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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.02 01-Mar-2010  Version 8.34 xx-xxxx-201x
5    --------------------------
6    
7    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
8        executable memory. Patch inspired by Carsten Klein.
9    
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.
17    
18    3.  Make a small performance improvement in strlen16() and strlen32() in
19        pcretest.
20    
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.
24    
25    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
26    
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.
34    
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.
37    
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.
40    
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:
44    
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.
49    
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.
54    
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.
60    
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.
63    
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.
66    
67    13. Added the -T and -TM options to pcretest.
68    
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.
77    
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.
82    
83    16. Unicode character properties were updated from Unicode 6.3.0.
84    
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.
90    
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".
94    
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.
100    
101    20. Two patches to the CMake build system, by Alexander Barkov:
102    
103          (1) Replace the "source" command by "." in CMakeLists.txt because
104              "source" is a bash-ism.
105    
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.
108    
109    
110    Version 8.33 28-May-2013
111    ------------------------
112    
113    1.  Added 'U' to some constants that are compared to unsigned integers, to
114        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
115        variables that are added to signed variables, to ensure the result is
116        signed and can be negated.
117    
118    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
119        CMake config files.
120    
121    3.  Revise the creation of config.h.generic so that all boolean macros are
122        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
123        overriding via -D on the command line possible.
124    
125    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
126        to unsigned int is reported to make a quite noticeable speed difference in
127        a specific Windows environment. Testing on Linux did also appear to show
128        some benefit (and it is clearly not harmful). Also fixed the definition of
129        Xop which should be unsigned.
130    
131    5.  Related to (4), changing the definition of the intermediate variable cc
132        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
133        improvements.
134    
135    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
136        unnecessary spaces.
137    
138    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
139        and later.
140    
141    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
142    
143    9.  Optimizing fast_forward_start_bits in JIT.
144    
145    10. Adding support for callouts in JIT, and fixing some issues revealed
146        during this work. Namely:
147    
148        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
149    
150        (b) Minimum length was not checked before the matching is started.
151    
152    11. The value of capture_last that is passed to callouts was incorrect in some
153        cases when there was a capture on one path that was subsequently abandoned
154        after a backtrack. Also, the capture_last value is now reset after a
155        recursion, since all captures are also reset in this case.
156    
157    12. The interpreter no longer returns the "too many substrings" error in the
158        case when an overflowing capture is in a branch that is subsequently
159        abandoned after a backtrack.
160    
161    13. In the pathological case when an offset vector of size 2 is used, pcretest
162        now prints out the matched string after a yield of 0 or 1.
163    
164    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
165        Only supported by the JIT compiler at the moment.
166    
167    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
168    
169    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
170        offset of the starting point of the matching process, provided the offsets
171        vector is large enough.
172    
173    17. The \A escape now records a lookbehind value of 1, though its execution
174        does not actually inspect the previous character. This is to ensure that,
175        in partial multi-segment matching, at least one character from the old
176        segment is retained when a new segment is processed. Otherwise, if there
177        are no lookbehinds in the pattern, \A might match incorrectly at the start
178        of a new segment.
179    
180    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
181    
182    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
183        gives some modest performance improvement in 8-bit mode.
184    
185    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
186        be expressed in certain programming languages using Universal Character
187        Names.
188    
189    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
190        which points out that "non characters" are not "characters that may not
191        appear in Unicode strings" but rather "characters that are reserved for
192        internal use and have only local meaning".
193    
194    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
195        there was a conditional group that depended on an assertion, if the
196        assertion was false, the callout that immediately followed the alternation
197        in the condition was skipped when pcre_exec() was used for matching.
198    
199    23. Allow an explicit callout to be inserted before an assertion that is the
200        condition for a conditional group, for compatibility with automatic
201        callouts, which always insert a callout at this point.
202    
203    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
204        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
205    
206    25. (*PRUNE) is now supported by the JIT compiler.
207    
208    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
209    
210    27. Fix the case where there are two or more SKIPs with arguments that may be
211        ignored.
212    
213    28. (*SKIP) is now supported by the JIT compiler.
214    
215    29. (*THEN) is now supported by the JIT compiler.
216    
217    30. Update RunTest with additional test selector options.
218    
219    31. The way PCRE handles backtracking verbs has been changed in two ways.
220    
221        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
222        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
223        backtracking. In some cases this makes it more Perl-compatible, but Perl's
224        rather obscure rules do not always do the same thing.
225    
226        (2) Previously, backtracking verbs were confined within assertions. This is
227        no longer the case for positive assertions, except for (*ACCEPT). Again,
228        this sometimes improves Perl compatibility, and sometimes does not.
229    
230    32. A number of tests that were in test 2 because Perl did things differently
231        have been moved to test 1, because either Perl or PCRE has changed, and
232        these tests are now compatible.
233    
234    32. Backtracking control verbs are now handled in the same way in JIT and
235        interpreter.
236    
237    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
238        contained a forward subroutine reference caused a compile error.
239    
240    34. Auto-detect and optimize limited repetitions in JIT.
241    
242    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
243        blocking (*UTF) etc.
244    
245    36. In the interpreter, maximizing pattern repetitions for characters and
246        character types now use tail recursion, which reduces stack usage.
247    
248    37. The value of the max lookbehind was not correctly preserved if a compiled
249        and saved regex was reloaded on a host of different endianness.
250    
251    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
252        of the compiled pattern block, expand the flags field from 16 to 32 bits
253        because it was almost full.
254    
255    39. Try madvise first before posix_madvise.
256    
257    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
258        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
259        original change locked out all matches of empty strings. This has been
260        changed so that one match of an empty string per line is recognized.
261        Subsequent searches on the same line (for colouring or for --only-matching,
262        for example) do not recognize empty strings.
263    
264    41. Applied a user patch to fix a number of spelling mistakes in comments.
265    
266    42. Data lines longer than 65536 caused pcretest to crash.
267    
268    43. Clarified the data type for length and startoffset arguments for pcre_exec
269        and pcre_dfa_exec in the function-specific man pages, where they were
270        explicitly stated to be in bytes, never having been updated. I also added
271        some clarification to the pcreapi man page.
272    
273    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
274        a segmentation fault.
