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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.9 xx-xxx-09  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.
63    Version 8.31 06-July-2012
64    -------------------------
66    1.  Fixing a wrong JIT test case and some compiler warnings.
68    2.  Removed a bashism from the RunTest script.
70    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
71        to unsigned type, result still unsigned" that was given by an MS compiler
72        on encountering the code "-sizeof(xxx)".
74    4.  Partial matching support is added to the JIT compiler.
76    5.  Fixed several bugs concerned with partial matching of items that consist
77        of more than one character:
79        (a) /^(..)\1/ did not partially match "aba" because checking references was
80            done on an "all or nothing" basis. This also applied to repeated
81            references.
83        (b) \R did not give a hard partial match if \r was found at the end of the
84            subject.
86        (c) \X did not give a hard partial match after matching one or more
87            characters at the end of the subject.
89        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
90            a partial match for the string "\r".
92        (e) When newline was set to CRLF, the metacharacter "." did not recognize
93            a partial match for a CR character at the end of the subject string.
95    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
96        running pcretest, the text "(JIT)" added to the output whenever JIT is
97        actually used to run the match.
99    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
100        or /S+[+] with a digit between 1 and 7.
102    8.  OP_NOT now supports any UTF character not just single-byte ones.
104    9.  (*MARK) control verb is now supported by the JIT compiler.
106    10. The command "./RunTest list" lists the available tests without actually
107        running any of them. (Because I keep forgetting what they all are.)
111    12. Applied a (slightly modified) user-supplied patch that improves performance
112        when the heap is used for recursion (compiled with --disable-stack-for-
113        recursion). Instead of malloc and free for each heap frame each time a
114        logical recursion happens, frames are retained on a chain and re-used where
115        possible. This sometimes gives as much as 30% improvement.
117    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
118        call.
120    14. As documented, (*COMMIT) is now confined to within a positive assertion.
122    15. It is now possible to link pcretest with libedit as an alternative to
123        libreadline.
125    16. (*COMMIT) control verb is now supported by the JIT compiler.
127    17. The Unicode data tables have been updated to Unicode 6.1.0.
129    18. Added --file-list option to pcregrep.
131    19. Added binary file support to pcregrep, including the -a, --binary-files,
132        -I, and --text options.
134    20. The madvise function is renamed for posix_madvise for QNX compatibility
135        reasons. Fixed by Giuseppe D'Angelo.
137    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
139    22. Changed the option for creating symbolic links for 16-bit man pages from
140        -s to -sf so that re-installing does not cause issues.
142    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
144    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
145        matches in certain environments (the workspace was not being correctly
146        retained). Also added to pcre_dfa_exec() a simple plausibility check on
147        some of the workspace data at the beginning of a restart.
149    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
150        was not doing so when it should - probably a typo introduced by SVN 528
151        (change 8.10/14).
153    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
154        \w+ when the character tables indicated that \x{c4} was a word character.
155        There were several related cases, all because the tests for doing a table
156        lookup were testing for characters less than 127 instead of 255.
158    27. If a pattern contains capturing parentheses that are not used in a match,
159        their slots in the ovector are set to -1. For those that are higher than
160        any matched groups, this happens at the end of processing. In the case when
161        there were back references that the ovector was too small to contain
162        (causing temporary malloc'd memory to be used during matching), and the
163        highest capturing number was not used, memory off the end of the ovector
164        was incorrectly being set to -1. (It was using the size of the temporary
165        memory instead of the true size.)
167    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
168        ovector size, it uses memory at the end of the block that it has got.
170    29. Check for an overlong MARK name and give an error at compile time. The
171        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
173    30. JIT compiler update.
175    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
176        Rill for the patch.
178    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
180    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
182    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
183        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
184        was enabled.
186    35. Improve JIT code generation for greedy plus quantifier.
188    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
189        1 to "aa" instead of to an empty string. The bug affected repeated groups
190        that could potentially match an empty string.
192    37. Optimizing single character iterators in JIT.
194    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
195        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
196        codepoints that are too big for the mode are faulted, and in a UTF mode,
197        disallowed codepoints are also faulted.
199    39. If PCRE was compiled with UTF support, in three places in the DFA
200        matcher there was code that should only have been obeyed in UTF mode, but
201        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
202        processing when bytes with values greater than 127 were present. In 16-bit
203        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
204        both cases the values are those that cannot be the first data item in a UTF
205        character. The three items that might have provoked this were recursions,
206        possessively repeated groups, and atomic groups.
208    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
209        and pcregrep, because some OS require shared objects to be explicitly
210        passed to ld, causing the link step to fail if they are not.
212    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
213        mode, patterns that started with \h* or \R* might be incorrectly matched.
216    Version 8.30 04-February-2012
217    -----------------------------
219    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
220        name is defined in ctype.h.
222    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
223        only in quite long subpatterns.
225    3.  Removed the function pcre_info(), which has been obsolete and deprecated
226        since it was replaced by pcre_fullinfo() in February 2000.
228    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
229        match a (*MARK), and the match failed at the start of the subject, a
230        reference to memory before the start of the subject could occur. This bug
231        was introduced by fix 17 of release 8.21.
233    5.  A reference to an unset group with zero minimum repetition was giving
234        totally wrong answers (in non-JavaScript-compatibility mode). For example,
235        /(another)?(\1?)test/ matched against "hello world test". This bug was
236        introduced in release 8.13.
238    6.  Add support for 16-bit character strings (a large amount of work involving
239        many changes and refactorings).
241    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
242        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
243        from a file.
245    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
246        rounding is not applied in this particular case).
248    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
249        if they appear, or are escaped, in patterns.
251    10. Get rid of a number of -Wunused-but-set-variable warnings.
253    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
254        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
255        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
256        also returns the mark "x". This bug applied to capturing parentheses,
257        non-capturing parentheses, and atomic parentheses. It also applied to some
258        assertions.
260    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
261        information out of configure.ac instead of relying on pcre.h.generic, which
262        is not stored in the repository.
