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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.35-RC1 04-March-2014
5    ------------------------------
6    
7    1.  A new flag is set, when property checks are present in an XCLASS.
8        When this flag is not set, PCRE can perform certain optimizations
9        such as studying these XCLASS-es.
10    
11    2.  The auto-possessification of character sets were improved: a normal
12        and an extended character set can be compared now. Furthermore
13        the JIT compiler optimizes more character set checks.
14    
15    3.  Got rid of some compiler warnings for potentially uninitialized variables
16        that show up only when compiled with -O2.
17    
18    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
19        of a match later then the end of the match. The pcretest program was not
20        handling the case sensibly - it was outputting from the start to the next
21        binary zero. It now reports this situation in a message, and outputs the
22        text from the end to the start.
23    
24    5.  Fast forward search is improved in JIT. Instead of the first three
25        characters, any three characters with fixed position can be searched.
26        Search order: first, last, middle.
27    
28    6.  Improve character range checks in JIT. Characters are read by an inprecise
29        function now, which returns with an unknown value if the character code is
30        above a certain treshold (e.g: 256). The only limitation is that the value
31        must be bigger than the treshold as well. This function is useful, when
32        the characters above the treshold are handled in the same way.
33    
34    7.  The macros whose names start with RAWUCHAR are placeholders for a future
35        mode in which only the bottom 21 bits of 32-bit data items are used. To
36        make this more memorable for those maintaining the code, the names have
37        been changed to start with UCHAR21, and an extensive comment has been added
38        to their definition.
39    
40    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
41        to the export list in Makefile.am (they were accidentally omitted from the
42        8.34 tarball).
43    
44    9.  The informational output from pcretest used the phrase "starting byte set"
45        which is inappropriate for the 16-bit and 32-bit libraries. As the output
46        for "first char" and "need char" really means "non-UTF-char", I've changed
47        "byte" to "char", and slightly reworded the output. The documentation about
48        these values has also been (I hope) clarified.
49    
50    10. Another JIT related optimization: use table jumps for selecting the correct
51        backtracking path, when more than four alternatives are present inside a
52        bracket.
53    
54    11. Empty match is not possible, when the minimum length is greater than zero,
55        and there is no \K in the pattern. JIT should avoid empty match checks in
56        such cases.
57    
58    12. In a caseless character class with UCP support, when a character with more
59        than one alternative case was not the first character of a range, not all
60        the alternative cases were added to the class. For example, s and \x{17f}
61        are both alternative cases for S: the class [RST] was handled correctly,
62        but [R-T] was not.
63    
64    13. The configure.ac file always checked for pthread support when JIT was
65        enabled. This is not used in Windows, so I have put this test inside a
66        check for the presence of windows.h (which was already tested for).
67    
68    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
69        The algorithm provides a way to skip certain starting offsets, and usually
70        faster than linear prefix searches.
71    
72    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
73        as for 'fr_FR' and 'french'. For some reason, however, it then used the
74        Windows-specific input and output files, which have 'french' screwed in.
75        So this could never have worked. One of the problems with locales is that
76        they aren't always the same. I have now updated RunTest so that it checks
77        the output of the locale test (test 3) against three different output
78        files, and it allows the test to pass if any one of them matches. With luck
79        this should make the test pass on some versions of Solaris where it was
80        failing. Because of the uncertainty, the script did not used to stop if
81        test 3 failed; it now does. If further versions of a French locale ever
82        come to light, they can now easily be added.
83    
84    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
85        there was a message during ./configure, but it did not stop. This now
86        provokes an error. The invalid example in README has been corrected.
87        If a value less than the minimum is given, the minimum value has always
88        been used, but now a warning is given.
89    
90    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
91        was a bug in the test system, which is now fixed. Also, the list of various
92        configurations that are tested for each release did not have one with both
93        16/32 bits and --enable-bar-anycrlf. It now does.
94    
95    18. pcretest was missing "-C bsr" for displaying the \R default setting.
96    
97    19. Little endian PowerPC systems are supported now by the JIT compiler.
98    
99    20. The fast forward newline mechanism could enter to an infinite loop on
100        certain invalid UTF-8 input. Although we don't support these cases
101        this issue can be fixed by a performance optimization.
102    
103    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
104        not take account if existing stack usage. There is now a new global
105        variable called pcre_stack_guard that can be set to point to an external
106        function to check stack availability. It is called at the start of
107        processing every parenthesized group.
108    
109    22. A typo in the code meant that in ungreedy mode the max/min qualifier
110        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
111        not match "ab".
112    
113    
114    Version 8.34 15-December-2013
115    -----------------------------
116    
117    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
118        executable memory. Patch inspired by Carsten Klein.
119    
120    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
121        this macro is never tested and has no effect, because the work to support
122        coverage involves only compiling and linking options and special targets in
123        the Makefile. The comment in config.h implied that defining the macro would
124        enable coverage support, which is totally false. There was also support for
125        setting this macro in the CMake files (my fault, I just copied it from
126        configure). SUPPORT_GCOV has now been removed.
127    
128    3.  Make a small performance improvement in strlen16() and strlen32() in
129        pcretest.
130    
131    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
132        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
133        these cases). There was also one in pcretest.c.
134    
135    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
136    
137    6.  In UTF mode, the code for checking whether a group could match an empty
138        string (which is used for indefinitely repeated groups to allow for
139        breaking an infinite loop) was broken when the group contained a repeated
140        negated single-character class with a character that occupied more than one
141        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
142        UTF-8 mode). The effect was undefined: the group might or might not be
143        deemed as matching an empty string, or the program might have crashed.
144    
145    7.  The code for checking whether a group could match an empty string was not
146        recognizing that \h, \H, \v, \V, and \R must match a character.
147    
148    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
149        an empty string. If it can, pcretest shows this in its information output.
150    
151    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
152        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
153        matched by pcre_exec() without using JIT:
154    
155        (a) If the rest of the pattern did not match after a maximal run of
156            grapheme clusters, the code for backing up to try with fewer of them
157            did not always back up over a full grapheme when characters that do not
158            have the modifier quality were involved, e.g. Hangul syllables.
159    
160        (b) If the match point in a subject started with modifier character, and
161            there was no match, the code could incorrectly back up beyond the match
162            point, and potentially beyond the first character in the subject,
163            leading to a segfault or an incorrect match result.
164    
165    10. A conditional group with an assertion condition could lead to PCRE
166        recording an incorrect first data item for a match if no other first data
167        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
168        first data item, and therefore matched "ca" after "c" instead of at the
169        start.
170    
171    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
172        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
173    
174    12. The source of pcregrep now includes z/OS-specific code so that it can be
175        compiled for z/OS as part of the special z/OS distribution.
176    
177    13. Added the -T and -TM options to pcretest.
178    
179    14. The code in pcre_compile.c for creating the table of named capturing groups
180        has been refactored. Instead of creating the table dynamically during the
181        actual compiling pass, the information is remembered during the pre-compile
182        pass (on the stack unless there are more than 20 named groups, in which
183        case malloc() is used) and the whole table is created before the actual
184        compile happens. This has simplified the code (it is now nearly 150 lines
185        shorter) and prepared the way for better handling of references to groups
186        with duplicate names.
187    
188    15. A back reference to a named subpattern when there is more than one of the
189        same name now checks them in the order in which they appear in the pattern.
190        The first one that is set is used for the reference. Previously only the
191        first one was inspected. This change makes PCRE more compatible with Perl.
192    
193    16. Unicode character properties were updated from Unicode 6.3.0.
194    
195    17. The compile-time code for auto-possessification has been refactored, based
196        on a patch by Zoltan Herczeg. It now happens after instead of during
197        compilation. The code is cleaner, and more cases are handled. The option
198        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
199        options in pcretest are provided to set it. It can also be set by
200        (*NO_AUTO_POSSESS) at the start of a pattern.
201    
202    18. The character VT has been added to the default ("C" locale) set of
203        characters that match \s and are generally treated as white space,
204        following this same change in Perl 5.18. There is now no difference between
205        "Perl space" and "POSIX space". Whether VT is treated as white space in
206        other locales depends on the locale.
207    
208    19. The code for checking named groups as conditions, either for being set or
209        for being recursed, has been refactored (this is related to 14 and 15
210        above). Processing unduplicated named groups should now be as fast at
211        numerical groups, and processing duplicated groups should be faster than
212        before.
213    
214    20. Two patches to the CMake build system, by Alexander Barkov:
215    
216          (1) Replace the "source" command by "." in CMakeLists.txt because
217              "source" is a bash-ism.
218    
219          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
220              without these the CMake build does not work on Solaris.
221    
222    21. Perl has changed its handling of \8 and \9. If there is no previously
223        encountered capturing group of those numbers, they are treated as the
224        literal characters 8 and 9 instead of a binary zero followed by the
225        literals. PCRE now does the same.