275    
276    
277    Version 8.32 30-November-2012
278    -----------------------------
279    
280    1.  Improved JIT compiler optimizations for first character search and single
281        character iterators.
282    
283    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
284        Patch by Daniel Richard G.
285    
286    3.  Single character iterator optimizations in the JIT compiler.
287    
288    4.  Improved JIT compiler optimizations for character ranges.
289    
290    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
291        Reported by Giuseppe D'Angelo.
292    
293    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
294        of a line, was being set incorrectly in cases where .* appeared inside
295        atomic brackets at the start of a pattern, or where there was a subsequent
296        *PRUNE or *SKIP.
297    
298    7.  Improved instruction cache flush for POWER/PowerPC.
299        Patch by Daniel Richard G.
300    
301    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
302        grep:
303    
304        (a) There is now no limit to the number of patterns to be matched.
305    
306        (b) An error is given if a pattern is too long.
307    
308        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
309            are now supported.
310    
311        (d) --exclude-from and --include-from (multiple use) have been added.
312    
313        (e) Exclusions and inclusions now apply to all files and directories, not
314            just to those obtained from scanning a directory recursively.
315    
316        (f) Multiple uses of -f and --file-list are now supported.
317    
318        (g) In a Windows environment, the default for -d has been changed from
319            "read" (the GNU grep default) to "skip", because otherwise the presence
320            of a directory in the file list provokes an error.
321    
322        (h) The documentation has been revised and clarified in places.
323    
324    9.  Improve the matching speed of capturing brackets.
325    
326    10. Changed the meaning of \X so that it now matches a Unicode extended
327        grapheme cluster.
328    
329    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
330        out POSIX threads when JIT support is configured.
331    
332    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
333    
334    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
335        structure could go wrong in environments where size_t is not the same size
336        as int.
337    
338    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
339        set.
340    
341    15. The EBCDIC support had decayed; later updates to the code had included
342        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
343        general tidy up of EBCDIC-related issues, and the documentation was also
344        not quite right. There is now a test that can be run on ASCII systems to
345        check some of the EBCDIC-related things (but is it not a full test).
346    
347    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
348        in a small tidy to the code.
349    
350    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
351    
352    18. If the --only-matching (-o) option in pcregrep is specified multiple
353        times, each one causes appropriate output. For example, -o1 -o2 outputs the
354        substrings matched by the 1st and 2nd capturing parentheses. A separating
355        string can be specified by --om-separator (default empty).
356    
357    19. Improving the first n character searches.
358    
359    20. Turn case lists for horizontal and vertical white space into macros so that
360        they are defined only once.
361    
362    21. This set of changes together give more compatible Unicode case-folding
363        behaviour for characters that have more than one other case when UCP
364        support is available.
365    
366        (a) The Unicode property table now has offsets into a new table of sets of
367            three or more characters that are case-equivalent. The MultiStage2.py
368            script that generates these tables (the pcre_ucd.c file) now scans
369            CaseFolding.txt instead of UnicodeData.txt for character case
370            information.
371    
372        (b) The code for adding characters or ranges of characters to a character
373            class has been abstracted into a generalized function that also handles
374            case-independence. In UTF-mode with UCP support, this uses the new data
375            to handle characters with more than one other case.
376    
377        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
378            whose other case is greater than 256 are now correctly matched
379            caselessly. Previously, the high codepoint matched the low one, but not
380            vice versa.
381    
382        (d) The processing of \h, \H, \v, and \ in character classes now makes use
383            of the new class addition function, using character lists defined as
384            macros alongside the case definitions of 20 above.
385    
386        (e) Caseless back references now work with characters that have more than
387            one other case.
388    
389        (f) General caseless matching of characters with more than one other case
390            is supported.
391    
392    22. Unicode character properties were updated from Unicode 6.2.0
393    
394    23. Improved CMake support under Windows. Patch by Daniel Richard G.
395    
396    24. Add support for 32-bit character strings, and UTF-32
397    
398    25. Major JIT compiler update (code refactoring and bugfixing).
399        Experimental Sparc 32 support is added.
400    
401    26. Applied a modified version of Daniel Richard G's patch to create
402        pcre.h.generic and config.h.generic by "make" instead of in the
403        PrepareRelease script.
404    
405    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
406        pcre_compile.c when checking for a zero character.
407    
408    28. Introducing a native interface for JIT. Through this interface, the compiled
409        machine code can be directly executed. The purpose of this interface is to
410        provide fast pattern matching, so several sanity checks are not performed.
411        However, feature tests are still performed. The new interface provides
412        1.4x speedup compared to the old one.
413    
414    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
415        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
416        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
417    
418    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
419        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
420        the "old" RFC 2279). Instead, it ended up passing a negative length to
421        pcre_exec().
422    
423    31. Add support for GCC's visibility feature to hide internal functions.
424    
425    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
426        "unknown -C option" after outputting 0 or 1.
427    
428    33. There is now support for generating a code coverage report for the test
429        suite in environments where gcc is the compiler and lcov is installed. This
430        is mainly for the benefit of the developers.
431    
432    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
433        unaddressable using valgrind annotations, allowing valgrind to detect
434        invalid memory accesses. This is mainly for the benefit of the developers.
435    
436    25. (*UTF) can now be used to start a pattern in any of the three libraries.
437    
438    26. Give configure error if --enable-cpp but no C++ compiler found.
439    
440    
441    Version 8.31 06-July-2012
442    -------------------------
443    
444    1.  Fixing a wrong JIT test case and some compiler warnings.
445    
446    2.  Removed a bashism from the RunTest script.
447    
448    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
449        to unsigned type, result still unsigned" that was given by an MS compiler
450        on encountering the code "-sizeof(xxx)".
451    
452    4.  Partial matching support is added to the JIT compiler.
453    
454    5.  Fixed several bugs concerned with partial matching of items that consist
455        of more than one character:
456    
457        (a) /^(..)\1/ did not partially match "aba" because checking references was
458            done on an "all or nothing" basis. This also applied to repeated
459            references.
460    
461        (b) \R did not give a hard partial match if \r was found at the end of the
462            subject.
463    
464        (c) \X did not give a hard partial match after matching one or more
465            characters at the end of the subject.
