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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.0 02 Jul-08  Version 8.34 xx-xxxx-201x
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_POSSESSIFY is added for testing purposes, and the -O and /O
89        options in pcretest are provided to set it.
91    18. The character VT has been added to the set of characters that match \s and
92        are generally treated as white space, following this same change in Perl
93        5.18. There is now no difference between "Perl space" and "POSIX space".
95    19. The code for checking named groups as conditions, either for being set or
96        for being recursed, has been refactored (this is related to 14 and 15
97        above). Processing unduplicated named groups should now be as fast at
98        numerical groups, and processing duplicated groups should be faster than
99        before.
101    20. Two patches to the CMake build system, by Alexander Barkov:
103          (1) Replace the "source" command by "." in CMakeLists.txt because
104              "source" is a bash-ism.
106          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
107              without these the CMake build does not work on Solaris.
109    21. Perl has changed its handling of \8 and \9. If there is no previously
110        encountered capturing group of those numbers, they are treated as the
111        literal characters 8 and 9 instead of a binary zero followed by the
112        literals. PCRE now does the same.
114    22. Following Perl, added \o{} to specify codepoints in octal, making it
115        possible to specify values greater than 0777 and also making them
116        unambiguous.
118    23. Perl now gives an error for missing closing braces after \x{... instead of
119        treating the string as literal. PCRE now does the same.
121    24. RunTest used to grumble if an inappropriate test was selected explicitly,
122        but just skip it when running all tests. This make it awkward to run ranges
123        of tests when one of them was inappropriate. Now it just skips any
124        inappropriate tests, as it always did when running all tests.
126    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
127        character types such as \d or \w, too many callouts were inserted, and the
128        data that they returned was rubbish.
130    26. In UCP mode, \s was not matching two of the characters that Perl matches,
131        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
132        were matched by \h. The code has now been refactored so that the lists of
133        the horizontal and vertical whitespace characters used for \h and \v (which
134        are defined only in one place) are now also used for \s.
136    27. Add JIT support for the 64 bit TileGX architecture.
137        Patch by Jiong Wang (Tilera Corporation).
139    28. Possessive quantifiers for classes (both explicit and automatically
140        generated) now use special opcodes instead of wrapping in ONCE brackets.
142    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
143        (because it's meaningless), this was not happening when PCRE_CASELESS was
144        set. Not wrong, but inefficient.
146    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
147        properties for \w, \d, etc) is present in a test regex. Otherwise if the
148        test contains no characters greater than 255, Perl doesn't realise it
149        should be using Unicode semantics.
151    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
152        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
153        does in Unicode mode.
155    32. Added the "forbid" facility to pcretest so that putting tests into the
156        wrong test files can sometimes be quickly detected.
158    33. There is now a limit (default 250) on the depth of nesting of parentheses.
159        This limit is imposed to control the amount of system stack used at compile
160        time. It can be changed at build time by --with-parens-nest-limit=xxx or
161        the equivalent in CMake.
164    Version 8.33 28-May-2013
165    ------------------------
167    1.  Added 'U' to some constants that are compared to unsigned integers, to
168        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
169        variables that are added to signed variables, to ensure the result is
170        signed and can be negated.
172    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
173        CMake config files.
175    3.  Revise the creation of config.h.generic so that all boolean macros are
176        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
177        overriding via -D on the command line possible.
179    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
180        to unsigned int is reported to make a quite noticeable speed difference in
181        a specific Windows environment. Testing on Linux did also appear to show
182        some benefit (and it is clearly not harmful). Also fixed the definition of
183        Xop which should be unsigned.
185    5.  Related to (4), changing the definition of the intermediate variable cc
186        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
187        improvements.
189    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
190        unnecessary spaces.
192    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
193        and later.
195    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
197    9.  Optimizing fast_forward_start_bits in JIT.
199    10. Adding support for callouts in JIT, and fixing some issues revealed
200        during this work. Namely:
202        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
204        (b) Minimum length was not checked before the matching is started.
206    11. The value of capture_last that is passed to callouts was incorrect in some
207        cases when there was a capture on one path that was subsequently abandoned
208        after a backtrack. Also, the capture_last value is now reset after a
209        recursion, since all captures are also reset in this case.
211    12. The interpreter no longer returns the "too many substrings" error in the
212        case when an overflowing capture is in a branch that is subsequently
213        abandoned after a backtrack.
215    13. In the pathological case when an offset vector of size 2 is used, pcretest
216        now prints out the matched string after a yield of 0 or 1.
218    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
219        Only supported by the JIT compiler at the moment.
221    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
223    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
224        offset of the starting point of the matching process, provided the offsets
225        vector is large enough.
227    17. The \A escape now records a lookbehind value of 1, though its execution
228        does not actually inspect the previous character. This is to ensure that,
229        in partial multi-segment matching, at least one character from the old
230        segment is retained when a new segment is processed. Otherwise, if there
231        are no lookbehinds in the pattern, \A might match incorrectly at the start
232        of a new segment.
234    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
236    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
237        gives some modest performance improvement in 8-bit mode.
239    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
240        be expressed in certain programming languages using Universal Character
241        Names.
243    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
244        which points out that "non characters" are not "characters that may not
245        appear in Unicode strings" but rather "characters that are reserved for
246        internal use and have only local meaning".
248    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
249        there was a conditional group that depended on an assertion, if the
250        assertion was false, the callout that immediately followed the alternation
251        in the condition was skipped when pcre_exec() was used for matching.
253    23. Allow an explicit callout to be inserted before an assertion that is the
254        condition for a conditional group, for compatibility with automatic
255        callouts, which always insert a callout at this point.
257    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
258        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
260    25. (*PRUNE) is now supported by the JIT compiler.
262    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
264    27. Fix the case where there are two or more SKIPs with arguments that may be
265        ignored.
267    28. (*SKIP) is now supported by the JIT compiler.
269    29. (*THEN) is now supported by the JIT compiler.
271    30. Update RunTest with additional test selector options.
273    31. The way PCRE handles backtracking verbs has been changed in two ways.
275        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
276        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
277        backtracking. In some cases this makes it more Perl-compatible, but Perl's
278        rather obscure rules do not always do the same thing.
280        (2) Previously, backtracking verbs were confined within assertions. This is
281        no longer the case for positive assertions, except for (*ACCEPT). Again,
282        this sometimes improves Perl compatibility, and sometimes does not.
284    32. A number of tests that were in test 2 because Perl did things differently
285        have been moved to test 1, because either Perl or PCRE has changed, and
286        these tests are now compatible.
288    32. Backtracking control verbs are now handled in the same way in JIT and
289        interpreter.
291    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
292        contained a forward subroutine reference caused a compile error.
294    34. Auto-detect and optimize limited repetitions in JIT.
296    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
297        blocking (*UTF) etc.
299    36. In the interpreter, maximizing pattern repetitions for characters and
300        character types now use tail recursion, which reduces stack usage.
302    37. The value of the max lookbehind was not correctly preserved if a compiled
303        and saved regex was reloaded on a host of different endianness.
305    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
306        of the compiled pattern block, expand the flags field from 16 to 32 bits
307        because it was almost full.
309    39. Try madvise first before posix_madvise.
311    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
312        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
313        original change locked out all matches of empty strings. This has been
314        changed so that one match of an empty string per line is recognized.
315        Subsequent searches on the same line (for colouring or for --only-matching,
316        for example) do not recognize empty strings.
318    41. Applied a user patch to fix a number of spelling mistakes in comments.
320    42. Data lines longer than 65536 caused pcretest to crash.
322    43. Clarified the data type for length and startoffset arguments for pcre_exec
323        and pcre_dfa_exec in the function-specific man pages, where they were
324        explicitly stated to be in bytes, never having been updated. I also added
325        some clarification to the pcreapi man page.
327    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
328        a segmentation fault.
