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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.9 xx-xxx-09  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    21. Perl has changed its handling of \8 and \9. If there is no previously
110        encountered capturing group of those numbers, they are treated as the
111        literal characters 8 and 9 instead of a binary zero followed by the
112        literals. PCRE now does the same.
113    
114    22. Following Perl, added \o{} to specify codepoints in octal, making it
115        possible to specify values greater than 0777 and also making them
116        unambiguous.
117    
118    23. Perl now gives an error for missing closing braces after \x{... instead of
119        treating the string as literal. PCRE now does the same.
120    
121    24. RunTest used to grumble if an inappropriate test was selected explicitly,
122        but just skip it when running all tests. This make it awkward to run ranges
123        of tests when one of them was inappropriate. Now it just skips any
124        inappropriate tests, as it always did when running all tests.
125    
126    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
127        character types such as \d or \w, too many callouts were inserted, and the
128        data that they returned was rubbish.
129    
130    26. In UCP mode, \s was not matching two of the characters that Perl matches,
131        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
132        were matched by \h. The code has now been refactored so that the lists of
133        the horizontal and vertical whitespace characters used for \h and \v (which
134        are defined only in one place) are now also used for \s.
135    
136    27. Add JIT support for the 64 bit TileGX architecture.
137        Patch by Jiong Wang (Tilera Corporation).
138    
139    28. Possessive quantifiers for classes (both explicit and automatically
140        generated) now use special opcodes instead of wrapping in ONCE brackets.
141    
142    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
143        (because it's meaningless), this was not happening when PCRE_CASELESS was
144        set. Not wrong, but inefficient.
145    
146    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
147        properties for \w, \d, etc) is present in a test regex. Otherwise if the
148        test contains no characters greater than 255, Perl doesn't realise it
149        should be using Unicode semantics.
150    
151    
152    Version 8.33 28-May-2013
153    ------------------------
154    
155    1.  Added 'U' to some constants that are compared to unsigned integers, to
156        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
157        variables that are added to signed variables, to ensure the result is
158        signed and can be negated.
159    
160    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
161        CMake config files.
162    
163    3.  Revise the creation of config.h.generic so that all boolean macros are
164        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
165        overriding via -D on the command line possible.
166    
167    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
168        to unsigned int is reported to make a quite noticeable speed difference in
169        a specific Windows environment. Testing on Linux did also appear to show
170        some benefit (and it is clearly not harmful). Also fixed the definition of
171        Xop which should be unsigned.
172    
173    5.  Related to (4), changing the definition of the intermediate variable cc
174        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
175        improvements.
176    
177    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
178        unnecessary spaces.
179    
180    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
181        and later.
182    
183    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
184    
185    9.  Optimizing fast_forward_start_bits in JIT.
186    
187    10. Adding support for callouts in JIT, and fixing some issues revealed
188        during this work. Namely:
189    
190        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
191    
192        (b) Minimum length was not checked before the matching is started.
193    
194    11. The value of capture_last that is passed to callouts was incorrect in some
195        cases when there was a capture on one path that was subsequently abandoned
196        after a backtrack. Also, the capture_last value is now reset after a
197        recursion, since all captures are also reset in this case.
198    
199    12. The interpreter no longer returns the "too many substrings" error in the
200        case when an overflowing capture is in a branch that is subsequently
201        abandoned after a backtrack.
202    
203    13. In the pathological case when an offset vector of size 2 is used, pcretest
204        now prints out the matched string after a yield of 0 or 1.
205    
206    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
207        Only supported by the JIT compiler at the moment.
208    
209    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
210    
211    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
212        offset of the starting point of the matching process, provided the offsets
213        vector is large enough.
214    
215    17. The \A escape now records a lookbehind value of 1, though its execution
216        does not actually inspect the previous character. This is to ensure that,
217        in partial multi-segment matching, at least one character from the old
218        segment is retained when a new segment is processed. Otherwise, if there
219        are no lookbehinds in the pattern, \A might match incorrectly at the start
220        of a new segment.
221    
222    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
223    
224    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
225        gives some modest performance improvement in 8-bit mode.
226    
227    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
228        be expressed in certain programming languages using Universal Character
229        Names.
230    
231    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
232        which points out that "non characters" are not "characters that may not
233        appear in Unicode strings" but rather "characters that are reserved for
234        internal use and have only local meaning".
235    
236    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
237        there was a conditional group that depended on an assertion, if the
238        assertion was false, the callout that immediately followed the alternation
239        in the condition was skipped when pcre_exec() was used for matching.
240    
241    23. Allow an explicit callout to be inserted before an assertion that is the
242        condition for a conditional group, for compatibility with automatic
243        callouts, which always insert a callout at this point.
244    
245    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
246        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
247    
248    25. (*PRUNE) is now supported by the JIT compiler.
249    
250    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
251    
252    27. Fix the case where there are two or more SKIPs with arguments that may be
253        ignored.
254    
255    28. (*SKIP) is now supported by the JIT compiler.
256    
257    29. (*THEN) is now supported by the JIT compiler.
258    
259    30. Update RunTest with additional test selector options.
260    
261    31. The way PCRE handles backtracking verbs has been changed in two ways.
262    
263        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
264        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
265        backtracking. In some cases this makes it more Perl-compatible, but Perl's
266        rather obscure rules do not always do the same thing.
267    
268        (2) Previously, backtracking verbs were confined within assertions. This is
269        no longer the case for positive assertions, except for (*ACCEPT). Again,
270        this sometimes improves Perl compatibility, and sometimes does not.
271    
272    32. A number of tests that were in test 2 because Perl did things differently
273        have been moved to test 1, because either Perl or PCRE has changed, and
274        these tests are now compatible.
275    
276    32. Backtracking control verbs are now handled in the same way in JIT and
277        interpreter.
278    
279    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
280        contained a forward subroutine reference caused a compile error.
281    
282    34. Auto-detect and optimize limited repetitions in JIT.
283    
284    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
285        blocking (*UTF) etc.
286    
287    36. In the interpreter, maximizing pattern repetitions for characters and
288        character types now use tail recursion, which reduces stack usage.
289    
290    37. The value of the max lookbehind was not correctly preserved if a compiled
291        and saved regex was reloaded on a host of different endianness.
292    
293    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
294        of the compiled pattern block, expand the flags field from 16 to 32 bits
295        because it was almost full.
296    
297    39. Try madvise first before posix_madvise.
298    
299    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
300        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
301        original change locked out all matches of empty strings. This has been
302        changed so that one match of an empty string per line is recognized.
303        Subsequent searches on the same line (for colouring or for --only-matching,
304        for example) do not recognize empty strings.
305    
306    41. Applied a user patch to fix a number of spelling mistakes in comments.
307    
308    42. Data lines longer than 65536 caused pcretest to crash.
309    
310    43. Clarified the data type for length and startoffset arguments for pcre_exec
311        and pcre_dfa_exec in the function-specific man pages, where they were
312        explicitly stated to be in bytes, never having been updated. I also added
313        some clarification to the pcreapi man page.
314    
315    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
316        a segmentation fault.
317    
318    
319    Version 8.32 30-November-2012
320    -----------------------------
321    
322    1.  Improved JIT compiler optimizations for first character search and single
323        character iterators.
324    
325    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
326        Patch by Daniel Richard G.
327    
328    3.  Single character iterator optimizations in the JIT compiler.
329    
330    4.  Improved JIT compiler optimizations for character ranges.
331    
332    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
333        Reported by Giuseppe D'Angelo.
334    
335    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
336        of a line, was being set incorrectly in cases where .* appeared inside
337        atomic brackets at the start of a pattern, or where there was a subsequent
338        *PRUNE or *SKIP.
