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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.02 01-Mar-2010  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_POSSESS is added for testing purposes, and the -O and /O
89        options in pcretest are provided to set it. It can also be set by
90        (*NO_AUTO_POSSESS) at the start of a pattern.
92    18. The character VT has been added to the set of characters that match \s and
93        are generally treated as white space, following this same change in Perl
94        5.18. There is now no difference between "Perl space" and "POSIX space".
96    19. The code for checking named groups as conditions, either for being set or
97        for being recursed, has been refactored (this is related to 14 and 15
98        above). Processing unduplicated named groups should now be as fast at
99        numerical groups, and processing duplicated groups should be faster than
100        before.
102    20. Two patches to the CMake build system, by Alexander Barkov:
104          (1) Replace the "source" command by "." in CMakeLists.txt because
105              "source" is a bash-ism.
107          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
108              without these the CMake build does not work on Solaris.
110    21. Perl has changed its handling of \8 and \9. If there is no previously
111        encountered capturing group of those numbers, they are treated as the
112        literal characters 8 and 9 instead of a binary zero followed by the
113        literals. PCRE now does the same.
115    22. Following Perl, added \o{} to specify codepoints in octal, making it
116        possible to specify values greater than 0777 and also making them
117        unambiguous.
119    23. Perl now gives an error for missing closing braces after \x{... instead of
120        treating the string as literal. PCRE now does the same.
122    24. RunTest used to grumble if an inappropriate test was selected explicitly,
123        but just skip it when running all tests. This make it awkward to run ranges
124        of tests when one of them was inappropriate. Now it just skips any
125        inappropriate tests, as it always did when running all tests.
127    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
128        character types such as \d or \w, too many callouts were inserted, and the
129        data that they returned was rubbish.
131    26. In UCP mode, \s was not matching two of the characters that Perl matches,
132        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
133        were matched by \h. The code has now been refactored so that the lists of
134        the horizontal and vertical whitespace characters used for \h and \v (which
135        are defined only in one place) are now also used for \s.
137    27. Add JIT support for the 64 bit TileGX architecture.
138        Patch by Jiong Wang (Tilera Corporation).
140    28. Possessive quantifiers for classes (both explicit and automatically
141        generated) now use special opcodes instead of wrapping in ONCE brackets.
143    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
144        (because it's meaningless), this was not happening when PCRE_CASELESS was
145        set. Not wrong, but inefficient.
147    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
148        properties for \w, \d, etc) is present in a test regex. Otherwise if the
149        test contains no characters greater than 255, Perl doesn't realise it
150        should be using Unicode semantics.
152    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
153        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
154        does in Unicode mode.
156    32. Added the "forbid" facility to pcretest so that putting tests into the
157        wrong test files can sometimes be quickly detected.
159    33. There is now a limit (default 250) on the depth of nesting of parentheses.
160        This limit is imposed to control the amount of system stack used at compile
161        time. It can be changed at build time by --with-parens-nest-limit=xxx or
162        the equivalent in CMake.
164    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
165        errors. Perl warns for these when in warning mode, but PCRE has no facility
166        for giving warnings.
168    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
169        However, this was not working for (?!) because it is optimized to (*FAIL),
170        for which PCRE does not allow quantifiers. The optimization is now disabled
171        when a quantifier follows (?!). I can't see any use for this, but it makes
172        things uniform.
174    36. Perl no longer allows group names to start with digits, so I have made this
175        change also in PCRE. It simplifies the code a bit.
177    37. In extended mode, Perl ignores spaces before a + that indicates a
178        possessive quantifier. PCRE allowed a space before the quantifier, but not
179        before the possessive +. It now does.
181    38. The use of \K (reset reported match start) within a repeated possessive
182        group such as (a\Kb)*+ was not working.
185    Version 8.33 28-May-2013
186    ------------------------
188    1.  Added 'U' to some constants that are compared to unsigned integers, to
189        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
190        variables that are added to signed variables, to ensure the result is
191        signed and can be negated.
193    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
194        CMake config files.
196    3.  Revise the creation of config.h.generic so that all boolean macros are
197        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
198        overriding via -D on the command line possible.
200    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
201        to unsigned int is reported to make a quite noticeable speed difference in
202        a specific Windows environment. Testing on Linux did also appear to show
203        some benefit (and it is clearly not harmful). Also fixed the definition of
204        Xop which should be unsigned.
206    5.  Related to (4), changing the definition of the intermediate variable cc
207        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
208        improvements.
210    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
211        unnecessary spaces.
213    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
214        and later.
216    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
218    9.  Optimizing fast_forward_start_bits in JIT.
220    10. Adding support for callouts in JIT, and fixing some issues revealed
221        during this work. Namely:
223        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
225        (b) Minimum length was not checked before the matching is started.
227    11. The value of capture_last that is passed to callouts was incorrect in some
228        cases when there was a capture on one path that was subsequently abandoned
229        after a backtrack. Also, the capture_last value is now reset after a
230        recursion, since all captures are also reset in this case.
232    12. The interpreter no longer returns the "too many substrings" error in the
233        case when an overflowing capture is in a branch that is subsequently
234        abandoned after a backtrack.
236    13. In the pathological case when an offset vector of size 2 is used, pcretest
237        now prints out the matched string after a yield of 0 or 1.
239    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
240        Only supported by the JIT compiler at the moment.
242    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
244    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
245        offset of the starting point of the matching process, provided the offsets
246        vector is large enough.
248    17. The \A escape now records a lookbehind value of 1, though its execution
249        does not actually inspect the previous character. This is to ensure that,
250        in partial multi-segment matching, at least one character from the old
251        segment is retained when a new segment is processed. Otherwise, if there
252        are no lookbehinds in the pattern, \A might match incorrectly at the start
253        of a new segment.
255    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
257    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
258        gives some modest performance improvement in 8-bit mode.
260    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
261        be expressed in certain programming languages using Universal Character
262        Names.
264    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
265        which points out that "non characters" are not "characters that may not
266        appear in Unicode strings" but rather "characters that are reserved for
267        internal use and have only local meaning".