226    
227    22. Following Perl, added \o{} to specify codepoints in octal, making it
228        possible to specify values greater than 0777 and also making them
229        unambiguous.
230    
231    23. Perl now gives an error for missing closing braces after \x{... instead of
232        treating the string as literal. PCRE now does the same.
233    
234    24. RunTest used to grumble if an inappropriate test was selected explicitly,
235        but just skip it when running all tests. This make it awkward to run ranges
236        of tests when one of them was inappropriate. Now it just skips any
237        inappropriate tests, as it always did when running all tests.
238    
239    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
240        character types such as \d or \w, too many callouts were inserted, and the
241        data that they returned was rubbish.
242    
243    26. In UCP mode, \s was not matching two of the characters that Perl matches,
244        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
245        were matched by \h. The code has now been refactored so that the lists of
246        the horizontal and vertical whitespace characters used for \h and \v (which
247        are defined only in one place) are now also used for \s.
248    
249    27. Add JIT support for the 64 bit TileGX architecture.
250        Patch by Jiong Wang (Tilera Corporation).
251    
252    28. Possessive quantifiers for classes (both explicit and automatically
253        generated) now use special opcodes instead of wrapping in ONCE brackets.
254    
255    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
256        (because it's meaningless), this was not happening when PCRE_CASELESS was
257        set. Not wrong, but inefficient.
258    
259    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
260        properties for \w, \d, etc) is present in a test regex. Otherwise if the
261        test contains no characters greater than 255, Perl doesn't realise it
262        should be using Unicode semantics.
263    
264    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
265        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
266        does in Unicode mode.
267    
268    32. Added the "forbid" facility to pcretest so that putting tests into the
269        wrong test files can sometimes be quickly detected.
270    
271    33. There is now a limit (default 250) on the depth of nesting of parentheses.
272        This limit is imposed to control the amount of system stack used at compile
273        time. It can be changed at build time by --with-parens-nest-limit=xxx or
274        the equivalent in CMake.
275    
276    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
277        errors. Perl warns for these when in warning mode, but PCRE has no facility
278        for giving warnings.
279    
280    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
281        However, this was not working for (?!) because it is optimized to (*FAIL),
282        for which PCRE does not allow quantifiers. The optimization is now disabled
283        when a quantifier follows (?!). I can't see any use for this, but it makes
284        things uniform.
285    
286    36. Perl no longer allows group names to start with digits, so I have made this
287        change also in PCRE. It simplifies the code a bit.
288    
289    37. In extended mode, Perl ignores spaces before a + that indicates a
290        possessive quantifier. PCRE allowed a space before the quantifier, but not
291        before the possessive +. It now does.
292    
293    38. The use of \K (reset reported match start) within a repeated possessive
294        group such as (a\Kb)*+ was not working.
295    
296    40. Document that the same character tables must be used at compile time and
297        run time, and that the facility to pass tables to pcre_exec() and
298        pcre_dfa_exec() is for use only with saved/restored patterns.
299    
300    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
301        features for Builds with MSVC:
302    
303        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
304           builds). The .rc files can be used to set FileDescription and many other
305           attributes.
306    
307        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
308           This allows higher-level build scripts which want .pdb files to avoid
309           hard-coding the exact files needed."
310    
311    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
312        mean "start of word" and "end of word", respectively, as a transition aid.
313    
314    43. A minimizing repeat of a class containing codepoints greater than 255 in
315        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
316        compiled to use the heap for recursion.
317    
318    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
319        is configured.
320    
321    
322    Version 8.33 28-May-2013
323    ------------------------
324    
325    1.  Added 'U' to some constants that are compared to unsigned integers, to
326        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
327        variables that are added to signed variables, to ensure the result is
328        signed and can be negated.
329    
330    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
331        CMake config files.
332    
333    3.  Revise the creation of config.h.generic so that all boolean macros are
334        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
335        overriding via -D on the command line possible.
336    
337    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
338        to unsigned int is reported to make a quite noticeable speed difference in
339        a specific Windows environment. Testing on Linux did also appear to show
340        some benefit (and it is clearly not harmful). Also fixed the definition of
341        Xop which should be unsigned.
342    
343    5.  Related to (4), changing the definition of the intermediate variable cc
344        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
345        improvements.
346    
347    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
348        unnecessary spaces.
349    
350    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
351        and later.
352    
353    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
354    
355    9.  Optimizing fast_forward_start_bits in JIT.
356    
357    10. Adding support for callouts in JIT, and fixing some issues revealed
358        during this work. Namely:
359    
360        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
361    
362        (b) Minimum length was not checked before the matching is started.
363    
364    11. The value of capture_last that is passed to callouts was incorrect in some
365        cases when there was a capture on one path that was subsequently abandoned
366        after a backtrack. Also, the capture_last value is now reset after a
367        recursion, since all captures are also reset in this case.
368    
369    12. The interpreter no longer returns the "too many substrings" error in the
370        case when an overflowing capture is in a branch that is subsequently
371        abandoned after a backtrack.
372    
373    13. In the pathological case when an offset vector of size 2 is used, pcretest
374        now prints out the matched string after a yield of 0 or 1.
375    
376    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
377        Only supported by the JIT compiler at the moment.
378    
379    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
380    
381    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
382        offset of the starting point of the matching process, provided the offsets
383        vector is large enough.
384    
385    17. The \A escape now records a lookbehind value of 1, though its execution
386        does not actually inspect the previous character. This is to ensure that,
387        in partial multi-segment matching, at least one character from the old
388        segment is retained when a new segment is processed. Otherwise, if there
389        are no lookbehinds in the pattern, \A might match incorrectly at the start
390        of a new segment.
391    
392    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
393    
394    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
395        gives some modest performance improvement in 8-bit mode.
396    
397    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
398        be expressed in certain programming languages using Universal Character
399        Names.
400    
401    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
402        which points out that "non characters" are not "characters that may not
403        appear in Unicode strings" but rather "characters that are reserved for
404        internal use and have only local meaning".
405    
406    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
407        there was a conditional group that depended on an assertion, if the
408        assertion was false, the callout that immediately followed the alternation
409        in the condition was skipped when pcre_exec() was used for matching.
410    
411    23. Allow an explicit callout to be inserted before an assertion that is the
412        condition for a conditional group, for compatibility with automatic
413        callouts, which always insert a callout at this point.
414    
415    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
416        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
417    
418    25. (*PRUNE) is now supported by the JIT compiler.
419    
420    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
421    
422    27. Fix the case where there are two or more SKIPs with arguments that may be
423        ignored.
424    
425    28. (*SKIP) is now supported by the JIT compiler.
426    
427    29. (*THEN) is now supported by the JIT compiler.
428    
429    30. Update RunTest with additional test selector options.
430    
431    31. The way PCRE handles backtracking verbs has been changed in two ways.
432    
433        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
434        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
435        backtracking. In some cases this makes it more Perl-compatible, but Perl's
436        rather obscure rules do not always do the same thing.
437    
438        (2) Previously, backtracking verbs were confined within assertions. This is
439        no longer the case for positive assertions, except for (*ACCEPT). Again,
440        this sometimes improves Perl compatibility, and sometimes does not.
441    
442    32. A number of tests that were in test 2 because Perl did things differently
443        have been moved to test 1, because either Perl or PCRE has changed, and
444        these tests are now compatible.
445    
446    32. Backtracking control verbs are now handled in the same way in JIT and
447        interpreter.
448    
449    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
450        contained a forward subroutine reference caused a compile error.
451    
452    34. Auto-detect and optimize limited repetitions in JIT.
453    
454    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
455        blocking (*UTF) etc.
456    
457    36. In the interpreter, maximizing pattern repetitions for characters and
458        character types now use tail recursion, which reduces stack usage.
459    
460    37. The value of the max lookbehind was not correctly preserved if a compiled
461        and saved regex was reloaded on a host of different endianness.
462    
463    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
464        of the compiled pattern block, expand the flags field from 16 to 32 bits
465        because it was almost full.
466    
467    39. Try madvise first before posix_madvise.
468    
469    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
470        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
471        original change locked out all matches of empty strings. This has been
472        changed so that one match of an empty string per line is recognized.
473        Subsequent searches on the same line (for colouring or for --only-matching,
474        for example) do not recognize empty strings.
475    
476    41. Applied a user patch to fix a number of spelling mistakes in comments.
477    
478    42. Data lines longer than 65536 caused pcretest to crash.
479    
480    43. Clarified the data type for length and startoffset arguments for pcre_exec
481        and pcre_dfa_exec in the function-specific man pages, where they were
482        explicitly stated to be in bytes, never having been updated. I also added
483        some clarification to the pcreapi man page.
484    
485    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
486        a segmentation fault.