339    
340    7.  Improved instruction cache flush for POWER/PowerPC.
341        Patch by Daniel Richard G.
342    
343    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
344        grep:
345    
346        (a) There is now no limit to the number of patterns to be matched.
347    
348        (b) An error is given if a pattern is too long.
349    
350        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
351            are now supported.
352    
353        (d) --exclude-from and --include-from (multiple use) have been added.
354    
355        (e) Exclusions and inclusions now apply to all files and directories, not
356            just to those obtained from scanning a directory recursively.
357    
358        (f) Multiple uses of -f and --file-list are now supported.
359    
360        (g) In a Windows environment, the default for -d has been changed from
361            "read" (the GNU grep default) to "skip", because otherwise the presence
362            of a directory in the file list provokes an error.
363    
364        (h) The documentation has been revised and clarified in places.
365    
366    9.  Improve the matching speed of capturing brackets.
367    
368    10. Changed the meaning of \X so that it now matches a Unicode extended
369        grapheme cluster.
370    
371    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
372        out POSIX threads when JIT support is configured.
373    
374    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
375    
376    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
377        structure could go wrong in environments where size_t is not the same size
378        as int.
379    
380    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
381        set.
382    
383    15. The EBCDIC support had decayed; later updates to the code had included
384        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
385        general tidy up of EBCDIC-related issues, and the documentation was also
386        not quite right. There is now a test that can be run on ASCII systems to
387        check some of the EBCDIC-related things (but is it not a full test).
388    
389    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
390        in a small tidy to the code.
391    
392    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
393    
394    18. If the --only-matching (-o) option in pcregrep is specified multiple
395        times, each one causes appropriate output. For example, -o1 -o2 outputs the
396        substrings matched by the 1st and 2nd capturing parentheses. A separating
397        string can be specified by --om-separator (default empty).
398    
399    19. Improving the first n character searches.
400    
401    20. Turn case lists for horizontal and vertical white space into macros so that
402        they are defined only once.
403    
404    21. This set of changes together give more compatible Unicode case-folding
405        behaviour for characters that have more than one other case when UCP
406        support is available.
407    
408        (a) The Unicode property table now has offsets into a new table of sets of
409            three or more characters that are case-equivalent. The MultiStage2.py
410            script that generates these tables (the pcre_ucd.c file) now scans
411            CaseFolding.txt instead of UnicodeData.txt for character case
412            information.
413    
414        (b) The code for adding characters or ranges of characters to a character
415            class has been abstracted into a generalized function that also handles
416            case-independence. In UTF-mode with UCP support, this uses the new data
417            to handle characters with more than one other case.
418    
419        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
420            whose other case is greater than 256 are now correctly matched
421            caselessly. Previously, the high codepoint matched the low one, but not
422            vice versa.
423    
424        (d) The processing of \h, \H, \v, and \ in character classes now makes use
425            of the new class addition function, using character lists defined as
426            macros alongside the case definitions of 20 above.
427    
428        (e) Caseless back references now work with characters that have more than
429            one other case.
430    
431        (f) General caseless matching of characters with more than one other case
432            is supported.
433    
434    22. Unicode character properties were updated from Unicode 6.2.0
435    
436    23. Improved CMake support under Windows. Patch by Daniel Richard G.
437    
438    24. Add support for 32-bit character strings, and UTF-32
439    
440    25. Major JIT compiler update (code refactoring and bugfixing).
441        Experimental Sparc 32 support is added.
442    
443    26. Applied a modified version of Daniel Richard G's patch to create
444        pcre.h.generic and config.h.generic by "make" instead of in the
445        PrepareRelease script.
446    
447    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
448        pcre_compile.c when checking for a zero character.
449    
450    28. Introducing a native interface for JIT. Through this interface, the compiled
451        machine code can be directly executed. The purpose of this interface is to
452        provide fast pattern matching, so several sanity checks are not performed.
453        However, feature tests are still performed. The new interface provides
454        1.4x speedup compared to the old one.
455    
456    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
457        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
458        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
459    
460    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
461        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
462        the "old" RFC 2279). Instead, it ended up passing a negative length to
463        pcre_exec().
464    
465    31. Add support for GCC's visibility feature to hide internal functions.
466    
467    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
468        "unknown -C option" after outputting 0 or 1.
469    
470    33. There is now support for generating a code coverage report for the test
471        suite in environments where gcc is the compiler and lcov is installed. This
472        is mainly for the benefit of the developers.
473    
474    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
475        unaddressable using valgrind annotations, allowing valgrind to detect
476        invalid memory accesses. This is mainly for the benefit of the developers.
477    
478    25. (*UTF) can now be used to start a pattern in any of the three libraries.
479    
480    26. Give configure error if --enable-cpp but no C++ compiler found.
481    
482    
483    Version 8.31 06-July-2012
484    -------------------------
485    
486    1.  Fixing a wrong JIT test case and some compiler warnings.
487    
488    2.  Removed a bashism from the RunTest script.
489    
490    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
491        to unsigned type, result still unsigned" that was given by an MS compiler
492        on encountering the code "-sizeof(xxx)".
493    
494    4.  Partial matching support is added to the JIT compiler.
495    
496    5.  Fixed several bugs concerned with partial matching of items that consist
497        of more than one character:
498    
499        (a) /^(..)\1/ did not partially match "aba" because checking references was
500            done on an "all or nothing" basis. This also applied to repeated
501            references.
502    
503        (b) \R did not give a hard partial match if \r was found at the end of the
504            subject.
505    
506        (c) \X did not give a hard partial match after matching one or more
507            characters at the end of the subject.
508    
509        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
510            a partial match for the string "\r".
511    
512        (e) When newline was set to CRLF, the metacharacter "." did not recognize
513            a partial match for a CR character at the end of the subject string.
514    
515    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
516        running pcretest, the text "(JIT)" added to the output whenever JIT is
517        actually used to run the match.
518    
519    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
520        or /S+[+] with a digit between 1 and 7.
521    
522    8.  OP_NOT now supports any UTF character not just single-byte ones.
523    
524    9.  (*MARK) control verb is now supported by the JIT compiler.
525    
526    10. The command "./RunTest list" lists the available tests without actually
527        running any of them. (Because I keep forgetting what they all are.)
528    
529    11. Add PCRE_INFO_MAXLOOKBEHIND.
530    
531    12. Applied a (slightly modified) user-supplied patch that improves performance
532        when the heap is used for recursion (compiled with --disable-stack-for-
533        recursion). Instead of malloc and free for each heap frame each time a
534        logical recursion happens, frames are retained on a chain and re-used where
535        possible. This sometimes gives as much as 30% improvement.
536    
537    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
538        call.
539    
540    14. As documented, (*COMMIT) is now confined to within a positive assertion.
541    
542    15. It is now possible to link pcretest with libedit as an alternative to
543        libreadline.
544    
545    16. (*COMMIT) control verb is now supported by the JIT compiler.
546    
547    17. The Unicode data tables have been updated to Unicode 6.1.0.
548    
549    18. Added --file-list option to pcregrep.
550    
551    19. Added binary file support to pcregrep, including the -a, --binary-files,
552        -I, and --text options.
553    
554    20. The madvise function is renamed for posix_madvise for QNX compatibility
555        reasons. Fixed by Giuseppe D'Angelo.
556    
557    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
558    
559    22. Changed the option for creating symbolic links for 16-bit man pages from
560        -s to -sf so that re-installing does not cause issues.
