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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.13 30-Apr-2011  Version 8.37 xx-xxx-201x
5    ------------------------
7    1.  When an (*ACCEPT) is triggered inside capturing parentheses, it arranges
8        for those parentheses to be closed with whatever has been captured so far.
9        However, it was failing to mark any other groups between the hightest
10        capture so far and the currrent group as "unset". Thus, the ovector for
11        those groups contained whatever was previously there. An example is the
12        pattern /(x)|((*ACCEPT))/ when matched against "abcd".
14    2.  If an assertion condition was quantified with a minimum of zero (an odd
15        thing to do, but it happened), SIGSEGV or other misbehaviour could occur.
17    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
18        unrecognized modifier, a crash could occur.
22    Version 8.36 26-September-2014
23    ------------------------------
25    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
26        -Wmissing-field-initializers and -Wunused-parameter.
28    2.  The tests for quantifiers being too big (greater than 65535) were being
29        applied after reading the number, and stupidly assuming that integer
30        overflow would give a negative number. The tests are now applied as the
31        numbers are read.
33    3.  Tidy code in pcre_exec.c where two branches that used to be different are
34        now the same.
36    4.  The JIT compiler did not generate match limit checks for certain
37        bracketed expressions with quantifiers. This may lead to exponential
38        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
39        issue should be resolved now.
41    5.  Fixed an issue, which occures when nested alternatives are optimized
42        with table jumps.
44    6.  Inserted two casts and changed some ints to size_t in the light of some
45        reported 64-bit compiler warnings (Bugzilla 1477).
47    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
48        an empty string, which sometimes were behaving incorrectly in the
49        interpreter (though correctly in the JIT matcher). This pcretest input is
50        an example:
52          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
55        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
56        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
57        for an empty string was breaking the inner loop and carrying on at a lower
58        level, when possessive repeated groups should always return to a higher
59        level as they have no backtrack points in them. The empty string test now
60        occurs at the outer level.
62    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
63        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
65    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
66        doesn't).
68    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
69        to hold a pattern to be incorrectly computed (too small) when there were
70        named back references to duplicated names. This could cause "internal
71        error: code overflow" or "double free or corruption" or other memory
72        handling errors.
74    11. When named subpatterns had the same prefixes, back references could be
75        confused. For example, in this pattern:
77          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
79        the reference to 'Name' was incorrectly treated as a reference to a
80        duplicate name.
82    12. A pattern such as /^s?c/mi8 where the optional character has more than
83        one "other case" was incorrectly compiled such that it would only try to
84        match starting at "c".
86    13. When a pattern starting with \s was studied, VT was not included in the
87        list of possible starting characters; this should have been part of the
88        8.34/18 patch.
90    14. If a character class started [\Qx]... where x is any character, the class
91        was incorrectly terminated at the ].
93    15. If a pattern that started with a caseless match for a character with more
94        than one "other case" was studied, PCRE did not set up the starting code
95        unit bit map for the list of possible characters. Now it does. This is an
96        optimization improvement, not a bug fix.
98    16. The Unicode data tables have been updated to Unicode 7.0.0.
100    17. Fixed a number of memory leaks in pcregrep.
102    18. Avoid a compiler warning (from some compilers) for a function call with
103        a cast that removes "const" from an lvalue by using an intermediate
104        variable (to which the compiler does not object).
106    19. Incorrect code was compiled if a group that contained an internal recursive
107        back reference was optional (had quantifier with a minimum of zero). This
108        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
109        caused segmentation faults because of stack overflows at compile time.
111    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
112        group that is quantified with an indefinite repeat, caused a compile-time
113        loop which used up all the system stack and provoked a segmentation fault.
114        This was not the same bug as 19 above.
116    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
117        Patch by Mike Frysinger.
120    Version 8.35 04-April-2014
121    --------------------------
123    1.  A new flag is set, when property checks are present in an XCLASS.
124        When this flag is not set, PCRE can perform certain optimizations
125        such as studying these XCLASS-es.
127    2.  The auto-possessification of character sets were improved: a normal
128        and an extended character set can be compared now. Furthermore
129        the JIT compiler optimizes more character set checks.
131    3.  Got rid of some compiler warnings for potentially uninitialized variables
132        that show up only when compiled with -O2.
134    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
135        of a match later then the end of the match. The pcretest program was not
136        handling the case sensibly - it was outputting from the start to the next
137        binary zero. It now reports this situation in a message, and outputs the
138        text from the end to the start.