331    Version 8.32 30-November-2012
332    -----------------------------
334    1.  Improved JIT compiler optimizations for first character search and single
335        character iterators.
337    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
338        Patch by Daniel Richard G.
340    3.  Single character iterator optimizations in the JIT compiler.
342    4.  Improved JIT compiler optimizations for character ranges.
344    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
345        Reported by Giuseppe D'Angelo.
347    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
348        of a line, was being set incorrectly in cases where .* appeared inside
349        atomic brackets at the start of a pattern, or where there was a subsequent
350        *PRUNE or *SKIP.
352    7.  Improved instruction cache flush for POWER/PowerPC.
353        Patch by Daniel Richard G.
355    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
356        grep:
358        (a) There is now no limit to the number of patterns to be matched.
360        (b) An error is given if a pattern is too long.
362        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
363            are now supported.
365        (d) --exclude-from and --include-from (multiple use) have been added.
367        (e) Exclusions and inclusions now apply to all files and directories, not
368            just to those obtained from scanning a directory recursively.
370        (f) Multiple uses of -f and --file-list are now supported.
372        (g) In a Windows environment, the default for -d has been changed from
373            "read" (the GNU grep default) to "skip", because otherwise the presence
374            of a directory in the file list provokes an error.
376        (h) The documentation has been revised and clarified in places.
378    9.  Improve the matching speed of capturing brackets.
380    10. Changed the meaning of \X so that it now matches a Unicode extended
381        grapheme cluster.
383    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
384        out POSIX threads when JIT support is configured.
386    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
388    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
389        structure could go wrong in environments where size_t is not the same size
390        as int.
392    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
393        set.
395    15. The EBCDIC support had decayed; later updates to the code had included
396        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
397        general tidy up of EBCDIC-related issues, and the documentation was also
398        not quite right. There is now a test that can be run on ASCII systems to
399        check some of the EBCDIC-related things (but is it not a full test).
401    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
402        in a small tidy to the code.
404    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
406    18. If the --only-matching (-o) option in pcregrep is specified multiple
407        times, each one causes appropriate output. For example, -o1 -o2 outputs the
408        substrings matched by the 1st and 2nd capturing parentheses. A separating
409        string can be specified by --om-separator (default empty).
411    19. Improving the first n character searches.
413    20. Turn case lists for horizontal and vertical white space into macros so that
414        they are defined only once.
416    21. This set of changes together give more compatible Unicode case-folding
417        behaviour for characters that have more than one other case when UCP
418        support is available.
420        (a) The Unicode property table now has offsets into a new table of sets of
421            three or more characters that are case-equivalent. The MultiStage2.py
422            script that generates these tables (the pcre_ucd.c file) now scans
423            CaseFolding.txt instead of UnicodeData.txt for character case
424            information.
426        (b) The code for adding characters or ranges of characters to a character
427            class has been abstracted into a generalized function that also handles
428            case-independence. In UTF-mode with UCP support, this uses the new data
429            to handle characters with more than one other case.
431        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
432            whose other case is greater than 256 are now correctly matched
433            caselessly. Previously, the high codepoint matched the low one, but not
434            vice versa.
436        (d) The processing of \h, \H, \v, and \ in character classes now makes use
437            of the new class addition function, using character lists defined as
438            macros alongside the case definitions of 20 above.
440        (e) Caseless back references now work with characters that have more than
441            one other case.
443        (f) General caseless matching of characters with more than one other case
444            is supported.
446    22. Unicode character properties were updated from Unicode 6.2.0
448    23. Improved CMake support under Windows. Patch by Daniel Richard G.
450    24. Add support for 32-bit character strings, and UTF-32
452    25. Major JIT compiler update (code refactoring and bugfixing).
453        Experimental Sparc 32 support is added.
455    26. Applied a modified version of Daniel Richard G's patch to create
456        pcre.h.generic and config.h.generic by "make" instead of in the
457        PrepareRelease script.
459    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
460        pcre_compile.c when checking for a zero character.
462    28. Introducing a native interface for JIT. Through this interface, the compiled
463        machine code can be directly executed. The purpose of this interface is to
464        provide fast pattern matching, so several sanity checks are not performed.
465        However, feature tests are still performed. The new interface provides
466        1.4x speedup compared to the old one.
468    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
469        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
470        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
472    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
473        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
474        the "old" RFC 2279). Instead, it ended up passing a negative length to
475        pcre_exec().
477    31. Add support for GCC's visibility feature to hide internal functions.
479    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
480        "unknown -C option" after outputting 0 or 1.
482    33. There is now support for generating a code coverage report for the test
483        suite in environments where gcc is the compiler and lcov is installed. This
484        is mainly for the benefit of the developers.
486    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
487        unaddressable using valgrind annotations, allowing valgrind to detect
488        invalid memory accesses. This is mainly for the benefit of the developers.
490    25. (*UTF) can now be used to start a pattern in any of the three libraries.
492    26. Give configure error if --enable-cpp but no C++ compiler found.
495    Version 8.31 06-July-2012
496    -------------------------
498    1.  Fixing a wrong JIT test case and some compiler warnings.
500    2.  Removed a bashism from the RunTest script.
502    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
503        to unsigned type, result still unsigned" that was given by an MS compiler
504        on encountering the code "-sizeof(xxx)".
506    4.  Partial matching support is added to the JIT compiler.
508    5.  Fixed several bugs concerned with partial matching of items that consist
509        of more than one character:
511        (a) /^(..)\1/ did not partially match "aba" because checking references was
512            done on an "all or nothing" basis. This also applied to repeated
513            references.
515        (b) \R did not give a hard partial match if \r was found at the end of the
516            subject.
518        (c) \X did not give a hard partial match after matching one or more
519            characters at the end of the subject.
521        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
522            a partial match for the string "\r".
524        (e) When newline was set to CRLF, the metacharacter "." did not recognize
525            a partial match for a CR character at the end of the subject string.
527    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
528        running pcretest, the text "(JIT)" added to the output whenever JIT is
529        actually used to run the match.
531    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
532        or /S+[+] with a digit between 1 and 7.
534    8.  OP_NOT now supports any UTF character not just single-byte ones.
536    9.  (*MARK) control verb is now supported by the JIT compiler.
538    10. The command "./RunTest list" lists the available tests without actually
539        running any of them. (Because I keep forgetting what they all are.)
543    12. Applied a (slightly modified) user-supplied patch that improves performance
544        when the heap is used for recursion (compiled with --disable-stack-for-
545        recursion). Instead of malloc and free for each heap frame each time a
546        logical recursion happens, frames are retained on a chain and re-used where
547        possible. This sometimes gives as much as 30% improvement.
549    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
550        call.
552    14. As documented, (*COMMIT) is now confined to within a positive assertion.
554    15. It is now possible to link pcretest with libedit as an alternative to
555        libreadline.
557    16. (*COMMIT) control verb is now supported by the JIT compiler.
559    17. The Unicode data tables have been updated to Unicode 6.1.0.
561    18. Added --file-list option to pcregrep.
563    19. Added binary file support to pcregrep, including the -a, --binary-files,
564        -I, and --text options.
566    20. The madvise function is renamed for posix_madvise for QNX compatibility
567        reasons. Fixed by Giuseppe D'Angelo.
569    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
571    22. Changed the option for creating symbolic links for 16-bit man pages from
572        -s to -sf so that re-installing does not cause issues.
574    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
576    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
577        matches in certain environments (the workspace was not being correctly
578        retained). Also added to pcre_dfa_exec() a simple plausibility check on
579        some of the workspace data at the beginning of a restart.
581    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
582        was not doing so when it should - probably a typo introduced by SVN 528
583        (change 8.10/14).
585    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
586        \w+ when the character tables indicated that \x{c4} was a word character.
587        There were several related cases, all because the tests for doing a table
588        lookup were testing for characters less than 127 instead of 255.