561    
562    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
563    
564    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
565        matches in certain environments (the workspace was not being correctly
566        retained). Also added to pcre_dfa_exec() a simple plausibility check on
567        some of the workspace data at the beginning of a restart.
568    
569    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
570        was not doing so when it should - probably a typo introduced by SVN 528
571        (change 8.10/14).
572    
573    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
574        \w+ when the character tables indicated that \x{c4} was a word character.
575        There were several related cases, all because the tests for doing a table
576        lookup were testing for characters less than 127 instead of 255.
577    
578    27. If a pattern contains capturing parentheses that are not used in a match,
579        their slots in the ovector are set to -1. For those that are higher than
580        any matched groups, this happens at the end of processing. In the case when
581        there were back references that the ovector was too small to contain
582        (causing temporary malloc'd memory to be used during matching), and the
583        highest capturing number was not used, memory off the end of the ovector
584        was incorrectly being set to -1. (It was using the size of the temporary
585        memory instead of the true size.)
586    
587    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
588        ovector size, it uses memory at the end of the block that it has got.
589    
590    29. Check for an overlong MARK name and give an error at compile time. The
591        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
592    
593    30. JIT compiler update.
594    
595    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
596        Rill for the patch.
597    
598    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
599    
600    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
601    
602    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
603        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
604        was enabled.
605    
606    35. Improve JIT code generation for greedy plus quantifier.
607    
608    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
609        1 to "aa" instead of to an empty string. The bug affected repeated groups
610        that could potentially match an empty string.
611    
612    37. Optimizing single character iterators in JIT.
613    
614    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
615        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
616        codepoints that are too big for the mode are faulted, and in a UTF mode,
617        disallowed codepoints are also faulted.
618    
619    39. If PCRE was compiled with UTF support, in three places in the DFA
620        matcher there was code that should only have been obeyed in UTF mode, but
621        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
622        processing when bytes with values greater than 127 were present. In 16-bit
623        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
624        both cases the values are those that cannot be the first data item in a UTF
625        character. The three items that might have provoked this were recursions,
626        possessively repeated groups, and atomic groups.
627    
628    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
629        and pcregrep, because some OS require shared objects to be explicitly
630        passed to ld, causing the link step to fail if they are not.
631    
632    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
633        mode, patterns that started with \h* or \R* might be incorrectly matched.
634    
635    
636    Version 8.30 04-February-2012
637    -----------------------------
638    
639    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
640        name is defined in ctype.h.
641    
642    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
643        only in quite long subpatterns.
644    
645    3.  Removed the function pcre_info(), which has been obsolete and deprecated
646        since it was replaced by pcre_fullinfo() in February 2000.
647    
648    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
649        match a (*MARK), and the match failed at the start of the subject, a
650        reference to memory before the start of the subject could occur. This bug
651        was introduced by fix 17 of release 8.21.
652    
653    5.  A reference to an unset group with zero minimum repetition was giving
654        totally wrong answers (in non-JavaScript-compatibility mode). For example,
655        /(another)?(\1?)test/ matched against "hello world test". This bug was
656        introduced in release 8.13.
657    
658    6.  Add support for 16-bit character strings (a large amount of work involving
659        many changes and refactorings).
660    
661    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
662        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
663        from a file.
664    
665    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
666        rounding is not applied in this particular case).
667    
668    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
669        if they appear, or are escaped, in patterns.
670    
671    10. Get rid of a number of -Wunused-but-set-variable warnings.
672    
673    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
674        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
675        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
676        also returns the mark "x". This bug applied to capturing parentheses,
677        non-capturing parentheses, and atomic parentheses. It also applied to some
678        assertions.
679    
680    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
681        information out of configure.ac instead of relying on pcre.h.generic, which
682        is not stored in the repository.
683    
684    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
685        -lreadline.
686    
687    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
688    
689    15. Applied Graycode's patch to put the top-level frame on the stack rather
690        than the heap when not using the stack for recursion. This gives a
691        performance improvement in many cases when recursion is not deep.
692    
693    16. Experimental code added to "pcretest -C" to output the stack frame size.
694    
695    
696    Version 8.21 12-Dec-2011
697    ------------------------
698    
699    1.  Updating the JIT compiler.
700    
701    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
702        are added as well.
703    
704    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
705        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
706        calling _pcre_jit_exec. Some extra comments are added.
707    
708    4.  (*MARK) settings inside atomic groups that do not contain any capturing
709        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
710        was introduced by change 18 for 8.20.
711    
712    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
713        ECMA-262 standard.
714    
715    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
716        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
717        This bug was probably introduced by change 9 of 8.13.
718    
719    7.  While fixing 6 above, I noticed that a number of other items were being
720        incorrectly rejected as "not fixed length". This arose partly because newer
721        opcodes had not been added to the fixed-length checking code. I have (a)
722        corrected the bug and added tests for these items, and (b) arranged for an
723        error to occur if an unknown opcode is encountered while checking for fixed
724        length instead of just assuming "not fixed length". The items that were
725        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
726        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
727        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
728    
729    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
730        being incorrectly compiled and would have given unpredicatble results.
731    
732    9.  A possessively repeated subpattern with minimum repeat count greater than
733        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
734        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
735        the first (A) could occur when it should not.
736    
737    10. Add a cast and remove a redundant test from the code.
738    
739    11. JIT should use pcre_malloc/pcre_free for allocation.
740    
741    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
742        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
743        is anything other than /usr, -L is still shown).
744    
745    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
746    
747    14. Perl does not support \N without a following name in a [] class; PCRE now
748        also gives an error.
749    
750    15. If a forward reference was repeated with an upper limit of around 2000,
751        it caused the error "internal error: overran compiling workspace". The
752        maximum number of forward references (including repeats) was limited by the
753        internal workspace, and dependent on the LINK_SIZE. The code has been
754        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
755        the default depends on LINK_SIZE. There is a new upper limit (for safety)
756        of around 200,000 forward references. While doing this, I also speeded up
757        the filling in of repeated forward references.
758    
759    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
760        incorrectly expecting the subject to contain another "a" after the start.
761    
762    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
763        in the match, the SKIP should be ignored. This was not happening; instead
764        the SKIP was being treated as NOMATCH. For patterns such as
765        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
766        tested.
767    
768    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
769        now much more compatible with Perl, in particular in cases where the result
770        is a non-match for a non-anchored pattern. For example, if
771        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
772        "m", where previously it did not return a name. A side effect of this
773        change is that for partial matches, the last encountered mark name is
774        returned, as for non matches. A number of tests that were previously not
775        Perl-compatible have been moved into the Perl-compatible test files. The
776        refactoring has had the pleasing side effect of removing one argument from
777        the match() function, thus reducing its stack requirements.
778    
779    19. If the /S+ option was used in pcretest to study a pattern using JIT,
780        subsequent uses of /S (without +) incorrectly behaved like /S+.
781    
782    21. Retrieve executable code size support for the JIT compiler and fixing
783        some warnings.
784    
785    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
786        not work when the shorter character appeared right at the end of the
787        subject string.
788    
789    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
790        systems.
791    
792    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
793        output it when the /M option is used in pcretest.
794    
795    25. The CheckMan script was not being included in the distribution. Also, added
796        an explicit "perl" to run Perl scripts from the PrepareRelease script
797        because this is reportedly needed in Windows.
798    
799    26. If study data was being save in a file and studying had not found a set of
800        "starts with" bytes for the pattern, the data written to the file (though
801        never used) was taken from uninitialized memory and so caused valgrind to
802        complain.
803    
804    27. Updated RunTest.bat as provided by Sheri Pierce.