466    
467        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
468            a partial match for the string "\r".
469    
470        (e) When newline was set to CRLF, the metacharacter "." did not recognize
471            a partial match for a CR character at the end of the subject string.
472    
473    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
474        running pcretest, the text "(JIT)" added to the output whenever JIT is
475        actually used to run the match.
476    
477    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
478        or /S+[+] with a digit between 1 and 7.
479    
480    8.  OP_NOT now supports any UTF character not just single-byte ones.
481    
482    9.  (*MARK) control verb is now supported by the JIT compiler.
483    
484    10. The command "./RunTest list" lists the available tests without actually
485        running any of them. (Because I keep forgetting what they all are.)
486    
487    11. Add PCRE_INFO_MAXLOOKBEHIND.
488    
489    12. Applied a (slightly modified) user-supplied patch that improves performance
490        when the heap is used for recursion (compiled with --disable-stack-for-
491        recursion). Instead of malloc and free for each heap frame each time a
492        logical recursion happens, frames are retained on a chain and re-used where
493        possible. This sometimes gives as much as 30% improvement.
494    
495    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
496        call.
497    
498    14. As documented, (*COMMIT) is now confined to within a positive assertion.
499    
500    15. It is now possible to link pcretest with libedit as an alternative to
501        libreadline.
502    
503    16. (*COMMIT) control verb is now supported by the JIT compiler.
504    
505    17. The Unicode data tables have been updated to Unicode 6.1.0.
506    
507    18. Added --file-list option to pcregrep.
508    
509    19. Added binary file support to pcregrep, including the -a, --binary-files,
510        -I, and --text options.
511    
512    20. The madvise function is renamed for posix_madvise for QNX compatibility
513        reasons. Fixed by Giuseppe D'Angelo.
514    
515    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
516    
517    22. Changed the option for creating symbolic links for 16-bit man pages from
518        -s to -sf so that re-installing does not cause issues.
519    
520    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
521    
522    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
523        matches in certain environments (the workspace was not being correctly
524        retained). Also added to pcre_dfa_exec() a simple plausibility check on
525        some of the workspace data at the beginning of a restart.
526    
527    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
528        was not doing so when it should - probably a typo introduced by SVN 528
529        (change 8.10/14).
530    
531    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
532        \w+ when the character tables indicated that \x{c4} was a word character.
533        There were several related cases, all because the tests for doing a table
534        lookup were testing for characters less than 127 instead of 255.
535    
536    27. If a pattern contains capturing parentheses that are not used in a match,
537        their slots in the ovector are set to -1. For those that are higher than
538        any matched groups, this happens at the end of processing. In the case when
539        there were back references that the ovector was too small to contain
540        (causing temporary malloc'd memory to be used during matching), and the
541        highest capturing number was not used, memory off the end of the ovector
542        was incorrectly being set to -1. (It was using the size of the temporary
543        memory instead of the true size.)
544    
545    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
546        ovector size, it uses memory at the end of the block that it has got.
547    
548    29. Check for an overlong MARK name and give an error at compile time. The
549        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
550    
551    30. JIT compiler update.
552    
553    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
554        Rill for the patch.
555    
556    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
557    
558    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
559    
560    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
561        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
562        was enabled.
563    
564    35. Improve JIT code generation for greedy plus quantifier.
565    
566    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
567        1 to "aa" instead of to an empty string. The bug affected repeated groups
568        that could potentially match an empty string.
569    
570    37. Optimizing single character iterators in JIT.
571    
572    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
573        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
574        codepoints that are too big for the mode are faulted, and in a UTF mode,
575        disallowed codepoints are also faulted.
576    
577    39. If PCRE was compiled with UTF support, in three places in the DFA
578        matcher there was code that should only have been obeyed in UTF mode, but
579        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
580        processing when bytes with values greater than 127 were present. In 16-bit
581        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
582        both cases the values are those that cannot be the first data item in a UTF
583        character. The three items that might have provoked this were recursions,
584        possessively repeated groups, and atomic groups.
585    
586    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
587        and pcregrep, because some OS require shared objects to be explicitly
588        passed to ld, causing the link step to fail if they are not.
589    
590    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
591        mode, patterns that started with \h* or \R* might be incorrectly matched.
592    
593    
594    Version 8.30 04-February-2012
595    -----------------------------
596    
597    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
598        name is defined in ctype.h.
599    
600    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
601        only in quite long subpatterns.
602    
603    3.  Removed the function pcre_info(), which has been obsolete and deprecated
604        since it was replaced by pcre_fullinfo() in February 2000.
605    
606    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
607        match a (*MARK), and the match failed at the start of the subject, a
608        reference to memory before the start of the subject could occur. This bug
609        was introduced by fix 17 of release 8.21.
610    
611    5.  A reference to an unset group with zero minimum repetition was giving
612        totally wrong answers (in non-JavaScript-compatibility mode). For example,
613        /(another)?(\1?)test/ matched against "hello world test". This bug was
614        introduced in release 8.13.
615    
616    6.  Add support for 16-bit character strings (a large amount of work involving
617        many changes and refactorings).
618    
619    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
620        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
621        from a file.
622    
623    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
624        rounding is not applied in this particular case).
625    
626    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
627        if they appear, or are escaped, in patterns.
628    
629    10. Get rid of a number of -Wunused-but-set-variable warnings.
630    
631    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
632        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
633        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
634        also returns the mark "x". This bug applied to capturing parentheses,
635        non-capturing parentheses, and atomic parentheses. It also applied to some
636        assertions.
637    
638    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
639        information out of configure.ac instead of relying on pcre.h.generic, which
640        is not stored in the repository.
641    
642    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
643        -lreadline.
644    
645    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
646    
647    15. Applied Graycode's patch to put the top-level frame on the stack rather
648        than the heap when not using the stack for recursion. This gives a
649        performance improvement in many cases when recursion is not deep.
650    
651    16. Experimental code added to "pcretest -C" to output the stack frame size.
652    
653    
654    Version 8.21 12-Dec-2011
655    ------------------------
656    
657    1.  Updating the JIT compiler.
658    
659    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
660        are added as well.
661    
662    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
663        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
664        calling _pcre_jit_exec. Some extra comments are added.