590    27. If a pattern contains capturing parentheses that are not used in a match,
591        their slots in the ovector are set to -1. For those that are higher than
592        any matched groups, this happens at the end of processing. In the case when
593        there were back references that the ovector was too small to contain
594        (causing temporary malloc'd memory to be used during matching), and the
595        highest capturing number was not used, memory off the end of the ovector
596        was incorrectly being set to -1. (It was using the size of the temporary
597        memory instead of the true size.)
599    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
600        ovector size, it uses memory at the end of the block that it has got.
602    29. Check for an overlong MARK name and give an error at compile time. The
603        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
605    30. JIT compiler update.
607    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
608        Rill for the patch.
610    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
612    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
614    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
615        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
616        was enabled.
618    35. Improve JIT code generation for greedy plus quantifier.
620    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
621        1 to "aa" instead of to an empty string. The bug affected repeated groups
622        that could potentially match an empty string.
624    37. Optimizing single character iterators in JIT.
626    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
627        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
628        codepoints that are too big for the mode are faulted, and in a UTF mode,
629        disallowed codepoints are also faulted.
631    39. If PCRE was compiled with UTF support, in three places in the DFA
632        matcher there was code that should only have been obeyed in UTF mode, but
633        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
634        processing when bytes with values greater than 127 were present. In 16-bit
635        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
636        both cases the values are those that cannot be the first data item in a UTF
637        character. The three items that might have provoked this were recursions,
638        possessively repeated groups, and atomic groups.
640    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
641        and pcregrep, because some OS require shared objects to be explicitly
642        passed to ld, causing the link step to fail if they are not.
644    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
645        mode, patterns that started with \h* or \R* might be incorrectly matched.
648    Version 8.30 04-February-2012
649    -----------------------------
651    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
652        name is defined in ctype.h.
654    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
655        only in quite long subpatterns.
657    3.  Removed the function pcre_info(), which has been obsolete and deprecated
658        since it was replaced by pcre_fullinfo() in February 2000.
660    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
661        match a (*MARK), and the match failed at the start of the subject, a
662        reference to memory before the start of the subject could occur. This bug
663        was introduced by fix 17 of release 8.21.
665    5.  A reference to an unset group with zero minimum repetition was giving
666        totally wrong answers (in non-JavaScript-compatibility mode). For example,
667        /(another)?(\1?)test/ matched against "hello world test". This bug was
668        introduced in release 8.13.
670    6.  Add support for 16-bit character strings (a large amount of work involving
671        many changes and refactorings).
673    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
674        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
675        from a file.
677    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
678        rounding is not applied in this particular case).
680    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
681        if they appear, or are escaped, in patterns.
683    10. Get rid of a number of -Wunused-but-set-variable warnings.
685    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
686        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
687        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
688        also returns the mark "x". This bug applied to capturing parentheses,
689        non-capturing parentheses, and atomic parentheses. It also applied to some
690        assertions.
692    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
693        information out of configure.ac instead of relying on pcre.h.generic, which
694        is not stored in the repository.
696    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
697        -lreadline.
699    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
701    15. Applied Graycode's patch to put the top-level frame on the stack rather
702        than the heap when not using the stack for recursion. This gives a
703        performance improvement in many cases when recursion is not deep.
705    16. Experimental code added to "pcretest -C" to output the stack frame size.
708    Version 8.21 12-Dec-2011
709    ------------------------
711    1.  Updating the JIT compiler.
713    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
714        are added as well.
716    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
717        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
718        calling _pcre_jit_exec. Some extra comments are added.
720    4.  (*MARK) settings inside atomic groups that do not contain any capturing
721        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
722        was introduced by change 18 for 8.20.
724    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
725        ECMA-262 standard.
727    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
728        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
729        This bug was probably introduced by change 9 of 8.13.
731    7.  While fixing 6 above, I noticed that a number of other items were being
732        incorrectly rejected as "not fixed length". This arose partly because newer
733        opcodes had not been added to the fixed-length checking code. I have (a)
734        corrected the bug and added tests for these items, and (b) arranged for an
735        error to occur if an unknown opcode is encountered while checking for fixed
736        length instead of just assuming "not fixed length". The items that were
737        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
738        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
739        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
741    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
742        being incorrectly compiled and would have given unpredicatble results.
744    9.  A possessively repeated subpattern with minimum repeat count greater than
745        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
746        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
747        the first (A) could occur when it should not.
749    10. Add a cast and remove a redundant test from the code.
751    11. JIT should use pcre_malloc/pcre_free for allocation.
753    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
754        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
755        is anything other than /usr, -L is still shown).
757    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
759    14. Perl does not support \N without a following name in a [] class; PCRE now
760        also gives an error.
762    15. If a forward reference was repeated with an upper limit of around 2000,
763        it caused the error "internal error: overran compiling workspace". The
764        maximum number of forward references (including repeats) was limited by the
765        internal workspace, and dependent on the LINK_SIZE. The code has been
766        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
767        the default depends on LINK_SIZE. There is a new upper limit (for safety)
768        of around 200,000 forward references. While doing this, I also speeded up
769        the filling in of repeated forward references.
771    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
772        incorrectly expecting the subject to contain another "a" after the start.
774    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
775        in the match, the SKIP should be ignored. This was not happening; instead
776        the SKIP was being treated as NOMATCH. For patterns such as
777        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
778        tested.
780    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
781        now much more compatible with Perl, in particular in cases where the result
782        is a non-match for a non-anchored pattern. For example, if
783        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
784        "m", where previously it did not return a name. A side effect of this
785        change is that for partial matches, the last encountered mark name is
786        returned, as for non matches. A number of tests that were previously not
787        Perl-compatible have been moved into the Perl-compatible test files. The
788        refactoring has had the pleasing side effect of removing one argument from
789        the match() function, thus reducing its stack requirements.
791    19. If the /S+ option was used in pcretest to study a pattern using JIT,
792        subsequent uses of /S (without +) incorrectly behaved like /S+.
794    21. Retrieve executable code size support for the JIT compiler and fixing
795        some warnings.
797    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
798        not work when the shorter character appeared right at the end of the
799        subject string.
801    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
802        systems.
804    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
805        output it when the /M option is used in pcretest.
807    25. The CheckMan script was not being included in the distribution. Also, added
808        an explicit "perl" to run Perl scripts from the PrepareRelease script
809        because this is reportedly needed in Windows.
811    26. If study data was being save in a file and studying had not found a set of
812        "starts with" bytes for the pattern, the data written to the file (though
813        never used) was taken from uninitialized memory and so caused valgrind to
814        complain.
816    27. Updated RunTest.bat as provided by Sheri Pierce.
818    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
820    29. Computation of memory usage for the table of capturing group names was
821        giving an unnecessarily large value.
824    Version 8.20 21-Oct-2011
825    ------------------------
827    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
828        a POSIX class. After further experiments with Perl, which convinced me that
829        Perl has bugs and confusions, a closing square bracket is no longer allowed
830        in a POSIX name. This bug also affected patterns with classes that started
831        with full stops.
833    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
834        captured substring, but while checking the failing first alternative,
835        substring 1 is temporarily captured. If the output vector supplied to
836        pcre_exec() was not big enough for this capture, the yield of the function
837        was still zero ("insufficient space for captured substrings"). This cannot
838        be totally fixed without adding another stack variable, which seems a lot
839        of expense for a edge case. However, I have improved the situation in cases
840        such as /(a)(b)x|abc/ matched against "abc", where the return code
841        indicates that fewer than the maximum number of slots in the ovector have
842        been set.
844    3.  Related to (2) above: when there are more back references in a pattern than
845        slots in the output vector, pcre_exec() uses temporary memory during
846        matching, and copies in the captures as far as possible afterwards. It was
847        using the entire output vector, but this conflicts with the specification
848        that only 2/3 is used for passing back captured substrings. Now it uses
849        only the first 2/3, for compatibility. This is, of course, another edge
850        case.
