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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.13 30-Apr-2011  Version 8.34 15-December-2013
5    -----------------------------
7    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
8        executable memory. Patch inspired by Carsten Klein.
10    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
11        this macro is never tested and has no effect, because the work to support
12        coverage involves only compiling and linking options and special targets in
13        the Makefile. The comment in config.h implied that defining the macro would
14        enable coverage support, which is totally false. There was also support for
15        setting this macro in the CMake files (my fault, I just copied it from
16        configure). SUPPORT_GCOV has now been removed.
18    3.  Make a small performance improvement in strlen16() and strlen32() in
19        pcretest.
21    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
22        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
23        these cases). There was also one in pcretest.c.
25    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
27    6.  In UTF mode, the code for checking whether a group could match an empty
28        string (which is used for indefinitely repeated groups to allow for
29        breaking an infinite loop) was broken when the group contained a repeated
30        negated single-character class with a character that occupied more than one
31        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
32        UTF-8 mode). The effect was undefined: the group might or might not be
33        deemed as matching an empty string, or the program might have crashed.
35    7.  The code for checking whether a group could match an empty string was not
36        recognizing that \h, \H, \v, \V, and \R must match a character.
38    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
39        an empty string. If it can, pcretest shows this in its information output.
41    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
42        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
43        matched by pcre_exec() without using JIT:
45        (a) If the rest of the pattern did not match after a maximal run of
46            grapheme clusters, the code for backing up to try with fewer of them
47            did not always back up over a full grapheme when characters that do not
48            have the modifier quality were involved, e.g. Hangul syllables.
50        (b) If the match point in a subject started with modifier character, and
51            there was no match, the code could incorrectly back up beyond the match
52            point, and potentially beyond the first character in the subject,
53            leading to a segfault or an incorrect match result.
55    10. A conditional group with an assertion condition could lead to PCRE
56        recording an incorrect first data item for a match if no other first data
57        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
58        first data item, and therefore matched "ca" after "c" instead of at the
59        start.
61    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
62        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
64    12. The source of pcregrep now includes z/OS-specific code so that it can be
65        compiled for z/OS as part of the special z/OS distribution.
67    13. Added the -T and -TM options to pcretest.
69    14. The code in pcre_compile.c for creating the table of named capturing groups
70        has been refactored. Instead of creating the table dynamically during the
71        actual compiling pass, the information is remembered during the pre-compile
72        pass (on the stack unless there are more than 20 named groups, in which
73        case malloc() is used) and the whole table is created before the actual
74        compile happens. This has simplified the code (it is now nearly 150 lines
75        shorter) and prepared the way for better handling of references to groups
76        with duplicate names.
78    15. A back reference to a named subpattern when there is more than one of the
79        same name now checks them in the order in which they appear in the pattern.
80        The first one that is set is used for the reference. Previously only the
81        first one was inspected. This change makes PCRE more compatible with Perl.
83    16. Unicode character properties were updated from Unicode 6.3.0.
85    17. The compile-time code for auto-possessification has been refactored, based
86        on a patch by Zoltan Herczeg. It now happens after instead of during
87        compilation. The code is cleaner, and more cases are handled. The option
88        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
89        options in pcretest are provided to set it. It can also be set by
90        (*NO_AUTO_POSSESS) at the start of a pattern.
92    18. The character VT has been added to the default ("C" locale) set of
93        characters that match \s and are generally treated as white space,
94        following this same change in Perl 5.18. There is now no difference between
95        "Perl space" and "POSIX space". Whether VT is treated as white space in
96        other locales depends on the locale.
98    19. The code for checking named groups as conditions, either for being set or
99        for being recursed, has been refactored (this is related to 14 and 15
100        above). Processing unduplicated named groups should now be as fast at
101        numerical groups, and processing duplicated groups should be faster than
102        before.
104    20. Two patches to the CMake build system, by Alexander Barkov:
106          (1) Replace the "source" command by "." in CMakeLists.txt because
107              "source" is a bash-ism.
109          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
110              without these the CMake build does not work on Solaris.
112    21. Perl has changed its handling of \8 and \9. If there is no previously
113        encountered capturing group of those numbers, they are treated as the
114        literal characters 8 and 9 instead of a binary zero followed by the
115        literals. PCRE now does the same.
117    22. Following Perl, added \o{} to specify codepoints in octal, making it
118        possible to specify values greater than 0777 and also making them
119        unambiguous.
121    23. Perl now gives an error for missing closing braces after \x{... instead of
122        treating the string as literal. PCRE now does the same.
124    24. RunTest used to grumble if an inappropriate test was selected explicitly,
125        but just skip it when running all tests. This make it awkward to run ranges
126        of tests when one of them was inappropriate. Now it just skips any
127        inappropriate tests, as it always did when running all tests.
129    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
130        character types such as \d or \w, too many callouts were inserted, and the
131        data that they returned was rubbish.
133    26. In UCP mode, \s was not matching two of the characters that Perl matches,
134        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
135        were matched by \h. The code has now been refactored so that the lists of
136        the horizontal and vertical whitespace characters used for \h and \v (which
137        are defined only in one place) are now also used for \s.
139    27. Add JIT support for the 64 bit TileGX architecture.