805    
806    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
807    
808    29. Computation of memory usage for the table of capturing group names was
809        giving an unnecessarily large value.
810    
811    
812    Version 8.20 21-Oct-2011
813    ------------------------
814    
815    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
816        a POSIX class. After further experiments with Perl, which convinced me that
817        Perl has bugs and confusions, a closing square bracket is no longer allowed
818        in a POSIX name. This bug also affected patterns with classes that started
819        with full stops.
820    
821    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
822        captured substring, but while checking the failing first alternative,
823        substring 1 is temporarily captured. If the output vector supplied to
824        pcre_exec() was not big enough for this capture, the yield of the function
825        was still zero ("insufficient space for captured substrings"). This cannot
826        be totally fixed without adding another stack variable, which seems a lot
827        of expense for a edge case. However, I have improved the situation in cases
828        such as /(a)(b)x|abc/ matched against "abc", where the return code
829        indicates that fewer than the maximum number of slots in the ovector have
830        been set.
831    
832    3.  Related to (2) above: when there are more back references in a pattern than
833        slots in the output vector, pcre_exec() uses temporary memory during
834        matching, and copies in the captures as far as possible afterwards. It was
835        using the entire output vector, but this conflicts with the specification
836        that only 2/3 is used for passing back captured substrings. Now it uses
837        only the first 2/3, for compatibility. This is, of course, another edge
838        case.
839    
840    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
841        main code base, and can be used by building with --enable-jit. When this is
842        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
843        runtime --no-jit option is given.
844    
845    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
846        ovector, the return from the function was zero, implying that there were
847        other matches that did not fit. The correct "exactly full" value is now
848        returned.
849    
850    6.  If a subpattern that was called recursively or as a subroutine contained
851        (*PRUNE) or any other control that caused it to give a non-standard return,
852        invalid errors such as "Error -26 (nested recursion at the same subject
853        position)" or even infinite loops could occur.
854    
855    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
856        computing the minimum length on reaching *ACCEPT, and so ended up with the
857        wrong value of 1 rather than 0. Further investigation indicates that
858        computing a minimum subject length in the presence of *ACCEPT is difficult
859        (think back references, subroutine calls), and so I have changed the code
860        so that no minimum is registered for a pattern that contains *ACCEPT.
861    
862    8.  If (*THEN) was present in the first (true) branch of a conditional group,
863        it was not handled as intended. [But see 16 below.]
864    
865    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
866        Sheri Pierce.
867    
868    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
869        the first byte in a match must be "a".
870    
871    11. Change 17 for 8.13 increased the recursion depth for patterns like
872        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
873        pattern contains any instances of (*THEN). If it does not, the old
874        optimizations are restored. It would be nice to do this on a per-group
875        basis, but at the moment that is not feasible.
876    
877    12. In some environments, the output of pcretest -C is CRLF terminated. This
878        broke RunTest's code that checks for the link size. A single white space
879        character after the value is now allowed for.
880    
881    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
882        For "fr", it uses the Windows-specific input and output files.
883    
884    14. If (*THEN) appeared in a group that was called recursively or as a
885        subroutine, it did not work as intended. [But see next item.]
886    
887    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
888        pattern fragments (but not containing any | characters). If A and B are
889        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
890        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
891        D. In other words, Perl considers parentheses that do not contain any |
892        characters to be part of a surrounding alternative, whereas PCRE was
893        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
894        differently. PCRE now behaves in the same way as Perl, except in the case
895        of subroutine/recursion calls such as (?1) which have in any case always
896        been different (but PCRE had them first :-).
897    
898    16. Related to 15 above: Perl does not treat the | in a conditional group as
899        creating alternatives. Such a group is treated in the same way as an
900        ordinary group without any | characters when processing (*THEN). PCRE has
901        been changed to match Perl's behaviour.
902    
903    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
904        RunGrepTest script failed.
905    
906    18. Change 22 for version 13 caused atomic groups to use more stack. This is
907        inevitable for groups that contain captures, but it can lead to a lot of
908        stack use in large patterns. The old behaviour has been restored for atomic
909        groups that do not contain any capturing parentheses.
910    
911    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
912        suppress the check for a minimum subject length at run time. (If it was
913        given to pcre_exec() or pcre_dfa_exec() it did work.)
914    
915    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
916        fail to work when decoding hex characters in data strings in EBCDIC
917        environments.
918    
919    21. It appears that in at least one Mac OS environment, the isxdigit() function
920        is implemented as a macro that evaluates to its argument more than once,
921        contravening the C 90 Standard (I haven't checked a later standard). There
922        was an instance in pcretest which caused it to go wrong when processing
923        \x{...} escapes in subject strings. The has been rewritten to avoid using
924        things like p++ in the argument of isxdigit().
925    
926    
927    Version 8.13 16-Aug-2011
928    ------------------------
929    
930    1.  The Unicode data tables have been updated to Unicode 6.0.0.
931    
932    2.  Two minor typos in pcre_internal.h have been fixed.
933    
934    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
935        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
936        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
937    
938    4.  There were a number of related bugs in the code for matching backrefences
939        caselessly in UTF-8 mode when codes for the characters concerned were
940        different numbers of bytes. For example, U+023A and U+2C65 are an upper
941        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
942        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
943        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
944        2-byte code at the end of the subject (it thought there wasn't enough data
945        left).
946    
947    5.  Comprehensive information about what went wrong is now returned by
948        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
949        as the output vector has at least 2 elements. The offset of the start of
950        the failing character and a reason code are placed in the vector.
951    
952    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
953        now returned is for the first byte of the failing character, instead of the
954        last byte inspected. This is an incompatible change, but I hope it is small
955        enough not to be a problem. It makes the returned offset consistent with
956        pcre_exec() and pcre_dfa_exec().
957    
958    7.  pcretest now gives a text phrase as well as the error number when
959        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
960        failure, the offset and reason code are output.
961    
962    8.  When \R was used with a maximizing quantifier it failed to skip backwards
963        over a \r\n pair if the subsequent match failed. Instead, it just skipped
964        back over a single character (\n). This seems wrong (because it treated the
965        two characters as a single entity when going forwards), conflicts with the
966        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
967        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
968        has been changed.
969    
970    9.  Some internal refactoring has changed the processing so that the handling
971        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
972        time (the PCRE_DOTALL option was changed this way some time ago: version
973        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
974        which was always a bit of a fudge. It also means that there is one less
975        argument for the match() function, which reduces its stack requirements
976        slightly. This change also fixes an incompatibility with Perl: the pattern
977        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
978    
979    10. More internal refactoring has drastically reduced the number of recursive
980        calls to match() for possessively repeated groups such as (abc)++ when
981        using pcre_exec().
982    
983    11. While implementing 10, a number of bugs in the handling of groups were
984        discovered and fixed:
985    
986        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
987        (a|)*(?1) gave a compile-time internal error.
988        ((a|)+)+  did not notice that the outer group could match an empty string.
989        (^a|^)+   was not marked as anchored.
990        (.*a|.*)+ was not marked as matching at start or after a newline.
991    
992    12. Yet more internal refactoring has removed another argument from the match()
993        function. Special calls to this function are now indicated by setting a
994        value in a variable in the "match data" data block.
995    
996    13. Be more explicit in pcre_study() instead of relying on "default" for
997        opcodes that mean there is no starting character; this means that when new
998        ones are added and accidentally left out of pcre_study(), testing should
999        pick them up.