269    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
270        there was a conditional group that depended on an assertion, if the
271        assertion was false, the callout that immediately followed the alternation
272        in the condition was skipped when pcre_exec() was used for matching.
274    23. Allow an explicit callout to be inserted before an assertion that is the
275        condition for a conditional group, for compatibility with automatic
276        callouts, which always insert a callout at this point.
278    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
279        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
281    25. (*PRUNE) is now supported by the JIT compiler.
283    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
285    27. Fix the case where there are two or more SKIPs with arguments that may be
286        ignored.
288    28. (*SKIP) is now supported by the JIT compiler.
290    29. (*THEN) is now supported by the JIT compiler.
292    30. Update RunTest with additional test selector options.
294    31. The way PCRE handles backtracking verbs has been changed in two ways.
296        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
297        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
298        backtracking. In some cases this makes it more Perl-compatible, but Perl's
299        rather obscure rules do not always do the same thing.
301        (2) Previously, backtracking verbs were confined within assertions. This is
302        no longer the case for positive assertions, except for (*ACCEPT). Again,
303        this sometimes improves Perl compatibility, and sometimes does not.
305    32. A number of tests that were in test 2 because Perl did things differently
306        have been moved to test 1, because either Perl or PCRE has changed, and
307        these tests are now compatible.
309    32. Backtracking control verbs are now handled in the same way in JIT and
310        interpreter.
312    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
313        contained a forward subroutine reference caused a compile error.
315    34. Auto-detect and optimize limited repetitions in JIT.
317    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
318        blocking (*UTF) etc.
320    36. In the interpreter, maximizing pattern repetitions for characters and
321        character types now use tail recursion, which reduces stack usage.
323    37. The value of the max lookbehind was not correctly preserved if a compiled
324        and saved regex was reloaded on a host of different endianness.
326    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
327        of the compiled pattern block, expand the flags field from 16 to 32 bits
328        because it was almost full.
330    39. Try madvise first before posix_madvise.
332    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
333        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
334        original change locked out all matches of empty strings. This has been
335        changed so that one match of an empty string per line is recognized.
336        Subsequent searches on the same line (for colouring or for --only-matching,
337        for example) do not recognize empty strings.
339    41. Applied a user patch to fix a number of spelling mistakes in comments.
341    42. Data lines longer than 65536 caused pcretest to crash.
343    43. Clarified the data type for length and startoffset arguments for pcre_exec
344        and pcre_dfa_exec in the function-specific man pages, where they were
345        explicitly stated to be in bytes, never having been updated. I also added
346        some clarification to the pcreapi man page.
348    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
349        a segmentation fault.
352    Version 8.32 30-November-2012
353    -----------------------------
355    1.  Improved JIT compiler optimizations for first character search and single
356        character iterators.
358    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
359        Patch by Daniel Richard G.
361    3.  Single character iterator optimizations in the JIT compiler.
363    4.  Improved JIT compiler optimizations for character ranges.
365    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
366        Reported by Giuseppe D'Angelo.
368    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
369        of a line, was being set incorrectly in cases where .* appeared inside
370        atomic brackets at the start of a pattern, or where there was a subsequent
371        *PRUNE or *SKIP.
373    7.  Improved instruction cache flush for POWER/PowerPC.
374        Patch by Daniel Richard G.
376    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
377        grep:
379        (a) There is now no limit to the number of patterns to be matched.
381        (b) An error is given if a pattern is too long.
383        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
384            are now supported.
386        (d) --exclude-from and --include-from (multiple use) have been added.
388        (e) Exclusions and inclusions now apply to all files and directories, not
389            just to those obtained from scanning a directory recursively.
391        (f) Multiple uses of -f and --file-list are now supported.
393        (g) In a Windows environment, the default for -d has been changed from
394            "read" (the GNU grep default) to "skip", because otherwise the presence
395            of a directory in the file list provokes an error.
397        (h) The documentation has been revised and clarified in places.
399    9.  Improve the matching speed of capturing brackets.
401    10. Changed the meaning of \X so that it now matches a Unicode extended
402        grapheme cluster.
404    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
405        out POSIX threads when JIT support is configured.
407    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
409    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
410        structure could go wrong in environments where size_t is not the same size
411        as int.
413    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
414        set.
416    15. The EBCDIC support had decayed; later updates to the code had included
417        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
418        general tidy up of EBCDIC-related issues, and the documentation was also
419        not quite right. There is now a test that can be run on ASCII systems to
420        check some of the EBCDIC-related things (but is it not a full test).
422    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
423        in a small tidy to the code.
425    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
427    18. If the --only-matching (-o) option in pcregrep is specified multiple
428        times, each one causes appropriate output. For example, -o1 -o2 outputs the
429        substrings matched by the 1st and 2nd capturing parentheses. A separating
430        string can be specified by --om-separator (default empty).
432    19. Improving the first n character searches.
434    20. Turn case lists for horizontal and vertical white space into macros so that
435        they are defined only once.
437    21. This set of changes together give more compatible Unicode case-folding
438        behaviour for characters that have more than one other case when UCP
439        support is available.
441        (a) The Unicode property table now has offsets into a new table of sets of
442            three or more characters that are case-equivalent. The MultiStage2.py
443            script that generates these tables (the pcre_ucd.c file) now scans
444            CaseFolding.txt instead of UnicodeData.txt for character case
445            information.
447        (b) The code for adding characters or ranges of characters to a character
448            class has been abstracted into a generalized function that also handles
449            case-independence. In UTF-mode with UCP support, this uses the new data
450            to handle characters with more than one other case.
452        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
453            whose other case is greater than 256 are now correctly matched
454            caselessly. Previously, the high codepoint matched the low one, but not
455            vice versa.
457        (d) The processing of \h, \H, \v, and \ in character classes now makes use
458            of the new class addition function, using character lists defined as
459            macros alongside the case definitions of 20 above.
461        (e) Caseless back references now work with characters that have more than
462            one other case.
464        (f) General caseless matching of characters with more than one other case
465            is supported.