264    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
265        -lreadline.
267    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
269    15. Applied Graycode's patch to put the top-level frame on the stack rather
270        than the heap when not using the stack for recursion. This gives a
271        performance improvement in many cases when recursion is not deep.
273    16. Experimental code added to "pcretest -C" to output the stack frame size.
276    Version 8.21 12-Dec-2011
277    ------------------------
279    1.  Updating the JIT compiler.
281    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
282        are added as well.
284    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
285        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
286        calling _pcre_jit_exec. Some extra comments are added.
288    4.  (*MARK) settings inside atomic groups that do not contain any capturing
289        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
290        was introduced by change 18 for 8.20.
292    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
293        ECMA-262 standard.
295    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
296        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
297        This bug was probably introduced by change 9 of 8.13.
299    7.  While fixing 6 above, I noticed that a number of other items were being
300        incorrectly rejected as "not fixed length". This arose partly because newer
301        opcodes had not been added to the fixed-length checking code. I have (a)
302        corrected the bug and added tests for these items, and (b) arranged for an
303        error to occur if an unknown opcode is encountered while checking for fixed
304        length instead of just assuming "not fixed length". The items that were
305        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
306        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
307        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
309    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
310        being incorrectly compiled and would have given unpredicatble results.
312    9.  A possessively repeated subpattern with minimum repeat count greater than
313        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
314        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
315        the first (A) could occur when it should not.
317    10. Add a cast and remove a redundant test from the code.
319    11. JIT should use pcre_malloc/pcre_free for allocation.
321    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
322        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
323        is anything other than /usr, -L is still shown).
325    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
327    14. Perl does not support \N without a following name in a [] class; PCRE now
328        also gives an error.
330    15. If a forward reference was repeated with an upper limit of around 2000,
331        it caused the error "internal error: overran compiling workspace". The
332        maximum number of forward references (including repeats) was limited by the
333        internal workspace, and dependent on the LINK_SIZE. The code has been
334        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
335        the default depends on LINK_SIZE. There is a new upper limit (for safety)
336        of around 200,000 forward references. While doing this, I also speeded up
337        the filling in of repeated forward references.
339    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
340        incorrectly expecting the subject to contain another "a" after the start.
342    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
343        in the match, the SKIP should be ignored. This was not happening; instead
344        the SKIP was being treated as NOMATCH. For patterns such as
345        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
346        tested.
348    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
349        now much more compatible with Perl, in particular in cases where the result
350        is a non-match for a non-anchored pattern. For example, if
351        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
352        "m", where previously it did not return a name. A side effect of this
353        change is that for partial matches, the last encountered mark name is
354        returned, as for non matches. A number of tests that were previously not
355        Perl-compatible have been moved into the Perl-compatible test files. The
356        refactoring has had the pleasing side effect of removing one argument from
357        the match() function, thus reducing its stack requirements.
359    19. If the /S+ option was used in pcretest to study a pattern using JIT,
360        subsequent uses of /S (without +) incorrectly behaved like /S+.
362    21. Retrieve executable code size support for the JIT compiler and fixing
363        some warnings.
365    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
366        not work when the shorter character appeared right at the end of the
367        subject string.
369    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
370        systems.
372    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
373        output it when the /M option is used in pcretest.
375    25. The CheckMan script was not being included in the distribution. Also, added
376        an explicit "perl" to run Perl scripts from the PrepareRelease script
377        because this is reportedly needed in Windows.
379    26. If study data was being save in a file and studying had not found a set of
380        "starts with" bytes for the pattern, the data written to the file (though
381        never used) was taken from uninitialized memory and so caused valgrind to
382        complain.
384    27. Updated RunTest.bat as provided by Sheri Pierce.
386    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
388    29. Computation of memory usage for the table of capturing group names was
389        giving an unnecessarily large value.
392    Version 8.20 21-Oct-2011
393    ------------------------
395    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
396        a POSIX class. After further experiments with Perl, which convinced me that
397        Perl has bugs and confusions, a closing square bracket is no longer allowed
398        in a POSIX name. This bug also affected patterns with classes that started
399        with full stops.
401    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
402        captured substring, but while checking the failing first alternative,
403        substring 1 is temporarily captured. If the output vector supplied to
404        pcre_exec() was not big enough for this capture, the yield of the function
405        was still zero ("insufficient space for captured substrings"). This cannot
406        be totally fixed without adding another stack variable, which seems a lot
407        of expense for a edge case. However, I have improved the situation in cases
408        such as /(a)(b)x|abc/ matched against "abc", where the return code
409        indicates that fewer than the maximum number of slots in the ovector have
410        been set.
412    3.  Related to (2) above: when there are more back references in a pattern than
413        slots in the output vector, pcre_exec() uses temporary memory during
414        matching, and copies in the captures as far as possible afterwards. It was
415        using the entire output vector, but this conflicts with the specification
416        that only 2/3 is used for passing back captured substrings. Now it uses
417        only the first 2/3, for compatibility. This is, of course, another edge
418        case.
420    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
421        main code base, and can be used by building with --enable-jit. When this is
422        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
423        runtime --no-jit option is given.
425    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
426        ovector, the return from the function was zero, implying that there were
427        other matches that did not fit. The correct "exactly full" value is now
428        returned.
430    6.  If a subpattern that was called recursively or as a subroutine contained
431        (*PRUNE) or any other control that caused it to give a non-standard return,
432        invalid errors such as "Error -26 (nested recursion at the same subject
433        position)" or even infinite loops could occur.
435    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
436        computing the minimum length on reaching *ACCEPT, and so ended up with the
437        wrong value of 1 rather than 0. Further investigation indicates that
438        computing a minimum subject length in the presence of *ACCEPT is difficult
439        (think back references, subroutine calls), and so I have changed the code
440        so that no minimum is registered for a pattern that contains *ACCEPT.
442    8.  If (*THEN) was present in the first (true) branch of a conditional group,
443        it was not handled as intended. [But see 16 below.]