140        Patch by Jiong Wang (Tilera Corporation).
142    28. Possessive quantifiers for classes (both explicit and automatically
143        generated) now use special opcodes instead of wrapping in ONCE brackets.
145    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
146        (because it's meaningless), this was not happening when PCRE_CASELESS was
147        set. Not wrong, but inefficient.
149    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
150        properties for \w, \d, etc) is present in a test regex. Otherwise if the
151        test contains no characters greater than 255, Perl doesn't realise it
152        should be using Unicode semantics.
154    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
155        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
156        does in Unicode mode.
158    32. Added the "forbid" facility to pcretest so that putting tests into the
159        wrong test files can sometimes be quickly detected.
161    33. There is now a limit (default 250) on the depth of nesting of parentheses.
162        This limit is imposed to control the amount of system stack used at compile
163        time. It can be changed at build time by --with-parens-nest-limit=xxx or
164        the equivalent in CMake.
166    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
167        errors. Perl warns for these when in warning mode, but PCRE has no facility
168        for giving warnings.
170    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
171        However, this was not working for (?!) because it is optimized to (*FAIL),
172        for which PCRE does not allow quantifiers. The optimization is now disabled
173        when a quantifier follows (?!). I can't see any use for this, but it makes
174        things uniform.
176    36. Perl no longer allows group names to start with digits, so I have made this
177        change also in PCRE. It simplifies the code a bit.
179    37. In extended mode, Perl ignores spaces before a + that indicates a
180        possessive quantifier. PCRE allowed a space before the quantifier, but not
181        before the possessive +. It now does.
183    38. The use of \K (reset reported match start) within a repeated possessive
184        group such as (a\Kb)*+ was not working.
186    40. Document that the same character tables must be used at compile time and
187        run time, and that the facility to pass tables to pcre_exec() and
188        pcre_dfa_exec() is for use only with saved/restored patterns.
190    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
191        features for Builds with MSVC:
193        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
194           builds). The .rc files can be used to set FileDescription and many other
195           attributes.
197        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
198           This allows higher-level build scripts which want .pdb files to avoid
199           hard-coding the exact files needed."
201    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
202        mean "start of word" and "end of word", respectively, as a transition aid.
204    43. A minimizing repeat of a class containing codepoints greater than 255 in
205        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
206        compiled to use the heap for recursion.
208    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
209        is configured.
212    Version 8.33 28-May-2013
213    ------------------------
215    1.  Added 'U' to some constants that are compared to unsigned integers, to
216        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
217        variables that are added to signed variables, to ensure the result is
218        signed and can be negated.
220    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
221        CMake config files.
223    3.  Revise the creation of config.h.generic so that all boolean macros are
224        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
225        overriding via -D on the command line possible.
227    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
228        to unsigned int is reported to make a quite noticeable speed difference in
229        a specific Windows environment. Testing on Linux did also appear to show
230        some benefit (and it is clearly not harmful). Also fixed the definition of
231        Xop which should be unsigned.
233    5.  Related to (4), changing the definition of the intermediate variable cc
234        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
235        improvements.
237    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
238        unnecessary spaces.
240    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
241        and later.
243    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
245    9.  Optimizing fast_forward_start_bits in JIT.
247    10. Adding support for callouts in JIT, and fixing some issues revealed
248        during this work. Namely:
250        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
252        (b) Minimum length was not checked before the matching is started.
254    11. The value of capture_last that is passed to callouts was incorrect in some
255        cases when there was a capture on one path that was subsequently abandoned
256        after a backtrack. Also, the capture_last value is now reset after a
257        recursion, since all captures are also reset in this case.
259    12. The interpreter no longer returns the "too many substrings" error in the
260        case when an overflowing capture is in a branch that is subsequently
261        abandoned after a backtrack.
263    13. In the pathological case when an offset vector of size 2 is used, pcretest
264        now prints out the matched string after a yield of 0 or 1.
266    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
267        Only supported by the JIT compiler at the moment.
269    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
271    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
272        offset of the starting point of the matching process, provided the offsets
273        vector is large enough.
275    17. The \A escape now records a lookbehind value of 1, though its execution
276        does not actually inspect the previous character. This is to ensure that,
277        in partial multi-segment matching, at least one character from the old
278        segment is retained when a new segment is processed. Otherwise, if there
279        are no lookbehinds in the pattern, \A might match incorrectly at the start
280        of a new segment.
282    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
284    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
285        gives some modest performance improvement in 8-bit mode.
287    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
288        be expressed in certain programming languages using Universal Character
289        Names.
291    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
292        which points out that "non characters" are not "characters that may not
293        appear in Unicode strings" but rather "characters that are reserved for
294        internal use and have only local meaning".
296    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
297        there was a conditional group that depended on an assertion, if the
298        assertion was false, the callout that immediately followed the alternation
299        in the condition was skipped when pcre_exec() was used for matching.
301    23. Allow an explicit callout to be inserted before an assertion that is the
302        condition for a conditional group, for compatibility with automatic
303        callouts, which always insert a callout at this point.
305    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
306        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
308    25. (*PRUNE) is now supported by the JIT compiler.