487    
488    
489    Version 8.32 30-November-2012
490    -----------------------------
491    
492    1.  Improved JIT compiler optimizations for first character search and single
493        character iterators.
494    
495    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
496        Patch by Daniel Richard G.
497    
498    3.  Single character iterator optimizations in the JIT compiler.
499    
500    4.  Improved JIT compiler optimizations for character ranges.
501    
502    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
503        Reported by Giuseppe D'Angelo.
504    
505    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
506        of a line, was being set incorrectly in cases where .* appeared inside
507        atomic brackets at the start of a pattern, or where there was a subsequent
508        *PRUNE or *SKIP.
509    
510    7.  Improved instruction cache flush for POWER/PowerPC.
511        Patch by Daniel Richard G.
512    
513    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
514        grep:
515    
516        (a) There is now no limit to the number of patterns to be matched.
517    
518        (b) An error is given if a pattern is too long.
519    
520        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
521            are now supported.
522    
523        (d) --exclude-from and --include-from (multiple use) have been added.
524    
525        (e) Exclusions and inclusions now apply to all files and directories, not
526            just to those obtained from scanning a directory recursively.
527    
528        (f) Multiple uses of -f and --file-list are now supported.
529    
530        (g) In a Windows environment, the default for -d has been changed from
531            "read" (the GNU grep default) to "skip", because otherwise the presence
532            of a directory in the file list provokes an error.
533    
534        (h) The documentation has been revised and clarified in places.
535    
536    9.  Improve the matching speed of capturing brackets.
537    
538    10. Changed the meaning of \X so that it now matches a Unicode extended
539        grapheme cluster.
540    
541    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
542        out POSIX threads when JIT support is configured.
543    
544    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
545    
546    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
547        structure could go wrong in environments where size_t is not the same size
548        as int.
549    
550    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
551        set.
552    
553    15. The EBCDIC support had decayed; later updates to the code had included
554        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
555        general tidy up of EBCDIC-related issues, and the documentation was also
556        not quite right. There is now a test that can be run on ASCII systems to
557        check some of the EBCDIC-related things (but is it not a full test).
558    
559    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
560        in a small tidy to the code.
561    
562    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
563    
564    18. If the --only-matching (-o) option in pcregrep is specified multiple
565        times, each one causes appropriate output. For example, -o1 -o2 outputs the
566        substrings matched by the 1st and 2nd capturing parentheses. A separating
567        string can be specified by --om-separator (default empty).
568    
569    19. Improving the first n character searches.
570    
571    20. Turn case lists for horizontal and vertical white space into macros so that
572        they are defined only once.
573    
574    21. This set of changes together give more compatible Unicode case-folding
575        behaviour for characters that have more than one other case when UCP
576        support is available.
577    
578        (a) The Unicode property table now has offsets into a new table of sets of
579            three or more characters that are case-equivalent. The MultiStage2.py
580            script that generates these tables (the pcre_ucd.c file) now scans
581            CaseFolding.txt instead of UnicodeData.txt for character case
582            information.
583    
584        (b) The code for adding characters or ranges of characters to a character
585            class has been abstracted into a generalized function that also handles
586            case-independence. In UTF-mode with UCP support, this uses the new data
587            to handle characters with more than one other case.
588    
589        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
590            whose other case is greater than 256 are now correctly matched
591            caselessly. Previously, the high codepoint matched the low one, but not
592            vice versa.
593    
594        (d) The processing of \h, \H, \v, and \ in character classes now makes use
595            of the new class addition function, using character lists defined as
596            macros alongside the case definitions of 20 above.
597    
598        (e) Caseless back references now work with characters that have more than
599            one other case.
600    
601        (f) General caseless matching of characters with more than one other case
602            is supported.
603    
604    22. Unicode character properties were updated from Unicode 6.2.0
605    
606    23. Improved CMake support under Windows. Patch by Daniel Richard G.
607    
608    24. Add support for 32-bit character strings, and UTF-32
609    
610    25. Major JIT compiler update (code refactoring and bugfixing).
611        Experimental Sparc 32 support is added.
612    
613    26. Applied a modified version of Daniel Richard G's patch to create
614        pcre.h.generic and config.h.generic by "make" instead of in the
615        PrepareRelease script.
616    
617    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
618        pcre_compile.c when checking for a zero character.
619    
620    28. Introducing a native interface for JIT. Through this interface, the compiled
621        machine code can be directly executed. The purpose of this interface is to
622        provide fast pattern matching, so several sanity checks are not performed.
623        However, feature tests are still performed. The new interface provides
624        1.4x speedup compared to the old one.
625    
626    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
627        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
628        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
629    
630    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
631        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
632        the "old" RFC 2279). Instead, it ended up passing a negative length to
633        pcre_exec().
634    
635    31. Add support for GCC's visibility feature to hide internal functions.
636    
637    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
638        "unknown -C option" after outputting 0 or 1.
639    
640    33. There is now support for generating a code coverage report for the test
641        suite in environments where gcc is the compiler and lcov is installed. This
642        is mainly for the benefit of the developers.
643    
644    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
645        unaddressable using valgrind annotations, allowing valgrind to detect
646        invalid memory accesses. This is mainly for the benefit of the developers.
647    
648    25. (*UTF) can now be used to start a pattern in any of the three libraries.
649    
650    26. Give configure error if --enable-cpp but no C++ compiler found.
651    
652    
653    Version 8.31 06-July-2012
654    -------------------------
655    
656    1.  Fixing a wrong JIT test case and some compiler warnings.
657    
658    2.  Removed a bashism from the RunTest script.
659    
660    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
661        to unsigned type, result still unsigned" that was given by an MS compiler
662        on encountering the code "-sizeof(xxx)".
663    
664    4.  Partial matching support is added to the JIT compiler.
665    
666    5.  Fixed several bugs concerned with partial matching of items that consist
667        of more than one character:
668    
669        (a) /^(..)\1/ did not partially match "aba" because checking references was
670            done on an "all or nothing" basis. This also applied to repeated
671            references.
672    
673        (b) \R did not give a hard partial match if \r was found at the end of the
674            subject.
675    
676        (c) \X did not give a hard partial match after matching one or more
677            characters at the end of the subject.
678    
679        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
680            a partial match for the string "\r".
681    
682        (e) When newline was set to CRLF, the metacharacter "." did not recognize
683            a partial match for a CR character at the end of the subject string.
684    
685    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
686        running pcretest, the text "(JIT)" added to the output whenever JIT is
687        actually used to run the match.
688    
689    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
690        or /S+[+] with a digit between 1 and 7.
691    
692    8.  OP_NOT now supports any UTF character not just single-byte ones.
693    
694    9.  (*MARK) control verb is now supported by the JIT compiler.
695    
696    10. The command "./RunTest list" lists the available tests without actually
697        running any of them. (Because I keep forgetting what they all are.)
698    
699    11. Add PCRE_INFO_MAXLOOKBEHIND.
700    
701    12. Applied a (slightly modified) user-supplied patch that improves performance
702        when the heap is used for recursion (compiled with --disable-stack-for-
703        recursion). Instead of malloc and free for each heap frame each time a
704        logical recursion happens, frames are retained on a chain and re-used where
705        possible. This sometimes gives as much as 30% improvement.
706    
707    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
708        call.
709    
710    14. As documented, (*COMMIT) is now confined to within a positive assertion.
711    
712    15. It is now possible to link pcretest with libedit as an alternative to
713        libreadline.
714    
715    16. (*COMMIT) control verb is now supported by the JIT compiler.
716    
717    17. The Unicode data tables have been updated to Unicode 6.1.0.
718    
719    18. Added --file-list option to pcregrep.
720    
721    19. Added binary file support to pcregrep, including the -a, --binary-files,
722        -I, and --text options.
723    
724    20. The madvise function is renamed for posix_madvise for QNX compatibility
725        reasons. Fixed by Giuseppe D'Angelo.
726    
727    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
728    
729    22. Changed the option for creating symbolic links for 16-bit man pages from
730        -s to -sf so that re-installing does not cause issues.
731    
732    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
733    
734    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
735        matches in certain environments (the workspace was not being correctly
736        retained). Also added to pcre_dfa_exec() a simple plausibility check on
737        some of the workspace data at the beginning of a restart.
738    
739    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
740        was not doing so when it should - probably a typo introduced by SVN 528
741        (change 8.10/14).
742    
743    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
744        \w+ when the character tables indicated that \x{c4} was a word character.
745        There were several related cases, all because the tests for doing a table
746        lookup were testing for characters less than 127 instead of 255.
747    
748    27. If a pattern contains capturing parentheses that are not used in a match,
749        their slots in the ovector are set to -1. For those that are higher than
750        any matched groups, this happens at the end of processing. In the case when
751        there were back references that the ovector was too small to contain
752        (causing temporary malloc'd memory to be used during matching), and the
753        highest capturing number was not used, memory off the end of the ovector
754        was incorrectly being set to -1. (It was using the size of the temporary
755        memory instead of the true size.)