445    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
446        Sheri Pierce.
448    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
449        the first byte in a match must be "a".
451    11. Change 17 for 8.13 increased the recursion depth for patterns like
452        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
453        pattern contains any instances of (*THEN). If it does not, the old
454        optimizations are restored. It would be nice to do this on a per-group
455        basis, but at the moment that is not feasible.
457    12. In some environments, the output of pcretest -C is CRLF terminated. This
458        broke RunTest's code that checks for the link size. A single white space
459        character after the value is now allowed for.
461    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
462        For "fr", it uses the Windows-specific input and output files.
464    14. If (*THEN) appeared in a group that was called recursively or as a
465        subroutine, it did not work as intended. [But see next item.]
467    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
468        pattern fragments (but not containing any | characters). If A and B are
469        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
470        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
471        D. In other words, Perl considers parentheses that do not contain any |
472        characters to be part of a surrounding alternative, whereas PCRE was
473        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
474        differently. PCRE now behaves in the same way as Perl, except in the case
475        of subroutine/recursion calls such as (?1) which have in any case always
476        been different (but PCRE had them first :-).
478    16. Related to 15 above: Perl does not treat the | in a conditional group as
479        creating alternatives. Such a group is treated in the same way as an
480        ordinary group without any | characters when processing (*THEN). PCRE has
481        been changed to match Perl's behaviour.
483    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
484        RunGrepTest script failed.
486    18. Change 22 for version 13 caused atomic groups to use more stack. This is
487        inevitable for groups that contain captures, but it can lead to a lot of
488        stack use in large patterns. The old behaviour has been restored for atomic
489        groups that do not contain any capturing parentheses.
491    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
492        suppress the check for a minimum subject length at run time. (If it was
493        given to pcre_exec() or pcre_dfa_exec() it did work.)
495    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
496        fail to work when decoding hex characters in data strings in EBCDIC
497        environments.
499    21. It appears that in at least one Mac OS environment, the isxdigit() function
500        is implemented as a macro that evaluates to its argument more than once,
501        contravening the C 90 Standard (I haven't checked a later standard). There
502        was an instance in pcretest which caused it to go wrong when processing
503        \x{...} escapes in subject strings. The has been rewritten to avoid using
504        things like p++ in the argument of isxdigit().
507    Version 8.13 16-Aug-2011
508    ------------------------
510    1.  The Unicode data tables have been updated to Unicode 6.0.0.
512    2.  Two minor typos in pcre_internal.h have been fixed.
514    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
515        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
516        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
518    4.  There were a number of related bugs in the code for matching backrefences
519        caselessly in UTF-8 mode when codes for the characters concerned were
520        different numbers of bytes. For example, U+023A and U+2C65 are an upper
521        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
522        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
523        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
524        2-byte code at the end of the subject (it thought there wasn't enough data
525        left).
527    5.  Comprehensive information about what went wrong is now returned by
528        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
529        as the output vector has at least 2 elements. The offset of the start of
530        the failing character and a reason code are placed in the vector.
532    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
533        now returned is for the first byte of the failing character, instead of the
534        last byte inspected. This is an incompatible change, but I hope it is small
535        enough not to be a problem. It makes the returned offset consistent with
536        pcre_exec() and pcre_dfa_exec().
538    7.  pcretest now gives a text phrase as well as the error number when
539        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
540        failure, the offset and reason code are output.
542    8.  When \R was used with a maximizing quantifier it failed to skip backwards
543        over a \r\n pair if the subsequent match failed. Instead, it just skipped
544        back over a single character (\n). This seems wrong (because it treated the
545        two characters as a single entity when going forwards), conflicts with the
546        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
547        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
548        has been changed.
550    9.  Some internal refactoring has changed the processing so that the handling
551        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
552        time (the PCRE_DOTALL option was changed this way some time ago: version
553        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
554        which was always a bit of a fudge. It also means that there is one less
555        argument for the match() function, which reduces its stack requirements
556        slightly. This change also fixes an incompatibility with Perl: the pattern
557        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
559    10. More internal refactoring has drastically reduced the number of recursive
560        calls to match() for possessively repeated groups such as (abc)++ when
561        using pcre_exec().
563    11. While implementing 10, a number of bugs in the handling of groups were
564        discovered and fixed:
566        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
567        (a|)*(?1) gave a compile-time internal error.
568        ((a|)+)+  did not notice that the outer group could match an empty string.
569        (^a|^)+   was not marked as anchored.
570        (.*a|.*)+ was not marked as matching at start or after a newline.
572    12. Yet more internal refactoring has removed another argument from the match()
573        function. Special calls to this function are now indicated by setting a
574        value in a variable in the "match data" data block.
576    13. Be more explicit in pcre_study() instead of relying on "default" for
577        opcodes that mean there is no starting character; this means that when new
578        ones are added and accidentally left out of pcre_study(), testing should
579        pick them up.
581    14. The -s option of pcretest has been documented for ages as being an old
582        synonym of -m (show memory usage). I have changed it to mean "force study
583        for every regex", that is, assume /S for every regex. This is similar to -i
584        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
585        using it. It makes it easier to run collections of tests with and without
586        study enabled, and thereby test pcre_study() more easily. All the standard
587        tests are now run with and without -s (but some patterns can be marked as
588        "never study" - see 20 below).
590    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
591        restoration of the capturing data to the outer values was not happening
592        correctly.
594    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
595        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
596        pattern had matched an empty string, and so incorrectly returned a no
597        match.
599    17. There was optimizing code for the last branch of non-capturing parentheses,
600        and also for the obeyed branch of a conditional subexpression, which used
601        tail recursion to cut down on stack usage. Unfortunately, now that there is
602        the possibility of (*THEN) occurring in these branches, tail recursion is
603        no longer possible because the return has to be checked for (*THEN). These
604        two optimizations have therefore been removed. [But see 8.20/11 above.]
606    18. If a pattern containing \R was studied, it was assumed that \R always
607        matched two bytes, thus causing the minimum subject length to be
608        incorrectly computed because \R can also match just one byte.