310    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
312    27. Fix the case where there are two or more SKIPs with arguments that may be
313        ignored.
315    28. (*SKIP) is now supported by the JIT compiler.
317    29. (*THEN) is now supported by the JIT compiler.
319    30. Update RunTest with additional test selector options.
321    31. The way PCRE handles backtracking verbs has been changed in two ways.
323        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
324        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
325        backtracking. In some cases this makes it more Perl-compatible, but Perl's
326        rather obscure rules do not always do the same thing.
328        (2) Previously, backtracking verbs were confined within assertions. This is
329        no longer the case for positive assertions, except for (*ACCEPT). Again,
330        this sometimes improves Perl compatibility, and sometimes does not.
332    32. A number of tests that were in test 2 because Perl did things differently
333        have been moved to test 1, because either Perl or PCRE has changed, and
334        these tests are now compatible.
336    32. Backtracking control verbs are now handled in the same way in JIT and
337        interpreter.
339    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
340        contained a forward subroutine reference caused a compile error.
342    34. Auto-detect and optimize limited repetitions in JIT.
344    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
345        blocking (*UTF) etc.
347    36. In the interpreter, maximizing pattern repetitions for characters and
348        character types now use tail recursion, which reduces stack usage.
350    37. The value of the max lookbehind was not correctly preserved if a compiled
351        and saved regex was reloaded on a host of different endianness.
353    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
354        of the compiled pattern block, expand the flags field from 16 to 32 bits
355        because it was almost full.
357    39. Try madvise first before posix_madvise.
359    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
360        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
361        original change locked out all matches of empty strings. This has been
362        changed so that one match of an empty string per line is recognized.
363        Subsequent searches on the same line (for colouring or for --only-matching,
364        for example) do not recognize empty strings.
366    41. Applied a user patch to fix a number of spelling mistakes in comments.
368    42. Data lines longer than 65536 caused pcretest to crash.
370    43. Clarified the data type for length and startoffset arguments for pcre_exec
371        and pcre_dfa_exec in the function-specific man pages, where they were
372        explicitly stated to be in bytes, never having been updated. I also added
373        some clarification to the pcreapi man page.
375    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
376        a segmentation fault.
379    Version 8.32 30-November-2012
380    -----------------------------
382    1.  Improved JIT compiler optimizations for first character search and single
383        character iterators.
385    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
386        Patch by Daniel Richard G.
388    3.  Single character iterator optimizations in the JIT compiler.
390    4.  Improved JIT compiler optimizations for character ranges.
392    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
393        Reported by Giuseppe D'Angelo.
395    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
396        of a line, was being set incorrectly in cases where .* appeared inside
397        atomic brackets at the start of a pattern, or where there was a subsequent
398        *PRUNE or *SKIP.
400    7.  Improved instruction cache flush for POWER/PowerPC.
401        Patch by Daniel Richard G.
403    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
404        grep:
406        (a) There is now no limit to the number of patterns to be matched.
408        (b) An error is given if a pattern is too long.
410        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
411            are now supported.
413        (d) --exclude-from and --include-from (multiple use) have been added.
415        (e) Exclusions and inclusions now apply to all files and directories, not
416            just to those obtained from scanning a directory recursively.
418        (f) Multiple uses of -f and --file-list are now supported.
420        (g) In a Windows environment, the default for -d has been changed from
421            "read" (the GNU grep default) to "skip", because otherwise the presence
422            of a directory in the file list provokes an error.
424        (h) The documentation has been revised and clarified in places.
426    9.  Improve the matching speed of capturing brackets.
428    10. Changed the meaning of \X so that it now matches a Unicode extended
429        grapheme cluster.
431    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
432        out POSIX threads when JIT support is configured.
434    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
436    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
437        structure could go wrong in environments where size_t is not the same size
438        as int.
440    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
441        set.
443    15. The EBCDIC support had decayed; later updates to the code had included
444        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
445        general tidy up of EBCDIC-related issues, and the documentation was also
446        not quite right. There is now a test that can be run on ASCII systems to
447        check some of the EBCDIC-related things (but is it not a full test).
449    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
450        in a small tidy to the code.
452    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
454    18. If the --only-matching (-o) option in pcregrep is specified multiple
455        times, each one causes appropriate output. For example, -o1 -o2 outputs the
456        substrings matched by the 1st and 2nd capturing parentheses. A separating
457        string can be specified by --om-separator (default empty).
459    19. Improving the first n character searches.
461    20. Turn case lists for horizontal and vertical white space into macros so that
462        they are defined only once.
464    21. This set of changes together give more compatible Unicode case-folding
465        behaviour for characters that have more than one other case when UCP
466        support is available.
468        (a) The Unicode property table now has offsets into a new table of sets of
469            three or more characters that are case-equivalent. The MultiStage2.py
470            script that generates these tables (the pcre_ucd.c file) now scans
471            CaseFolding.txt instead of UnicodeData.txt for character case
472            information.
474        (b) The code for adding characters or ranges of characters to a character
475            class has been abstracted into a generalized function that also handles
476            case-independence. In UTF-mode with UCP support, this uses the new data
477            to handle characters with more than one other case.