756    
757    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
758        ovector size, it uses memory at the end of the block that it has got.
759    
760    29. Check for an overlong MARK name and give an error at compile time. The
761        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
762    
763    30. JIT compiler update.
764    
765    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
766        Rill for the patch.
767    
768    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
769    
770    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
771    
772    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
773        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
774        was enabled.
775    
776    35. Improve JIT code generation for greedy plus quantifier.
777    
778    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
779        1 to "aa" instead of to an empty string. The bug affected repeated groups
780        that could potentially match an empty string.
781    
782    37. Optimizing single character iterators in JIT.
783    
784    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
785        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
786        codepoints that are too big for the mode are faulted, and in a UTF mode,
787        disallowed codepoints are also faulted.
788    
789    39. If PCRE was compiled with UTF support, in three places in the DFA
790        matcher there was code that should only have been obeyed in UTF mode, but
791        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
792        processing when bytes with values greater than 127 were present. In 16-bit
793        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
794        both cases the values are those that cannot be the first data item in a UTF
795        character. The three items that might have provoked this were recursions,
796        possessively repeated groups, and atomic groups.
797    
798    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
799        and pcregrep, because some OS require shared objects to be explicitly
800        passed to ld, causing the link step to fail if they are not.
801    
802    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
803        mode, patterns that started with \h* or \R* might be incorrectly matched.
804    
805    
806    Version 8.30 04-February-2012
807    -----------------------------
808    
809    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
810        name is defined in ctype.h.
811    
812    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
813        only in quite long subpatterns.
814    
815    3.  Removed the function pcre_info(), which has been obsolete and deprecated
816        since it was replaced by pcre_fullinfo() in February 2000.
817    
818    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
819        match a (*MARK), and the match failed at the start of the subject, a
820        reference to memory before the start of the subject could occur. This bug
821        was introduced by fix 17 of release 8.21.
822    
823    5.  A reference to an unset group with zero minimum repetition was giving
824        totally wrong answers (in non-JavaScript-compatibility mode). For example,
825        /(another)?(\1?)test/ matched against "hello world test". This bug was
826        introduced in release 8.13.
827    
828    6.  Add support for 16-bit character strings (a large amount of work involving
829        many changes and refactorings).
830    
831    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
832        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
833        from a file.
834    
835    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
836        rounding is not applied in this particular case).
837    
838    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
839        if they appear, or are escaped, in patterns.
840    
841    10. Get rid of a number of -Wunused-but-set-variable warnings.
842    
843    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
844        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
845        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
846        also returns the mark "x". This bug applied to capturing parentheses,
847        non-capturing parentheses, and atomic parentheses. It also applied to some
848        assertions.
849    
850    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
851        information out of configure.ac instead of relying on pcre.h.generic, which
852        is not stored in the repository.
853    
854    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
855        -lreadline.
856    
857    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
858    
859    15. Applied Graycode's patch to put the top-level frame on the stack rather
860        than the heap when not using the stack for recursion. This gives a
861        performance improvement in many cases when recursion is not deep.
862    
863    16. Experimental code added to "pcretest -C" to output the stack frame size.
864    
865    
866    Version 8.21 12-Dec-2011
867    ------------------------
868    
869    1.  Updating the JIT compiler.
870    
871    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
872        are added as well.
873    
874    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
875        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
876        calling _pcre_jit_exec. Some extra comments are added.
877    
878    4.  (*MARK) settings inside atomic groups that do not contain any capturing
879        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
880        was introduced by change 18 for 8.20.
881    
882    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
883        ECMA-262 standard.
884    
885    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
886        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
887        This bug was probably introduced by change 9 of 8.13.
888    
889    7.  While fixing 6 above, I noticed that a number of other items were being
890        incorrectly rejected as "not fixed length". This arose partly because newer
891        opcodes had not been added to the fixed-length checking code. I have (a)
892        corrected the bug and added tests for these items, and (b) arranged for an
893        error to occur if an unknown opcode is encountered while checking for fixed
894        length instead of just assuming "not fixed length". The items that were
895        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
896        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
897        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
898    
899    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
900        being incorrectly compiled and would have given unpredicatble results.
901    
902    9.  A possessively repeated subpattern with minimum repeat count greater than
903        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
904        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
905        the first (A) could occur when it should not.
906    
907    10. Add a cast and remove a redundant test from the code.
908    
909    11. JIT should use pcre_malloc/pcre_free for allocation.
910    
911    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
912        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
913        is anything other than /usr, -L is still shown).
914    
915    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
916    
917    14. Perl does not support \N without a following name in a [] class; PCRE now
918        also gives an error.
919    
920    15. If a forward reference was repeated with an upper limit of around 2000,
921        it caused the error "internal error: overran compiling workspace". The
922        maximum number of forward references (including repeats) was limited by the
923        internal workspace, and dependent on the LINK_SIZE. The code has been
924        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
925        the default depends on LINK_SIZE. There is a new upper limit (for safety)
926        of around 200,000 forward references. While doing this, I also speeded up
927        the filling in of repeated forward references.
928    
929    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
930        incorrectly expecting the subject to contain another "a" after the start.
931    
932    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
933        in the match, the SKIP should be ignored. This was not happening; instead
934        the SKIP was being treated as NOMATCH. For patterns such as
935        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
936        tested.
937    
938    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
939        now much more compatible with Perl, in particular in cases where the result
940        is a non-match for a non-anchored pattern. For example, if
941        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
942        "m", where previously it did not return a name. A side effect of this
943        change is that for partial matches, the last encountered mark name is
944        returned, as for non matches. A number of tests that were previously not
945        Perl-compatible have been moved into the Perl-compatible test files. The
946        refactoring has had the pleasing side effect of removing one argument from
947        the match() function, thus reducing its stack requirements.
948    
949    19. If the /S+ option was used in pcretest to study a pattern using JIT,
950        subsequent uses of /S (without +) incorrectly behaved like /S+.
951    
952    21. Retrieve executable code size support for the JIT compiler and fixing
953        some warnings.
954    
955    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
956        not work when the shorter character appeared right at the end of the
957        subject string.
958    
959    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
960        systems.
961    
962    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
963        output it when the /M option is used in pcretest.
964    
965    25. The CheckMan script was not being included in the distribution. Also, added
966        an explicit "perl" to run Perl scripts from the PrepareRelease script
967        because this is reportedly needed in Windows.
968    
969    26. If study data was being save in a file and studying had not found a set of
970        "starts with" bytes for the pattern, the data written to the file (though
971        never used) was taken from uninitialized memory and so caused valgrind to
972        complain.
973    
974    27. Updated RunTest.bat as provided by Sheri Pierce.
975    
976    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
977    
978    29. Computation of memory usage for the table of capturing group names was
979        giving an unnecessarily large value.
980    
981    
982    Version 8.20 21-Oct-2011
983    ------------------------
984    
985    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
986        a POSIX class. After further experiments with Perl, which convinced me that
987        Perl has bugs and confusions, a closing square bracket is no longer allowed
988        in a POSIX name. This bug also affected patterns with classes that started
989        with full stops.
990    
991    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
992        captured substring, but while checking the failing first alternative,
993        substring 1 is temporarily captured. If the output vector supplied to
994        pcre_exec() was not big enough for this capture, the yield of the function
995        was still zero ("insufficient space for captured substrings"). This cannot
996        be totally fixed without adding another stack variable, which seems a lot
997        of expense for a edge case. However, I have improved the situation in cases
998        such as /(a)(b)x|abc/ matched against "abc", where the return code
999        indicates that fewer than the maximum number of slots in the ovector have
1000        been set.
1001    
1002    3.  Related to (2) above: when there are more back references in a pattern than
1003        slots in the output vector, pcre_exec() uses temporary memory during
1004        matching, and copies in the captures as far as possible afterwards. It was
1005        using the entire output vector, but this conflicts with the specification
1006        that only 2/3 is used for passing back captured substrings. Now it uses
1007        only the first 2/3, for compatibility. This is, of course, another edge
1008        case.
1009    
1010    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1011        main code base, and can be used by building with --enable-jit. When this is
1012        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1013        runtime --no-jit option is given.
1014    
1015    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1016        ovector, the return from the function was zero, implying that there were
1017        other matches that did not fit. The correct "exactly full" value is now
1018        returned.
1019    
1020    6.  If a subpattern that was called recursively or as a subroutine contained
1021        (*PRUNE) or any other control that caused it to give a non-standard return,
1022        invalid errors such as "Error -26 (nested recursion at the same subject
1023        position)" or even infinite loops could occur.