665    
666    4.  (*MARK) settings inside atomic groups that do not contain any capturing
667        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
668        was introduced by change 18 for 8.20.
669    
670    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
671        ECMA-262 standard.
672    
673    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
674        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
675        This bug was probably introduced by change 9 of 8.13.
676    
677    7.  While fixing 6 above, I noticed that a number of other items were being
678        incorrectly rejected as "not fixed length". This arose partly because newer
679        opcodes had not been added to the fixed-length checking code. I have (a)
680        corrected the bug and added tests for these items, and (b) arranged for an
681        error to occur if an unknown opcode is encountered while checking for fixed
682        length instead of just assuming "not fixed length". The items that were
683        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
684        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
685        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
686    
687    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
688        being incorrectly compiled and would have given unpredicatble results.
689    
690    9.  A possessively repeated subpattern with minimum repeat count greater than
691        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
692        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
693        the first (A) could occur when it should not.
694    
695    10. Add a cast and remove a redundant test from the code.
696    
697    11. JIT should use pcre_malloc/pcre_free for allocation.
698    
699    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
700        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
701        is anything other than /usr, -L is still shown).
702    
703    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
704    
705    14. Perl does not support \N without a following name in a [] class; PCRE now
706        also gives an error.
707    
708    15. If a forward reference was repeated with an upper limit of around 2000,
709        it caused the error "internal error: overran compiling workspace". The
710        maximum number of forward references (including repeats) was limited by the
711        internal workspace, and dependent on the LINK_SIZE. The code has been
712        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
713        the default depends on LINK_SIZE. There is a new upper limit (for safety)
714        of around 200,000 forward references. While doing this, I also speeded up
715        the filling in of repeated forward references.
716    
717    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
718        incorrectly expecting the subject to contain another "a" after the start.
719    
720    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
721        in the match, the SKIP should be ignored. This was not happening; instead
722        the SKIP was being treated as NOMATCH. For patterns such as
723        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
724        tested.
725    
726    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
727        now much more compatible with Perl, in particular in cases where the result
728        is a non-match for a non-anchored pattern. For example, if
729        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
730        "m", where previously it did not return a name. A side effect of this
731        change is that for partial matches, the last encountered mark name is
732        returned, as for non matches. A number of tests that were previously not
733        Perl-compatible have been moved into the Perl-compatible test files. The
734        refactoring has had the pleasing side effect of removing one argument from
735        the match() function, thus reducing its stack requirements.
736    
737    19. If the /S+ option was used in pcretest to study a pattern using JIT,
738        subsequent uses of /S (without +) incorrectly behaved like /S+.
739    
740    21. Retrieve executable code size support for the JIT compiler and fixing
741        some warnings.
742    
743    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
744        not work when the shorter character appeared right at the end of the
745        subject string.
746    
747    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
748        systems.
749    
750    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
751        output it when the /M option is used in pcretest.
752    
753    25. The CheckMan script was not being included in the distribution. Also, added
754        an explicit "perl" to run Perl scripts from the PrepareRelease script
755        because this is reportedly needed in Windows.
756    
757    26. If study data was being save in a file and studying had not found a set of
758        "starts with" bytes for the pattern, the data written to the file (though
759        never used) was taken from uninitialized memory and so caused valgrind to
760        complain.
761    
762    27. Updated RunTest.bat as provided by Sheri Pierce.
763    
764    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
765    
766    29. Computation of memory usage for the table of capturing group names was
767        giving an unnecessarily large value.
768    
769    
770    Version 8.20 21-Oct-2011
771    ------------------------
772    
773    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
774        a POSIX class. After further experiments with Perl, which convinced me that
775        Perl has bugs and confusions, a closing square bracket is no longer allowed
776        in a POSIX name. This bug also affected patterns with classes that started
777        with full stops.
778    
779    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
780        captured substring, but while checking the failing first alternative,
781        substring 1 is temporarily captured. If the output vector supplied to
782        pcre_exec() was not big enough for this capture, the yield of the function
783        was still zero ("insufficient space for captured substrings"). This cannot
784        be totally fixed without adding another stack variable, which seems a lot
785        of expense for a edge case. However, I have improved the situation in cases
786        such as /(a)(b)x|abc/ matched against "abc", where the return code
787        indicates that fewer than the maximum number of slots in the ovector have
788        been set.
789    
790    3.  Related to (2) above: when there are more back references in a pattern than
791        slots in the output vector, pcre_exec() uses temporary memory during
792        matching, and copies in the captures as far as possible afterwards. It was
793        using the entire output vector, but this conflicts with the specification
794        that only 2/3 is used for passing back captured substrings. Now it uses
795        only the first 2/3, for compatibility. This is, of course, another edge
796        case.
797    
798    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
799        main code base, and can be used by building with --enable-jit. When this is
800        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
801        runtime --no-jit option is given.
802    
803    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
804        ovector, the return from the function was zero, implying that there were
805        other matches that did not fit. The correct "exactly full" value is now
806        returned.
807    
808    6.  If a subpattern that was called recursively or as a subroutine contained
809        (*PRUNE) or any other control that caused it to give a non-standard return,
810        invalid errors such as "Error -26 (nested recursion at the same subject
811        position)" or even infinite loops could occur.
812    
813    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
814        computing the minimum length on reaching *ACCEPT, and so ended up with the
815        wrong value of 1 rather than 0. Further investigation indicates that
816        computing a minimum subject length in the presence of *ACCEPT is difficult
817        (think back references, subroutine calls), and so I have changed the code
818        so that no minimum is registered for a pattern that contains *ACCEPT.
819    
820    8.  If (*THEN) was present in the first (true) branch of a conditional group,
821        it was not handled as intended. [But see 16 below.]
822    
823    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
824        Sheri Pierce.
825    
826    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
827        the first byte in a match must be "a".
828    
829    11. Change 17 for 8.13 increased the recursion depth for patterns like
830        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
831        pattern contains any instances of (*THEN). If it does not, the old
832        optimizations are restored. It would be nice to do this on a per-group
833        basis, but at the moment that is not feasible.
834    
835    12. In some environments, the output of pcretest -C is CRLF terminated. This
836        broke RunTest's code that checks for the link size. A single white space
837        character after the value is now allowed for.