479        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
480            whose other case is greater than 256 are now correctly matched
481            caselessly. Previously, the high codepoint matched the low one, but not
482            vice versa.
484        (d) The processing of \h, \H, \v, and \ in character classes now makes use
485            of the new class addition function, using character lists defined as
486            macros alongside the case definitions of 20 above.
488        (e) Caseless back references now work with characters that have more than
489            one other case.
491        (f) General caseless matching of characters with more than one other case
492            is supported.
494    22. Unicode character properties were updated from Unicode 6.2.0
496    23. Improved CMake support under Windows. Patch by Daniel Richard G.
498    24. Add support for 32-bit character strings, and UTF-32
500    25. Major JIT compiler update (code refactoring and bugfixing).
501        Experimental Sparc 32 support is added.
503    26. Applied a modified version of Daniel Richard G's patch to create
504        pcre.h.generic and config.h.generic by "make" instead of in the
505        PrepareRelease script.
507    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
508        pcre_compile.c when checking for a zero character.
510    28. Introducing a native interface for JIT. Through this interface, the compiled
511        machine code can be directly executed. The purpose of this interface is to
512        provide fast pattern matching, so several sanity checks are not performed.
513        However, feature tests are still performed. The new interface provides
514        1.4x speedup compared to the old one.
516    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
517        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
518        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
520    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
521        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
522        the "old" RFC 2279). Instead, it ended up passing a negative length to
523        pcre_exec().
525    31. Add support for GCC's visibility feature to hide internal functions.
527    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
528        "unknown -C option" after outputting 0 or 1.
530    33. There is now support for generating a code coverage report for the test
531        suite in environments where gcc is the compiler and lcov is installed. This
532        is mainly for the benefit of the developers.
534    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
535        unaddressable using valgrind annotations, allowing valgrind to detect
536        invalid memory accesses. This is mainly for the benefit of the developers.
538    25. (*UTF) can now be used to start a pattern in any of the three libraries.
540    26. Give configure error if --enable-cpp but no C++ compiler found.
543    Version 8.31 06-July-2012
544    -------------------------
546    1.  Fixing a wrong JIT test case and some compiler warnings.
548    2.  Removed a bashism from the RunTest script.
550    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
551        to unsigned type, result still unsigned" that was given by an MS compiler
552        on encountering the code "-sizeof(xxx)".
554    4.  Partial matching support is added to the JIT compiler.
556    5.  Fixed several bugs concerned with partial matching of items that consist
557        of more than one character:
559        (a) /^(..)\1/ did not partially match "aba" because checking references was
560            done on an "all or nothing" basis. This also applied to repeated
561            references.
563        (b) \R did not give a hard partial match if \r was found at the end of the
564            subject.
566        (c) \X did not give a hard partial match after matching one or more
567            characters at the end of the subject.
569        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
570            a partial match for the string "\r".
572        (e) When newline was set to CRLF, the metacharacter "." did not recognize
573            a partial match for a CR character at the end of the subject string.
575    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
576        running pcretest, the text "(JIT)" added to the output whenever JIT is
577        actually used to run the match.
579    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
580        or /S+[+] with a digit between 1 and 7.
582    8.  OP_NOT now supports any UTF character not just single-byte ones.
584    9.  (*MARK) control verb is now supported by the JIT compiler.
586    10. The command "./RunTest list" lists the available tests without actually
587        running any of them. (Because I keep forgetting what they all are.)
591    12. Applied a (slightly modified) user-supplied patch that improves performance
592        when the heap is used for recursion (compiled with --disable-stack-for-
593        recursion). Instead of malloc and free for each heap frame each time a
594        logical recursion happens, frames are retained on a chain and re-used where
595        possible. This sometimes gives as much as 30% improvement.
597    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
598        call.
600    14. As documented, (*COMMIT) is now confined to within a positive assertion.
602    15. It is now possible to link pcretest with libedit as an alternative to
603        libreadline.
605    16. (*COMMIT) control verb is now supported by the JIT compiler.
607    17. The Unicode data tables have been updated to Unicode 6.1.0.
609    18. Added --file-list option to pcregrep.
611    19. Added binary file support to pcregrep, including the -a, --binary-files,
612        -I, and --text options.
614    20. The madvise function is renamed for posix_madvise for QNX compatibility
615        reasons. Fixed by Giuseppe D'Angelo.
617    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
619    22. Changed the option for creating symbolic links for 16-bit man pages from
620        -s to -sf so that re-installing does not cause issues.
622    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
624    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
625        matches in certain environments (the workspace was not being correctly
626        retained). Also added to pcre_dfa_exec() a simple plausibility check on
627        some of the workspace data at the beginning of a restart.
629    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
630        was not doing so when it should - probably a typo introduced by SVN 528
631        (change 8.10/14).
633    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
634        \w+ when the character tables indicated that \x{c4} was a word character.
635        There were several related cases, all because the tests for doing a table
636        lookup were testing for characters less than 127 instead of 255.
638    27. If a pattern contains capturing parentheses that are not used in a match,
639        their slots in the ovector are set to -1. For those that are higher than
640        any matched groups, this happens at the end of processing. In the case when
641        there were back references that the ovector was too small to contain
642        (causing temporary malloc'd memory to be used during matching), and the
643        highest capturing number was not used, memory off the end of the ovector
644        was incorrectly being set to -1. (It was using the size of the temporary
645        memory instead of the true size.)