467    22. Unicode character properties were updated from Unicode 6.2.0
469    23. Improved CMake support under Windows. Patch by Daniel Richard G.
471    24. Add support for 32-bit character strings, and UTF-32
473    25. Major JIT compiler update (code refactoring and bugfixing).
474        Experimental Sparc 32 support is added.
476    26. Applied a modified version of Daniel Richard G's patch to create
477        pcre.h.generic and config.h.generic by "make" instead of in the
478        PrepareRelease script.
480    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
481        pcre_compile.c when checking for a zero character.
483    28. Introducing a native interface for JIT. Through this interface, the compiled
484        machine code can be directly executed. The purpose of this interface is to
485        provide fast pattern matching, so several sanity checks are not performed.
486        However, feature tests are still performed. The new interface provides
487        1.4x speedup compared to the old one.
489    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
490        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
491        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
493    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
494        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
495        the "old" RFC 2279). Instead, it ended up passing a negative length to
496        pcre_exec().
498    31. Add support for GCC's visibility feature to hide internal functions.
500    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
501        "unknown -C option" after outputting 0 or 1.
503    33. There is now support for generating a code coverage report for the test
504        suite in environments where gcc is the compiler and lcov is installed. This
505        is mainly for the benefit of the developers.
507    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
508        unaddressable using valgrind annotations, allowing valgrind to detect
509        invalid memory accesses. This is mainly for the benefit of the developers.
511    25. (*UTF) can now be used to start a pattern in any of the three libraries.
513    26. Give configure error if --enable-cpp but no C++ compiler found.
516    Version 8.31 06-July-2012
517    -------------------------
519    1.  Fixing a wrong JIT test case and some compiler warnings.
521    2.  Removed a bashism from the RunTest script.
523    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
524        to unsigned type, result still unsigned" that was given by an MS compiler
525        on encountering the code "-sizeof(xxx)".
527    4.  Partial matching support is added to the JIT compiler.
529    5.  Fixed several bugs concerned with partial matching of items that consist
530        of more than one character:
532        (a) /^(..)\1/ did not partially match "aba" because checking references was
533            done on an "all or nothing" basis. This also applied to repeated
534            references.
536        (b) \R did not give a hard partial match if \r was found at the end of the
537            subject.
539        (c) \X did not give a hard partial match after matching one or more
540            characters at the end of the subject.
542        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
543            a partial match for the string "\r".
545        (e) When newline was set to CRLF, the metacharacter "." did not recognize
546            a partial match for a CR character at the end of the subject string.
548    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
549        running pcretest, the text "(JIT)" added to the output whenever JIT is
550        actually used to run the match.
552    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
553        or /S+[+] with a digit between 1 and 7.
555    8.  OP_NOT now supports any UTF character not just single-byte ones.
557    9.  (*MARK) control verb is now supported by the JIT compiler.
559    10. The command "./RunTest list" lists the available tests without actually
560        running any of them. (Because I keep forgetting what they all are.)
564    12. Applied a (slightly modified) user-supplied patch that improves performance
565        when the heap is used for recursion (compiled with --disable-stack-for-
566        recursion). Instead of malloc and free for each heap frame each time a
567        logical recursion happens, frames are retained on a chain and re-used where
568        possible. This sometimes gives as much as 30% improvement.
570    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
571        call.
573    14. As documented, (*COMMIT) is now confined to within a positive assertion.
575    15. It is now possible to link pcretest with libedit as an alternative to
576        libreadline.
578    16. (*COMMIT) control verb is now supported by the JIT compiler.
580    17. The Unicode data tables have been updated to Unicode 6.1.0.
582    18. Added --file-list option to pcregrep.
584    19. Added binary file support to pcregrep, including the -a, --binary-files,
585        -I, and --text options.
587    20. The madvise function is renamed for posix_madvise for QNX compatibility
588        reasons. Fixed by Giuseppe D'Angelo.
590    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
592    22. Changed the option for creating symbolic links for 16-bit man pages from
593        -s to -sf so that re-installing does not cause issues.
595    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
597    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
598        matches in certain environments (the workspace was not being correctly
599        retained). Also added to pcre_dfa_exec() a simple plausibility check on
600        some of the workspace data at the beginning of a restart.
602    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
603        was not doing so when it should - probably a typo introduced by SVN 528
604        (change 8.10/14).
606    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
607        \w+ when the character tables indicated that \x{c4} was a word character.
608        There were several related cases, all because the tests for doing a table
609        lookup were testing for characters less than 127 instead of 255.
611    27. If a pattern contains capturing parentheses that are not used in a match,
612        their slots in the ovector are set to -1. For those that are higher than
613        any matched groups, this happens at the end of processing. In the case when
614        there were back references that the ovector was too small to contain
615        (causing temporary malloc'd memory to be used during matching), and the
616        highest capturing number was not used, memory off the end of the ovector
617        was incorrectly being set to -1. (It was using the size of the temporary
618        memory instead of the true size.)
620    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
621        ovector size, it uses memory at the end of the block that it has got.
623    29. Check for an overlong MARK name and give an error at compile time. The
624        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
626    30. JIT compiler update.
628    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
629        Rill for the patch.
631    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
633    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
635    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
636        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
637        was enabled.
639    35. Improve JIT code generation for greedy plus quantifier.
641    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
642        1 to "aa" instead of to an empty string. The bug affected repeated groups
643        that could potentially match an empty string.
645    37. Optimizing single character iterators in JIT.
647    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
648        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
649        codepoints that are too big for the mode are faulted, and in a UTF mode,
650        disallowed codepoints are also faulted.
652    39. If PCRE was compiled with UTF support, in three places in the DFA
653        matcher there was code that should only have been obeyed in UTF mode, but
654        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
655        processing when bytes with values greater than 127 were present. In 16-bit
656        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
657        both cases the values are those that cannot be the first data item in a UTF
658        character. The three items that might have provoked this were recursions,
659        possessively repeated groups, and atomic groups.
661    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
662        and pcregrep, because some OS require shared objects to be explicitly
663        passed to ld, causing the link step to fail if they are not.