838    
839    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
840        For "fr", it uses the Windows-specific input and output files.
841    
842    14. If (*THEN) appeared in a group that was called recursively or as a
843        subroutine, it did not work as intended. [But see next item.]
844    
845    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
846        pattern fragments (but not containing any | characters). If A and B are
847        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
848        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
849        D. In other words, Perl considers parentheses that do not contain any |
850        characters to be part of a surrounding alternative, whereas PCRE was
851        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
852        differently. PCRE now behaves in the same way as Perl, except in the case
853        of subroutine/recursion calls such as (?1) which have in any case always
854        been different (but PCRE had them first :-).
855    
856    16. Related to 15 above: Perl does not treat the | in a conditional group as
857        creating alternatives. Such a group is treated in the same way as an
858        ordinary group without any | characters when processing (*THEN). PCRE has
859        been changed to match Perl's behaviour.
860    
861    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
862        RunGrepTest script failed.
863    
864    18. Change 22 for version 13 caused atomic groups to use more stack. This is
865        inevitable for groups that contain captures, but it can lead to a lot of
866        stack use in large patterns. The old behaviour has been restored for atomic
867        groups that do not contain any capturing parentheses.
868    
869    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
870        suppress the check for a minimum subject length at run time. (If it was
871        given to pcre_exec() or pcre_dfa_exec() it did work.)
872    
873    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
874        fail to work when decoding hex characters in data strings in EBCDIC
875        environments.
876    
877    21. It appears that in at least one Mac OS environment, the isxdigit() function
878        is implemented as a macro that evaluates to its argument more than once,
879        contravening the C 90 Standard (I haven't checked a later standard). There
880        was an instance in pcretest which caused it to go wrong when processing
881        \x{...} escapes in subject strings. The has been rewritten to avoid using
882        things like p++ in the argument of isxdigit().
883    
884    
885    Version 8.13 16-Aug-2011
886    ------------------------
887    
888    1.  The Unicode data tables have been updated to Unicode 6.0.0.
889    
890    2.  Two minor typos in pcre_internal.h have been fixed.
891    
892    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
893        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
894        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
895    
896    4.  There were a number of related bugs in the code for matching backrefences
897        caselessly in UTF-8 mode when codes for the characters concerned were
898        different numbers of bytes. For example, U+023A and U+2C65 are an upper
899        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
900        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
901        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
902        2-byte code at the end of the subject (it thought there wasn't enough data
903        left).
904    
905    5.  Comprehensive information about what went wrong is now returned by
906        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
907        as the output vector has at least 2 elements. The offset of the start of
908        the failing character and a reason code are placed in the vector.
909    
910    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
911        now returned is for the first byte of the failing character, instead of the
912        last byte inspected. This is an incompatible change, but I hope it is small
913        enough not to be a problem. It makes the returned offset consistent with
914        pcre_exec() and pcre_dfa_exec().
915    
916    7.  pcretest now gives a text phrase as well as the error number when
917        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
918        failure, the offset and reason code are output.
919    
920    8.  When \R was used with a maximizing quantifier it failed to skip backwards
921        over a \r\n pair if the subsequent match failed. Instead, it just skipped
922        back over a single character (\n). This seems wrong (because it treated the
923        two characters as a single entity when going forwards), conflicts with the
924        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
925        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
926        has been changed.
927    
928    9.  Some internal refactoring has changed the processing so that the handling
929        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
930        time (the PCRE_DOTALL option was changed this way some time ago: version
931        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
932        which was always a bit of a fudge. It also means that there is one less
933        argument for the match() function, which reduces its stack requirements
934        slightly. This change also fixes an incompatibility with Perl: the pattern
935        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
936    
937    10. More internal refactoring has drastically reduced the number of recursive
938        calls to match() for possessively repeated groups such as (abc)++ when
939        using pcre_exec().
940    
941    11. While implementing 10, a number of bugs in the handling of groups were
942        discovered and fixed:
943    
944        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
945        (a|)*(?1) gave a compile-time internal error.
946        ((a|)+)+  did not notice that the outer group could match an empty string.
947        (^a|^)+   was not marked as anchored.
948        (.*a|.*)+ was not marked as matching at start or after a newline.
949    
950    12. Yet more internal refactoring has removed another argument from the match()
951        function. Special calls to this function are now indicated by setting a
952        value in a variable in the "match data" data block.
953    
954    13. Be more explicit in pcre_study() instead of relying on "default" for
955        opcodes that mean there is no starting character; this means that when new
956        ones are added and accidentally left out of pcre_study(), testing should
957        pick them up.
958    
959    14. The -s option of pcretest has been documented for ages as being an old
960        synonym of -m (show memory usage). I have changed it to mean "force study
961        for every regex", that is, assume /S for every regex. This is similar to -i
962        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
963        using it. It makes it easier to run collections of tests with and without
964        study enabled, and thereby test pcre_study() more easily. All the standard
965        tests are now run with and without -s (but some patterns can be marked as
966        "never study" - see 20 below).
967    
968    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
969        restoration of the capturing data to the outer values was not happening
970        correctly.
971    
972    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
973        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
974        pattern had matched an empty string, and so incorrectly returned a no
975        match.
976    
977    17. There was optimizing code for the last branch of non-capturing parentheses,
978        and also for the obeyed branch of a conditional subexpression, which used
979        tail recursion to cut down on stack usage. Unfortunately, now that there is
980        the possibility of (*THEN) occurring in these branches, tail recursion is
981        no longer possible because the return has to be checked for (*THEN). These
982        two optimizations have therefore been removed. [But see 8.20/11 above.]
983    
984    18. If a pattern containing \R was studied, it was assumed that \R always
985        matched two bytes, thus causing the minimum subject length to be
986        incorrectly computed because \R can also match just one byte.
987    
988    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
989        was incorrectly computed.
990    
991    20. If /S is present twice on a test pattern in pcretest input, it now
992        *disables* studying, thereby overriding the use of -s on the command line
993        (see 14 above). This is necessary for one or two tests to keep the output
994        identical in both cases.