610    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
611        was incorrectly computed.
613    20. If /S is present twice on a test pattern in pcretest input, it now
614        *disables* studying, thereby overriding the use of -s on the command line
615        (see 14 above). This is necessary for one or two tests to keep the output
616        identical in both cases.
618    21. When (*ACCEPT) was used in an assertion that matched an empty string and
619        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
621    22. When an atomic group that contained a capturing parenthesis was
622        successfully matched, but the branch in which it appeared failed, the
623        capturing was not being forgotten if a higher numbered group was later
624        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
625        group 1 to "a", when in fact it should be unset. This applied to multi-
626        branched capturing and non-capturing groups, repeated or not, and also to
627        positive assertions (capturing in negative assertions does not happen
628        in PCRE) and also to nested atomic groups.
630    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
631        subject after a captured substring, to make it easier to tell which of a
632        number of identical substrings has been captured.
634    24. The way atomic groups are processed by pcre_exec() has been changed so that
635        if they are repeated, backtracking one repetition now resets captured
636        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
637        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
638        "aaa". Previously, it would have been "a". As part of this code
639        refactoring, the way recursive calls are handled has also been changed.
641    25. If an assertion condition captured any substrings, they were not passed
642        back unless some other capturing happened later. For example, if
643        (?(?=(a))a) was matched against "a", no capturing was returned.
645    26. When studying a pattern that contained subroutine calls or assertions,
646        the code for finding the minimum length of a possible match was handling
647        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
648        group 1 called group 2 while simultaneously a separate group 2 called group
649        1). A stack overflow occurred in this case. I have fixed this by limiting
650        the recursion depth to 10.
652    27. Updated RunTest.bat in the distribution to the version supplied by Tom
653        Fortmann. This supports explicit test numbers on the command line, and has
654        argument validation and error reporting.
656    28. An instance of \X with an unlimited repeat could fail if at any point the
657        first character it looked at was a mark character.
659    29. Some minor code refactoring concerning Unicode properties and scripts
660        should reduce the stack requirement of match() slightly.
662    30. Added the '=' option to pcretest to check the setting of unused capturing
663        slots at the end of the pattern, which are documented as being -1, but are
664        not included in the return count.
666    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
667        compiled something random. Now it gives a compile-time error (as does
668        Perl).
670    32. A *MARK encountered during the processing of a positive assertion is now
671        recorded and passed back (compatible with Perl).
673    33. If --only-matching or --colour was set on a pcregrep call whose pattern
674        had alternative anchored branches, the search for a second match in a line
675        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
676        matched the line "0102" twice. The same bug affected patterns that started
677        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
678        twice.
680    34. Previously, PCRE did not allow quantification of assertions. However, Perl
681        does, and because of capturing effects, quantifying parenthesized
682        assertions may at times be useful. Quantifiers are now allowed for
683        parenthesized assertions.
685    35. A minor code tidy in pcre_compile() when checking options for \R usage.
687    36. \g was being checked for fancy things in a character class, when it should
688        just be a literal "g".
690    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
691        appearance of a nested POSIX class supersedes an apparent external class.
692        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
693        unescaped square brackets may also appear as part of class names. For
694        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
695        more like Perl. (But see 8.20/1 above.)
697    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
698        was because it thought it was \N{name}, which is not supported).
700    39. Add minix to OS list not supporting the -S option in pcretest.
702    40. PCRE tries to detect cases of infinite recursion at compile time, but it
703        cannot analyze patterns in sufficient detail to catch mutual recursions
704        such as ((?1))((?2)). There is now a runtime test that gives an error if a
705        subgroup is called recursively as a subpattern for a second time at the
706        same position in the subject string. In previous releases this might have
707        been caught by the recursion limit, or it might have run out of stack.
709    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
710        happen only once. PCRE was, however incorrectly giving a compile time error
711        "recursive call could loop indefinitely" because it cannot analyze the
712        pattern in sufficient detail. The compile time test no longer happens when
713        PCRE is compiling a conditional subpattern, but actual runaway loops are
714        now caught at runtime (see 40 above).
716    42. It seems that Perl allows any characters other than a closing parenthesis
717        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
718        has been changed to be the same.
720    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
721        as not to get warnings when autogen.sh is called. Also changed
722        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
724    44. To help people who use pcregrep to scan files containing exceedingly long
725        lines, the following changes have been made:
727        (a) The default value of the buffer size parameter has been increased from
728            8K to 20K. (The actual buffer used is three times this size.)
730        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
731            PCRE is built.
733        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
734            to be set at run time.
736        (d) Numerical values in pcregrep options can be followed by K or M, for
737            example --buffer-size=50K.
739        (e) If a line being scanned overflows pcregrep's buffer, an error is now
740            given and the return code is set to 2.
742    45. Add a pointer to the latest mark to the callout data block.
744    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
745        partial match of an empty string instead of no match. This was specific to
746        the use of ".".
748    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
749        complete match instead of a partial match. This bug was dependent on both
750        the PCRE_UTF8 and PCRE_DOTALL options being set.
752    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
753        starting byte set, because \b was not being ignored.
756    Version 8.12 15-Jan-2011
757    ------------------------
759    1.  Fixed some typos in the markup of the man pages, and wrote a script that
760        checks for such things as part of the documentation building process.
762    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
763        --match-limit and --recursion-limit options (added for 8.11). In
764        particular, this made one of the standard tests fail. (The integer value
765        went into the wrong half of a long int.)
767    3.  If the --colour option was given to pcregrep with -v (invert match), it
768        did strange things, either producing crazy output, or crashing. It should,
769        of course, ignore a request for colour when reporting lines that do not
770        match.
772    4.  Another pcregrep bug caused similar problems if --colour was specified with
773        -M (multiline) and the pattern match finished with a line ending.
775    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
776        matched in multiline mode, the following line was shown as part of the
777        match. This seems wrong, so I have changed it.