1024    
1025    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1026        computing the minimum length on reaching *ACCEPT, and so ended up with the
1027        wrong value of 1 rather than 0. Further investigation indicates that
1028        computing a minimum subject length in the presence of *ACCEPT is difficult
1029        (think back references, subroutine calls), and so I have changed the code
1030        so that no minimum is registered for a pattern that contains *ACCEPT.
1031    
1032    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1033        it was not handled as intended. [But see 16 below.]
1034    
1035    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1036        Sheri Pierce.
1037    
1038    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1039        the first byte in a match must be "a".
1040    
1041    11. Change 17 for 8.13 increased the recursion depth for patterns like
1042        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1043        pattern contains any instances of (*THEN). If it does not, the old
1044        optimizations are restored. It would be nice to do this on a per-group
1045        basis, but at the moment that is not feasible.
1046    
1047    12. In some environments, the output of pcretest -C is CRLF terminated. This
1048        broke RunTest's code that checks for the link size. A single white space
1049        character after the value is now allowed for.
1050    
1051    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1052        For "fr", it uses the Windows-specific input and output files.
1053    
1054    14. If (*THEN) appeared in a group that was called recursively or as a
1055        subroutine, it did not work as intended. [But see next item.]
1056    
1057    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1058        pattern fragments (but not containing any | characters). If A and B are
1059        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1060        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1061        D. In other words, Perl considers parentheses that do not contain any |
1062        characters to be part of a surrounding alternative, whereas PCRE was
1063        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1064        differently. PCRE now behaves in the same way as Perl, except in the case
1065        of subroutine/recursion calls such as (?1) which have in any case always
1066        been different (but PCRE had them first :-).
1067    
1068    16. Related to 15 above: Perl does not treat the | in a conditional group as
1069        creating alternatives. Such a group is treated in the same way as an
1070        ordinary group without any | characters when processing (*THEN). PCRE has
1071        been changed to match Perl's behaviour.
1072    
1073    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1074        RunGrepTest script failed.
1075    
1076    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1077        inevitable for groups that contain captures, but it can lead to a lot of
1078        stack use in large patterns. The old behaviour has been restored for atomic
1079        groups that do not contain any capturing parentheses.
1080    
1081    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1082        suppress the check for a minimum subject length at run time. (If it was
1083        given to pcre_exec() or pcre_dfa_exec() it did work.)
1084    
1085    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1086        fail to work when decoding hex characters in data strings in EBCDIC
1087        environments.
1088    
1089    21. It appears that in at least one Mac OS environment, the isxdigit() function
1090        is implemented as a macro that evaluates to its argument more than once,
1091        contravening the C 90 Standard (I haven't checked a later standard). There
1092        was an instance in pcretest which caused it to go wrong when processing
1093        \x{...} escapes in subject strings. The has been rewritten to avoid using
1094        things like p++ in the argument of isxdigit().
1095    
1096    
1097    Version 8.13 16-Aug-2011
1098    ------------------------
1099    
1100    1.  The Unicode data tables have been updated to Unicode 6.0.0.
1101    
1102    2.  Two minor typos in pcre_internal.h have been fixed.
1103    
1104    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
1105        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
1106        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
1107    
1108    4.  There were a number of related bugs in the code for matching backrefences
1109        caselessly in UTF-8 mode when codes for the characters concerned were
1110        different numbers of bytes. For example, U+023A and U+2C65 are an upper
1111        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
1112        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
1113        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1114        2-byte code at the end of the subject (it thought there wasn't enough data
1115        left).
1116    
1117    5.  Comprehensive information about what went wrong is now returned by
1118        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1119        as the output vector has at least 2 elements. The offset of the start of
1120        the failing character and a reason code are placed in the vector.
1121    
1122    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1123        now returned is for the first byte of the failing character, instead of the
1124        last byte inspected. This is an incompatible change, but I hope it is small
1125        enough not to be a problem. It makes the returned offset consistent with
1126        pcre_exec() and pcre_dfa_exec().
1127    
1128    7.  pcretest now gives a text phrase as well as the error number when
1129        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1130        failure, the offset and reason code are output.
1131    
1132    8.  When \R was used with a maximizing quantifier it failed to skip backwards
1133        over a \r\n pair if the subsequent match failed. Instead, it just skipped
1134        back over a single character (\n). This seems wrong (because it treated the
1135        two characters as a single entity when going forwards), conflicts with the
1136        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1137        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1138        has been changed.
1139    
1140    9.  Some internal refactoring has changed the processing so that the handling
1141        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1142        time (the PCRE_DOTALL option was changed this way some time ago: version
1143        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1144        which was always a bit of a fudge. It also means that there is one less
1145        argument for the match() function, which reduces its stack requirements
1146        slightly. This change also fixes an incompatibility with Perl: the pattern
1147        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1148    
1149    10. More internal refactoring has drastically reduced the number of recursive
1150        calls to match() for possessively repeated groups such as (abc)++ when
1151        using pcre_exec().
1152    
1153    11. While implementing 10, a number of bugs in the handling of groups were
1154        discovered and fixed:
1155    
1156        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1157        (a|)*(?1) gave a compile-time internal error.
1158        ((a|)+)+  did not notice that the outer group could match an empty string.
1159        (^a|^)+   was not marked as anchored.
1160        (.*a|.*)+ was not marked as matching at start or after a newline.
1161    
1162    12. Yet more internal refactoring has removed another argument from the match()
1163        function. Special calls to this function are now indicated by setting a
1164        value in a variable in the "match data" data block.
1165    
1166    13. Be more explicit in pcre_study() instead of relying on "default" for
1167        opcodes that mean there is no starting character; this means that when new
1168        ones are added and accidentally left out of pcre_study(), testing should
1169        pick them up.
1170    
1171    14. The -s option of pcretest has been documented for ages as being an old
1172        synonym of -m (show memory usage). I have changed it to mean "force study
1173        for every regex", that is, assume /S for every regex. This is similar to -i
1174        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1175        using it. It makes it easier to run collections of tests with and without
1176        study enabled, and thereby test pcre_study() more easily. All the standard
1177        tests are now run with and without -s (but some patterns can be marked as
1178        "never study" - see 20 below).
1179    
1180    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1181        restoration of the capturing data to the outer values was not happening
1182        correctly.
1183    
1184    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1185        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1186        pattern had matched an empty string, and so incorrectly returned a no
1187        match.
1188    
1189    17. There was optimizing code for the last branch of non-capturing parentheses,
1190        and also for the obeyed branch of a conditional subexpression, which used
1191        tail recursion to cut down on stack usage. Unfortunately, now that there is
1192        the possibility of (*THEN) occurring in these branches, tail recursion is
1193        no longer possible because the return has to be checked for (*THEN). These
1194        two optimizations have therefore been removed. [But see 8.20/11 above.]
1195    
1196    18. If a pattern containing \R was studied, it was assumed that \R always
1197        matched two bytes, thus causing the minimum subject length to be
1198        incorrectly computed because \R can also match just one byte.
1199    
1200    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1201        was incorrectly computed.
1202    
1203    20. If /S is present twice on a test pattern in pcretest input, it now
1204        *disables* studying, thereby overriding the use of -s on the command line
1205        (see 14 above). This is necessary for one or two tests to keep the output
1206        identical in both cases.
1207    
1208    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1209        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1210    
1211    22. When an atomic group that contained a capturing parenthesis was
1212        successfully matched, but the branch in which it appeared failed, the
1213        capturing was not being forgotten if a higher numbered group was later
1214        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1215        group 1 to "a", when in fact it should be unset. This applied to multi-
1216        branched capturing and non-capturing groups, repeated or not, and also to
1217        positive assertions (capturing in negative assertions does not happen
1218        in PCRE) and also to nested atomic groups.
1219    
1220    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1221        subject after a captured substring, to make it easier to tell which of a
1222        number of identical substrings has been captured.
1223    
1224    24. The way atomic groups are processed by pcre_exec() has been changed so that
1225        if they are repeated, backtracking one repetition now resets captured
1226        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1227        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1228        "aaa". Previously, it would have been "a". As part of this code
1229        refactoring, the way recursive calls are handled has also been changed.
1230    
1231    25. If an assertion condition captured any substrings, they were not passed
1232        back unless some other capturing happened later. For example, if
1233        (?(?=(a))a) was matched against "a", no capturing was returned.
1234    
1235    26. When studying a pattern that contained subroutine calls or assertions,
1236        the code for finding the minimum length of a possible match was handling
1237        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1238        group 1 called group 2 while simultaneously a separate group 2 called group
1239        1). A stack overflow occurred in this case. I have fixed this by limiting
1240        the recursion depth to 10.
1241    
1242    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1243        Fortmann. This supports explicit test numbers on the command line, and has
1244        argument validation and error reporting.
1245    
1246    28. An instance of \X with an unlimited repeat could fail if at any point the
1247        first character it looked at was a mark character.