995    
996    21. When (*ACCEPT) was used in an assertion that matched an empty string and
997        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
998    
999    22. When an atomic group that contained a capturing parenthesis was
1000        successfully matched, but the branch in which it appeared failed, the
1001        capturing was not being forgotten if a higher numbered group was later
1002        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1003        group 1 to "a", when in fact it should be unset. This applied to multi-
1004        branched capturing and non-capturing groups, repeated or not, and also to
1005        positive assertions (capturing in negative assertions does not happen
1006        in PCRE) and also to nested atomic groups.
1007    
1008    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1009        subject after a captured substring, to make it easier to tell which of a
1010        number of identical substrings has been captured.
1011    
1012    24. The way atomic groups are processed by pcre_exec() has been changed so that
1013        if they are repeated, backtracking one repetition now resets captured
1014        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1015        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1016        "aaa". Previously, it would have been "a". As part of this code
1017        refactoring, the way recursive calls are handled has also been changed.
1018    
1019    25. If an assertion condition captured any substrings, they were not passed
1020        back unless some other capturing happened later. For example, if
1021        (?(?=(a))a) was matched against "a", no capturing was returned.
1022    
1023    26. When studying a pattern that contained subroutine calls or assertions,
1024        the code for finding the minimum length of a possible match was handling
1025        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1026        group 1 called group 2 while simultaneously a separate group 2 called group
1027        1). A stack overflow occurred in this case. I have fixed this by limiting
1028        the recursion depth to 10.
1029    
1030    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1031        Fortmann. This supports explicit test numbers on the command line, and has
1032        argument validation and error reporting.
1033    
1034    28. An instance of \X with an unlimited repeat could fail if at any point the
1035        first character it looked at was a mark character.
1036    
1037    29. Some minor code refactoring concerning Unicode properties and scripts
1038        should reduce the stack requirement of match() slightly.
1039    
1040    30. Added the '=' option to pcretest to check the setting of unused capturing
1041        slots at the end of the pattern, which are documented as being -1, but are
1042        not included in the return count.
1043    
1044    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1045        compiled something random. Now it gives a compile-time error (as does
1046        Perl).
1047    
1048    32. A *MARK encountered during the processing of a positive assertion is now
1049        recorded and passed back (compatible with Perl).
1050    
1051    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1052        had alternative anchored branches, the search for a second match in a line
1053        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1054        matched the line "0102" twice. The same bug affected patterns that started
1055        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1056        twice.
1057    
1058    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1059        does, and because of capturing effects, quantifying parenthesized
1060        assertions may at times be useful. Quantifiers are now allowed for
1061        parenthesized assertions.
1062    
1063    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1064    
1065    36. \g was being checked for fancy things in a character class, when it should
1066        just be a literal "g".
1067    
1068    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1069        appearance of a nested POSIX class supersedes an apparent external class.
1070        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1071        unescaped square brackets may also appear as part of class names. For
1072        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1073        more like Perl. (But see 8.20/1 above.)
1074    
1075    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1076        was because it thought it was \N{name}, which is not supported).
1077    
1078    39. Add minix to OS list not supporting the -S option in pcretest.
1079    
1080    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1081        cannot analyze patterns in sufficient detail to catch mutual recursions
1082        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1083        subgroup is called recursively as a subpattern for a second time at the
1084        same position in the subject string. In previous releases this might have
1085        been caught by the recursion limit, or it might have run out of stack.
1086    
1087    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1088        happen only once. PCRE was, however incorrectly giving a compile time error
1089        "recursive call could loop indefinitely" because it cannot analyze the
1090        pattern in sufficient detail. The compile time test no longer happens when
1091        PCRE is compiling a conditional subpattern, but actual runaway loops are
1092        now caught at runtime (see 40 above).
1093    
1094    42. It seems that Perl allows any characters other than a closing parenthesis
1095        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1096        has been changed to be the same.
1097    
1098    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1099        as not to get warnings when autogen.sh is called. Also changed
1100        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1101    
1102    44. To help people who use pcregrep to scan files containing exceedingly long
1103        lines, the following changes have been made:
1104    
1105        (a) The default value of the buffer size parameter has been increased from
1106            8K to 20K. (The actual buffer used is three times this size.)
1107    
1108        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1109            PCRE is built.
1110    
1111        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1112            to be set at run time.
1113    
1114        (d) Numerical values in pcregrep options can be followed by K or M, for
1115            example --buffer-size=50K.
1116    
1117        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1118            given and the return code is set to 2.
1119    
1120    45. Add a pointer to the latest mark to the callout data block.
1121    
1122    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1123        partial match of an empty string instead of no match. This was specific to
1124        the use of ".".
1125    
1126    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1127        complete match instead of a partial match. This bug was dependent on both
1128        the PCRE_UTF8 and PCRE_DOTALL options being set.
1129    
1130    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1131        starting byte set, because \b was not being ignored.
1132    
1133    
1134    Version 8.12 15-Jan-2011
1135    ------------------------
1136    
1137    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1138        checks for such things as part of the documentation building process.
1139    
1140    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1141        --match-limit and --recursion-limit options (added for 8.11). In
1142        particular, this made one of the standard tests fail. (The integer value
1143        went into the wrong half of a long int.)
1144    
1145    3.  If the --colour option was given to pcregrep with -v (invert match), it
1146        did strange things, either producing crazy output, or crashing. It should,
1147        of course, ignore a request for colour when reporting lines that do not
1148        match.
1149    
1150    4.  Another pcregrep bug caused similar problems if --colour was specified with
1151        -M (multiline) and the pattern match finished with a line ending.
1152    
1153    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1154        matched in multiline mode, the following line was shown as part of the
1155        match. This seems wrong, so I have changed it.
1156    
1157    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1158        the check for further matches in the same line (so they could be coloured)
1159        to overrun the end of the current line. If another match was found, it was
1160        incorrectly shown (and then shown again when found in the next line).
1161    
1162    7.  If pcregrep was compiled under Windows, there was a reference to the
1163        function pcregrep_exit() before it was defined. I am assuming this was
1164        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1165        reported by a user. I've moved the definition above the reference.