779    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
780        the check for further matches in the same line (so they could be coloured)
781        to overrun the end of the current line. If another match was found, it was
782        incorrectly shown (and then shown again when found in the next line).
784    7.  If pcregrep was compiled under Windows, there was a reference to the
785        function pcregrep_exit() before it was defined. I am assuming this was
786        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
787        reported by a user. I've moved the definition above the reference.
790    Version 8.11 10-Dec-2010
791    ------------------------
793    1.  (*THEN) was not working properly if there were untried alternatives prior
794        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
795        backtracked to try for "b" instead of moving to the next alternative branch
796        at the same level (in this case, to look for "c"). The Perl documentation
797        is clear that when (*THEN) is backtracked onto, it goes to the "next
798        alternative in the innermost enclosing group".
800    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
801        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
802        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
803        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
804        (*THEN).
806    3.  If \s appeared in a character class, it removed the VT character from
807        the class, even if it had been included by some previous item, for example
808        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
809        of \s, but is part of the POSIX "space" class.)
811    4.  A partial match never returns an empty string (because you can always
812        match an empty string at the end of the subject); however the checking for
813        an empty string was starting at the "start of match" point. This has been
814        changed to the "earliest inspected character" point, because the returned
815        data for a partial match starts at this character. This means that, for
816        example, /(?<=abc)def/ gives a partial match for the subject "abc"
817        (previously it gave "no match").
819    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
820        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
821        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
822        has an implication that the given string is incomplete (because a partial
823        match is preferred over a full match). For this reason, these items now
824        give a partial match in this situation. [Aside: previously, the one case
825        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
826        match rather than a full match, which was wrong by the old rules, but is
827        now correct.]
829    6.  There was a bug in the handling of #-introduced comments, recognized when
830        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
831        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
832        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
833        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
834        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
835        places in pcre_compile().
837    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
838        comments when looking ahead for named forward references to subpatterns,
839        the only newline sequence it recognized was NL. It now handles newlines
840        according to the set newline convention.
842    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
843        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
844        cater for a lack of strerror(). These oversights have been fixed.
846    9.  Added --match-limit and --recursion-limit to pcregrep.
848    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
850    11. When the -o option was used, pcregrep was setting a return code of 1, even
851        when matches were found, and --line-buffered was not being honoured.
853    12. Added an optional parentheses number to the -o and --only-matching options
854        of pcregrep.
856    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
857        can match an empty string. The code to do it in pcretest and pcredemo
858        needed fixing:
860        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
861            only one byte after an empty string match just before CRLF (this case
862            just got forgotten; "any" and "anycrlf" were OK).
864        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
865            mode when an empty string match preceded an ASCII character followed by
866            a non-ASCII character. (The code for advancing by one character rather
867            than one byte was nonsense.)
869        (c) The pcredemo.c sample program did not have any code at all to handle
870            the cases when CRLF is a valid newline sequence.
872    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
873        as a starting offset was within the subject string. There is now a new
874        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
875        negative or greater than the length of the string. In order to test this,
876        pcretest is extended to allow the setting of negative starting offsets.
878    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
879        starting offset points to the beginning of a UTF-8 character was
880        unnecessarily clumsy. I tidied it up.
882    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
883        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
885    17. Nobody had reported that the --include_dir option, which was added in
886        release 7.7 should have been called --include-dir (hyphen, not underscore)
887        for compatibility with GNU grep. I have changed it to --include-dir, but
888        left --include_dir as an undocumented synonym, and the same for
889        --exclude-dir, though that is not available in GNU grep, at least as of
890        release 2.5.4.
892    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
893        characters from a string of bytes) have been redefined so as not to use
894        loops, in order to improve performance in some environments. At the same
895        time, I abstracted some of the common code into auxiliary macros to save
896        repetition (this should not affect the compiled code).
898    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
899        compile-time error is now given if \c is not followed by an ASCII
900        character, that is, a byte less than 128. (In EBCDIC mode, the code is
901        different, and any byte value is allowed.)
903    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
904        START_OPTIMIZE option, which is now allowed at compile time - but just
905        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
906        to pcregrep and other applications that have no direct access to PCRE
907        options. The new /Y option in pcretest sets this option when calling
908        pcre_compile().
910    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
911        back references. Groups containing recursive back references were forced to
912        be atomic by that change, but in the case of named groups, the amount of
913        memory required was incorrectly computed, leading to "Failed: internal
914        error: code overflow". This has been fixed.
916    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
917        pcretest.c, to avoid build problems in some Borland environments.
920    Version 8.10 25-Jun-2010
921    ------------------------
923    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
924        THEN.
926    2.  (*ACCEPT) was not working when inside an atomic group.
928    3.  Inside a character class, \B is treated as a literal by default, but
929        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
930        causes the error). The code is unchanged, but I tidied the documentation.
932    4.  Inside a character class, PCRE always treated \R and \X as literals,
933        whereas Perl faults them if its -w option is set. I have changed PCRE so
934        that it faults them when PCRE_EXTRA is set.
936    5.  Added support for \N, which always matches any character other than
937        newline. (It is the same as "." when PCRE_DOTALL is not set.)
939    6.  When compiling pcregrep with newer versions of gcc which may have
940        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
941        declared with attribute warn_unused_result" were given. Just casting the
942        result to (void) does not stop the warnings; a more elaborate fudge is
943        needed. I've used a macro to implement this.
945    7.  Minor change to pcretest.c to avoid a compiler warning.
947    8.  Added four artifical Unicode properties to help with an option to make
948        \s etc use properties (see next item). The new properties are: Xan
949        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
951    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
952        use Unicode properties. (*UCP) at the start of a pattern can be used to set
953        this option. Modified pcretest to add /W to test this facility. Added
954        REG_UCP to make it available via the POSIX interface.
956    10. Added --line-buffered to pcregrep.
958    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
959        studied, and the match started with a letter with a code point greater than
960        127 whose first byte was different to the first byte of the other case of
961        the letter, the other case of this starting letter was not recognized
962        (#976).