665    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
666        mode, patterns that started with \h* or \R* might be incorrectly matched.
669    Version 8.30 04-February-2012
670    -----------------------------
672    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
673        name is defined in ctype.h.
675    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
676        only in quite long subpatterns.
678    3.  Removed the function pcre_info(), which has been obsolete and deprecated
679        since it was replaced by pcre_fullinfo() in February 2000.
681    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
682        match a (*MARK), and the match failed at the start of the subject, a
683        reference to memory before the start of the subject could occur. This bug
684        was introduced by fix 17 of release 8.21.
686    5.  A reference to an unset group with zero minimum repetition was giving
687        totally wrong answers (in non-JavaScript-compatibility mode). For example,
688        /(another)?(\1?)test/ matched against "hello world test". This bug was
689        introduced in release 8.13.
691    6.  Add support for 16-bit character strings (a large amount of work involving
692        many changes and refactorings).
694    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
695        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
696        from a file.
698    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
699        rounding is not applied in this particular case).
701    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
702        if they appear, or are escaped, in patterns.
704    10. Get rid of a number of -Wunused-but-set-variable warnings.
706    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
707        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
708        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
709        also returns the mark "x". This bug applied to capturing parentheses,
710        non-capturing parentheses, and atomic parentheses. It also applied to some
711        assertions.
713    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
714        information out of configure.ac instead of relying on pcre.h.generic, which
715        is not stored in the repository.
717    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
718        -lreadline.
720    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
722    15. Applied Graycode's patch to put the top-level frame on the stack rather
723        than the heap when not using the stack for recursion. This gives a
724        performance improvement in many cases when recursion is not deep.
726    16. Experimental code added to "pcretest -C" to output the stack frame size.
729    Version 8.21 12-Dec-2011
730    ------------------------
732    1.  Updating the JIT compiler.
734    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
735        are added as well.
737    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
738        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
739        calling _pcre_jit_exec. Some extra comments are added.
741    4.  (*MARK) settings inside atomic groups that do not contain any capturing
742        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
743        was introduced by change 18 for 8.20.
745    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
746        ECMA-262 standard.
748    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
749        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
750        This bug was probably introduced by change 9 of 8.13.
752    7.  While fixing 6 above, I noticed that a number of other items were being
753        incorrectly rejected as "not fixed length". This arose partly because newer
754        opcodes had not been added to the fixed-length checking code. I have (a)
755        corrected the bug and added tests for these items, and (b) arranged for an
756        error to occur if an unknown opcode is encountered while checking for fixed
757        length instead of just assuming "not fixed length". The items that were
758        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
759        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
760        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
762    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
763        being incorrectly compiled and would have given unpredicatble results.
765    9.  A possessively repeated subpattern with minimum repeat count greater than
766        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
767        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
768        the first (A) could occur when it should not.
770    10. Add a cast and remove a redundant test from the code.
772    11. JIT should use pcre_malloc/pcre_free for allocation.
774    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
775        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
776        is anything other than /usr, -L is still shown).
778    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
780    14. Perl does not support \N without a following name in a [] class; PCRE now
781        also gives an error.
783    15. If a forward reference was repeated with an upper limit of around 2000,
784        it caused the error "internal error: overran compiling workspace". The
785        maximum number of forward references (including repeats) was limited by the
786        internal workspace, and dependent on the LINK_SIZE. The code has been
787        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
788        the default depends on LINK_SIZE. There is a new upper limit (for safety)
789        of around 200,000 forward references. While doing this, I also speeded up
790        the filling in of repeated forward references.
792    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
793        incorrectly expecting the subject to contain another "a" after the start.
795    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
796        in the match, the SKIP should be ignored. This was not happening; instead
797        the SKIP was being treated as NOMATCH. For patterns such as
798        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
799        tested.
801    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
802        now much more compatible with Perl, in particular in cases where the result
803        is a non-match for a non-anchored pattern. For example, if
804        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
805        "m", where previously it did not return a name. A side effect of this
806        change is that for partial matches, the last encountered mark name is
807        returned, as for non matches. A number of tests that were previously not
808        Perl-compatible have been moved into the Perl-compatible test files. The
809        refactoring has had the pleasing side effect of removing one argument from
810        the match() function, thus reducing its stack requirements.
812    19. If the /S+ option was used in pcretest to study a pattern using JIT,
813        subsequent uses of /S (without +) incorrectly behaved like /S+.
815    21. Retrieve executable code size support for the JIT compiler and fixing
816        some warnings.
818    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
819        not work when the shorter character appeared right at the end of the
820        subject string.
822    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
823        systems.
825    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
826        output it when the /M option is used in pcretest.
828    25. The CheckMan script was not being included in the distribution. Also, added
829        an explicit "perl" to run Perl scripts from the PrepareRelease script
830        because this is reportedly needed in Windows.
832    26. If study data was being save in a file and studying had not found a set of
833        "starts with" bytes for the pattern, the data written to the file (though
834        never used) was taken from uninitialized memory and so caused valgrind to
835        complain.
837    27. Updated RunTest.bat as provided by Sheri Pierce.
839    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
841    29. Computation of memory usage for the table of capturing group names was
842        giving an unnecessarily large value.
845    Version 8.20 21-Oct-2011
846    ------------------------
848    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
849        a POSIX class. After further experiments with Perl, which convinced me that
850        Perl has bugs and confusions, a closing square bracket is no longer allowed
851        in a POSIX name. This bug also affected patterns with classes that started
852        with full stops.
854    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
855        captured substring, but while checking the failing first alternative,
856        substring 1 is temporarily captured. If the output vector supplied to
857        pcre_exec() was not big enough for this capture, the yield of the function
858        was still zero ("insufficient space for captured substrings"). This cannot
859        be totally fixed without adding another stack variable, which seems a lot
860        of expense for a edge case. However, I have improved the situation in cases
861        such as /(a)(b)x|abc/ matched against "abc", where the return code
862        indicates that fewer than the maximum number of slots in the ovector have
863        been set.