852    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
853        main code base, and can be used by building with --enable-jit. When this is
854        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
855        runtime --no-jit option is given.
857    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
858        ovector, the return from the function was zero, implying that there were
859        other matches that did not fit. The correct "exactly full" value is now
860        returned.
862    6.  If a subpattern that was called recursively or as a subroutine contained
863        (*PRUNE) or any other control that caused it to give a non-standard return,
864        invalid errors such as "Error -26 (nested recursion at the same subject
865        position)" or even infinite loops could occur.
867    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
868        computing the minimum length on reaching *ACCEPT, and so ended up with the
869        wrong value of 1 rather than 0. Further investigation indicates that
870        computing a minimum subject length in the presence of *ACCEPT is difficult
871        (think back references, subroutine calls), and so I have changed the code
872        so that no minimum is registered for a pattern that contains *ACCEPT.
874    8.  If (*THEN) was present in the first (true) branch of a conditional group,
875        it was not handled as intended. [But see 16 below.]
877    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
878        Sheri Pierce.
880    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
881        the first byte in a match must be "a".
883    11. Change 17 for 8.13 increased the recursion depth for patterns like
884        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
885        pattern contains any instances of (*THEN). If it does not, the old
886        optimizations are restored. It would be nice to do this on a per-group
887        basis, but at the moment that is not feasible.
889    12. In some environments, the output of pcretest -C is CRLF terminated. This
890        broke RunTest's code that checks for the link size. A single white space
891        character after the value is now allowed for.
893    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
894        For "fr", it uses the Windows-specific input and output files.
896    14. If (*THEN) appeared in a group that was called recursively or as a
897        subroutine, it did not work as intended. [But see next item.]
899    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
900        pattern fragments (but not containing any | characters). If A and B are
901        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
902        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
903        D. In other words, Perl considers parentheses that do not contain any |
904        characters to be part of a surrounding alternative, whereas PCRE was
905        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
906        differently. PCRE now behaves in the same way as Perl, except in the case
907        of subroutine/recursion calls such as (?1) which have in any case always
908        been different (but PCRE had them first :-).
910    16. Related to 15 above: Perl does not treat the | in a conditional group as
911        creating alternatives. Such a group is treated in the same way as an
912        ordinary group without any | characters when processing (*THEN). PCRE has
913        been changed to match Perl's behaviour.
915    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
916        RunGrepTest script failed.
918    18. Change 22 for version 13 caused atomic groups to use more stack. This is
919        inevitable for groups that contain captures, but it can lead to a lot of
920        stack use in large patterns. The old behaviour has been restored for atomic
921        groups that do not contain any capturing parentheses.
923    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
924        suppress the check for a minimum subject length at run time. (If it was
925        given to pcre_exec() or pcre_dfa_exec() it did work.)
927    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
928        fail to work when decoding hex characters in data strings in EBCDIC
929        environments.
931    21. It appears that in at least one Mac OS environment, the isxdigit() function
932        is implemented as a macro that evaluates to its argument more than once,
933        contravening the C 90 Standard (I haven't checked a later standard). There
934        was an instance in pcretest which caused it to go wrong when processing
935        \x{...} escapes in subject strings. The has been rewritten to avoid using
936        things like p++ in the argument of isxdigit().
939    Version 8.13 16-Aug-2011
940    ------------------------
942    1.  The Unicode data tables have been updated to Unicode 6.0.0.
944    2.  Two minor typos in pcre_internal.h have been fixed.
946    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
947        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
948        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
950    4.  There were a number of related bugs in the code for matching backrefences
951        caselessly in UTF-8 mode when codes for the characters concerned were
952        different numbers of bytes. For example, U+023A and U+2C65 are an upper
953        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
954        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
955        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
956        2-byte code at the end of the subject (it thought there wasn't enough data
957        left).
959    5.  Comprehensive information about what went wrong is now returned by
960        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
961        as the output vector has at least 2 elements. The offset of the start of
962        the failing character and a reason code are placed in the vector.
964    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
965        now returned is for the first byte of the failing character, instead of the
966        last byte inspected. This is an incompatible change, but I hope it is small
967        enough not to be a problem. It makes the returned offset consistent with
968        pcre_exec() and pcre_dfa_exec().
970    7.  pcretest now gives a text phrase as well as the error number when
971        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
972        failure, the offset and reason code are output.
974    8.  When \R was used with a maximizing quantifier it failed to skip backwards
975        over a \r\n pair if the subsequent match failed. Instead, it just skipped
976        back over a single character (\n). This seems wrong (because it treated the
977        two characters as a single entity when going forwards), conflicts with the
978        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
979        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
980        has been changed.
982    9.  Some internal refactoring has changed the processing so that the handling
983        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
984        time (the PCRE_DOTALL option was changed this way some time ago: version
985        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
986        which was always a bit of a fudge. It also means that there is one less
987        argument for the match() function, which reduces its stack requirements
988        slightly. This change also fixes an incompatibility with Perl: the pattern
989        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
991    10. More internal refactoring has drastically reduced the number of recursive
992        calls to match() for possessively repeated groups such as (abc)++ when
993        using pcre_exec().
995    11. While implementing 10, a number of bugs in the handling of groups were
996        discovered and fixed:
998        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
999        (a|)*(?1) gave a compile-time internal error.
1000        ((a|)+)+  did not notice that the outer group could match an empty string.
1001        (^a|^)+   was not marked as anchored.
1002        (.*a|.*)+ was not marked as matching at start or after a newline.
1004    12. Yet more internal refactoring has removed another argument from the match()
1005        function. Special calls to this function are now indicated by setting a
1006        value in a variable in the "match data" data block.
1008    13. Be more explicit in pcre_study() instead of relying on "default" for
1009        opcodes that mean there is no starting character; this means that when new
1010        ones are added and accidentally left out of pcre_study(), testing should
1011        pick them up.
1013    14. The -s option of pcretest has been documented for ages as being an old
1014        synonym of -m (show memory usage). I have changed it to mean "force study
1015        for every regex", that is, assume /S for every regex. This is similar to -i
1016        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1017        using it. It makes it easier to run collections of tests with and without
1018        study enabled, and thereby test pcre_study() more easily. All the standard
1019        tests are now run with and without -s (but some patterns can be marked as
1020        "never study" - see 20 below).
1022    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1023        restoration of the capturing data to the outer values was not happening
1024        correctly.
1026    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1027        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1028        pattern had matched an empty string, and so incorrectly returned a no
1029        match.
1031    17. There was optimizing code for the last branch of non-capturing parentheses,
1032        and also for the obeyed branch of a conditional subexpression, which used
1033        tail recursion to cut down on stack usage. Unfortunately, now that there is
1034        the possibility of (*THEN) occurring in these branches, tail recursion is
1035        no longer possible because the return has to be checked for (*THEN). These
1036        two optimizations have therefore been removed. [But see 8.20/11 above.]
1038    18. If a pattern containing \R was studied, it was assumed that \R always
1039        matched two bytes, thus causing the minimum subject length to be
1040        incorrectly computed because \R can also match just one byte.
1042    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1043        was incorrectly computed.
1045    20. If /S is present twice on a test pattern in pcretest input, it now
1046        *disables* studying, thereby overriding the use of -s on the command line
1047        (see 14 above). This is necessary for one or two tests to keep the output
1048        identical in both cases.
1050    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1051        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1053    22. When an atomic group that contained a capturing parenthesis was
1054        successfully matched, but the branch in which it appeared failed, the
1055        capturing was not being forgotten if a higher numbered group was later
1056        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1057        group 1 to "a", when in fact it should be unset. This applied to multi-
1058        branched capturing and non-capturing groups, repeated or not, and also to
1059        positive assertions (capturing in negative assertions does not happen
1060        in PCRE) and also to nested atomic groups.