964    12. If a pattern that was studied started with a repeated Unicode property
965        test, for example, \p{Nd}+, there was the theoretical possibility of
966        setting up an incorrect bitmap of starting bytes, but fortunately it could
967        not have actually happened in practice until change 8 above was made (it
968        added property types that matched character-matching opcodes).
970    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
971        possible starting bytes for non-anchored patterns.
973    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
974        \R, and also a number of cases that involve Unicode properties, both
975        explicit and implicit when PCRE_UCP is set.
977    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
978        input, it could crash or give wrong results if characters with values
979        greater than 0xc0 were present in the subject string. (Detail: it assumed
980        UTF-8 input when processing these items.)
982    16. Added a lot of (int) casts to avoid compiler warnings in systems where
983        size_t is 64-bit (#991).
985    17. Added a check for running out of memory when PCRE is compiled with
986        --disable-stack-for-recursion (#990).
988    18. If the last data line in a file for pcretest does not have a newline on
989        the end, a newline was missing in the output.
991    19. The default pcre_chartables.c file recognizes only ASCII characters (values
992        less than 128) in its various bitmaps. However, there is a facility for
993        generating tables according to the current locale when PCRE is compiled. It
994        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
995        characters, are recognized by isspace() and therefore were getting set in
996        these tables, and indeed these tables seem to approximate to ISO 8859. This
997        caused a problem in UTF-8 mode when pcre_study() was used to create a list
998        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
999        which of course cannot start UTF-8 characters. I have changed the code so
1000        that only real ASCII characters (less than 128) and the correct starting
1001        bytes for UTF-8 encodings are set for characters greater than 127 when in
1002        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1003        altogether.)
1005    20. Added the /T option to pcretest so as to be able to run tests with non-
1006        standard character tables, thus making it possible to include the tests
1007        used for 19 above in the standard set of tests.
1009    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1010        reference to a subpattern the other side of a comment that contains an
1011        opening parenthesis caused either an internal compiling error, or a
1012        reference to the wrong subpattern.
1015    Version 8.02 19-Mar-2010
1016    ------------------------
1018    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1020    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1021        configured.
1023    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1024        original author of that file, following a query about its status.
1026    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1027        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1029    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1030        quantifier applied to a forward-referencing subroutine call, could compile
1031        incorrect code or give the error "internal error: previously-checked
1032        referenced subpattern not found".
1034    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1035        variables to point to external functions. For these systems, therefore,
1036        pcre_malloc etc. are now initialized to local functions that call the
1037        relevant global functions.
1039    7.  There were two entries missing in the vectors called coptable and poptable
1040        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1041        I've fixed the data, and added a kludgy way of testing at compile time that
1042        the lengths are correct (equal to the number of opcodes).
1044    8.  Following on from 7, I added a similar kludge to check the length of the
1045        eint vector in pcreposix.c.
1047    9.  Error texts for pcre_compile() are held as one long string to avoid too
1048        much relocation at load time. To find a text, the string is searched,
1049        counting zeros. There was no check for running off the end of the string,
1050        which could happen if a new error number was added without updating the
1051        string.
1053    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1055    11. \K was not working if it appeared in an atomic group or in a group that
1056        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1057        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1058        the assertion is positive, but not if it is negative.
1060    12. Change 11 fortuitously reduced the size of the stack frame used in the
1061        "match()" function of pcre_exec.c by one pointer. Forthcoming
1062        implementation of support for (*MARK) will need an extra pointer on the
1063        stack; I have reserved it now, so that the stack frame size does not
1064        decrease.
1066    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1067        item in branch that calls a recursion is a subroutine call - as in the
1068        second branch in the above example - was incorrectly given the compile-
1069        time error "recursive call could loop indefinitely" because pcre_compile()
1070        was not correctly checking the subroutine for matching a non-empty string.
1072    14. The checks for overrunning compiling workspace could trigger after an
1073        overrun had occurred. This is a "should never occur" error, but it can be
1074        triggered by pathological patterns such as hundreds of nested parentheses.
1075        The checks now trigger 100 bytes before the end of the workspace.
1077    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1080    Version 8.01 19-Jan-2010
1081    ------------------------
1083    1.  If a pattern contained a conditional subpattern with only one branch (in
1084        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1085        computed the wrong minimum data length (which is of course zero for such
1086        subpatterns). This could cause incorrect "no match" results.
1088    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1089        the pattern is reset in the first branch, pcre_compile() failed with
1090        "internal error: code overflow at offset...". This happened only when
1091        the reset was to the original external option setting. (An optimization
1092        abstracts leading options settings into an external setting, which was the
1093        cause of this.)
1095    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1096        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1097        assertion pattern did not match (meaning that the assertion was true), it
1098        was incorrectly treated as false if the SKIP had been reached during the
1099        matching. This also applied to assertions used as conditions.
1101    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1102        assertion subpattern, including such a pattern used as a condition,
1103        unpredictable results occurred, instead of the error return
1106    5.  The C++ GlobalReplace function was not working like Perl for the special
1107        situation when an empty string is matched. It now does the fancy magic
1108        stuff that is necessary.
1110    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1111        removed. (These were left over from very, very early versions of PCRE.)
1113    7.  Some cosmetic changes to the code to make life easier when compiling it
1114        as part of something else:
1116        (a) Change DEBUG to PCRE_DEBUG.
1118        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1119            called "current" as "current_branch", to prevent a collision with the
1120            Linux macro when compiled as a kernel module.
1122        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1123            prevent a collision with the Linux macro when compiled as a kernel
1124            module.
1126    8.  In pcre_compile() there are some checks for integer overflows that used to
1127        cast potentially large values to (double). This has been changed to that
1128        when building, a check for int64_t is made, and if it is found, it is used
1129        instead, thus avoiding the use of floating point arithmetic. (There is no
1130        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1131        double.
1133    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1134        2005 (difference between two addresses compared to an unsigned value).
1136    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1137        custom one, because of the following reported problem in Windows:
1139          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1140              under Win32.