865    3.  Related to (2) above: when there are more back references in a pattern than
866        slots in the output vector, pcre_exec() uses temporary memory during
867        matching, and copies in the captures as far as possible afterwards. It was
868        using the entire output vector, but this conflicts with the specification
869        that only 2/3 is used for passing back captured substrings. Now it uses
870        only the first 2/3, for compatibility. This is, of course, another edge
871        case.
873    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
874        main code base, and can be used by building with --enable-jit. When this is
875        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
876        runtime --no-jit option is given.
878    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
879        ovector, the return from the function was zero, implying that there were
880        other matches that did not fit. The correct "exactly full" value is now
881        returned.
883    6.  If a subpattern that was called recursively or as a subroutine contained
884        (*PRUNE) or any other control that caused it to give a non-standard return,
885        invalid errors such as "Error -26 (nested recursion at the same subject
886        position)" or even infinite loops could occur.
888    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
889        computing the minimum length on reaching *ACCEPT, and so ended up with the
890        wrong value of 1 rather than 0. Further investigation indicates that
891        computing a minimum subject length in the presence of *ACCEPT is difficult
892        (think back references, subroutine calls), and so I have changed the code
893        so that no minimum is registered for a pattern that contains *ACCEPT.
895    8.  If (*THEN) was present in the first (true) branch of a conditional group,
896        it was not handled as intended. [But see 16 below.]
898    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
899        Sheri Pierce.
901    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
902        the first byte in a match must be "a".
904    11. Change 17 for 8.13 increased the recursion depth for patterns like
905        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
906        pattern contains any instances of (*THEN). If it does not, the old
907        optimizations are restored. It would be nice to do this on a per-group
908        basis, but at the moment that is not feasible.
910    12. In some environments, the output of pcretest -C is CRLF terminated. This
911        broke RunTest's code that checks for the link size. A single white space
912        character after the value is now allowed for.
914    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
915        For "fr", it uses the Windows-specific input and output files.
917    14. If (*THEN) appeared in a group that was called recursively or as a
918        subroutine, it did not work as intended. [But see next item.]
920    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
921        pattern fragments (but not containing any | characters). If A and B are
922        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
923        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
924        D. In other words, Perl considers parentheses that do not contain any |
925        characters to be part of a surrounding alternative, whereas PCRE was
926        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
927        differently. PCRE now behaves in the same way as Perl, except in the case
928        of subroutine/recursion calls such as (?1) which have in any case always
929        been different (but PCRE had them first :-).
931    16. Related to 15 above: Perl does not treat the | in a conditional group as
932        creating alternatives. Such a group is treated in the same way as an
933        ordinary group without any | characters when processing (*THEN). PCRE has
934        been changed to match Perl's behaviour.
936    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
937        RunGrepTest script failed.
939    18. Change 22 for version 13 caused atomic groups to use more stack. This is
940        inevitable for groups that contain captures, but it can lead to a lot of
941        stack use in large patterns. The old behaviour has been restored for atomic
942        groups that do not contain any capturing parentheses.
944    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
945        suppress the check for a minimum subject length at run time. (If it was
946        given to pcre_exec() or pcre_dfa_exec() it did work.)
948    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
949        fail to work when decoding hex characters in data strings in EBCDIC
950        environments.
952    21. It appears that in at least one Mac OS environment, the isxdigit() function
953        is implemented as a macro that evaluates to its argument more than once,
954        contravening the C 90 Standard (I haven't checked a later standard). There
955        was an instance in pcretest which caused it to go wrong when processing
956        \x{...} escapes in subject strings. The has been rewritten to avoid using
957        things like p++ in the argument of isxdigit().
960    Version 8.13 16-Aug-2011
961    ------------------------
963    1.  The Unicode data tables have been updated to Unicode 6.0.0.
965    2.  Two minor typos in pcre_internal.h have been fixed.
967    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
968        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
969        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
971    4.  There were a number of related bugs in the code for matching backrefences
972        caselessly in UTF-8 mode when codes for the characters concerned were
973        different numbers of bytes. For example, U+023A and U+2C65 are an upper
974        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
975        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
976        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
977        2-byte code at the end of the subject (it thought there wasn't enough data
978        left).
980    5.  Comprehensive information about what went wrong is now returned by
981        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
982        as the output vector has at least 2 elements. The offset of the start of
983        the failing character and a reason code are placed in the vector.
985    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
986        now returned is for the first byte of the failing character, instead of the
987        last byte inspected. This is an incompatible change, but I hope it is small
988        enough not to be a problem. It makes the returned offset consistent with
989        pcre_exec() and pcre_dfa_exec().
991    7.  pcretest now gives a text phrase as well as the error number when
992        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
993        failure, the offset and reason code are output.
995    8.  When \R was used with a maximizing quantifier it failed to skip backwards
996        over a \r\n pair if the subsequent match failed. Instead, it just skipped
997        back over a single character (\n). This seems wrong (because it treated the
998        two characters as a single entity when going forwards), conflicts with the
999        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1000        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1001        has been changed.
1003    9.  Some internal refactoring has changed the processing so that the handling
1004        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1005        time (the PCRE_DOTALL option was changed this way some time ago: version
1006        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1007        which was always a bit of a fudge. It also means that there is one less
1008        argument for the match() function, which reduces its stack requirements
1009        slightly. This change also fixes an incompatibility with Perl: the pattern
1010        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1012    10. More internal refactoring has drastically reduced the number of recursive
1013        calls to match() for possessively repeated groups such as (abc)++ when
1014        using pcre_exec().
1016    11. While implementing 10, a number of bugs in the handling of groups were
1017        discovered and fixed:
1019        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1020        (a|)*(?1) gave a compile-time internal error.
1021        ((a|)+)+  did not notice that the outer group could match an empty string.
1022        (^a|^)+   was not marked as anchored.
1023        (.*a|.*)+ was not marked as matching at start or after a newline.
1025    12. Yet more internal refactoring has removed another argument from the match()
1026        function. Special calls to this function are now indicated by setting a
1027        value in a variable in the "match data" data block.