647    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
648        ovector size, it uses memory at the end of the block that it has got.
650    29. Check for an overlong MARK name and give an error at compile time. The
651        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
653    30. JIT compiler update.
655    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
656        Rill for the patch.
658    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
660    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
662    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
663        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
664        was enabled.
666    35. Improve JIT code generation for greedy plus quantifier.
668    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
669        1 to "aa" instead of to an empty string. The bug affected repeated groups
670        that could potentially match an empty string.
672    37. Optimizing single character iterators in JIT.
674    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
675        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
676        codepoints that are too big for the mode are faulted, and in a UTF mode,
677        disallowed codepoints are also faulted.
679    39. If PCRE was compiled with UTF support, in three places in the DFA
680        matcher there was code that should only have been obeyed in UTF mode, but
681        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
682        processing when bytes with values greater than 127 were present. In 16-bit
683        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
684        both cases the values are those that cannot be the first data item in a UTF
685        character. The three items that might have provoked this were recursions,
686        possessively repeated groups, and atomic groups.
688    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
689        and pcregrep, because some OS require shared objects to be explicitly
690        passed to ld, causing the link step to fail if they are not.
692    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
693        mode, patterns that started with \h* or \R* might be incorrectly matched.
696    Version 8.30 04-February-2012
697    -----------------------------
699    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
700        name is defined in ctype.h.
702    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
703        only in quite long subpatterns.
705    3.  Removed the function pcre_info(), which has been obsolete and deprecated
706        since it was replaced by pcre_fullinfo() in February 2000.
708    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
709        match a (*MARK), and the match failed at the start of the subject, a
710        reference to memory before the start of the subject could occur. This bug
711        was introduced by fix 17 of release 8.21.
713    5.  A reference to an unset group with zero minimum repetition was giving
714        totally wrong answers (in non-JavaScript-compatibility mode). For example,
715        /(another)?(\1?)test/ matched against "hello world test". This bug was
716        introduced in release 8.13.
718    6.  Add support for 16-bit character strings (a large amount of work involving
719        many changes and refactorings).
721    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
722        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
723        from a file.
725    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
726        rounding is not applied in this particular case).
728    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
729        if they appear, or are escaped, in patterns.
731    10. Get rid of a number of -Wunused-but-set-variable warnings.
733    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
734        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
735        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
736        also returns the mark "x". This bug applied to capturing parentheses,
737        non-capturing parentheses, and atomic parentheses. It also applied to some
738        assertions.
740    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
741        information out of configure.ac instead of relying on pcre.h.generic, which
742        is not stored in the repository.
744    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
745        -lreadline.
747    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
749    15. Applied Graycode's patch to put the top-level frame on the stack rather
750        than the heap when not using the stack for recursion. This gives a
751        performance improvement in many cases when recursion is not deep.
753    16. Experimental code added to "pcretest -C" to output the stack frame size.
756    Version 8.21 12-Dec-2011
757    ------------------------
759    1.  Updating the JIT compiler.
761    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
762        are added as well.
764    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
765        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
766        calling _pcre_jit_exec. Some extra comments are added.
768    4.  (*MARK) settings inside atomic groups that do not contain any capturing
769        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
770        was introduced by change 18 for 8.20.
772    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
773        ECMA-262 standard.
775    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
776        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
777        This bug was probably introduced by change 9 of 8.13.
779    7.  While fixing 6 above, I noticed that a number of other items were being
780        incorrectly rejected as "not fixed length". This arose partly because newer
781        opcodes had not been added to the fixed-length checking code. I have (a)
782        corrected the bug and added tests for these items, and (b) arranged for an
783        error to occur if an unknown opcode is encountered while checking for fixed
784        length instead of just assuming "not fixed length". The items that were
785        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
786        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
787        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
789    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
790        being incorrectly compiled and would have given unpredicatble results.
792    9.  A possessively repeated subpattern with minimum repeat count greater than
793        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
794        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
795        the first (A) could occur when it should not.
797    10. Add a cast and remove a redundant test from the code.
799    11. JIT should use pcre_malloc/pcre_free for allocation.
801    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
802        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
803        is anything other than /usr, -L is still shown).
805    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
807    14. Perl does not support \N without a following name in a [] class; PCRE now
808        also gives an error.
810    15. If a forward reference was repeated with an upper limit of around 2000,
811        it caused the error "internal error: overran compiling workspace". The
812        maximum number of forward references (including repeats) was limited by the
813        internal workspace, and dependent on the LINK_SIZE. The code has been
814        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
815        the default depends on LINK_SIZE. There is a new upper limit (for safety)
816        of around 200,000 forward references. While doing this, I also speeded up
817        the filling in of repeated forward references.
819    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
820        incorrectly expecting the subject to contain another "a" after the start.
822    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
823        in the match, the SKIP should be ignored. This was not happening; instead
824        the SKIP was being treated as NOMATCH. For patterns such as
825        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
826        tested.