1000    
1001    14. The -s option of pcretest has been documented for ages as being an old
1002        synonym of -m (show memory usage). I have changed it to mean "force study
1003        for every regex", that is, assume /S for every regex. This is similar to -i
1004        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1005        using it. It makes it easier to run collections of tests with and without
1006        study enabled, and thereby test pcre_study() more easily. All the standard
1007        tests are now run with and without -s (but some patterns can be marked as
1008        "never study" - see 20 below).
1009    
1010    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1011        restoration of the capturing data to the outer values was not happening
1012        correctly.
1013    
1014    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1015        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1016        pattern had matched an empty string, and so incorrectly returned a no
1017        match.
1018    
1019    17. There was optimizing code for the last branch of non-capturing parentheses,
1020        and also for the obeyed branch of a conditional subexpression, which used
1021        tail recursion to cut down on stack usage. Unfortunately, now that there is
1022        the possibility of (*THEN) occurring in these branches, tail recursion is
1023        no longer possible because the return has to be checked for (*THEN). These
1024        two optimizations have therefore been removed. [But see 8.20/11 above.]
1025    
1026    18. If a pattern containing \R was studied, it was assumed that \R always
1027        matched two bytes, thus causing the minimum subject length to be
1028        incorrectly computed because \R can also match just one byte.
1029    
1030    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1031        was incorrectly computed.
1032    
1033    20. If /S is present twice on a test pattern in pcretest input, it now
1034        *disables* studying, thereby overriding the use of -s on the command line
1035        (see 14 above). This is necessary for one or two tests to keep the output
1036        identical in both cases.
1037    
1038    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1039        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1040    
1041    22. When an atomic group that contained a capturing parenthesis was
1042        successfully matched, but the branch in which it appeared failed, the
1043        capturing was not being forgotten if a higher numbered group was later
1044        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1045        group 1 to "a", when in fact it should be unset. This applied to multi-
1046        branched capturing and non-capturing groups, repeated or not, and also to
1047        positive assertions (capturing in negative assertions does not happen
1048        in PCRE) and also to nested atomic groups.
1049    
1050    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1051        subject after a captured substring, to make it easier to tell which of a
1052        number of identical substrings has been captured.
1053    
1054    24. The way atomic groups are processed by pcre_exec() has been changed so that
1055        if they are repeated, backtracking one repetition now resets captured
1056        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1057        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1058        "aaa". Previously, it would have been "a". As part of this code
1059        refactoring, the way recursive calls are handled has also been changed.
1060    
1061    25. If an assertion condition captured any substrings, they were not passed
1062        back unless some other capturing happened later. For example, if
1063        (?(?=(a))a) was matched against "a", no capturing was returned.
1064    
1065    26. When studying a pattern that contained subroutine calls or assertions,
1066        the code for finding the minimum length of a possible match was handling
1067        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1068        group 1 called group 2 while simultaneously a separate group 2 called group
1069        1). A stack overflow occurred in this case. I have fixed this by limiting
1070        the recursion depth to 10.
1071    
1072    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1073        Fortmann. This supports explicit test numbers on the command line, and has
1074        argument validation and error reporting.
1075    
1076    28. An instance of \X with an unlimited repeat could fail if at any point the
1077        first character it looked at was a mark character.
1078    
1079    29. Some minor code refactoring concerning Unicode properties and scripts
1080        should reduce the stack requirement of match() slightly.
1081    
1082    30. Added the '=' option to pcretest to check the setting of unused capturing
1083        slots at the end of the pattern, which are documented as being -1, but are
1084        not included in the return count.
1085    
1086    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1087        compiled something random. Now it gives a compile-time error (as does
1088        Perl).
1089    
1090    32. A *MARK encountered during the processing of a positive assertion is now
1091        recorded and passed back (compatible with Perl).
1092    
1093    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1094        had alternative anchored branches, the search for a second match in a line
1095        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1096        matched the line "0102" twice. The same bug affected patterns that started
1097        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1098        twice.
1099    
1100    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1101        does, and because of capturing effects, quantifying parenthesized
1102        assertions may at times be useful. Quantifiers are now allowed for
1103        parenthesized assertions.
1104    
1105    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1106    
1107    36. \g was being checked for fancy things in a character class, when it should
1108        just be a literal "g".
1109    
1110    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1111        appearance of a nested POSIX class supersedes an apparent external class.
1112        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1113        unescaped square brackets may also appear as part of class names. For
1114        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1115        more like Perl. (But see 8.20/1 above.)
1116    
1117    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1118        was because it thought it was \N{name}, which is not supported).
1119    
1120    39. Add minix to OS list not supporting the -S option in pcretest.
1121    
1122    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1123        cannot analyze patterns in sufficient detail to catch mutual recursions
1124        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1125        subgroup is called recursively as a subpattern for a second time at the
1126        same position in the subject string. In previous releases this might have
1127        been caught by the recursion limit, or it might have run out of stack.
1128    
1129    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1130        happen only once. PCRE was, however incorrectly giving a compile time error
1131        "recursive call could loop indefinitely" because it cannot analyze the
1132        pattern in sufficient detail. The compile time test no longer happens when
1133        PCRE is compiling a conditional subpattern, but actual runaway loops are
1134        now caught at runtime (see 40 above).
1135    
1136    42. It seems that Perl allows any characters other than a closing parenthesis
1137        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1138        has been changed to be the same.
1139    
1140    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1141        as not to get warnings when autogen.sh is called. Also changed
1142        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1143    
1144    44. To help people who use pcregrep to scan files containing exceedingly long
1145        lines, the following changes have been made:
1146    
1147        (a) The default value of the buffer size parameter has been increased from
1148            8K to 20K. (The actual buffer used is three times this size.)
1149    
1150        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1151            PCRE is built.
1152    
1153        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1154            to be set at run time.
1155    
1156        (d) Numerical values in pcregrep options can be followed by K or M, for
1157            example --buffer-size=50K.
1158    
1159        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1160            given and the return code is set to 2.
1161    
1162    45. Add a pointer to the latest mark to the callout data block.
1163    
1164    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1165        partial match of an empty string instead of no match. This was specific to
1166        the use of ".".
1167    
1168    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1169        complete match instead of a partial match. This bug was dependent on both
1170        the PCRE_UTF8 and PCRE_DOTALL options being set.
1171    
1172    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1173        starting byte set, because \b was not being ignored.
1174    
1175    
1176    Version 8.12 15-Jan-2011
1177    ------------------------
1178    
1179    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1180        checks for such things as part of the documentation building process.
1181    
1182    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1183        --match-limit and --recursion-limit options (added for 8.11). In
1184        particular, this made one of the standard tests fail. (The integer value
1185        went into the wrong half of a long int.)
1186    
1187    3.  If the --colour option was given to pcregrep with -v (invert match), it
1188        did strange things, either producing crazy output, or crashing. It should,
1189        of course, ignore a request for colour when reporting lines that do not
1190        match.
1191    
1192    4.  Another pcregrep bug caused similar problems if --colour was specified with
1193        -M (multiline) and the pattern match finished with a line ending.
1194    
1195    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1196        matched in multiline mode, the following line was shown as part of the
1197        match. This seems wrong, so I have changed it.
1198    
1199    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1200        the check for further matches in the same line (so they could be coloured)
1201        to overrun the end of the current line. If another match was found, it was
1202        incorrectly shown (and then shown again when found in the next line).
1203    
1204    7.  If pcregrep was compiled under Windows, there was a reference to the
1205        function pcregrep_exit() before it was defined. I am assuming this was
1206        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1207        reported by a user. I've moved the definition above the reference.