1029    13. Be more explicit in pcre_study() instead of relying on "default" for
1030        opcodes that mean there is no starting character; this means that when new
1031        ones are added and accidentally left out of pcre_study(), testing should
1032        pick them up.
1034    14. The -s option of pcretest has been documented for ages as being an old
1035        synonym of -m (show memory usage). I have changed it to mean "force study
1036        for every regex", that is, assume /S for every regex. This is similar to -i
1037        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1038        using it. It makes it easier to run collections of tests with and without
1039        study enabled, and thereby test pcre_study() more easily. All the standard
1040        tests are now run with and without -s (but some patterns can be marked as
1041        "never study" - see 20 below).
1043    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1044        restoration of the capturing data to the outer values was not happening
1045        correctly.
1047    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1048        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1049        pattern had matched an empty string, and so incorrectly returned a no
1050        match.
1052    17. There was optimizing code for the last branch of non-capturing parentheses,
1053        and also for the obeyed branch of a conditional subexpression, which used
1054        tail recursion to cut down on stack usage. Unfortunately, now that there is
1055        the possibility of (*THEN) occurring in these branches, tail recursion is
1056        no longer possible because the return has to be checked for (*THEN). These
1057        two optimizations have therefore been removed. [But see 8.20/11 above.]
1059    18. If a pattern containing \R was studied, it was assumed that \R always
1060        matched two bytes, thus causing the minimum subject length to be
1061        incorrectly computed because \R can also match just one byte.
1063    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1064        was incorrectly computed.
1066    20. If /S is present twice on a test pattern in pcretest input, it now
1067        *disables* studying, thereby overriding the use of -s on the command line
1068        (see 14 above). This is necessary for one or two tests to keep the output
1069        identical in both cases.
1071    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1072        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1074    22. When an atomic group that contained a capturing parenthesis was
1075        successfully matched, but the branch in which it appeared failed, the
1076        capturing was not being forgotten if a higher numbered group was later
1077        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1078        group 1 to "a", when in fact it should be unset. This applied to multi-
1079        branched capturing and non-capturing groups, repeated or not, and also to
1080        positive assertions (capturing in negative assertions does not happen
1081        in PCRE) and also to nested atomic groups.
1083    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1084        subject after a captured substring, to make it easier to tell which of a
1085        number of identical substrings has been captured.
1087    24. The way atomic groups are processed by pcre_exec() has been changed so that
1088        if they are repeated, backtracking one repetition now resets captured
1089        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1090        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1091        "aaa". Previously, it would have been "a". As part of this code
1092        refactoring, the way recursive calls are handled has also been changed.
1094    25. If an assertion condition captured any substrings, they were not passed
1095        back unless some other capturing happened later. For example, if
1096        (?(?=(a))a) was matched against "a", no capturing was returned.
1098    26. When studying a pattern that contained subroutine calls or assertions,
1099        the code for finding the minimum length of a possible match was handling
1100        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1101        group 1 called group 2 while simultaneously a separate group 2 called group
1102        1). A stack overflow occurred in this case. I have fixed this by limiting
1103        the recursion depth to 10.
1105    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1106        Fortmann. This supports explicit test numbers on the command line, and has
1107        argument validation and error reporting.
1109    28. An instance of \X with an unlimited repeat could fail if at any point the
1110        first character it looked at was a mark character.
1112    29. Some minor code refactoring concerning Unicode properties and scripts
1113        should reduce the stack requirement of match() slightly.
1115    30. Added the '=' option to pcretest to check the setting of unused capturing
1116        slots at the end of the pattern, which are documented as being -1, but are
1117        not included in the return count.
1119    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1120        compiled something random. Now it gives a compile-time error (as does
1121        Perl).
1123    32. A *MARK encountered during the processing of a positive assertion is now
1124        recorded and passed back (compatible with Perl).
1126    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1127        had alternative anchored branches, the search for a second match in a line
1128        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1129        matched the line "0102" twice. The same bug affected patterns that started
1130        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1131        twice.
1133    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1134        does, and because of capturing effects, quantifying parenthesized
1135        assertions may at times be useful. Quantifiers are now allowed for
1136        parenthesized assertions.
1138    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1140    36. \g was being checked for fancy things in a character class, when it should
1141        just be a literal "g".
1143    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1144        appearance of a nested POSIX class supersedes an apparent external class.
1145        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1146        unescaped square brackets may also appear as part of class names. For
1147        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1148        more like Perl. (But see 8.20/1 above.)
1150    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1151        was because it thought it was \N{name}, which is not supported).
1153    39. Add minix to OS list not supporting the -S option in pcretest.
1155    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1156        cannot analyze patterns in sufficient detail to catch mutual recursions
1157        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1158        subgroup is called recursively as a subpattern for a second time at the
1159        same position in the subject string. In previous releases this might have
1160        been caught by the recursion limit, or it might have run out of stack.
1162    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1163        happen only once. PCRE was, however incorrectly giving a compile time error
1164        "recursive call could loop indefinitely" because it cannot analyze the
1165        pattern in sufficient detail. The compile time test no longer happens when
1166        PCRE is compiling a conditional subpattern, but actual runaway loops are
1167        now caught at runtime (see 40 above).
1169    42. It seems that Perl allows any characters other than a closing parenthesis
1170        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1171        has been changed to be the same.
1173    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1174        as not to get warnings when autogen.sh is called. Also changed
1175        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1177    44. To help people who use pcregrep to scan files containing exceedingly long
1178        lines, the following changes have been made:
1180        (a) The default value of the buffer size parameter has been increased from
1181            8K to 20K. (The actual buffer used is three times this size.)
1183        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1184            PCRE is built.
1186        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1187            to be set at run time.
1189        (d) Numerical values in pcregrep options can be followed by K or M, for
1190            example --buffer-size=50K.
1192        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1193            given and the return code is set to 2.
1195    45. Add a pointer to the latest mark to the callout data block.
1197    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1198        partial match of an empty string instead of no match. This was specific to
1199        the use of ".".
1201    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1202        complete match instead of a partial match. This bug was dependent on both
1203        the PCRE_UTF8 and PCRE_DOTALL options being set.