828    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
829        now much more compatible with Perl, in particular in cases where the result
830        is a non-match for a non-anchored pattern. For example, if
831        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
832        "m", where previously it did not return a name. A side effect of this
833        change is that for partial matches, the last encountered mark name is
834        returned, as for non matches. A number of tests that were previously not
835        Perl-compatible have been moved into the Perl-compatible test files. The
836        refactoring has had the pleasing side effect of removing one argument from
837        the match() function, thus reducing its stack requirements.
839    19. If the /S+ option was used in pcretest to study a pattern using JIT,
840        subsequent uses of /S (without +) incorrectly behaved like /S+.
842    21. Retrieve executable code size support for the JIT compiler and fixing
843        some warnings.
845    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
846        not work when the shorter character appeared right at the end of the
847        subject string.
849    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
850        systems.
852    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
853        output it when the /M option is used in pcretest.
855    25. The CheckMan script was not being included in the distribution. Also, added
856        an explicit "perl" to run Perl scripts from the PrepareRelease script
857        because this is reportedly needed in Windows.
859    26. If study data was being save in a file and studying had not found a set of
860        "starts with" bytes for the pattern, the data written to the file (though
861        never used) was taken from uninitialized memory and so caused valgrind to
862        complain.
864    27. Updated RunTest.bat as provided by Sheri Pierce.
866    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
868    29. Computation of memory usage for the table of capturing group names was
869        giving an unnecessarily large value.
872    Version 8.20 21-Oct-2011
873    ------------------------
875    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
876        a POSIX class. After further experiments with Perl, which convinced me that
877        Perl has bugs and confusions, a closing square bracket is no longer allowed
878        in a POSIX name. This bug also affected patterns with classes that started
879        with full stops.
881    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
882        captured substring, but while checking the failing first alternative,
883        substring 1 is temporarily captured. If the output vector supplied to
884        pcre_exec() was not big enough for this capture, the yield of the function
885        was still zero ("insufficient space for captured substrings"). This cannot
886        be totally fixed without adding another stack variable, which seems a lot
887        of expense for a edge case. However, I have improved the situation in cases
888        such as /(a)(b)x|abc/ matched against "abc", where the return code
889        indicates that fewer than the maximum number of slots in the ovector have
890        been set.
892    3.  Related to (2) above: when there are more back references in a pattern than
893        slots in the output vector, pcre_exec() uses temporary memory during
894        matching, and copies in the captures as far as possible afterwards. It was
895        using the entire output vector, but this conflicts with the specification
896        that only 2/3 is used for passing back captured substrings. Now it uses
897        only the first 2/3, for compatibility. This is, of course, another edge
898        case.
900    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
901        main code base, and can be used by building with --enable-jit. When this is
902        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
903        runtime --no-jit option is given.
905    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
906        ovector, the return from the function was zero, implying that there were
907        other matches that did not fit. The correct "exactly full" value is now
908        returned.
910    6.  If a subpattern that was called recursively or as a subroutine contained
911        (*PRUNE) or any other control that caused it to give a non-standard return,
912        invalid errors such as "Error -26 (nested recursion at the same subject
913        position)" or even infinite loops could occur.
915    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
916        computing the minimum length on reaching *ACCEPT, and so ended up with the
917        wrong value of 1 rather than 0. Further investigation indicates that
918        computing a minimum subject length in the presence of *ACCEPT is difficult
919        (think back references, subroutine calls), and so I have changed the code
920        so that no minimum is registered for a pattern that contains *ACCEPT.
922    8.  If (*THEN) was present in the first (true) branch of a conditional group,
923        it was not handled as intended. [But see 16 below.]
925    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
926        Sheri Pierce.
928    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
929        the first byte in a match must be "a".
931    11. Change 17 for 8.13 increased the recursion depth for patterns like
932        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
933        pattern contains any instances of (*THEN). If it does not, the old
934        optimizations are restored. It would be nice to do this on a per-group
935        basis, but at the moment that is not feasible.
937    12. In some environments, the output of pcretest -C is CRLF terminated. This
938        broke RunTest's code that checks for the link size. A single white space
939        character after the value is now allowed for.
941    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
942        For "fr", it uses the Windows-specific input and output files.
944    14. If (*THEN) appeared in a group that was called recursively or as a
945        subroutine, it did not work as intended. [But see next item.]
947    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
948        pattern fragments (but not containing any | characters). If A and B are
949        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
950        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
951        D. In other words, Perl considers parentheses that do not contain any |
952        characters to be part of a surrounding alternative, whereas PCRE was
953        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
954        differently. PCRE now behaves in the same way as Perl, except in the case
955        of subroutine/recursion calls such as (?1) which have in any case always
956        been different (but PCRE had them first :-).
958    16. Related to 15 above: Perl does not treat the | in a conditional group as
959        creating alternatives. Such a group is treated in the same way as an
960        ordinary group without any | characters when processing (*THEN). PCRE has
961        been changed to match Perl's behaviour.
963    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
964        RunGrepTest script failed.
966    18. Change 22 for version 13 caused atomic groups to use more stack. This is
967        inevitable for groups that contain captures, but it can lead to a lot of
968        stack use in large patterns. The old behaviour has been restored for atomic
969        groups that do not contain any capturing parentheses.