1062    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1063        subject after a captured substring, to make it easier to tell which of a
1064        number of identical substrings has been captured.
1066    24. The way atomic groups are processed by pcre_exec() has been changed so that
1067        if they are repeated, backtracking one repetition now resets captured
1068        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1069        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1070        "aaa". Previously, it would have been "a". As part of this code
1071        refactoring, the way recursive calls are handled has also been changed.
1073    25. If an assertion condition captured any substrings, they were not passed
1074        back unless some other capturing happened later. For example, if
1075        (?(?=(a))a) was matched against "a", no capturing was returned.
1077    26. When studying a pattern that contained subroutine calls or assertions,
1078        the code for finding the minimum length of a possible match was handling
1079        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1080        group 1 called group 2 while simultaneously a separate group 2 called group
1081        1). A stack overflow occurred in this case. I have fixed this by limiting
1082        the recursion depth to 10.
1084    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1085        Fortmann. This supports explicit test numbers on the command line, and has
1086        argument validation and error reporting.
1088    28. An instance of \X with an unlimited repeat could fail if at any point the
1089        first character it looked at was a mark character.
1091    29. Some minor code refactoring concerning Unicode properties and scripts
1092        should reduce the stack requirement of match() slightly.
1094    30. Added the '=' option to pcretest to check the setting of unused capturing
1095        slots at the end of the pattern, which are documented as being -1, but are
1096        not included in the return count.
1098    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1099        compiled something random. Now it gives a compile-time error (as does
1100        Perl).
1102    32. A *MARK encountered during the processing of a positive assertion is now
1103        recorded and passed back (compatible with Perl).
1105    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1106        had alternative anchored branches, the search for a second match in a line
1107        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1108        matched the line "0102" twice. The same bug affected patterns that started
1109        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1110        twice.
1112    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1113        does, and because of capturing effects, quantifying parenthesized
1114        assertions may at times be useful. Quantifiers are now allowed for
1115        parenthesized assertions.
1117    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1119    36. \g was being checked for fancy things in a character class, when it should
1120        just be a literal "g".
1122    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1123        appearance of a nested POSIX class supersedes an apparent external class.
1124        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1125        unescaped square brackets may also appear as part of class names. For
1126        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1127        more like Perl. (But see 8.20/1 above.)
1129    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1130        was because it thought it was \N{name}, which is not supported).
1132    39. Add minix to OS list not supporting the -S option in pcretest.
1134    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1135        cannot analyze patterns in sufficient detail to catch mutual recursions
1136        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1137        subgroup is called recursively as a subpattern for a second time at the
1138        same position in the subject string. In previous releases this might have
1139        been caught by the recursion limit, or it might have run out of stack.
1141    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1142        happen only once. PCRE was, however incorrectly giving a compile time error
1143        "recursive call could loop indefinitely" because it cannot analyze the
1144        pattern in sufficient detail. The compile time test no longer happens when
1145        PCRE is compiling a conditional subpattern, but actual runaway loops are
1146        now caught at runtime (see 40 above).
1148    42. It seems that Perl allows any characters other than a closing parenthesis
1149        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1150        has been changed to be the same.
1152    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1153        as not to get warnings when autogen.sh is called. Also changed
1154        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1156    44. To help people who use pcregrep to scan files containing exceedingly long
1157        lines, the following changes have been made:
1159        (a) The default value of the buffer size parameter has been increased from
1160            8K to 20K. (The actual buffer used is three times this size.)
1162        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1163            PCRE is built.
1165        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1166            to be set at run time.
1168        (d) Numerical values in pcregrep options can be followed by K or M, for
1169            example --buffer-size=50K.
1171        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1172            given and the return code is set to 2.
1174    45. Add a pointer to the latest mark to the callout data block.
1176    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1177        partial match of an empty string instead of no match. This was specific to
1178        the use of ".".
1180    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1181        complete match instead of a partial match. This bug was dependent on both
1182        the PCRE_UTF8 and PCRE_DOTALL options being set.
1184    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1185        starting byte set, because \b was not being ignored.
1188    Version 8.12 15-Jan-2011
1189    ------------------------
1191    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1192        checks for such things as part of the documentation building process.
1194    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1195        --match-limit and --recursion-limit options (added for 8.11). In
1196        particular, this made one of the standard tests fail. (The integer value
1197        went into the wrong half of a long int.)
1199    3.  If the --colour option was given to pcregrep with -v (invert match), it
1200        did strange things, either producing crazy output, or crashing. It should,
1201        of course, ignore a request for colour when reporting lines that do not
1202        match.
1204    4.  Another pcregrep bug caused similar problems if --colour was specified with
1205        -M (multiline) and the pattern match finished with a line ending.
1207    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1208        matched in multiline mode, the following line was shown as part of the
1209        match. This seems wrong, so I have changed it.
1211    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1212        the check for further matches in the same line (so they could be coloured)
1213        to overrun the end of the current line. If another match was found, it was
1214        incorrectly shown (and then shown again when found in the next line).
1216    7.  If pcregrep was compiled under Windows, there was a reference to the
1217        function pcregrep_exit() before it was defined. I am assuming this was
1218        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1219        reported by a user. I've moved the definition above the reference.
1222    Version 8.11 10-Dec-2010
1223    ------------------------
1225    1.  (*THEN) was not working properly if there were untried alternatives prior
1226        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1227        backtracked to try for "b" instead of moving to the next alternative branch
1228        at the same level (in this case, to look for "c"). The Perl documentation
1229        is clear that when (*THEN) is backtracked onto, it goes to the "next
1230        alternative in the innermost enclosing group".
1232    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1233        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1234        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1235        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1236        (*THEN).
1238    3.  If \s appeared in a character class, it removed the VT character from
1239        the class, even if it had been included by some previous item, for example
1240        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1241        of \s, but is part of the POSIX "space" class.)
1243    4.  A partial match never returns an empty string (because you can always
1244        match an empty string at the end of the subject); however the checking for
1245        an empty string was starting at the "start of match" point. This has been
1246        changed to the "earliest inspected character" point, because the returned
1247        data for a partial match starts at this character. This means that, for
1248        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1249        (previously it gave "no match").
1251    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1252        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1253        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1254        has an implication that the given string is incomplete (because a partial
1255        match is preferred over a full match). For this reason, these items now
1256        give a partial match in this situation. [Aside: previously, the one case
1257        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1258        match rather than a full match, which was wrong by the old rules, but is
1259        now correct.]
1261    6.  There was a bug in the handling of #-introduced comments, recognized when
1262        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1263        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1264        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1265        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1266        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1267        places in pcre_compile().
1269    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1270        comments when looking ahead for named forward references to subpatterns,
1271        the only newline sequence it recognized was NL. It now handles newlines
1272        according to the set newline convention.
1274    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1275        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1276        cater for a lack of strerror(). These oversights have been fixed.
1278    9.  Added --match-limit and --recursion-limit to pcregrep.
1280    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1282    11. When the -o option was used, pcregrep was setting a return code of 1, even
1283        when matches were found, and --line-buffered was not being honoured.
1285    12. Added an optional parentheses number to the -o and --only-matching options
1286        of pcregrep.
1288    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1289        can match an empty string. The code to do it in pcretest and pcredemo
1290        needed fixing:
1292        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1293            only one byte after an empty string match just before CRLF (this case
1294            just got forgotten; "any" and "anycrlf" were OK).
1296        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1297            mode when an empty string match preceded an ASCII character followed by
1298            a non-ASCII character. (The code for advancing by one character rather
1299            than one byte was nonsense.)
1301        (c) The pcredemo.c sample program did not have any code at all to handle
1302            the cases when CRLF is a valid newline sequence.
1304    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1305        as a starting offset was within the subject string. There is now a new
1306        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1307        negative or greater than the length of the string. In order to test this,
1308        pcretest is extended to allow the setting of negative starting offsets.