1205    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1206        starting byte set, because \b was not being ignored.
1209    Version 8.12 15-Jan-2011
1210    ------------------------
1212    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1213        checks for such things as part of the documentation building process.
1215    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1216        --match-limit and --recursion-limit options (added for 8.11). In
1217        particular, this made one of the standard tests fail. (The integer value
1218        went into the wrong half of a long int.)
1220    3.  If the --colour option was given to pcregrep with -v (invert match), it
1221        did strange things, either producing crazy output, or crashing. It should,
1222        of course, ignore a request for colour when reporting lines that do not
1223        match.
1225    4.  Another pcregrep bug caused similar problems if --colour was specified with
1226        -M (multiline) and the pattern match finished with a line ending.
1228    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1229        matched in multiline mode, the following line was shown as part of the
1230        match. This seems wrong, so I have changed it.
1232    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1233        the check for further matches in the same line (so they could be coloured)
1234        to overrun the end of the current line. If another match was found, it was
1235        incorrectly shown (and then shown again when found in the next line).
1237    7.  If pcregrep was compiled under Windows, there was a reference to the
1238        function pcregrep_exit() before it was defined. I am assuming this was
1239        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1240        reported by a user. I've moved the definition above the reference.
1243    Version 8.11 10-Dec-2010
1244    ------------------------
1246    1.  (*THEN) was not working properly if there were untried alternatives prior
1247        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1248        backtracked to try for "b" instead of moving to the next alternative branch
1249        at the same level (in this case, to look for "c"). The Perl documentation
1250        is clear that when (*THEN) is backtracked onto, it goes to the "next
1251        alternative in the innermost enclosing group".
1253    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1254        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1255        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1256        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1257        (*THEN).
1259    3.  If \s appeared in a character class, it removed the VT character from
1260        the class, even if it had been included by some previous item, for example
1261        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1262        of \s, but is part of the POSIX "space" class.)
1264    4.  A partial match never returns an empty string (because you can always
1265        match an empty string at the end of the subject); however the checking for
1266        an empty string was starting at the "start of match" point. This has been
1267        changed to the "earliest inspected character" point, because the returned
1268        data for a partial match starts at this character. This means that, for
1269        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1270        (previously it gave "no match").
1272    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1273        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1274        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1275        has an implication that the given string is incomplete (because a partial
1276        match is preferred over a full match). For this reason, these items now
1277        give a partial match in this situation. [Aside: previously, the one case
1278        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1279        match rather than a full match, which was wrong by the old rules, but is
1280        now correct.]
1282    6.  There was a bug in the handling of #-introduced comments, recognized when
1283        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1284        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1285        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1286        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1287        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1288        places in pcre_compile().
1290    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1291        comments when looking ahead for named forward references to subpatterns,
1292        the only newline sequence it recognized was NL. It now handles newlines
1293        according to the set newline convention.
1295    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1296        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1297        cater for a lack of strerror(). These oversights have been fixed.
1299    9.  Added --match-limit and --recursion-limit to pcregrep.
1301    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1303    11. When the -o option was used, pcregrep was setting a return code of 1, even
1304        when matches were found, and --line-buffered was not being honoured.
1306    12. Added an optional parentheses number to the -o and --only-matching options
1307        of pcregrep.
1309    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1310        can match an empty string. The code to do it in pcretest and pcredemo
1311        needed fixing:
1313        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1314            only one byte after an empty string match just before CRLF (this case
1315            just got forgotten; "any" and "anycrlf" were OK).
1317        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1318            mode when an empty string match preceded an ASCII character followed by
1319            a non-ASCII character. (The code for advancing by one character rather
1320            than one byte was nonsense.)
1322        (c) The pcredemo.c sample program did not have any code at all to handle
1323            the cases when CRLF is a valid newline sequence.
1325    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1326        as a starting offset was within the subject string. There is now a new
1327        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1328        negative or greater than the length of the string. In order to test this,
1329        pcretest is extended to allow the setting of negative starting offsets.
1331    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1332        starting offset points to the beginning of a UTF-8 character was
1333        unnecessarily clumsy. I tidied it up.
1335    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1336        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1338    17. Nobody had reported that the --include_dir option, which was added in
1339        release 7.7 should have been called --include-dir (hyphen, not underscore)
1340        for compatibility with GNU grep. I have changed it to --include-dir, but
1341        left --include_dir as an undocumented synonym, and the same for
1342        --exclude-dir, though that is not available in GNU grep, at least as of
1343        release 2.5.4.
1345    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1346        characters from a string of bytes) have been redefined so as not to use
1347        loops, in order to improve performance in some environments. At the same
1348        time, I abstracted some of the common code into auxiliary macros to save
1349        repetition (this should not affect the compiled code).
1351    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1352        compile-time error is now given if \c is not followed by an ASCII
1353        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1354        different, and any byte value is allowed.)
1356    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1357        START_OPTIMIZE option, which is now allowed at compile time - but just
1358        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1359        to pcregrep and other applications that have no direct access to PCRE
1360        options. The new /Y option in pcretest sets this option when calling
1361        pcre_compile().
1363    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1364        back references. Groups containing recursive back references were forced to
1365        be atomic by that change, but in the case of named groups, the amount of
1366        memory required was incorrectly computed, leading to "Failed: internal
1367        error: code overflow". This has been fixed.
1369    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1370        pcretest.c, to avoid build problems in some Borland environments.
1373    Version 8.10 25-Jun-2010
1374    ------------------------
1376    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1377        THEN.
1379    2.  (*ACCEPT) was not working when inside an atomic group.
1381    3.  Inside a character class, \B is treated as a literal by default, but
1382        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1383        causes the error). The code is unchanged, but I tidied the documentation.
1385    4.  Inside a character class, PCRE always treated \R and \X as literals,
1386        whereas Perl faults them if its -w option is set. I have changed PCRE so
1387        that it faults them when PCRE_EXTRA is set.
