a custom pointer more persuasive (as requested by a user).
1500    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1501        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1502        pre-defined.
1504    28. Added support for (*UTF8) at the start of a pattern.
1506    29. Arrange for flags added by the "release type" setting in CMake to be shown
1507        in the configuration summary.
1510    Version 7.8 05-Sep-08
1511  ---------------------  ---------------------
1513  1.  Replaced UCP searching code with optimized version as implemented for Ad  1.  Replaced UCP searching code with optimized version as implemented for Ad
# Line 13  Version 8.0 02 Jul-08 Line 1519  Version 8.0 02 Jul-08
1520  2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more  2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1521      scripts.      scripts.
1523  3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained  3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1524      a group with a zero qualifier. The result of the study could be incorrect,      a group with a zero qualifier. The result of the study could be incorrect,
1525      or the function might crash, depending on the pattern.      or the function might crash, depending on the pattern.
1527    4.  Caseless matching was not working for non-ASCII characters in back
1528        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1529        It now works when Unicode Property Support is available.
1531    5.  In pcretest, an escape such as \x{de} in the data was always generating
1532        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1533        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1534        truncation.
1536    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1538    7.  Added two (int) casts to pcregrep when printing the difference of two
1539        pointers, in case they are 64-bit values.
1541    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1542        test 2 if it fails.
1544    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1545        and a #define of that name to empty if it is not externally set. This is to
1546        allow users of MSVC to set it if necessary.
1548    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1549        the convenience functions in the pcre_get.c source file.
1551    11. An option change at the start of a pattern that had top-level alternatives
1552        could cause overwriting and/or a crash. This command provoked a crash in
1553        some environments:
1555          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1557        This potential security problem was recorded as CVE-2008-2371.
1559    12. For a pattern where the match had to start at the beginning or immediately
1560        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1561        pcre_dfa_exec() could read past the end of the passed subject if there was
1562        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1563        pcretest so that it places the subject at the end of its malloc-ed buffer.
1565    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1566        exec() might read past the end of the data buffer in UTF-8 mode.
1568    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1569        the data contained the byte 0x85 as part of a UTF-8 character within its
1570        first line. This applied both to normal and DFA matching.
1572    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1573        /^[^d]*?$/8 failed to match "abc".
1575    16. Added a missing copyright notice to pcrecpp_internal.h.
1577    17. Make it more clear in the documentation that values returned from
1578        pcre_exec() in ovector are byte offsets, not character counts.
1580    18. Tidied a few places to stop certain compilers from issuing warnings.
1582    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1583        supplied by Stefan Weber. I made a further small update for 7.8 because
1584        there is a change of source arrangements: the pcre_searchfuncs.c module is
1585        replaced by pcre_ucd.c.
1588  Version 7.7 07-May-08  Version 7.7 07-May-08

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