1310    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1311        starting offset points to the beginning of a UTF-8 character was
1312        unnecessarily clumsy. I tidied it up.
1314    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1315        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1317    17. Nobody had reported that the --include_dir option, which was added in
1318        release 7.7 should have been called --include-dir (hyphen, not underscore)
1319        for compatibility with GNU grep. I have changed it to --include-dir, but
1320        left --include_dir as an undocumented synonym, and the same for
1321        --exclude-dir, though that is not available in GNU grep, at least as of
1322        release 2.5.4.
1324    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1325        characters from a string of bytes) have been redefined so as not to use
1326        loops, in order to improve performance in some environments. At the same
1327        time, I abstracted some of the common code into auxiliary macros to save
1328        repetition (this should not affect the compiled code).
1330    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1331        compile-time error is now given if \c is not followed by an ASCII
1332        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1333        different, and any byte value is allowed.)
1335    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1336        START_OPTIMIZE option, which is now allowed at compile time - but just
1337        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1338        to pcregrep and other applications that have no direct access to PCRE
1339        options. The new /Y option in pcretest sets this option when calling
1340        pcre_compile().
1342    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1343        back references. Groups containing recursive back references were forced to
1344        be atomic by that change, but in the case of named groups, the amount of
1345        memory required was incorrectly computed, leading to "Failed: internal
1346        error: code overflow". This has been fixed.
1348    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1349        pcretest.c, to avoid build problems in some Borland environments.
1352    Version 8.10 25-Jun-2010
1353    ------------------------
1355    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1356        THEN.
1358    2.  (*ACCEPT) was not working when inside an atomic group.
1360    3.  Inside a character class, \B is treated as a literal by default, but
1361        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1362        causes the error). The code is unchanged, but I tidied the documentation.
1364    4.  Inside a character class, PCRE always treated \R and \X as literals,
1365        whereas Perl faults them if its -w option is set. I have changed PCRE so
1366        that it faults them when PCRE_EXTRA is set.
1368    5.  Added support for \N, which always matches any character other than
1369        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1371    6.  When compiling pcregrep with newer versions of gcc which may have
1372        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1373        declared with attribute warn_unused_result" were given. Just casting the
1374        result to (void) does not stop the warnings; a more elaborate fudge is
1375        needed. I've used a macro to implement this.
1377    7.  Minor change to pcretest.c to avoid a compiler warning.
1379    8.  Added four artifical Unicode properties to help with an option to make
1380        \s etc use properties (see next item). The new properties are: Xan
1381        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1383    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1384        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1385        this option. Modified pcretest to add /W to test this facility. Added
1386        REG_UCP to make it available via the POSIX interface.
1388    10. Added --line-buffered to pcregrep.
1390    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1391        studied, and the match started with a letter with a code point greater than
1392        127 whose first byte was different to the first byte of the other case of
1393        the letter, the other case of this starting letter was not recognized
1394        (#976).
1396    12. If a pattern that was studied started with a repeated Unicode property
1397        test, for example, \p{Nd}+, there was the theoretical possibility of
1398        setting up an incorrect bitmap of starting bytes, but fortunately it could
1399        not have actually happened in practice until change 8 above was made (it
1400        added property types that matched character-matching opcodes).
1402    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1403        possible starting bytes for non-anchored patterns.
1405    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1406        \R, and also a number of cases that involve Unicode properties, both
1407        explicit and implicit when PCRE_UCP is set.
1409    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1410        input, it could crash or give wrong results if characters with values
1411        greater than 0xc0 were present in the subject string. (Detail: it assumed
1412        UTF-8 input when processing these items.)
1414    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1415        size_t is 64-bit (#991).
1417    17. Added a check for running out of memory when PCRE is compiled with
1418        --disable-stack-for-recursion (#990).
1420    18. If the last data line in a file for pcretest does not have a newline on
1421        the end, a newline was missing in the output.
1423    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1424        less than 128) in its various bitmaps. However, there is a facility for
1425        generating tables according to the current locale when PCRE is compiled. It
1426        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1427        characters, are recognized by isspace() and therefore were getting set in
1428        these tables, and indeed these tables seem to approximate to ISO 8859. This
1429        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1430        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1431        which of course cannot start UTF-8 characters. I have changed the code so
1432        that only real ASCII characters (less than 128) and the correct starting
1433        bytes for UTF-8 encodings are set for characters greater than 127 when in
1434        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1435        altogether.)
1437    20. Added the /T option to pcretest so as to be able to run tests with non-
1438        standard character tables, thus making it possible to include the tests
1439        used for 19 above in the standard set of tests.
1441    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1442        reference to a subpattern the other side of a comment that contains an
1443        opening parenthesis caused either an internal compiling error, or a
1444        reference to the wrong subpattern.
1447    Version 8.02 19-Mar-2010
1448    ------------------------
1450    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1452    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1453        configured.
1455    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1456        original author of that file, following a query about its status.
1458    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1459        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1461    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1462        quantifier applied to a forward-referencing subroutine call, could compile
1463        incorrect code or give the error "internal error: previously-checked
1464        referenced subpattern not found".
1466    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1467        variables to point to external functions. For these systems, therefore,
1468        pcre_malloc etc. are now initialized to local functions that call the
1469        relevant global functions.
1471    7.  There were two entries missing in the vectors called coptable and poptable
1472        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1473        I've fixed the data, and added a kludgy way of testing at compile time that
1474        the lengths are correct (equal to the number of opcodes).
1476    8.  Following on from 7, I added a similar kludge to check the length of the
1477        eint vector in pcreposix.c.
1479    9.  Error texts for pcre_compile() are held as one long string to avoid too
1480        much relocation at load time. To find a text, the string is searched,
1481        counting zeros. There was no check for running off the end of the string,
1482        which could happen if a new error number was added without updating the
1483        string.
1485    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1487    11. \K was not working if it appeared in an atomic group or in a group that
1488        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1489        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1490        the assertion is positive, but not if it is negative.
1492    12. Change 11 fortuitously reduced the size of the stack frame used in the
1493        "match()" function of pcre_exec.c by one pointer. Forthcoming
1494        implementation of support for (*MARK) will need an extra pointer on the
1495        stack; I have reserved it now, so that the stack frame size does not
1496        decrease.
1498    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1499        item in branch that calls a recursion is a subroutine call - as in the
1500        second branch in the above example - was incorrectly given the compile-
1501        time error "recursive call could loop indefinitely" because pcre_compile()
1502        was not correctly checking the subroutine for matching a non-empty string.
1504    14. The checks for overrunning compiling workspace could trigger after an
1505        overrun had occurred. This is a "should never occur" error, but it can be
1506        triggered by pathological patterns such as hundreds of nested parentheses.
1507        The checks now trigger 100 bytes before the end of the workspace.
1509    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1512    Version 8.01 19-Jan-2010
1513    ------------------------
1515    1.  If a pattern contained a conditional subpattern with only one branch (in
1516        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1517        computed the wrong minimum data length (which is of course zero for such
1518        subpatterns). This could cause incorrect "no match" results.
1520    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1521        the pattern is reset in the first branch, pcre_compile() failed with
1522        "internal error: code overflow at offset...". This happened only when
1523        the reset was to the original external option setting. (An optimization
1524        abstracts leading options settings into an external setting, which was the
1525        cause of this.)
1527    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1528        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1529        assertion pattern did not match (meaning that the assertion was true), it
1530        was incorrectly treated as false if the SKIP had been reached during the
1531        matching. This also applied to assertions used as conditions.
1533    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1534        assertion subpattern, including such a pattern used as a condition,
1535        unpredictable results occurred, instead of the error return
1538    5.  The C++ GlobalReplace function was not working like Perl for the special
1539        situation when an empty string is matched. It now does the fancy magic
1540        stuff that is necessary.
1542    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1543        removed. (These were left over from very, very early versions of PCRE.)