971    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
972        suppress the check for a minimum subject length at run time. (If it was
973        given to pcre_exec() or pcre_dfa_exec() it did work.)
975    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
976        fail to work when decoding hex characters in data strings in EBCDIC
977        environments.
979    21. It appears that in at least one Mac OS environment, the isxdigit() function
980        is implemented as a macro that evaluates to its argument more than once,
981        contravening the C 90 Standard (I haven't checked a later standard). There
982        was an instance in pcretest which caused it to go wrong when processing
983        \x{...} escapes in subject strings. The has been rewritten to avoid using
984        things like p++ in the argument of isxdigit().
987    Version 8.13 16-Aug-2011
988  ------------------------  ------------------------
990  1.  The Unicode data tables have been updated to Unicode 6.0.0.  1.  The Unicode data tables have been updated to Unicode 6.0.0.
# Line 20  Version 8.13 30-Apr-2011 Line 1003  Version 8.13 30-Apr-2011
1003      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1004      2-byte code at the end of the subject (it thought there wasn't enough data      2-byte code at the end of the subject (it thought there wasn't enough data
1005      left).      left).
1007  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
1008      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1009      as the output vector has at least 2 elements. The offset of the start of      as the output vector has at least 2 elements. The offset of the start of
1010      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
1012  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1013      now returned is for the first byte of the failing character, instead of the      now returned is for the first byte of the failing character, instead of the
1014      last byte inspected. This is an incompatible change, but I hope it is small      last byte inspected. This is an incompatible change, but I hope it is small
1015      enough not to be a problem. It makes the returned offset consistent with      enough not to be a problem. It makes the returned offset consistent with
1016      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
1018  7.  pcretest now gives a text phrase as well as the error number when  7.  pcretest now gives a text phrase as well as the error number when
1019      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1020      failure, the offset and reason code are output.      failure, the offset and reason code are output.
1022  8.  When \R was used with a maximizing quantifier it failed to skip backwards  8.  When \R was used with a maximizing quantifier it failed to skip backwards
1023      over a \r\n pair if the subsequent match failed. Instead, it just skipped      over a \r\n pair if the subsequent match failed. Instead, it just skipped
1024      back over a single character (\n). This seems wrong (because it treated the      back over a single character (\n). This seems wrong (because it treated the
1025      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
1026      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1027      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1028      has been changed.      has been changed.
1030    9.  Some internal refactoring has changed the processing so that the handling
1031        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1032        time (the PCRE_DOTALL option was changed this way some time ago: version
1033        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1034        which was always a bit of a fudge. It also means that there is one less
1035        argument for the match() function, which reduces its stack requirements
1036        slightly. This change also fixes an incompatibility with Perl: the pattern
1037        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1039    10. More internal refactoring has drastically reduced the number of recursive
1040        calls to match() for possessively repeated groups such as (abc)++ when
1041        using pcre_exec().
1043    11. While implementing 10, a number of bugs in the handling of groups were
1044        discovered and fixed:
1046        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1047        (a|)*(?1) gave a compile-time internal error.
1048        ((a|)+)+  did not notice that the outer group could match an empty string.
1049        (^a|^)+   was not marked as anchored.
1050        (.*a|.*)+ was not marked as matching at start or after a newline.
1052    12. Yet more internal refactoring has removed another argument from the match()
1053        function. Special calls to this function are now indicated by setting a
1054        value in a variable in the "match data" data block.
1056    13. Be more explicit in pcre_study() instead of relying on "default" for
1057        opcodes that mean there is no starting character; this means that when new
1058        ones are added and accidentally left out of pcre_study(), testing should
1059        pick them up.
1061    14. The -s option of pcretest has been documented for ages as being an old
1062        synonym of -m (show memory usage). I have changed it to mean "force study
1063        for every regex", that is, assume /S for every regex. This is similar to -i
1064        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1065        using it. It makes it easier to run collections of tests with and without
1066        study enabled, and thereby test pcre_study() more easily. All the standard
1067        tests are now run with and without -s (but some patterns can be marked as
1068        "never study" - see 20 below).
1070    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1071        restoration of the capturing data to the outer values was not happening
1072        correctly.
1074    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1075        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1076        pattern had matched an empty string, and so incorrectly returned a no
1077        match.
1079    17. There was optimizing code for the last branch of non-capturing parentheses,
1080        and also for the obeyed branch of a conditional subexpression, which used
1081        tail recursion to cut down on stack usage. Unfortunately, now that there is
1082        the possibility of (*THEN) occurring in these branches, tail recursion is
1083        no longer possible because the return has to be checked for (*THEN). These
1084        two optimizations have therefore been removed. [But see 8.20/11 above.]
1086    18. If a pattern containing \R was studied, it was assumed that \R always
1087        matched two bytes, thus causing the minimum subject length to be
1088        incorrectly computed because \R can also match just one byte.
1090    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1091        was incorrectly computed.
1093    20. If /S is present twice on a test pattern in pcretest input, it now
1094        *disables* studying, thereby overriding the use of -s on the command line
1095        (see 14 above). This is necessary for one or two tests to keep the output
1096        identical in both cases.