1208    
1209    
1210    Version 8.11 10-Dec-2010
1211    ------------------------
1212    
1213    1.  (*THEN) was not working properly if there were untried alternatives prior
1214        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1215        backtracked to try for "b" instead of moving to the next alternative branch
1216        at the same level (in this case, to look for "c"). The Perl documentation
1217        is clear that when (*THEN) is backtracked onto, it goes to the "next
1218        alternative in the innermost enclosing group".
1219    
1220    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1221        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1222        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1223        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1224        (*THEN).
1225    
1226    3.  If \s appeared in a character class, it removed the VT character from
1227        the class, even if it had been included by some previous item, for example
1228        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1229        of \s, but is part of the POSIX "space" class.)
1230    
1231    4.  A partial match never returns an empty string (because you can always
1232        match an empty string at the end of the subject); however the checking for
1233        an empty string was starting at the "start of match" point. This has been
1234        changed to the "earliest inspected character" point, because the returned
1235        data for a partial match starts at this character. This means that, for
1236        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1237        (previously it gave "no match").
1238    
1239    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1240        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1241        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1242        has an implication that the given string is incomplete (because a partial
1243        match is preferred over a full match). For this reason, these items now
1244        give a partial match in this situation. [Aside: previously, the one case
1245        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1246        match rather than a full match, which was wrong by the old rules, but is
1247        now correct.]
1248    
1249    6.  There was a bug in the handling of #-introduced comments, recognized when
1250        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1251        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1252        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1253        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1254        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1255        places in pcre_compile().
1256    
1257    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1258        comments when looking ahead for named forward references to subpatterns,
1259        the only newline sequence it recognized was NL. It now handles newlines
1260        according to the set newline convention.
1261    
1262    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1263        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1264        cater for a lack of strerror(). These oversights have been fixed.
1265    
1266    9.  Added --match-limit and --recursion-limit to pcregrep.
1267    
1268    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1269    
1270    11. When the -o option was used, pcregrep was setting a return code of 1, even
1271        when matches were found, and --line-buffered was not being honoured.
1272    
1273    12. Added an optional parentheses number to the -o and --only-matching options
1274        of pcregrep.
1275    
1276    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1277        can match an empty string. The code to do it in pcretest and pcredemo
1278        needed fixing:
1279    
1280        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1281            only one byte after an empty string match just before CRLF (this case
1282            just got forgotten; "any" and "anycrlf" were OK).
1283    
1284        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1285            mode when an empty string match preceded an ASCII character followed by
1286            a non-ASCII character. (The code for advancing by one character rather
1287            than one byte was nonsense.)
1288    
1289        (c) The pcredemo.c sample program did not have any code at all to handle
1290            the cases when CRLF is a valid newline sequence.
1291    
1292    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1293        as a starting offset was within the subject string. There is now a new
1294        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1295        negative or greater than the length of the string. In order to test this,
1296        pcretest is extended to allow the setting of negative starting offsets.
1297    
1298    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1299        starting offset points to the beginning of a UTF-8 character was
1300        unnecessarily clumsy. I tidied it up.
1301    
1302    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1303        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1304    
1305    17. Nobody had reported that the --include_dir option, which was added in
1306        release 7.7 should have been called --include-dir (hyphen, not underscore)
1307        for compatibility with GNU grep. I have changed it to --include-dir, but
1308        left --include_dir as an undocumented synonym, and the same for
1309        --exclude-dir, though that is not available in GNU grep, at least as of
1310        release 2.5.4.
1311    
1312    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1313        characters from a string of bytes) have been redefined so as not to use
1314        loops, in order to improve performance in some environments. At the same
1315        time, I abstracted some of the common code into auxiliary macros to save
1316        repetition (this should not affect the compiled code).
1317    
1318    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1319        compile-time error is now given if \c is not followed by an ASCII
1320        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1321        different, and any byte value is allowed.)
1322    
1323    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1324        START_OPTIMIZE option, which is now allowed at compile time - but just
1325        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1326        to pcregrep and other applications that have no direct access to PCRE
1327        options. The new /Y option in pcretest sets this option when calling
1328        pcre_compile().
1329    
1330    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1331        back references. Groups containing recursive back references were forced to
1332        be atomic by that change, but in the case of named groups, the amount of
1333        memory required was incorrectly computed, leading to "Failed: internal
1334        error: code overflow". This has been fixed.
1335    
1336    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1337        pcretest.c, to avoid build problems in some Borland environments.
1338    
1339    
1340    Version 8.10 25-Jun-2010
1341    ------------------------
1342    
1343    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1344        THEN.
1345    
1346    2.  (*ACCEPT) was not working when inside an atomic group.
1347    
1348    3.  Inside a character class, \B is treated as a literal by default, but
1349        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1350        causes the error). The code is unchanged, but I tidied the documentation.
1351    
1352    4.  Inside a character class, PCRE always treated \R and \X as literals,
1353        whereas Perl faults them if its -w option is set. I have changed PCRE so
1354        that it faults them when PCRE_EXTRA is set.
1355    
1356    5.  Added support for \N, which always matches any character other than
1357        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1358    
1359    6.  When compiling pcregrep with newer versions of gcc which may have
1360        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1361        declared with attribute warn_unused_result" were given. Just casting the
1362        result to (void) does not stop the warnings; a more elaborate fudge is
1363        needed. I've used a macro to implement this.
1364    
1365    7.  Minor change to pcretest.c to avoid a compiler warning.
1366    
1367    8.  Added four artifical Unicode properties to help with an option to make
1368        \s etc use properties (see next item). The new properties are: Xan
1369        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1370    
1371    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1372        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1373        this option. Modified pcretest to add /W to test this facility. Added
1374        REG_UCP to make it available via the POSIX interface.
1375    
1376    10. Added --line-buffered to pcregrep.
1377    
1378    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1379        studied, and the match started with a letter with a code point greater than
1380        127 whose first byte was different to the first byte of the other case of
1381        the letter, the other case of this starting letter was not recognized
1382        (#976).
1383    
1384    12. If a pattern that was studied started with a repeated Unicode property
1385        test, for example, \p{Nd}+, there was the theoretical possibility of
1386        setting up an incorrect bitmap of starting bytes, but fortunately it could
1387        not have actually happened in practice until change 8 above was made (it
1388        added property types that matched character-matching opcodes).
1389    
1390    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1391        possible starting bytes for non-anchored patterns.
1392    
1393    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1394        \R, and also a number of cases that involve Unicode properties, both
1395        explicit and implicit when PCRE_UCP is set.
1396    
1397    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1398        input, it could crash or give wrong results if characters with values
1399        greater than 0xc0 were present in the subject string. (Detail: it assumed
1400        UTF-8 input when processing these items.)
1401    
1402    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1403        size_t is 64-bit (#991).
1404    
1405    17. Added a check for running out of memory when PCRE is compiled with
1406        --disable-stack-for-recursion (#990).
1407    
1408    18. If the last data line in a file for pcretest does not have a newline on
1409        the end, a newline was missing in the output.
1410    
1411    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1412        less than 128) in its various bitmaps. However, there is a facility for
1413        generating tables according to the current locale when PCRE is compiled. It
1414        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1415        characters, are recognized by isspace() and therefore were getting set in
1416        these tables, and indeed these tables seem to approximate to ISO 8859. This
1417        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1418        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1419        which of course cannot start UTF-8 characters. I have changed the code so
1420        that only real ASCII characters (less than 128) and the correct starting
1421        bytes for UTF-8 encodings are set for characters greater than 127 when in
1422        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1423        altogether.)
1424    
1425    20. Added the /T option to pcretest so as to be able to run tests with non-
1426        standard character tables, thus making it possible to include the tests
1427        used for 19 above in the standard set of tests.