1545    7.  Some cosmetic changes to the code to make life easier when compiling it
1546        as part of something else:
1548        (a) Change DEBUG to PCRE_DEBUG.
1550        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1551            called "current" as "current_branch", to prevent a collision with the
1552            Linux macro when compiled as a kernel module.
1554        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1555            prevent a collision with the Linux macro when compiled as a kernel
1556            module.
1558    8.  In pcre_compile() there are some checks for integer overflows that used to
1559        cast potentially large values to (double). This has been changed to that
1560        when building, a check for int64_t is made, and if it is found, it is used
1561        instead, thus avoiding the use of floating point arithmetic. (There is no
1562        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1563        double.
1565    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1566        2005 (difference between two addresses compared to an unsigned value).
1568    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1569        custom one, because of the following reported problem in Windows:
1571          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1572              under Win32.
1573          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1574              therefore missing the function definition.
1575          - The compiler thus generates a "C" signature for the test function.
1576          - The linker fails to find the "C" function.
1577          - PCRE fails to configure if asked to do so against libbz2.
1579    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1580        messages were output:
1582          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1583          rerunning libtoolize, to keep the correct libtool macros in-tree.
1584          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1586        I have done both of these things.
1588    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1589        most of the time, it *can* run out if it is given a pattern that contains a
1590        runaway infinite recursion. I updated the discussion in the pcrestack man
1591        page.
1593    13. Now that we have gone to the x.xx style of version numbers, the minor
1594        version may start with zero. Using 08 or 09 is a bad idea because users
1595        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1596        interpreted as invalid octal numbers. I've updated the previous comment in
1597        configure.ac, and also added a check that gives an error if 08 or 09 are
1598        used.
1600    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1601        causing partial matching to fail when the end of the subject matched \W
1602        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1604    15. There were some discrepancies between the declarations in pcre_internal.h
1605        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1606        their definitions. The declarations used "const uschar *" and the
1607        definitions used USPTR. Even though USPTR is normally defined as "const
1608        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1609        reported that: "This difference in casting confuses some C++ compilers, for
1610        example, SunCC recognizes above declarations as different functions and
1611        generates broken code for hbpcre." I have changed the declarations to use
1612        USPTR.
1614    16. GNU libtool is named differently on some systems. The autogen.sh script now
1615        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1616        (FreeBSD).
1618    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1619        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1620        comment: "Figure out how to create a longlong from a string: strtoll and
1621        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1622        instance, but it only takes 2 args instead of 3!"
1624    18. A subtle bug concerned with back references has been fixed by a change of
1625        specification, with a corresponding code fix. A pattern such as
1626        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1627        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1628        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1629        same bug. Such groups have to be quantified to be useful, or contained
1630        inside another quantified group. (If there's no repetition, the reference
1631        can never match.) The problem arises because, having left the group and
1632        moved on to the rest of the pattern, a later failure that backtracks into
1633        the group uses the captured value from the final iteration of the group
1634        rather than the correct earlier one. I have fixed this in PCRE by forcing
1635        any group that contains a reference to itself to be an atomic group; that
1636        is, there cannot be any backtracking into it once it has completed. This is
1637        similar to recursive and subroutine calls.
1640    Version 8.00 19-Oct-09
1641    ----------------------
1643    1.  The table for translating pcre_compile() error codes into POSIX error codes
1644        was out-of-date, and there was no check on the pcre_compile() error code
1645        being within the table. This could lead to an OK return being given in
1646        error.
1648    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1649        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1650        in a Windows environment.
1652    3.  The pcregrep --count option prints the count for each file even when it is
1653        zero, as does GNU grep. However, pcregrep was also printing all files when
1654        --files-with-matches was added. Now, when both options are given, it prints
1655        counts only for those files that have at least one match. (GNU grep just
1656        prints the file name in this circumstance, but including the count seems
1657        more useful - otherwise, why use --count?) Also ensured that the
1658        combination -clh just lists non-zero counts, with no names.
1660    4.  The long form of the pcregrep -F option was incorrectly implemented as
1661        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1662        but it seems right to fix it, and I didn't think it was worth preserving
1663        the old behaviour.
1665    5.  The command line items --regex=pattern and --regexp=pattern were not
1666        recognized by pcregrep, which required --regex pattern or --regexp pattern
1667        (with a space rather than an '='). The man page documented the '=' forms,
1668        which are compatible with GNU grep; these now work.
1670    6.  No libpcreposix.pc file was created for pkg-config; there was just
1671        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1673    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1674        when UCP support is not needed, by modifying the Python script that
1675        generates it from Unicode data files. This should not matter if the module
1676        is correctly used as a library, but I received one complaint about 50K of
1677        unwanted data. My guess is that the person linked everything into his
1678        program rather than using a library. Anyway, it does no harm.
1680    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1681        was a minimum greater than 1 for a wide character in a possessive
1682        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1683        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1684        character. Chaos in the form of incorrect output or a compiling loop could
1685        result.
1687    9.  The restrictions on what a pattern can contain when partial matching is
1688        requested for pcre_exec() have been removed. All patterns can now be
1689        partially matched by this function. In addition, if there are at least two
1690        slots in the offset vector, the offset of the earliest inspected character
1691        for the match and the offset of the end of the subject are set in them when
1692        PCRE_ERROR_PARTIAL is returned.
1694    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1695        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1696        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1697        and may be more useful for multi-segment matching.
1699    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1700        used to be given if ever the end of the subject was reached; now it is
1701        given only if matching could not proceed because another character was
1702        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1703        string "Z", which now yields "no match" instead of "partial match". In the
1704        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1705        final character ended with (*FAIL).
1707    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1708        if the pattern had a "must contain" character that was already found in the
1709        earlier partial match, unless partial matching was again requested. For
1710        example, with the pattern /dog.(body)?/, the "must contain" character is
1711        "g". If the first part-match was for the string "dog", restarting with
1712        "sbody" failed. This bug has been fixed.
1714    13. The string returned by pcre_dfa_exec() after a partial match has been
1715        changed so that it starts at the first inspected character rather than the
1716        first character of the match. This makes a difference only if the pattern
1717        starts with a lookbehind assertion or \b or \B (\K is not supported by
1718        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1719        matching functions compatible, and I think it's the right thing to do.
1721    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1722        so that the demonstration program is easily available in environments where
1723        PCRE has not been installed from source.
1725    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1726        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1727        library.
1729    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1730        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1731        is not the first non-POSIX option to be added. Clearly some people find
1732        these options useful.
1734    17. If a caller to the POSIX matching function regexec() passes a non-zero
1735        value for nmatch with a NULL value for pmatch, the value of
1736        nmatch is forced to zero.
1738    18. RunGrepTest did not have a test for the availability of the -u option of
1739        the diff command, as RunTest does. It now checks in the same way as
1740        RunTest, and also checks for the -b option.
1742    19. If an odd number of negated classes containing just a single character
1743        interposed, within parentheses, between a forward reference to a named
1744        subpattern and the definition of the subpattern, compilation crashed with
1745        an internal error, complaining that it could not find the referenced
1746        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1747        [The bug was that it was starting one character too far in when skipping
1748        over the character class, thus treating the ] as data rather than
1749        terminating the class. This meant it could skip too much.]
1751    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1752        /g option in pcretest when the pattern contains \K, which makes it possible
1753        to have an empty string match not at the start, even when the pattern is
1754        anchored. Updated pcretest and pcredemo to use this option.
1756    21. If the maximum number of capturing subpatterns in a recursion was greater
1757        than the maximum at the outer level, the higher number was returned, but
1758        with unset values at the outer level. The correct (outer level) value is
1759        now given.
1761    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1762        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1763        make it do so. The string so far is captured, making this feature
1764        compatible with Perl.
1766    23. The tests have been re-organized, adding tests 11 and 12, to make it
1767        possible to check the Perl 5.10 features against Perl 5.10.