1141          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1142              therefore missing the function definition.
1143          - The compiler thus generates a "C" signature for the test function.
1144          - The linker fails to find the "C" function.
1145          - PCRE fails to configure if asked to do so against libbz2.
1147    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1148        messages were output:
1150          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1151          rerunning libtoolize, to keep the correct libtool macros in-tree.
1152          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1154        I have done both of these things.
1156    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1157        most of the time, it *can* run out if it is given a pattern that contains a
1158        runaway infinite recursion. I updated the discussion in the pcrestack man
1159        page.
1161    13. Now that we have gone to the x.xx style of version numbers, the minor
1162        version may start with zero. Using 08 or 09 is a bad idea because users
1163        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1164        interpreted as invalid octal numbers. I've updated the previous comment in
1165        configure.ac, and also added a check that gives an error if 08 or 09 are
1166        used.
1168    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1169        causing partial matching to fail when the end of the subject matched \W
1170        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1172    15. There were some discrepancies between the declarations in pcre_internal.h
1173        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1174        their definitions. The declarations used "const uschar *" and the
1175        definitions used USPTR. Even though USPTR is normally defined as "const
1176        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1177        reported that: "This difference in casting confuses some C++ compilers, for
1178        example, SunCC recognizes above declarations as different functions and
1179        generates broken code for hbpcre." I have changed the declarations to use
1180        USPTR.
1182    16. GNU libtool is named differently on some systems. The autogen.sh script now
1183        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1184        (FreeBSD).
1186    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1187        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1188        comment: "Figure out how to create a longlong from a string: strtoll and
1189        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1190        instance, but it only takes 2 args instead of 3!"
1192    18. A subtle bug concerned with back references has been fixed by a change of
1193        specification, with a corresponding code fix. A pattern such as
1194        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1195        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1196        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1197        same bug. Such groups have to be quantified to be useful, or contained
1198        inside another quantified group. (If there's no repetition, the reference
1199        can never match.) The problem arises because, having left the group and
1200        moved on to the rest of the pattern, a later failure that backtracks into
1201        the group uses the captured value from the final iteration of the group
1202        rather than the correct earlier one. I have fixed this in PCRE by forcing
1203        any group that contains a reference to itself to be an atomic group; that
1204        is, there cannot be any backtracking into it once it has completed. This is
1205        similar to recursive and subroutine calls.
1208    Version 8.00 19-Oct-09
1209    ----------------------
1211    1.  The table for translating pcre_compile() error codes into POSIX error codes
1212        was out-of-date, and there was no check on the pcre_compile() error code
1213        being within the table. This could lead to an OK return being given in
1214        error.
1216    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1217        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1218        in a Windows environment.
1220    3.  The pcregrep --count option prints the count for each file even when it is
1221        zero, as does GNU grep. However, pcregrep was also printing all files when
1222        --files-with-matches was added. Now, when both options are given, it prints
1223        counts only for those files that have at least one match. (GNU grep just
1224        prints the file name in this circumstance, but including the count seems
1225        more useful - otherwise, why use --count?) Also ensured that the
1226        combination -clh just lists non-zero counts, with no names.
1228    4.  The long form of the pcregrep -F option was incorrectly implemented as
1229        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1230        but it seems right to fix it, and I didn't think it was worth preserving
1231        the old behaviour.
1233    5.  The command line items --regex=pattern and --regexp=pattern were not
1234        recognized by pcregrep, which required --regex pattern or --regexp pattern
1235        (with a space rather than an '='). The man page documented the '=' forms,
1236        which are compatible with GNU grep; these now work.
1238    6.  No libpcreposix.pc file was created for pkg-config; there was just
1239        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1241    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1242        when UCP support is not needed, by modifying the Python script that
1243        generates it from Unicode data files. This should not matter if the module
1244        is correctly used as a library, but I received one complaint about 50K of
1245        unwanted data. My guess is that the person linked everything into his
1246        program rather than using a library. Anyway, it does no harm.
1248    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1249        was a minimum greater than 1 for a wide character in a possessive
1250        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1251        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1252        character. Chaos in the form of incorrect output or a compiling loop could
1253        result.
1255    9.  The restrictions on what a pattern can contain when partial matching is
1256        requested for pcre_exec() have been removed. All patterns can now be
1257        partially matched by this function. In addition, if there are at least two
1258        slots in the offset vector, the offset of the earliest inspected character
1259        for the match and the offset of the end of the subject are set in them when
1260        PCRE_ERROR_PARTIAL is returned.
1262    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1263        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1264        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1265        and may be more useful for multi-segment matching.
1267    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1268        used to be given if ever the end of the subject was reached; now it is
1269        given only if matching could not proceed because another character was
1270        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1271        string "Z", which now yields "no match" instead of "partial match". In the
1272        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1273        final character ended with (*FAIL).
1275    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1276        if the pattern had a "must contain" character that was already found in the
1277        earlier partial match, unless partial matching was again requested. For
1278        example, with the pattern /dog.(body)?/, the "must contain" character is
1279        "g". If the first part-match was for the string "dog", restarting with
1280        "sbody" failed. This bug has been fixed.
1282    13. The string returned by pcre_dfa_exec() after a partial match has been
1283        changed so that it starts at the first inspected character rather than the
1284        first character of the match. This makes a difference only if the pattern
1285        starts with a lookbehind assertion or \b or \B (\K is not supported by
1286        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1287        matching functions compatible, and I think it's the right thing to do.
1289    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1290        so that the demonstration program is easily available in environments where
1291        PCRE has not been installed from source.
1293    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1294        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1295        library.
1297    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1298        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1299        is not the first non-POSIX option to be added. Clearly some people find
1300        these options useful.
1302    17. If a caller to the POSIX matching function regexec() passes a non-zero
1303        value for nmatch with a NULL value for pmatch, the value of
1304        nmatch is forced to zero.