140    5.  Fast forward search is improved in JIT. Instead of the first three
141        characters, any three characters with fixed position can be searched.
142        Search order: first, last, middle.
144    6.  Improve character range checks in JIT. Characters are read by an inprecise
145        function now, which returns with an unknown value if the character code is
146        above a certain threshold (e.g: 256). The only limitation is that the value
147        must be bigger than the threshold as well. This function is useful when
148        the characters above the threshold are handled in the same way.
150    7.  The macros whose names start with RAWUCHAR are placeholders for a future
151        mode in which only the bottom 21 bits of 32-bit data items are used. To
152        make this more memorable for those maintaining the code, the names have
153        been changed to start with UCHAR21, and an extensive comment has been added
154        to their definition.
156    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
157        to the export list in Makefile.am (they were accidentally omitted from the
158        8.34 tarball).
160    9.  The informational output from pcretest used the phrase "starting byte set"
161        which is inappropriate for the 16-bit and 32-bit libraries. As the output
162        for "first char" and "need char" really means "non-UTF-char", I've changed
163        "byte" to "char", and slightly reworded the output. The documentation about
164        these values has also been (I hope) clarified.
166    10. Another JIT related optimization: use table jumps for selecting the correct
167        backtracking path, when more than four alternatives are present inside a
168        bracket.
170    11. Empty match is not possible, when the minimum length is greater than zero,
171        and there is no \K in the pattern. JIT should avoid empty match checks in
172        such cases.
174    12. In a caseless character class with UCP support, when a character with more
175        than one alternative case was not the first character of a range, not all
176        the alternative cases were added to the class. For example, s and \x{17f}
177        are both alternative cases for S: the class [RST] was handled correctly,
178        but [R-T] was not.
180    13. The configure.ac file always checked for pthread support when JIT was
181        enabled. This is not used in Windows, so I have put this test inside a
182        check for the presence of windows.h (which was already tested for).
184    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
185        The algorithm provides a way to skip certain starting offsets, and usually
186        faster than linear prefix searches.
188    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
189        as for 'fr_FR' and 'french'. For some reason, however, it then used the
190        Windows-specific input and output files, which have 'french' screwed in.
191        So this could never have worked. One of the problems with locales is that
192        they aren't always the same. I have now updated RunTest so that it checks
193        the output of the locale test (test 3) against three different output
194        files, and it allows the test to pass if any one of them matches. With luck
195        this should make the test pass on some versions of Solaris where it was
196        failing. Because of the uncertainty, the script did not used to stop if
197        test 3 failed; it now does. If further versions of a French locale ever
198        come to light, they can now easily be added.
200    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
201        there was a message during ./configure, but it did not stop. This now
202        provokes an error. The invalid example in README has been corrected.
203        If a value less than the minimum is given, the minimum value has always
204        been used, but now a warning is given.
206    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
207        was a bug in the test system, which is now fixed. Also, the list of various
208        configurations that are tested for each release did not have one with both
209        16/32 bits and --enable-bar-anycrlf. It now does.
211    18. pcretest was missing "-C bsr" for displaying the \R default setting.
213    19. Little endian PowerPC systems are supported now by the JIT compiler.
215    20. The fast forward newline mechanism could enter to an infinite loop on
216        certain invalid UTF-8 input. Although we don't support these cases
217        this issue can be fixed by a performance optimization.
219    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
220        not take account if existing stack usage. There is now a new global
221        variable called pcre_stack_guard that can be set to point to an external
222        function to check stack availability. It is called at the start of
223        processing every parenthesized group.
225    22. A typo in the code meant that in ungreedy mode the max/min qualifier
226        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
227        not match "ab".
229    23. When UTF was disabled, the JIT program reported some incorrect compile
230        errors. These messages are silenced now.
232    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
233        compiler.
235    25. Change all the temporary files used in RunGrepTest to be different to those
236        used by RunTest so that the tests can be run simultaneously, for example by
237        "make -j check".
240    Version 8.34 15-December-2013
241    -----------------------------
243    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
244        executable memory. Patch inspired by Carsten Klein.
246    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
247        this macro is never tested and has no effect, because the work to support
248        coverage involves only compiling and linking options and special targets in
249        the Makefile. The comment in config.h implied that defining the macro would
250        enable coverage support, which is totally false. There was also support for
251        setting this macro in the CMake files (my fault, I just copied it from
252        configure). SUPPORT_GCOV has now been removed.