1389    5.  Added support for \N, which always matches any character other than
1390        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1392    6.  When compiling pcregrep with newer versions of gcc which may have
1393        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1394        declared with attribute warn_unused_result" were given. Just casting the
1395        result to (void) does not stop the warnings; a more elaborate fudge is
1396        needed. I've used a macro to implement this.
1398    7.  Minor change to pcretest.c to avoid a compiler warning.
1400    8.  Added four artifical Unicode properties to help with an option to make
1401        \s etc use properties (see next item). The new properties are: Xan
1402        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1404    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1405        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1406        this option. Modified pcretest to add /W to test this facility. Added
1407        REG_UCP to make it available via the POSIX interface.
1409    10. Added --line-buffered to pcregrep.
1411    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1412        studied, and the match started with a letter with a code point greater than
1413        127 whose first byte was different to the first byte of the other case of
1414        the letter, the other case of this starting letter was not recognized
1415        (#976).
1417    12. If a pattern that was studied started with a repeated Unicode property
1418        test, for example, \p{Nd}+, there was the theoretical possibility of
1419        setting up an incorrect bitmap of starting bytes, but fortunately it could
1420        not have actually happened in practice until change 8 above was made (it
1421        added property types that matched character-matching opcodes).
1423    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1424        possible starting bytes for non-anchored patterns.
1426    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1427        \R, and also a number of cases that involve Unicode properties, both
1428        explicit and implicit when PCRE_UCP is set.
1430    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1431        input, it could crash or give wrong results if characters with values
1432        greater than 0xc0 were present in the subject string. (Detail: it assumed
1433        UTF-8 input when processing these items.)
1435    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1436        size_t is 64-bit (#991).
1438    17. Added a check for running out of memory when PCRE is compiled with
1439        --disable-stack-for-recursion (#990).
1441    18. If the last data line in a file for pcretest does not have a newline on
1442        the end, a newline was missing in the output.
1444    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1445        less than 128) in its various bitmaps. However, there is a facility for
1446        generating tables according to the current locale when PCRE is compiled. It
1447        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1448        characters, are recognized by isspace() and therefore were getting set in
1449        these tables, and indeed these tables seem to approximate to ISO 8859. This
1450        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1451        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1452        which of course cannot start UTF-8 characters. I have changed the code so
1453        that only real ASCII characters (less than 128) and the correct starting
1454        bytes for UTF-8 encodings are set for characters greater than 127 when in
1455        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1456        altogether.)
1458    20. Added the /T option to pcretest so as to be able to run tests with non-
1459        standard character tables, thus making it possible to include the tests
1460        used for 19 above in the standard set of tests.
1462    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1463        reference to a subpattern the other side of a comment that contains an
1464        opening parenthesis caused either an internal compiling error, or a
1465        reference to the wrong subpattern.
1468    Version 8.02 19-Mar-2010
1469  ------------------------  ------------------------
1471  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
1473  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1474      configured.      configured.
1476  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1477      original author of that file, following a query about its status.      original author of that file, following a query about its status.
1479  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1480      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1482  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1483      quantifier applied to a forward-referencing subroutine call, could compile      quantifier applied to a forward-referencing subroutine call, could compile
1484      incorrect code or give the error "internal error: previously-checked      incorrect code or give the error "internal error: previously-checked
1485      referenced subpattern not found".      referenced subpattern not found".
1487  6.  Both MS Visual Studio and Symbian OS have problems with initializing  6.  Both MS Visual Studio and Symbian OS have problems with initializing
1488      variables to point to external functions. For these systems, therefore,      variables to point to external functions. For these systems, therefore,
1489      pcre_malloc etc. are now initialized to local functions that call the      pcre_malloc etc. are now initialized to local functions that call the
1490      relevant global functions.      relevant global functions.
1492  7.  There were two entries missing in the vectors called coptable and poptable  7.  There were two entries missing in the vectors called coptable and poptable
1493      in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.      in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1494      I've fixed the data, and added a kludgy way of testing at compile time that      I've fixed the data, and added a kludgy way of testing at compile time that
1495      the lengths are correct (equal to the number of opcodes).      the lengths are correct (equal to the number of opcodes).
1497    8.  Following on from 7, I added a similar kludge to check the length of the
1498        eint vector in pcreposix.c.
1500    9.  Error texts for pcre_compile() are held as one long string to avoid too
1501        much relocation at load time. To find a text, the string is searched,
1502        counting zeros. There was no check for running off the end of the string,
1503        which could happen if a new error number was added without updating the
1504        string.
1506    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1508    11. \K was not working if it appeared in an atomic group or in a group that
1509        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1510        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1511        the assertion is positive, but not if it is negative.
1513    12. Change 11 fortuitously reduced the size of the stack frame used in the
1514        "match()" function of pcre_exec.c by one pointer. Forthcoming
1515        implementation of support for (*MARK) will need an extra pointer on the
1516        stack; I have reserved it now, so that the stack frame size does not
1517        decrease.
1519    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1520        item in branch that calls a recursion is a subroutine call - as in the
1521        second branch in the above example - was incorrectly given the compile-
1522        time error "recursive call could loop indefinitely" because pcre_compile()
1523        was not correctly checking the subroutine for matching a non-empty string.
1525    14. The checks for overrunning compiling workspace could trigger after an
1526        overrun had occurred. This is a "should never occur" error, but it can be
1527        triggered by pathological patterns such as hundreds of nested parentheses.
1528        The checks now trigger 100 bytes before the end of the workspace.
1530    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1533  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
# Line 357  Version 7.9 11-Apr-09 Line 1856  Version 7.9 11-Apr-09
1856  7.  A pattern that could match an empty string could cause pcregrep to loop; it  7.  A pattern that could match an empty string could cause pcregrep to loop; it
1857      doesn't make sense to accept an empty string match in pcregrep, so I have      doesn't make sense to accept an empty string match in pcregrep, so I have
1858      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1859      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1860        8.33.]
1862  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1863      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 600  Version 7.7 07-May-08 Line 2100  Version 7.7 07-May-08
2100      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2101      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2102      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2103      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2104      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2105      was subsequently set up correctly.)      was subsequently set up correctly.)

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