1769    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1770        pattern matches a fixed length string. PCRE did not allow this; now it
1771        does. Neither allows recursion.
1773    25. I finally figured out how to implement a request to provide the minimum
1774        length of subject string that was needed in order to match a given pattern.
1775        (It was back references and recursion that I had previously got hung up
1776        on.) This code has now been added to pcre_study(); it finds a lower bound
1777        to the length of subject needed. It is not necessarily the greatest lower
1778        bound, but using it to avoid searching strings that are too short does give
1779        some useful speed-ups. The value is available to calling programs via
1780        pcre_fullinfo().
1782    26. While implementing 25, I discovered to my embarrassment that pcretest had
1783        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1784        study optimizations had never been tested with that matching function.
1785        Oops. What is worse, even when it was passed study data, there was a bug in
1786        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1787        were also very few tests of studied patterns with pcre_dfa_exec().
1789    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1790        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1791        on the other side of the coin, they are no longer allowed to have different
1792        names, because these cannot be distinguished in PCRE, and this has caused
1793        confusion. (This is a difference from Perl.)
1795    28. When duplicate subpattern names are present (necessarily with different
1796        numbers, as required by 27 above), and a test is made by name in a
1797        conditional pattern, either for a subpattern having been matched, or for
1798        recursion in such a pattern, all the associated numbered subpatterns are
1799        tested, and the overall condition is true if the condition is true for any
1800        one of them. This is the way Perl works, and is also more like the way
1801        testing by number works.
1804    Version 7.9 11-Apr-09
1805    ---------------------
1807    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1808        (pcretest), all targets were linked against these libraries. This included
1809        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1810        libraries. This caused unwanted dependencies to be created. This problem
1811        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1812        pcretest is linked with readline.
1814    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1815        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1816        moved outside it again, because FALSE and TRUE are already defined in AIX,
1817        but BOOL is not.
1819    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1820        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1822    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1823        hyphens) following file names and line numbers when outputting matching
1824        lines. This is not true; no spaces are inserted. I have also clarified the
1825        wording for the --colour (or --color) option.
1827    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1828        was not coloured; this is different to GNU grep, so I have changed it to be
1829        the same.
1831    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1832        each matching line was coloured. Now it goes on to look for further matches
1833        of any of the test patterns, which is the same behaviour as GNU grep.
1835    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1836        doesn't make sense to accept an empty string match in pcregrep, so I have
1837        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1838        seems to be how GNU grep behaves. [But see later change 40 for release
1839        8.33.]
1841    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1842        start or after a newline", because the conditional assertion was not being
1843        correctly handled. The rule now is that both the assertion and what follows
1844        in the first alternative must satisfy the test.
1846    9.  If auto-callout was enabled in a pattern with a conditional group whose
1847        condition was an assertion, PCRE could crash during matching, both with
1848        pcre_exec() and pcre_dfa_exec().
1850    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1851        used for matching.
1853    11. Unicode property support in character classes was not working for
1854        characters (bytes) greater than 127 when not in UTF-8 mode.
1856    12. Added the -M command line option to pcretest.
1858    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1860    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1862    16. Added comments and documentation about mis-use of no_arg in the C++
1863        wrapper.
1865    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1866        from Martin Jerabek that uses macro names for all relevant character and
1867        string constants.
1869    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1870        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1871        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1872        these, but not everybody uses configure.
1874    19. A conditional group that had only one branch was not being correctly
1875        recognized as an item that could match an empty string. This meant that an
1876        enclosing group might also not be so recognized, causing infinite looping
1877        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1878        with the subject "ab", where knowledge that the repeated group can match
1879        nothing is needed in order to break the loop.
1881    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1882        exec(), but without supplying a callout function, matching went wrong.
1884    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1885        leak if the size of the offset vector was greater than 30. When the vector
1886        is smaller, the saved offsets during recursion go onto a local stack
1887        vector, but for larger vectors malloc() is used. It was failing to free
1888        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1889        error, in fact).
1891    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1892        heapframe that is used only when UTF-8 support is enabled. This caused no
1893        problem, but was untidy.
1895    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1896        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1897        included within another project.
1899    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1900        slightly modified by me:
1902          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1903              not building pcregrep.
1905          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1906              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1908    25. Forward references, both numeric and by name, in patterns that made use of
1909        duplicate group numbers, could behave incorrectly or give incorrect errors,
1910        because when scanning forward to find the reference group, PCRE was not
1911        taking into account the duplicate group numbers. A pattern such as
1912        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1914    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1915        the feature of a custom pointer more persuasive (as requested by a user).
1917    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1918        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1919        pre-defined.
1921    28. Added support for (*UTF8) at the start of a pattern.
1923    29. Arrange for flags added by the "release type" setting in CMake to be shown
1924        in the configuration summary.
1927    Version 7.8 05-Sep-08
1928  ---------------------  ---------------------
1930  1.  Replaced UCP searching code with optimized version as implemented for Ad  1.  Replaced UCP searching code with optimized version as implemented for Ad
# Line 31  Version 8.0 02 Jul-08 Line 1954  Version 8.0 02 Jul-08
1955  7.  Added two (int) casts to pcregrep when printing the difference of two  7.  Added two (int) casts to pcregrep when printing the difference of two
1956      pointers, in case they are 64-bit values.      pointers, in case they are 64-bit values.
1958  8.  Added comments about Mac OS X stack usage to the pcrestack man page and to  8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1959      test 2 if it fails.      test 2 if it fails.
1961  9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,  9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1962      and a #define of that name to empty if it is not externally set. This is to      and a #define of that name to empty if it is not externally set. This is to
1963      allow users of MSVC to set it if necessary.      allow users of MSVC to set it if necessary.
1965  10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from  10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1966      the convenience functions in the pcre_get.c source file.      the convenience functions in the pcre_get.c source file.
1968  11. An option change at the start of a pattern that had top-level alternatives  11. An option change at the start of a pattern that had top-level alternatives
1969      could cause overwriting and/or a crash. This command provoked a crash in      could cause overwriting and/or a crash. This command provoked a crash in
1970      some environments:      some environments:
1972        printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest        printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1974      This potential security problem was recorded as CVE-2008-2371.      This potential security problem was recorded as CVE-2008-2371.
1976  12. For a pattern where the match had to start at the beginning or immediately  12. For a pattern where the match had to start at the beginning or immediately
1977      after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and      after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1978      pcre_dfa_exec() could read past the end of the passed subject if there was      pcre_dfa_exec() could read past the end of the passed subject if there was
1979      no match. To help with detecting such bugs (e.g. with valgrind), I modified      no match. To help with detecting such bugs (e.g. with valgrind), I modified
1980      pcretest so that it places the subject at the end of its malloc-ed buffer.      pcretest so that it places the subject at the end of its malloc-ed buffer.
1982    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1983        exec() might read past the end of the data buffer in UTF-8 mode.
1985    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1986        the data contained the byte 0x85 as part of a UTF-8 character within its
1987        first line. This applied both to normal and DFA matching.
1989    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1990        /^[^d]*?$/8 failed to match "abc".
1992    16. Added a missing copyright notice to pcrecpp_internal.h.
1994    17. Make it more clear in the documentation that values returned from
1995        pcre_exec() in ovector are byte offsets, not character counts.
1997    18. Tidied a few places to stop certain compilers from issuing warnings.
1999    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
2000        supplied by Stefan Weber. I made a further small update for 7.8 because
2001        there is a change of source arrangements: the pcre_searchfuncs.c module is
2002        replaced by pcre_ucd.c.
2005  Version 7.7 07-May-08  Version 7.7 07-May-08
2006  ---------------------  ---------------------
# Line 134  Version 7.7 07-May-08 Line 2079  Version 7.7 07-May-08
2079      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2080      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2081      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2082      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2083      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2084      was subsequently set up correctly.)      was subsequently set up correctly.)

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