254    3.  Make a small performance improvement in strlen16() and strlen32() in
255        pcretest.
257    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
258        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
259        these cases). There was also one in pcretest.c.
261    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
263    6.  In UTF mode, the code for checking whether a group could match an empty
264        string (which is used for indefinitely repeated groups to allow for
265        breaking an infinite loop) was broken when the group contained a repeated
266        negated single-character class with a character that occupied more than one
267        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
268        UTF-8 mode). The effect was undefined: the group might or might not be
269        deemed as matching an empty string, or the program might have crashed.
271    7.  The code for checking whether a group could match an empty string was not
272        recognizing that \h, \H, \v, \V, and \R must match a character.
274    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
275        an empty string. If it can, pcretest shows this in its information output.
277    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
278        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
279        matched by pcre_exec() without using JIT:
281        (a) If the rest of the pattern did not match after a maximal run of
282            grapheme clusters, the code for backing up to try with fewer of them
283            did not always back up over a full grapheme when characters that do not
284            have the modifier quality were involved, e.g. Hangul syllables.
286        (b) If the match point in a subject started with modifier character, and
287            there was no match, the code could incorrectly back up beyond the match
288            point, and potentially beyond the first character in the subject,
289            leading to a segfault or an incorrect match result.
291    10. A conditional group with an assertion condition could lead to PCRE
292        recording an incorrect first data item for a match if no other first data
293        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
294        first data item, and therefore matched "ca" after "c" instead of at the
295        start.
297    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
298        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
300    12. The source of pcregrep now includes z/OS-specific code so that it can be
301        compiled for z/OS as part of the special z/OS distribution.
303    13. Added the -T and -TM options to pcretest.
305    14. The code in pcre_compile.c for creating the table of named capturing groups
306        has been refactored. Instead of creating the table dynamically during the
307        actual compiling pass, the information is remembered during the pre-compile
308        pass (on the stack unless there are more than 20 named groups, in which
309        case malloc() is used) and the whole table is created before the actual
310        compile happens. This has simplified the code (it is now nearly 150 lines
311        shorter) and prepared the way for better handling of references to groups
312        with duplicate names.
314    15. A back reference to a named subpattern when there is more than one of the
315        same name now checks them in the order in which they appear in the pattern.
316        The first one that is set is used for the reference. Previously only the
317        first one was inspected. This change makes PCRE more compatible with Perl.
319    16. Unicode character properties were updated from Unicode 6.3.0.
321    17. The compile-time code for auto-possessification has been refactored, based
322        on a patch by Zoltan Herczeg. It now happens after instead of during
323        compilation. The code is cleaner, and more cases are handled. The option
324        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
325        options in pcretest are provided to set it. It can also be set by
326        (*NO_AUTO_POSSESS) at the start of a pattern.
328    18. The character VT has been added to the default ("C" locale) set of
329        characters that match \s and are generally treated as white space,
330        following this same change in Perl 5.18. There is now no difference between
331        "Perl space" and "POSIX space". Whether VT is treated as white space in
332        other locales depends on the locale.
334    19. The code for checking named groups as conditions, either for being set or
335        for being recursed, has been refactored (this is related to 14 and 15
336        above). Processing unduplicated named groups should now be as fast at
337        numerical groups, and processing duplicated groups should be faster than
338        before.
340    20. Two patches to the CMake build system, by Alexander Barkov:
342          (1) Replace the "source" command by "." in CMakeLists.txt because
343              "source" is a bash-ism.
345          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
346              without these the CMake build does not work on Solaris.
348    21. Perl has changed its handling of \8 and \9. If there is no previously
349        encountered capturing group of those numbers, they are treated as the
350        literal characters 8 and 9 instead of a binary zero followed by the
351        literals. PCRE now does the same.
353    22. Following Perl, added \o{} to specify codepoints in octal, making it
354        possible to specify values greater than 0777 and also making them
355        unambiguous.
357    23. Perl now gives an error for missing closing braces after \x{... instead of
358        treating the string as literal. PCRE now does the same.
360    24. RunTest used to grumble if an inappropriate test was selected explicitly,
361        but just skip it when running all tests. This make it awkward to run ranges
362        of tests when one of them was inappropriate. Now it just skips any
363        inappropriate tests, as it always did when running all tests.