1166    
1167    
1168    Version 8.11 10-Dec-2010
1169    ------------------------
1170    
1171    1.  (*THEN) was not working properly if there were untried alternatives prior
1172        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1173        backtracked to try for "b" instead of moving to the next alternative branch
1174        at the same level (in this case, to look for "c"). The Perl documentation
1175        is clear that when (*THEN) is backtracked onto, it goes to the "next
1176        alternative in the innermost enclosing group".
1177    
1178    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1179        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1180        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1181        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1182        (*THEN).
1183    
1184    3.  If \s appeared in a character class, it removed the VT character from
1185        the class, even if it had been included by some previous item, for example
1186        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1187        of \s, but is part of the POSIX "space" class.)
1188    
1189    4.  A partial match never returns an empty string (because you can always
1190        match an empty string at the end of the subject); however the checking for
1191        an empty string was starting at the "start of match" point. This has been
1192        changed to the "earliest inspected character" point, because the returned
1193        data for a partial match starts at this character. This means that, for
1194        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1195        (previously it gave "no match").
1196    
1197    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1198        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1199        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1200        has an implication that the given string is incomplete (because a partial
1201        match is preferred over a full match). For this reason, these items now
1202        give a partial match in this situation. [Aside: previously, the one case
1203        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1204        match rather than a full match, which was wrong by the old rules, but is
1205        now correct.]
1206    
1207    6.  There was a bug in the handling of #-introduced comments, recognized when
1208        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1209        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1210        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1211        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1212        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1213        places in pcre_compile().
1214    
1215    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1216        comments when looking ahead for named forward references to subpatterns,
1217        the only newline sequence it recognized was NL. It now handles newlines
1218        according to the set newline convention.
1219    
1220    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1221        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1222        cater for a lack of strerror(). These oversights have been fixed.
1223    
1224    9.  Added --match-limit and --recursion-limit to pcregrep.
1225    
1226    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1227    
1228    11. When the -o option was used, pcregrep was setting a return code of 1, even
1229        when matches were found, and --line-buffered was not being honoured.
1230    
1231    12. Added an optional parentheses number to the -o and --only-matching options
1232        of pcregrep.
1233    
1234    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1235        can match an empty string. The code to do it in pcretest and pcredemo
1236        needed fixing:
1237    
1238        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1239            only one byte after an empty string match just before CRLF (this case
1240            just got forgotten; "any" and "anycrlf" were OK).
1241    
1242        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1243            mode when an empty string match preceded an ASCII character followed by
1244            a non-ASCII character. (The code for advancing by one character rather
1245            than one byte was nonsense.)
1246    
1247        (c) The pcredemo.c sample program did not have any code at all to handle
1248            the cases when CRLF is a valid newline sequence.
1249    
1250    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1251        as a starting offset was within the subject string. There is now a new
1252        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1253        negative or greater than the length of the string. In order to test this,
1254        pcretest is extended to allow the setting of negative starting offsets.
1255    
1256    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1257        starting offset points to the beginning of a UTF-8 character was
1258        unnecessarily clumsy. I tidied it up.
1259    
1260    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1261        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1262    
1263    17. Nobody had reported that the --include_dir option, which was added in
1264        release 7.7 should have been called --include-dir (hyphen, not underscore)
1265        for compatibility with GNU grep. I have changed it to --include-dir, but
1266        left --include_dir as an undocumented synonym, and the same for
1267        --exclude-dir, though that is not available in GNU grep, at least as of
1268        release 2.5.4.
1269    
1270    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1271        characters from a string of bytes) have been redefined so as not to use
1272        loops, in order to improve performance in some environments. At the same
1273        time, I abstracted some of the common code into auxiliary macros to save
1274        repetition (this should not affect the compiled code).
1275    
1276    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1277        compile-time error is now given if \c is not followed by an ASCII
1278        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1279        different, and any byte value is allowed.)
1280    
1281    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1282        START_OPTIMIZE option, which is now allowed at compile time - but just
1283        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1284        to pcregrep and other applications that have no direct access to PCRE
1285        options. The new /Y option in pcretest sets this option when calling
1286        pcre_compile().
1287    
1288    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1289        back references. Groups containing recursive back references were forced to
1290        be atomic by that change, but in the case of named groups, the amount of
1291        memory required was incorrectly computed, leading to "Failed: internal
1292        error: code overflow". This has been fixed.
1293    
1294    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1295        pcretest.c, to avoid build problems in some Borland environments.
1296    
1297    
1298    Version 8.10 25-Jun-2010
1299    ------------------------
1300    
1301    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1302        THEN.
1303    
1304    2.  (*ACCEPT) was not working when inside an atomic group.
1305    
1306    3.  Inside a character class, \B is treated as a literal by default, but
1307        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1308        causes the error). The code is unchanged, but I tidied the documentation.
1309    
1310    4.  Inside a character class, PCRE always treated \R and \X as literals,
1311        whereas Perl faults them if its -w option is set. I have changed PCRE so
1312        that it faults them when PCRE_EXTRA is set.
1313    
1314    5.  Added support for \N, which always matches any character other than
1315        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1316    
1317    6.  When compiling pcregrep with newer versions of gcc which may have
1318        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1319        declared with attribute warn_unused_result" were given. Just casting the
1320        result to (void) does not stop the warnings; a more elaborate fudge is
1321        needed. I've used a macro to implement this.
1322    
1323    7.  Minor change to pcretest.c to avoid a compiler warning.
1324    
1325    8.  Added four artifical Unicode properties to help with an option to make
1326        \s etc use properties (see next item). The new properties are: Xan
1327        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1328    
1329    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1330        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1331        this option. Modified pcretest to add /W to test this facility. Added
1332        REG_UCP to make it available via the POSIX interface.
1333    
1334    10. Added --line-buffered to pcregrep.
1335    
1336    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1337        studied, and the match started with a letter with a code point greater than
1338        127 whose first byte was different to the first byte of the other case of
1339        the letter, the other case of this starting letter was not recognized
1340        (#976).
1341    
1342    12. If a pattern that was studied started with a repeated Unicode property
1343        test, for example, \p{Nd}+, there was the theoretical possibility of
1344        setting up an incorrect bitmap of starting bytes, but fortunately it could
1345        not have actually happened in practice until change 8 above was made (it
1346        added property types that matched character-matching opcodes).