1306    18. RunGrepTest did not have a test for the availability of the -u option of
1307        the diff command, as RunTest does. It now checks in the same way as
1308        RunTest, and also checks for the -b option.
1310    19. If an odd number of negated classes containing just a single character
1311        interposed, within parentheses, between a forward reference to a named
1312        subpattern and the definition of the subpattern, compilation crashed with
1313        an internal error, complaining that it could not find the referenced
1314        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1315        [The bug was that it was starting one character too far in when skipping
1316        over the character class, thus treating the ] as data rather than
1317        terminating the class. This meant it could skip too much.]
1319    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1320        /g option in pcretest when the pattern contains \K, which makes it possible
1321        to have an empty string match not at the start, even when the pattern is
1322        anchored. Updated pcretest and pcredemo to use this option.
1324    21. If the maximum number of capturing subpatterns in a recursion was greater
1325        than the maximum at the outer level, the higher number was returned, but
1326        with unset values at the outer level. The correct (outer level) value is
1327        now given.
1329    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1330        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1331        make it do so. The string so far is captured, making this feature
1332        compatible with Perl.
1334    23. The tests have been re-organized, adding tests 11 and 12, to make it
1335        possible to check the Perl 5.10 features against Perl 5.10.
1337    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1338        pattern matches a fixed length string. PCRE did not allow this; now it
1339        does. Neither allows recursion.
1341    25. I finally figured out how to implement a request to provide the minimum
1342        length of subject string that was needed in order to match a given pattern.
1343        (It was back references and recursion that I had previously got hung up
1344        on.) This code has now been added to pcre_study(); it finds a lower bound
1345        to the length of subject needed. It is not necessarily the greatest lower
1346        bound, but using it to avoid searching strings that are too short does give
1347        some useful speed-ups. The value is available to calling programs via
1348        pcre_fullinfo().
1350    26. While implementing 25, I discovered to my embarrassment that pcretest had
1351        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1352        study optimizations had never been tested with that matching function.
1353        Oops. What is worse, even when it was passed study data, there was a bug in
1354        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1355        were also very few tests of studied patterns with pcre_dfa_exec().
1357    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1358        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1359        on the other side of the coin, they are no longer allowed to have different
1360        names, because these cannot be distinguished in PCRE, and this has caused
1361        confusion. (This is a difference from Perl.)
1363    28. When duplicate subpattern names are present (necessarily with different
1364        numbers, as required by 27 above), and a test is made by name in a
1365        conditional pattern, either for a subpattern having been matched, or for
1366        recursion in such a pattern, all the associated numbered subpatterns are
1367        tested, and the overall condition is true if the condition is true for any
1368        one of them. This is the way Perl works, and is also more like the way
1369        testing by number works.
1372    Version 7.9 11-Apr-09
1373  ---------------------  ---------------------
1375  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 1385  Version 7.9 xx-xxx-09
1385      but BOOL is not.      but BOOL is not.
1387  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1388      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1390  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
1391      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 42  Version 7.9 xx-xxx-09 Line 1410  Version 7.9 xx-xxx-09
1410      correctly handled. The rule now is that both the assertion and what follows      correctly handled. The rule now is that both the assertion and what follows
1411      in the first alternative must satisfy the test.      in the first alternative must satisfy the test.
1413  9.  If auto-callout was enabled in a pattern with a conditional group whose  9.  If auto-callout was enabled in a pattern with a conditional group whose
1414      condition was an assertion, PCRE could crash during matching, both with      condition was an assertion, PCRE could crash during matching, both with
1415      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
# Line 64  Version 7.9 xx-xxx-09 Line 1432  Version 7.9 xx-xxx-09
1432  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1433      from Martin Jerabek that uses macro names for all relevant character and      from Martin Jerabek that uses macro names for all relevant character and
1434      string constants.      string constants.
1436  18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and  18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1437      SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without      SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1438      SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of      SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1439      these, but not everybody uses configure.      these, but not everybody uses configure.
1441  19. A conditional group that had only one branch was not being correctly  19. A conditional group that had only one branch was not being correctly
1442      recognized as an item that could match an empty string. This meant that an      recognized as an item that could match an empty string. This meant that an
1443      enclosing group might also not be so recognized, causing infinite looping      enclosing group might also not be so recognized, causing infinite looping
1444      (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$      (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1445      with the subject "ab", where knowledge that the repeated group can match      with the subject "ab", where knowledge that the repeated group can match
1446      nothing is needed in order to break the loop.      nothing is needed in order to break the loop.
1448  20. If a pattern that was compiled with callouts was matched using pcre_dfa_  20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1449      exec(), but without supplying a callout function, matching went wrong.      exec(), but without supplying a callout function, matching went wrong.
1451  21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory  21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1452      leak if the size of the offset vector was greater than 30. When the vector      leak if the size of the offset vector was greater than 30. When the vector
1453      is smaller, the saved offsets during recursion go onto a local stack      is smaller, the saved offsets during recursion go onto a local stack
1454      vector, but for larger vectors malloc() is used. It was failing to free      vector, but for larger vectors malloc() is used. It was failing to free
1455      when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"      when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1456      error, in fact).      error, in fact).
1458  22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the  22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1459      heapframe that is used only when UTF-8 support is enabled. This caused no      heapframe that is used only when UTF-8 support is enabled. This caused no
1460      problem, but was untidy.      problem, but was untidy.
1462    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1463        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1464        included within another project.
1466    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1467        slightly modified by me:
1469          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1470              not building pcregrep.
1472          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1473              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1475    25. Forward references, both numeric and by name, in patterns that made use of
1476        duplicate group numbers, could behave incorrectly or give incorrect errors,
1477        because when scanning forward to find the reference group, PCRE was not
1478        taking into account the duplicate group numbers. A pattern such as
1479        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1481    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1482        the feature of a custom pointer more persuasive (as requested by a user).
1484    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1485        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1486        pre-defined.
1488    28. Added support for (*UTF8) at the start of a pattern.
1490    29. Arrange for flags added by the "release type" setting in CMake to be shown
1491        in the configuration summary.
1494  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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