1098    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1099        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1101    22. When an atomic group that contained a capturing parenthesis was
1102        successfully matched, but the branch in which it appeared failed, the
1103        capturing was not being forgotten if a higher numbered group was later
1104        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1105        group 1 to "a", when in fact it should be unset. This applied to multi-
1106        branched capturing and non-capturing groups, repeated or not, and also to
1107        positive assertions (capturing in negative assertions does not happen
1108        in PCRE) and also to nested atomic groups.
1110    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1111        subject after a captured substring, to make it easier to tell which of a
1112        number of identical substrings has been captured.
1114    24. The way atomic groups are processed by pcre_exec() has been changed so that
1115        if they are repeated, backtracking one repetition now resets captured
1116        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1117        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1118        "aaa". Previously, it would have been "a". As part of this code
1119        refactoring, the way recursive calls are handled has also been changed.
1121    25. If an assertion condition captured any substrings, they were not passed
1122        back unless some other capturing happened later. For example, if
1123        (?(?=(a))a) was matched against "a", no capturing was returned.
1125    26. When studying a pattern that contained subroutine calls or assertions,
1126        the code for finding the minimum length of a possible match was handling
1127        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1128        group 1 called group 2 while simultaneously a separate group 2 called group
1129        1). A stack overflow occurred in this case. I have fixed this by limiting
1130        the recursion depth to 10.
1132    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1133        Fortmann. This supports explicit test numbers on the command line, and has
1134        argument validation and error reporting.
1136    28. An instance of \X with an unlimited repeat could fail if at any point the
1137        first character it looked at was a mark character.
1139    29. Some minor code refactoring concerning Unicode properties and scripts
1140        should reduce the stack requirement of match() slightly.
1142    30. Added the '=' option to pcretest to check the setting of unused capturing
1143        slots at the end of the pattern, which are documented as being -1, but are
1144        not included in the return count.
1146    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1147        compiled something random. Now it gives a compile-time error (as does
1148        Perl).
1150    32. A *MARK encountered during the processing of a positive assertion is now
1151        recorded and passed back (compatible with Perl).
1153    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1154        had alternative anchored branches, the search for a second match in a line
1155        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1156        matched the line "0102" twice. The same bug affected patterns that started
1157        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1158        twice.
1160    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1161        does, and because of capturing effects, quantifying parenthesized
1162        assertions may at times be useful. Quantifiers are now allowed for
1163        parenthesized assertions.
1165    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1167    36. \g was being checked for fancy things in a character class, when it should
1168        just be a literal "g".
1170    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1171        appearance of a nested POSIX class supersedes an apparent external class.
1172        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1173        unescaped square brackets may also appear as part of class names. For
1174        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1175        more like Perl. (But see 8.20/1 above.)
1177    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1178        was because it thought it was \N{name}, which is not supported).
1180    39. Add minix to OS list not supporting the -S option in pcretest.
1182    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1183        cannot analyze patterns in sufficient detail to catch mutual recursions
1184        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1185        subgroup is called recursively as a subpattern for a second time at the
1186        same position in the subject string. In previous releases this might have
1187        been caught by the recursion limit, or it might have run out of stack.
1189    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1190        happen only once. PCRE was, however incorrectly giving a compile time error
1191        "recursive call could loop indefinitely" because it cannot analyze the
1192        pattern in sufficient detail. The compile time test no longer happens when
1193        PCRE is compiling a conditional subpattern, but actual runaway loops are
1194        now caught at runtime (see 40 above).
1196    42. It seems that Perl allows any characters other than a closing parenthesis
1197        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1198        has been changed to be the same.
1200    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1201        as not to get warnings when autogen.sh is called. Also changed
1202        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1204    44. To help people who use pcregrep to scan files containing exceedingly long
1205        lines, the following changes have been made:
1207        (a) The default value of the buffer size parameter has been increased from
1208            8K to 20K. (The actual buffer used is three times this size.)
1210        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1211            PCRE is built.
1213        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1214            to be set at run time.
1216        (d) Numerical values in pcregrep options can be followed by K or M, for
1217            example --buffer-size=50K.
1219        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1220            given and the return code is set to 2.
1222    45. Add a pointer to the latest mark to the callout data block.
1224    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1225        partial match of an empty string instead of no match. This was specific to
1226        the use of ".".
1228    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1229        complete match instead of a partial match. This bug was dependent on both
1230        the PCRE_UTF8 and PCRE_DOTALL options being set.
1232    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1233        starting byte set, because \b was not being ignored.
1236  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
1237  ------------------------  ------------------------
# Line 695  Version 7.9 11-Apr-09 Line 1883  Version 7.9 11-Apr-09
1883  7.  A pattern that could match an empty string could cause pcregrep to loop; it  7.  A pattern that could match an empty string could cause pcregrep to loop; it
1884      doesn't make sense to accept an empty string match in pcregrep, so I have      doesn't make sense to accept an empty string match in pcregrep, so I have
1885      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1886      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1887        8.33.]
1889  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1890      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 938  Version 7.7 07-May-08 Line 2127  Version 7.7 07-May-08
2127      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2128      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2129      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2130      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2131      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2132      was subsequently set up correctly.)      was subsequently set up correctly.)

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