1248    
1249    29. Some minor code refactoring concerning Unicode properties and scripts
1250        should reduce the stack requirement of match() slightly.
1251    
1252    30. Added the '=' option to pcretest to check the setting of unused capturing
1253        slots at the end of the pattern, which are documented as being -1, but are
1254        not included in the return count.
1255    
1256    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1257        compiled something random. Now it gives a compile-time error (as does
1258        Perl).
1259    
1260    32. A *MARK encountered during the processing of a positive assertion is now
1261        recorded and passed back (compatible with Perl).
1262    
1263    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1264        had alternative anchored branches, the search for a second match in a line
1265        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1266        matched the line "0102" twice. The same bug affected patterns that started
1267        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1268        twice.
1269    
1270    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1271        does, and because of capturing effects, quantifying parenthesized
1272        assertions may at times be useful. Quantifiers are now allowed for
1273        parenthesized assertions.
1274    
1275    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1276    
1277    36. \g was being checked for fancy things in a character class, when it should
1278        just be a literal "g".
1279    
1280    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1281        appearance of a nested POSIX class supersedes an apparent external class.
1282        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1283        unescaped square brackets may also appear as part of class names. For
1284        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1285        more like Perl. (But see 8.20/1 above.)
1286    
1287    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1288        was because it thought it was \N{name}, which is not supported).
1289    
1290    39. Add minix to OS list not supporting the -S option in pcretest.
1291    
1292    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1293        cannot analyze patterns in sufficient detail to catch mutual recursions
1294        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1295        subgroup is called recursively as a subpattern for a second time at the
1296        same position in the subject string. In previous releases this might have
1297        been caught by the recursion limit, or it might have run out of stack.
1298    
1299    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1300        happen only once. PCRE was, however incorrectly giving a compile time error
1301        "recursive call could loop indefinitely" because it cannot analyze the
1302        pattern in sufficient detail. The compile time test no longer happens when
1303        PCRE is compiling a conditional subpattern, but actual runaway loops are
1304        now caught at runtime (see 40 above).
1305    
1306    42. It seems that Perl allows any characters other than a closing parenthesis
1307        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1308        has been changed to be the same.
1309    
1310    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1311        as not to get warnings when autogen.sh is called. Also changed
1312        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1313    
1314    44. To help people who use pcregrep to scan files containing exceedingly long
1315        lines, the following changes have been made:
1316    
1317        (a) The default value of the buffer size parameter has been increased from
1318            8K to 20K. (The actual buffer used is three times this size.)
1319    
1320        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1321            PCRE is built.
1322    
1323        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1324            to be set at run time.
1325    
1326        (d) Numerical values in pcregrep options can be followed by K or M, for
1327            example --buffer-size=50K.
1328    
1329        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1330            given and the return code is set to 2.
1331    
1332    45. Add a pointer to the latest mark to the callout data block.
1333    
1334    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1335        partial match of an empty string instead of no match. This was specific to
1336        the use of ".".
1337    
1338    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1339        complete match instead of a partial match. This bug was dependent on both
1340        the PCRE_UTF8 and PCRE_DOTALL options being set.
1341    
1342    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1343        starting byte set, because \b was not being ignored.
1344    
1345    
1346    Version 8.12 15-Jan-2011
1347    ------------------------
1348    
1349    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1350        checks for such things as part of the documentation building process.
1351    
1352    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1353        --match-limit and --recursion-limit options (added for 8.11). In
1354        particular, this made one of the standard tests fail. (The integer value
1355        went into the wrong half of a long int.)
1356    
1357    3.  If the --colour option was given to pcregrep with -v (invert match), it
1358        did strange things, either producing crazy output, or crashing. It should,
1359        of course, ignore a request for colour when reporting lines that do not
1360        match.
1361    
1362    4.  Another pcregrep bug caused similar problems if --colour was specified with
1363        -M (multiline) and the pattern match finished with a line ending.
1364    
1365    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1366        matched in multiline mode, the following line was shown as part of the
1367        match. This seems wrong, so I have changed it.
1368    
1369    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1370        the check for further matches in the same line (so they could be coloured)
1371        to overrun the end of the current line. If another match was found, it was
1372        incorrectly shown (and then shown again when found in the next line).
1373    
1374    7.  If pcregrep was compiled under Windows, there was a reference to the
1375        function pcregrep_exit() before it was defined. I am assuming this was
1376        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1377        reported by a user. I've moved the definition above the reference.
1378    
1379    
1380    Version 8.11 10-Dec-2010
1381    ------------------------
1382    
1383    1.  (*THEN) was not working properly if there were untried alternatives prior
1384        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1385        backtracked to try for "b" instead of moving to the next alternative branch
1386        at the same level (in this case, to look for "c"). The Perl documentation
1387        is clear that when (*THEN) is backtracked onto, it goes to the "next
1388        alternative in the innermost enclosing group".
1389    
1390    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1391        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1392        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1393        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1394        (*THEN).
1395    
1396    3.  If \s appeared in a character class, it removed the VT character from
1397        the class, even if it had been included by some previous item, for example
1398        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1399        of \s, but is part of the POSIX "space" class.)
1400    
1401    4.  A partial match never returns an empty string (because you can always
1402        match an empty string at the end of the subject); however the checking for
1403        an empty string was starting at the "start of match" point. This has been
1404        changed to the "earliest inspected character" point, because the returned
1405        data for a partial match starts at this character. This means that, for
1406        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1407        (previously it gave "no match").
1408    
1409    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1410        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1411        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1412        has an implication that the given string is incomplete (because a partial
1413        match is preferred over a full match). For this reason, these items now
1414        give a partial match in this situation. [Aside: previously, the one case
1415        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1416        match rather than a full match, which was wrong by the old rules, but is
1417        now correct.]
1418    
1419    6.  There was a bug in the handling of #-introduced comments, recognized when
1420        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1421        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1422        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1423        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1424        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1425        places in pcre_compile().
1426    
1427    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1428        comments when looking ahead for named forward references to subpatterns,
1429        the only newline sequence it recognized was NL. It now handles newlines
1430        according to the set newline convention.
1431    
1432    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1433        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1434        cater for a lack of strerror(). These oversights have been fixed.
1435    
1436    9.  Added --match-limit and --recursion-limit to pcregrep.
1437    
1438    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1439    
1440    11. When the -o option was used, pcregrep was setting a return code of 1, even
1441        when matches were found, and --line-buffered was not being honoured.
1442    
1443    12. Added an optional parentheses number to the -o and --only-matching options
1444        of pcregrep.
1445    
1446    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1447        can match an empty string. The code to do it in pcretest and pcredemo
1448        needed fixing:
1449    
1450        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1451            only one byte after an empty string match just before CRLF (this case
1452            just got forgotten; "any" and "anycrlf" were OK).
1453    
1454        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1455            mode when an empty string match preceded an ASCII character followed by
1456            a non-ASCII character. (The code for advancing by one character rather
1457            than one byte was nonsense.)
1458    
1459        (c) The pcredemo.c sample program did not have any code at all to handle
1460            the cases when CRLF is a valid newline sequence.
1461    
1462    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1463        as a starting offset was within the subject string. There is now a new
1464        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1465        negative or greater than the length of the string. In order to test this,
1466        pcretest is extended to allow the setting of negative starting offsets.
1467    
1468    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1469        starting offset points to the beginning of a UTF-8 character was
1470        unnecessarily clumsy. I tidied it up.
1471    
1472    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1473        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1474    
1475    17. Nobody had reported that the --include_dir option, which was added in
1476        release 7.7 should have been called --include-dir (hyphen, not underscore)
1477        for compatibility with GNU grep. I have changed it to --include-dir, but
1478        left --include_dir as an undocumented synonym, and the same for
1479        --exclude-dir, though that is not available in GNU grep, at least as of
1480        release 2.5.4.
1481    
1482    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1483        characters from a string of bytes) have been redefined so as not to use
1484        loops, in order to improve performance in some environments. At the same
1485        time, I abstracted some of the common code into auxiliary macros to save
1486        repetition (this should not affect the compiled code).
1487    
1488    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1489        compile-time error is now given if \c is not followed by an ASCII
1490        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1491        different, and any byte value is allowed.)
1492    
1493    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1494        START_OPTIMIZE option, which is now allowed at compile time - but just
1495        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1496        to pcregrep and other applications that have no direct access to PCRE
1497        options. The new /Y option in pcretest sets this option when calling
1498        pcre_compile().
1499    
1500    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1501        back references. Groups containing recursive back references were forced to
1502        be atomic by that change, but in the case of named groups, the amount of
1503        memory required was incorrectly computed, leading to "Failed: internal
1504        error: code overflow". This has been fixed.
1505    
1506    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1507        pcretest.c, to avoid build problems in some Borland environments.