1428    
1429    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1430        reference to a subpattern the other side of a comment that contains an
1431        opening parenthesis caused either an internal compiling error, or a
1432        reference to the wrong subpattern.
1433    
1434    
1435    Version 8.02 19-Mar-2010
1436    ------------------------
1437    
1438    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1439    
1440    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1441        configured.
1442    
1443    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1444        original author of that file, following a query about its status.
1445    
1446    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1447        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1448    
1449    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1450        quantifier applied to a forward-referencing subroutine call, could compile
1451        incorrect code or give the error "internal error: previously-checked
1452        referenced subpattern not found".
1453    
1454    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1455        variables to point to external functions. For these systems, therefore,
1456        pcre_malloc etc. are now initialized to local functions that call the
1457        relevant global functions.
1458    
1459    7.  There were two entries missing in the vectors called coptable and poptable
1460        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1461        I've fixed the data, and added a kludgy way of testing at compile time that
1462        the lengths are correct (equal to the number of opcodes).
1463    
1464    8.  Following on from 7, I added a similar kludge to check the length of the
1465        eint vector in pcreposix.c.
1466    
1467    9.  Error texts for pcre_compile() are held as one long string to avoid too
1468        much relocation at load time. To find a text, the string is searched,
1469        counting zeros. There was no check for running off the end of the string,
1470        which could happen if a new error number was added without updating the
1471        string.
1472    
1473    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1474    
1475    11. \K was not working if it appeared in an atomic group or in a group that
1476        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1477        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1478        the assertion is positive, but not if it is negative.
1479    
1480    12. Change 11 fortuitously reduced the size of the stack frame used in the
1481        "match()" function of pcre_exec.c by one pointer. Forthcoming
1482        implementation of support for (*MARK) will need an extra pointer on the
1483        stack; I have reserved it now, so that the stack frame size does not
1484        decrease.
1485    
1486    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1487        item in branch that calls a recursion is a subroutine call - as in the
1488        second branch in the above example - was incorrectly given the compile-
1489        time error "recursive call could loop indefinitely" because pcre_compile()
1490        was not correctly checking the subroutine for matching a non-empty string.
1491    
1492    14. The checks for overrunning compiling workspace could trigger after an
1493        overrun had occurred. This is a "should never occur" error, but it can be
1494        triggered by pathological patterns such as hundreds of nested parentheses.
1495        The checks now trigger 100 bytes before the end of the workspace.
1496    
1497    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1498    
1499    
1500    Version 8.01 19-Jan-2010
1501    ------------------------
1502    
1503    1.  If a pattern contained a conditional subpattern with only one branch (in
1504        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1505        computed the wrong minimum data length (which is of course zero for such
1506        subpatterns). This could cause incorrect "no match" results.
1507    
1508    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1509        the pattern is reset in the first branch, pcre_compile() failed with
1510        "internal error: code overflow at offset...". This happened only when
1511        the reset was to the original external option setting. (An optimization
1512        abstracts leading options settings into an external setting, which was the
1513        cause of this.)
1514    
1515    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1516        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1517        assertion pattern did not match (meaning that the assertion was true), it
1518        was incorrectly treated as false if the SKIP had been reached during the
1519        matching. This also applied to assertions used as conditions.
1520    
1521    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1522        assertion subpattern, including such a pattern used as a condition,
1523        unpredictable results occurred, instead of the error return
1524        PCRE_ERROR_DFA_UITEM.
1525    
1526    5.  The C++ GlobalReplace function was not working like Perl for the special
1527        situation when an empty string is matched. It now does the fancy magic
1528        stuff that is necessary.
1529    
1530    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1531        removed. (These were left over from very, very early versions of PCRE.)
1532    
1533    7.  Some cosmetic changes to the code to make life easier when compiling it
1534        as part of something else:
1535    
1536        (a) Change DEBUG to PCRE_DEBUG.
1537    
1538        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1539            called "current" as "current_branch", to prevent a collision with the
1540            Linux macro when compiled as a kernel module.
1541    
1542        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1543            prevent a collision with the Linux macro when compiled as a kernel
1544            module.
1545    
1546    8.  In pcre_compile() there are some checks for integer overflows that used to
1547        cast potentially large values to (double). This has been changed to that
1548        when building, a check for int64_t is made, and if it is found, it is used
1549        instead, thus avoiding the use of floating point arithmetic. (There is no
1550        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1551        double.
1552    
1553    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1554        2005 (difference between two addresses compared to an unsigned value).
1555    
1556    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1557        custom one, because of the following reported problem in Windows:
1558    
1559          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1560              under Win32.
1561          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1562              therefore missing the function definition.
1563          - The compiler thus generates a "C" signature for the test function.
1564          - The linker fails to find the "C" function.
1565          - PCRE fails to configure if asked to do so against libbz2.
1566    
1567    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1568        messages were output:
1569    
1570          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1571          rerunning libtoolize, to keep the correct libtool macros in-tree.
1572          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1573    
1574        I have done both of these things.
1575    
1576    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1577        most of the time, it *can* run out if it is given a pattern that contains a
1578        runaway infinite recursion. I updated the discussion in the pcrestack man
1579        page.
1580    
1581    13. Now that we have gone to the x.xx style of version numbers, the minor
1582        version may start with zero. Using 08 or 09 is a bad idea because users
1583        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1584        interpreted as invalid octal numbers. I've updated the previous comment in
1585        configure.ac, and also added a check that gives an error if 08 or 09 are
1586        used.
1587    
1588    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1589        causing partial matching to fail when the end of the subject matched \W
1590        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1591    
1592    15. There were some discrepancies between the declarations in pcre_internal.h
1593        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1594        their definitions. The declarations used "const uschar *" and the
1595        definitions used USPTR. Even though USPTR is normally defined as "const
1596        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1597        reported that: "This difference in casting confuses some C++ compilers, for
1598        example, SunCC recognizes above declarations as different functions and
1599        generates broken code for hbpcre." I have changed the declarations to use
1600        USPTR.
1601    
1602    16. GNU libtool is named differently on some systems. The autogen.sh script now
1603        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1604        (FreeBSD).
1605    
1606    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1607        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1608        comment: "Figure out how to create a longlong from a string: strtoll and
1609        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1610        instance, but it only takes 2 args instead of 3!"
1611    
1612    18. A subtle bug concerned with back references has been fixed by a change of
1613        specification, with a corresponding code fix. A pattern such as
1614        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1615        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1616        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1617        same bug. Such groups have to be quantified to be useful, or contained
1618        inside another quantified group. (If there's no repetition, the reference
1619        can never match.) The problem arises because, having left the group and
1620        moved on to the rest of the pattern, a later failure that backtracks into
1621        the group uses the captured value from the final iteration of the group
1622        rather than the correct earlier one. I have fixed this in PCRE by forcing
1623        any group that contains a reference to itself to be an atomic group; that
1624        is, there cannot be any backtracking into it once it has completed. This is
1625        similar to recursive and subroutine calls.
1626    
1627    
1628    Version 8.00 19-Oct-09
1629    ----------------------
1630    
1631    1.  The table for translating pcre_compile() error codes into POSIX error codes
1632        was out-of-date, and there was no check on the pcre_compile() error code
1633        being within the table. This could lead to an OK return being given in
1634        error.
1635    
1636    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1637        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1638        in a Windows environment.