1347    
1348    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1349        possible starting bytes for non-anchored patterns.
1350    
1351    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1352        \R, and also a number of cases that involve Unicode properties, both
1353        explicit and implicit when PCRE_UCP is set.
1354    
1355    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1356        input, it could crash or give wrong results if characters with values
1357        greater than 0xc0 were present in the subject string. (Detail: it assumed
1358        UTF-8 input when processing these items.)
1359    
1360    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1361        size_t is 64-bit (#991).
1362    
1363    17. Added a check for running out of memory when PCRE is compiled with
1364        --disable-stack-for-recursion (#990).
1365    
1366    18. If the last data line in a file for pcretest does not have a newline on
1367        the end, a newline was missing in the output.
1368    
1369    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1370        less than 128) in its various bitmaps. However, there is a facility for
1371        generating tables according to the current locale when PCRE is compiled. It
1372        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1373        characters, are recognized by isspace() and therefore were getting set in
1374        these tables, and indeed these tables seem to approximate to ISO 8859. This
1375        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1376        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1377        which of course cannot start UTF-8 characters. I have changed the code so
1378        that only real ASCII characters (less than 128) and the correct starting
1379        bytes for UTF-8 encodings are set for characters greater than 127 when in
1380        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1381        altogether.)
1382    
1383    20. Added the /T option to pcretest so as to be able to run tests with non-
1384        standard character tables, thus making it possible to include the tests
1385        used for 19 above in the standard set of tests.
1386    
1387    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1388        reference to a subpattern the other side of a comment that contains an
1389        opening parenthesis caused either an internal compiling error, or a
1390        reference to the wrong subpattern.
1391    
1392    
1393    Version 8.02 19-Mar-2010
1394  ------------------------  ------------------------
1395    
1396  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.
1397    
1398  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
1399      configured.      configured.
1400    
1401  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
1402      original author of that file, following a query about its status.      original author of that file, following a query about its status.
1403    
1404  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
1405      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.
1406    
1407  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1408      quantifier applied to a forward-referencing subroutine call, could compile      quantifier applied to a forward-referencing subroutine call, could compile
1409      incorrect code or give the error "internal error: previously-checked      incorrect code or give the error "internal error: previously-checked
1410      referenced subpattern not found".      referenced subpattern not found".
1411    
1412  6.  Both MS Visual Studio and Symbian OS have problems with initializing  6.  Both MS Visual Studio and Symbian OS have problems with initializing
1413      variables to point to external functions. For these systems, therefore,      variables to point to external functions. For these systems, therefore,
1414      pcre_malloc etc. are now initialized to local functions that call the      pcre_malloc etc. are now initialized to local functions that call the
1415      relevant global functions.      relevant global functions.
1416    
1417  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
1418      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.
1419      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
1420      the lengths are correct (equal to the number of opcodes).      the lengths are correct (equal to the number of opcodes).
1421    
1422  8.  Following on from 7, I added a similar kludge to check the length of the  8.  Following on from 7, I added a similar kludge to check the length of the
1423      eint vector in pcreposix.c.      eint vector in pcreposix.c.
1424    
1425  9.  Error texts for pcre_compile() are held as one long string to avoid too  9.  Error texts for pcre_compile() are held as one long string to avoid too
1426      much relocation at load time. To find a text, the string is searched,      much relocation at load time. To find a text, the string is searched,
1427      counting zeros. There was no check for running off the end of the string,      counting zeros. There was no check for running off the end of the string,
1428      which could happen if a new error number was added without updating the      which could happen if a new error number was added without updating the
1429      string.      string.
1430    
1431  10. \K gave a compile-time error if it appeared in a lookbehind assersion.  10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1432    
1433  11. \K was not working if it appeared in an atomic group or in a group that  11. \K was not working if it appeared in an atomic group or in a group that
1434      was called as a "subroutine", or in an assertion. Perl 5.11 documents that      was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1435      \K is "not well defined" if used in an assertion. PCRE now accepts it if      \K is "not well defined" if used in an assertion. PCRE now accepts it if
1436      the assertion is positive, but not if it is negative.      the assertion is positive, but not if it is negative.
1437    
1438  12. Change 11 fortuitously reduced the size of the stack frame used in the  12. Change 11 fortuitously reduced the size of the stack frame used in the
1439      "match()" function of pcre_exec.c by one pointer. Forthcoming      "match()" function of pcre_exec.c by one pointer. Forthcoming
1440      implementation of support for (*MARK) will need an extra pointer on the      implementation of support for (*MARK) will need an extra pointer on the
1441      stack; I have reserved it now, so that the stack frame size does not      stack; I have reserved it now, so that the stack frame size does not
1442      decrease.      decrease.
1443    
1444  13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other  13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1445      item in branch that calls a recursion is a subroutine call - as in the      item in branch that calls a recursion is a subroutine call - as in the
1446      second branch in the above example - was incorrectly given the compile-      second branch in the above example - was incorrectly given the compile-
1447      time error "recursive call could loop indefinitely" because pcre_compile()      time error "recursive call could loop indefinitely" because pcre_compile()
1448      was not correctly checking the subroutine for matching a non-empty string.      was not correctly checking the subroutine for matching a non-empty string.
1449    
1450  14. The checks for overrunning compiling workspace could trigger after an  14. The checks for overrunning compiling workspace could trigger after an
1451      overrun had occurred. This is a "should never occur" error, but it can be      overrun had occurred. This is a "should never occur" error, but it can be
1452      triggered by pathological patterns such as hundreds of nested parentheses.      triggered by pathological patterns such as hundreds of nested parentheses.
1453      The checks now trigger 100 bytes before the end of the workspace.      The checks now trigger 100 bytes before the end of the workspace.
1454    
1455    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1456    
1457    
1458  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
# Line 390  Version 7.9 11-Apr-09 Line 1781  Version 7.9 11-Apr-09
1781  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
1782      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
1783      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1784      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1785        8.33.]
1786    
1787  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
1788      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 633  Version 7.7 07-May-08 Line 2025  Version 7.7 07-May-08
2025      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2026      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2027      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2028      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2029      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2030      was subsequently set up correctly.)      was subsequently set up correctly.)
2031    

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