1508    
1509    
1510    Version 8.10 25-Jun-2010
1511    ------------------------
1512    
1513    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1514        THEN.
1515    
1516    2.  (*ACCEPT) was not working when inside an atomic group.
1517    
1518    3.  Inside a character class, \B is treated as a literal by default, but
1519        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1520        causes the error). The code is unchanged, but I tidied the documentation.
1521    
1522    4.  Inside a character class, PCRE always treated \R and \X as literals,
1523        whereas Perl faults them if its -w option is set. I have changed PCRE so
1524        that it faults them when PCRE_EXTRA is set.
1525    
1526    5.  Added support for \N, which always matches any character other than
1527        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1528    
1529    6.  When compiling pcregrep with newer versions of gcc which may have
1530        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1531        declared with attribute warn_unused_result" were given. Just casting the
1532        result to (void) does not stop the warnings; a more elaborate fudge is
1533        needed. I've used a macro to implement this.
1534    
1535    7.  Minor change to pcretest.c to avoid a compiler warning.
1536    
1537    8.  Added four artifical Unicode properties to help with an option to make
1538        \s etc use properties (see next item). The new properties are: Xan
1539        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1540    
1541    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1542        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1543        this option. Modified pcretest to add /W to test this facility. Added
1544        REG_UCP to make it available via the POSIX interface.
1545    
1546    10. Added --line-buffered to pcregrep.
1547    
1548    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1549        studied, and the match started with a letter with a code point greater than
1550        127 whose first byte was different to the first byte of the other case of
1551        the letter, the other case of this starting letter was not recognized
1552        (#976).
1553    
1554    12. If a pattern that was studied started with a repeated Unicode property
1555        test, for example, \p{Nd}+, there was the theoretical possibility of
1556        setting up an incorrect bitmap of starting bytes, but fortunately it could
1557        not have actually happened in practice until change 8 above was made (it
1558        added property types that matched character-matching opcodes).
1559    
1560    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1561        possible starting bytes for non-anchored patterns.
1562    
1563    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1564        \R, and also a number of cases that involve Unicode properties, both
1565        explicit and implicit when PCRE_UCP is set.
1566    
1567    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1568        input, it could crash or give wrong results if characters with values
1569        greater than 0xc0 were present in the subject string. (Detail: it assumed
1570        UTF-8 input when processing these items.)
1571    
1572    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1573        size_t is 64-bit (#991).
1574    
1575    17. Added a check for running out of memory when PCRE is compiled with
1576        --disable-stack-for-recursion (#990).
1577    
1578    18. If the last data line in a file for pcretest does not have a newline on
1579        the end, a newline was missing in the output.
1580    
1581    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1582        less than 128) in its various bitmaps. However, there is a facility for
1583        generating tables according to the current locale when PCRE is compiled. It
1584        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1585        characters, are recognized by isspace() and therefore were getting set in
1586        these tables, and indeed these tables seem to approximate to ISO 8859. This
1587        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1588        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1589        which of course cannot start UTF-8 characters. I have changed the code so
1590        that only real ASCII characters (less than 128) and the correct starting
1591        bytes for UTF-8 encodings are set for characters greater than 127 when in
1592        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1593        altogether.)
1594    
1595    20. Added the /T option to pcretest so as to be able to run tests with non-
1596        standard character tables, thus making it possible to include the tests
1597        used for 19 above in the standard set of tests.
1598    
1599    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1600        reference to a subpattern the other side of a comment that contains an
1601        opening parenthesis caused either an internal compiling error, or a
1602        reference to the wrong subpattern.
1603    
1604    
1605    Version 8.02 19-Mar-2010
1606    ------------------------
1607    
1608    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1609    
1610    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1611        configured.
1612    
1613    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1614        original author of that file, following a query about its status.
1615    
1616    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1617        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1618    
1619    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1620        quantifier applied to a forward-referencing subroutine call, could compile
1621        incorrect code or give the error "internal error: previously-checked
1622        referenced subpattern not found".
1623    
1624    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1625        variables to point to external functions. For these systems, therefore,
1626        pcre_malloc etc. are now initialized to local functions that call the
1627        relevant global functions.
1628    
1629    7.  There were two entries missing in the vectors called coptable and poptable
1630        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1631        I've fixed the data, and added a kludgy way of testing at compile time that
1632        the lengths are correct (equal to the number of opcodes).
1633    
1634    8.  Following on from 7, I added a similar kludge to check the length of the
1635        eint vector in pcreposix.c.
1636    
1637    9.  Error texts for pcre_compile() are held as one long string to avoid too
1638        much relocation at load time. To find a text, the string is searched,
1639        counting zeros. There was no check for running off the end of the string,
1640        which could happen if a new error number was added without updating the
1641        string.
1642    
1643    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1644    
1645    11. \K was not working if it appeared in an atomic group or in a group that
1646        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1647        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1648        the assertion is positive, but not if it is negative.
1649    
1650    12. Change 11 fortuitously reduced the size of the stack frame used in the
1651        "match()" function of pcre_exec.c by one pointer. Forthcoming
1652        implementation of support for (*MARK) will need an extra pointer on the
1653        stack; I have reserved it now, so that the stack frame size does not
1654        decrease.
1655    
1656    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1657        item in branch that calls a recursion is a subroutine call - as in the
1658        second branch in the above example - was incorrectly given the compile-
1659        time error "recursive call could loop indefinitely" because pcre_compile()
1660        was not correctly checking the subroutine for matching a non-empty string.
1661    
1662    14. The checks for overrunning compiling workspace could trigger after an
1663        overrun had occurred. This is a "should never occur" error, but it can be
1664        triggered by pathological patterns such as hundreds of nested parentheses.
1665        The checks now trigger 100 bytes before the end of the workspace.
1666    
1667    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1668    
1669    
1670    Version 8.01 19-Jan-2010
1671    ------------------------
1672    
1673    1.  If a pattern contained a conditional subpattern with only one branch (in
1674        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1675        computed the wrong minimum data length (which is of course zero for such
1676        subpatterns). This could cause incorrect "no match" results.
1677    
1678    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1679        the pattern is reset in the first branch, pcre_compile() failed with
1680        "internal error: code overflow at offset...". This happened only when
1681        the reset was to the original external option setting. (An optimization
1682        abstracts leading options settings into an external setting, which was the
1683        cause of this.)
1684    
1685    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1686        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1687        assertion pattern did not match (meaning that the assertion was true), it
1688        was incorrectly treated as false if the SKIP had been reached during the
1689        matching. This also applied to assertions used as conditions.
1690    
1691    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1692        assertion subpattern, including such a pattern used as a condition,
1693        unpredictable results occurred, instead of the error return
1694        PCRE_ERROR_DFA_UITEM.
1695    
1696    5.  The C++ GlobalReplace function was not working like Perl for the special
1697        situation when an empty string is matched. It now does the fancy magic
1698        stuff that is necessary.
1699    
1700    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1701        removed. (These were left over from very, very early versions of PCRE.)
1702    
1703    7.  Some cosmetic changes to the code to make life easier when compiling it
1704        as part of something else:
1705    
1706        (a) Change DEBUG to PCRE_DEBUG.
1707    
1708        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1709            called "current" as "current_branch", to prevent a collision with the
1710            Linux macro when compiled as a kernel module.
1711    
1712        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1713            prevent a collision with the Linux macro when compiled as a kernel
1714            module.
1715    
1716    8.  In pcre_compile() there are some checks for integer overflows that used to
1717        cast potentially large values to (double). This has been changed to that
1718        when building, a check for int64_t is made, and if it is found, it is used
1719        instead, thus avoiding the use of floating point arithmetic. (There is no
1720        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1721        double.
1722    
1723    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1724        2005 (difference between two addresses compared to an unsigned value).
1725    
1726    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1727        custom one, because of the following reported problem in Windows:
1728    
1729          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1730              under Win32.
1731          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1732              therefore missing the function definition.
1733          - The compiler thus generates a "C" signature for the test function.
1734          - The linker fails to find the "C" function.
1735          - PCRE fails to configure if asked to do so against libbz2.
1736    
1737    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1738        messages were output:
1739    
1740          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1741          rerunning libtoolize, to keep the correct libtool macros in-tree.
1742          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1743    
1744        I have done both of these things.
1745    
1746    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1747        most of the time, it *can* run out if it is given a pattern that contains a
1748        runaway infinite recursion. I updated the discussion in the pcrestack man
1749        page.
1750    
1751    13. Now that we have gone to the x.xx style of version numbers, the minor
1752        version may start with zero. Using 08 or 09 is a bad idea because users
1753        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1754        interpreted as invalid octal numbers. I've updated the previous comment in
1755        configure.ac, and also added a check that gives an error if 08 or 09 are
1756        used.