1639    
1640    3.  The pcregrep --count option prints the count for each file even when it is
1641        zero, as does GNU grep. However, pcregrep was also printing all files when
1642        --files-with-matches was added. Now, when both options are given, it prints
1643        counts only for those files that have at least one match. (GNU grep just
1644        prints the file name in this circumstance, but including the count seems
1645        more useful - otherwise, why use --count?) Also ensured that the
1646        combination -clh just lists non-zero counts, with no names.
1647    
1648    4.  The long form of the pcregrep -F option was incorrectly implemented as
1649        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1650        but it seems right to fix it, and I didn't think it was worth preserving
1651        the old behaviour.
1652    
1653    5.  The command line items --regex=pattern and --regexp=pattern were not
1654        recognized by pcregrep, which required --regex pattern or --regexp pattern
1655        (with a space rather than an '='). The man page documented the '=' forms,
1656        which are compatible with GNU grep; these now work.
1657    
1658    6.  No libpcreposix.pc file was created for pkg-config; there was just
1659        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1660    
1661    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1662        when UCP support is not needed, by modifying the Python script that
1663        generates it from Unicode data files. This should not matter if the module
1664        is correctly used as a library, but I received one complaint about 50K of
1665        unwanted data. My guess is that the person linked everything into his
1666        program rather than using a library. Anyway, it does no harm.
1667    
1668    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1669        was a minimum greater than 1 for a wide character in a possessive
1670        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1671        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1672        character. Chaos in the form of incorrect output or a compiling loop could
1673        result.
1674    
1675    9.  The restrictions on what a pattern can contain when partial matching is
1676        requested for pcre_exec() have been removed. All patterns can now be
1677        partially matched by this function. In addition, if there are at least two
1678        slots in the offset vector, the offset of the earliest inspected character
1679        for the match and the offset of the end of the subject are set in them when
1680        PCRE_ERROR_PARTIAL is returned.
1681    
1682    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1683        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1684        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1685        and may be more useful for multi-segment matching.
1686    
1687    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1688        used to be given if ever the end of the subject was reached; now it is
1689        given only if matching could not proceed because another character was
1690        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1691        string "Z", which now yields "no match" instead of "partial match". In the
1692        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1693        final character ended with (*FAIL).
1694    
1695    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1696        if the pattern had a "must contain" character that was already found in the
1697        earlier partial match, unless partial matching was again requested. For
1698        example, with the pattern /dog.(body)?/, the "must contain" character is
1699        "g". If the first part-match was for the string "dog", restarting with
1700        "sbody" failed. This bug has been fixed.
1701    
1702    13. The string returned by pcre_dfa_exec() after a partial match has been
1703        changed so that it starts at the first inspected character rather than the
1704        first character of the match. This makes a difference only if the pattern
1705        starts with a lookbehind assertion or \b or \B (\K is not supported by
1706        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1707        matching functions compatible, and I think it's the right thing to do.
1708    
1709    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1710        so that the demonstration program is easily available in environments where
1711        PCRE has not been installed from source.
1712    
1713    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1714        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1715        library.
1716    
1717    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1718        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1719        is not the first non-POSIX option to be added. Clearly some people find
1720        these options useful.
1721    
1722    17. If a caller to the POSIX matching function regexec() passes a non-zero
1723        value for nmatch with a NULL value for pmatch, the value of
1724        nmatch is forced to zero.
1725    
1726    18. RunGrepTest did not have a test for the availability of the -u option of
1727        the diff command, as RunTest does. It now checks in the same way as
1728        RunTest, and also checks for the -b option.
1729    
1730    19. If an odd number of negated classes containing just a single character
1731        interposed, within parentheses, between a forward reference to a named
1732        subpattern and the definition of the subpattern, compilation crashed with
1733        an internal error, complaining that it could not find the referenced
1734        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1735        [The bug was that it was starting one character too far in when skipping
1736        over the character class, thus treating the ] as data rather than
1737        terminating the class. This meant it could skip too much.]
1738    
1739    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1740        /g option in pcretest when the pattern contains \K, which makes it possible
1741        to have an empty string match not at the start, even when the pattern is
1742        anchored. Updated pcretest and pcredemo to use this option.
1743    
1744    21. If the maximum number of capturing subpatterns in a recursion was greater
1745        than the maximum at the outer level, the higher number was returned, but
1746        with unset values at the outer level. The correct (outer level) value is
1747        now given.
1748    
1749    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1750        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1751        make it do so. The string so far is captured, making this feature
1752        compatible with Perl.
1753    
1754    23. The tests have been re-organized, adding tests 11 and 12, to make it
1755        possible to check the Perl 5.10 features against Perl 5.10.
1756    
1757    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1758        pattern matches a fixed length string. PCRE did not allow this; now it
1759        does. Neither allows recursion.
1760    
1761    25. I finally figured out how to implement a request to provide the minimum
1762        length of subject string that was needed in order to match a given pattern.
1763        (It was back references and recursion that I had previously got hung up
1764        on.) This code has now been added to pcre_study(); it finds a lower bound
1765        to the length of subject needed. It is not necessarily the greatest lower
1766        bound, but using it to avoid searching strings that are too short does give
1767        some useful speed-ups. The value is available to calling programs via
1768        pcre_fullinfo().
1769    
1770    26. While implementing 25, I discovered to my embarrassment that pcretest had
1771        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1772        study optimizations had never been tested with that matching function.
1773        Oops. What is worse, even when it was passed study data, there was a bug in
1774        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1775        were also very few tests of studied patterns with pcre_dfa_exec().
1776    
1777    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1778        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1779        on the other side of the coin, they are no longer allowed to have different
1780        names, because these cannot be distinguished in PCRE, and this has caused
1781        confusion. (This is a difference from Perl.)
1782    
1783    28. When duplicate subpattern names are present (necessarily with different
1784        numbers, as required by 27 above), and a test is made by name in a
1785        conditional pattern, either for a subpattern having been matched, or for
1786        recursion in such a pattern, all the associated numbered subpatterns are
1787        tested, and the overall condition is true if the condition is true for any
1788        one of them. This is the way Perl works, and is also more like the way
1789        testing by number works.
1790    
1791    
1792    Version 7.9 11-Apr-09
1793  ---------------------  ---------------------
1794    
1795  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 1805  Version 7.9 xx-xxx-09
1805      but BOOL is not.      but BOOL is not.
1806    
1807  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1808      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1809    
1810  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
1811      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 35  Version 7.9 xx-xxx-09 Line 1823  Version 7.9 xx-xxx-09
1823  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
1824      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
1825      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1826      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1827        8.33.]
1828    
1829  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
1830      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 95  Version 7.9 xx-xxx-09 Line 1884  Version 7.9 xx-xxx-09
1884      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1885      included within another project.      included within another project.
1886    
1887    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1888        slightly modified by me:
1889    
1890          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1891              not building pcregrep.
1892    
1893          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1894              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1895    
1896    25. Forward references, both numeric and by name, in patterns that made use of
1897        duplicate group numbers, could behave incorrectly or give incorrect errors,
1898        because when scanning forward to find the reference group, PCRE was not
1899        taking into account the duplicate group numbers. A pattern such as
1900        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1901    
1902    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1903        the feature of a custom pointer more persuasive (as requested by a user).
1904    
1905    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1906        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1907        pre-defined.
1908    
1909    28. Added support for (*UTF8) at the start of a pattern.
1910    
1911    29. Arrange for flags added by the "release type" setting in CMake to be shown
1912        in the configuration summary.
1913    
1914    
1915  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08
# Line 252  Version 7.7 07-May-08 Line 2067  Version 7.7 07-May-08
2067      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2068      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2069      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2070      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2071      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2072      was subsequently set up correctly.)      was subsequently set up correctly.)
2073    

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