1757    
1758    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1759        causing partial matching to fail when the end of the subject matched \W
1760        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1761    
1762    15. There were some discrepancies between the declarations in pcre_internal.h
1763        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1764        their definitions. The declarations used "const uschar *" and the
1765        definitions used USPTR. Even though USPTR is normally defined as "const
1766        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1767        reported that: "This difference in casting confuses some C++ compilers, for
1768        example, SunCC recognizes above declarations as different functions and
1769        generates broken code for hbpcre." I have changed the declarations to use
1770        USPTR.
1771    
1772    16. GNU libtool is named differently on some systems. The autogen.sh script now
1773        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1774        (FreeBSD).
1775    
1776    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1777        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1778        comment: "Figure out how to create a longlong from a string: strtoll and
1779        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1780        instance, but it only takes 2 args instead of 3!"
1781    
1782    18. A subtle bug concerned with back references has been fixed by a change of
1783        specification, with a corresponding code fix. A pattern such as
1784        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1785        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1786        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1787        same bug. Such groups have to be quantified to be useful, or contained
1788        inside another quantified group. (If there's no repetition, the reference
1789        can never match.) The problem arises because, having left the group and
1790        moved on to the rest of the pattern, a later failure that backtracks into
1791        the group uses the captured value from the final iteration of the group
1792        rather than the correct earlier one. I have fixed this in PCRE by forcing
1793        any group that contains a reference to itself to be an atomic group; that
1794        is, there cannot be any backtracking into it once it has completed. This is
1795        similar to recursive and subroutine calls.
1796    
1797    
1798    Version 8.00 19-Oct-09
1799  ----------------------  ----------------------
1800    
1801  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
1802      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
1803      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
1804      error.      error.
1805    
1806  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1807      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1808      in a Windows environment.      in a Windows environment.
1809    
1810  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
1811      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
1812      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
1813      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
1814      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
1815      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
1816      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
1817    
1818  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
1819      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
1820      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
1821      the old behaviour.      the old behaviour.
1822    
1823  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
1824      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
1825      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
1826      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
1827    
1828  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
1829      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1830    
1831  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1832      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
1833      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
1834      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
1835      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
1836      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
1837    
1838  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1839      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
1840      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1841      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1842      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
1843      result.      result.
1844    
1845  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
1846      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
1847      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
1848      slots in the offset vector, the offset of the earliest inspected character      slots in the offset vector, the offset of the earliest inspected character
1849      for the match and the offset of the end of the subject are set in them when      for the match and the offset of the end of the subject are set in them when
1850      PCRE_ERROR_PARTIAL is returned.      PCRE_ERROR_PARTIAL is returned.
1851    
1852  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1853      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
1854      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1855      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
1856      pcre_exec().  
1857    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1858  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
1859      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
1860      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1861      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
1862      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
1863      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
1864      final character ended with (*FAIL).  
   
1865  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1866      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
1867      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
1868      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
1869      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
1870      "sbody" failed. This bug has been fixed.      "sbody" failed. This bug has been fixed.
1871    
1872  13. The string returned by pcre_dfa_exec() after a partial match has been  13. The string returned by pcre_dfa_exec() after a partial match has been
1873      changed so that it starts at the first inspected character rather than the      changed so that it starts at the first inspected character rather than the
1874      first character of the match. This makes a difference only if the pattern      first character of the match. This makes a difference only if the pattern
1875      starts with a lookbehind assertion or \b or \B (\K is not supported by      starts with a lookbehind assertion or \b or \B (\K is not supported by
1876      pcre_dfa_exec()). It's an incompatible change, but it makes the two      pcre_dfa_exec()). It's an incompatible change, but it makes the two
1877      matching functions compatible, and I think it's the right thing to do.      matching functions compatible, and I think it's the right thing to do.
1878    
1879  14. Added a pcredemo man page, created automatically from the pcredemo.c file,  14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1880      so that the demonstration program is easily available in environments where      so that the demonstration program is easily available in environments where
1881      PCRE has not been installed from source.      PCRE has not been installed from source.
1882    
1883  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1884      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1885      library.      library.
1886    
1887  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1888      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1889      is not the first non-POSIX option to be added. Clearly some people find      is not the first non-POSIX option to be added. Clearly some people find
1890      these options useful.      these options useful.
1891    
1892  17. If a caller to the POSIX matching function regexec() passes a non-zero  17. If a caller to the POSIX matching function regexec() passes a non-zero
1893      value for nmatch with a NULL value for pmatch, the value of      value for nmatch with a NULL value for pmatch, the value of
1894      nmatch is forced to zero.      nmatch is forced to zero.
1895    
1896  18. RunGrepTest did not have a test for the availability of the -u option of  18. RunGrepTest did not have a test for the availability of the -u option of
1897      the diff command, as RunTest does. It now checks in the same way as      the diff command, as RunTest does. It now checks in the same way as
1898      RunTest, and also checks for the -b option.      RunTest, and also checks for the -b option.
1899    
1900  19. If an odd number of negated classes containing just a single character  19. If an odd number of negated classes containing just a single character
1901      interposed, within parentheses, between a forward reference to a named      interposed, within parentheses, between a forward reference to a named
1902      subpattern and the definition of the subpattern, compilation crashed with      subpattern and the definition of the subpattern, compilation crashed with
1903      an internal error, complaining that it could not find the referenced      an internal error, complaining that it could not find the referenced
1904      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1905      [The bug was that it was starting one character too far in when skipping      [The bug was that it was starting one character too far in when skipping
1906      over the character class, thus treating the ] as data rather than      over the character class, thus treating the ] as data rather than
1907      terminating the class. This meant it could skip too much.]      terminating the class. This meant it could skip too much.]
1908    
1909  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1910      /g option in pcretest when the pattern contains \K, which makes it possible      /g option in pcretest when the pattern contains \K, which makes it possible
1911      to have an empty string match not at the start, even when the pattern is      to have an empty string match not at the start, even when the pattern is
1912      anchored. Updated pcretest and pcredemo to use this option.      anchored. Updated pcretest and pcredemo to use this option.
1913    
1914  21. If the maximum number of capturing subpatterns in a recursion was greater  21. If the maximum number of capturing subpatterns in a recursion was greater
1915      than the maximum at the outer level, the higher number was returned, but      than the maximum at the outer level, the higher number was returned, but
1916      with unset values at the outer level. The correct (outer level) value is      with unset values at the outer level. The correct (outer level) value is
1917      now given.      now given.
1918    
1919  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1920      PCRE did not set those parentheses (unlike Perl). I have now found a way to      PCRE did not set those parentheses (unlike Perl). I have now found a way to
1921      make it do so. The string so far is captured, making this feature      make it do so. The string so far is captured, making this feature
1922      compatible with Perl.      compatible with Perl.
1923    
1924    23. The tests have been re-organized, adding tests 11 and 12, to make it
1925        possible to check the Perl 5.10 features against Perl 5.10.
1926    
1927    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1928        pattern matches a fixed length string. PCRE did not allow this; now it
1929        does. Neither allows recursion.
1930    
1931    25. I finally figured out how to implement a request to provide the minimum
1932        length of subject string that was needed in order to match a given pattern.
1933        (It was back references and recursion that I had previously got hung up
1934        on.) This code has now been added to pcre_study(); it finds a lower bound
1935        to the length of subject needed. It is not necessarily the greatest lower
1936        bound, but using it to avoid searching strings that are too short does give
1937        some useful speed-ups. The value is available to calling programs via
1938        pcre_fullinfo().
1939    
1940    26. While implementing 25, I discovered to my embarrassment that pcretest had
1941        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1942        study optimizations had never been tested with that matching function.
1943        Oops. What is worse, even when it was passed study data, there was a bug in
1944        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1945        were also very few tests of studied patterns with pcre_dfa_exec().
1946    
1947    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1948        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1949        on the other side of the coin, they are no longer allowed to have different
1950        names, because these cannot be distinguished in PCRE, and this has caused
1951        confusion. (This is a difference from Perl.)
1952    
1953    28. When duplicate subpattern names are present (necessarily with different
1954        numbers, as required by 27 above), and a test is made by name in a
1955        conditional pattern, either for a subpattern having been matched, or for
1956        recursion in such a pattern, all the associated numbered subpatterns are
1957        tested, and the overall condition is true if the condition is true for any
1958        one of them. This is the way Perl works, and is also more like the way
1959        testing by number works.
1960    
1961    
1962  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
1963  ---------------------  ---------------------
# Line 163  Version 7.9 11-Apr-09 Line 1993  Version 7.9 11-Apr-09
1993  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
1994      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
1995      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1996      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1997        8.33.]
1998    
1999  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
2000      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 406  Version 7.7 07-May-08 Line 2237  Version 7.7 07-May-08
2237      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2238      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2239      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2240      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2241      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2242      was subsequently set up correctly.)      was subsequently set up correctly.)
2243    

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