365    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
366        character types such as \d or \w, too many callouts were inserted, and the
367        data that they returned was rubbish.
369    26. In UCP mode, \s was not matching two of the characters that Perl matches,
370        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
371        were matched by \h. The code has now been refactored so that the lists of
372        the horizontal and vertical whitespace characters used for \h and \v (which
373        are defined only in one place) are now also used for \s.
375    27. Add JIT support for the 64 bit TileGX architecture.
376        Patch by Jiong Wang (Tilera Corporation).
378    28. Possessive quantifiers for classes (both explicit and automatically
379        generated) now use special opcodes instead of wrapping in ONCE brackets.
381    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
382        (because it's meaningless), this was not happening when PCRE_CASELESS was
383        set. Not wrong, but inefficient.
385    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
386        properties for \w, \d, etc) is present in a test regex. Otherwise if the
387        test contains no characters greater than 255, Perl doesn't realise it
388        should be using Unicode semantics.
390    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
391        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
392        does in Unicode mode.
394    32. Added the "forbid" facility to pcretest so that putting tests into the
395        wrong test files can sometimes be quickly detected.
397    33. There is now a limit (default 250) on the depth of nesting of parentheses.
398        This limit is imposed to control the amount of system stack used at compile
399        time. It can be changed at build time by --with-parens-nest-limit=xxx or
400        the equivalent in CMake.
402    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
403        errors. Perl warns for these when in warning mode, but PCRE has no facility
404        for giving warnings.
406    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
407        However, this was not working for (?!) because it is optimized to (*FAIL),
408        for which PCRE does not allow quantifiers. The optimization is now disabled
409        when a quantifier follows (?!). I can't see any use for this, but it makes
410        things uniform.
412    36. Perl no longer allows group names to start with digits, so I have made this
413        change also in PCRE. It simplifies the code a bit.
415    37. In extended mode, Perl ignores spaces before a + that indicates a
416        possessive quantifier. PCRE allowed a space before the quantifier, but not
417        before the possessive +. It now does.
419    38. The use of \K (reset reported match start) within a repeated possessive
420        group such as (a\Kb)*+ was not working.
422    40. Document that the same character tables must be used at compile time and
423        run time, and that the facility to pass tables to pcre_exec() and
424        pcre_dfa_exec() is for use only with saved/restored patterns.
426    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
427        features for Builds with MSVC:
429        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
430           builds). The .rc files can be used to set FileDescription and many other
431           attributes.
433        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
434           This allows higher-level build scripts which want .pdb files to avoid
435           hard-coding the exact files needed."
437    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
438        mean "start of word" and "end of word", respectively, as a transition aid.
440    43. A minimizing repeat of a class containing codepoints greater than 255 in
441        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
442        compiled to use the heap for recursion.
444    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
445        is configured.
448    Version 8.33 28-May-2013
449    ------------------------
451    1.  Added 'U' to some constants that are compared to unsigned integers, to
452        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
453        variables that are added to signed variables, to ensure the result is
454        signed and can be negated.
456    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
457        CMake config files.
459    3.  Revise the creation of config.h.generic so that all boolean macros are
460        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
461        overriding via -D on the command line possible.
463    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
464        to unsigned int is reported to make a quite noticeable speed difference in
465        a specific Windows environment. Testing on Linux did also appear to show
466        some benefit (and it is clearly not harmful). Also fixed the definition of
467        Xop which should be unsigned.
469    5.  Related to (4), changing the definition of the intermediate variable cc
470        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
471        improvements.
473    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
474        unnecessary spaces.
476    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
477        and later.
479    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
481    9.  Optimizing fast_forward_start_bits in JIT.
483    10. Adding support for callouts in JIT, and fixing some issues revealed
484        during this work. Namely:
486        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
488        (b) Minimum length was not checked before the matching is started.
490    11. The value of capture_last that is passed to callouts was incorrect in some
491        cases when there was a capture on one path that was subsequently abandoned
492        after a backtrack. Also, the capture_last value is now reset after a
493        recursion, since all captures are also reset in this case.
495    12. The interpreter no longer returns the "too many substrings" error in the
496        case when an overflowing capture is in a branch that is subsequently
497        abandoned after a backtrack.
499    13. In the pathological case when an offset vector of size 2 is used, pcretest
500        now prints out the matched string after a yield of 0 or 1.
502    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
503        Only supported by the JIT compiler at the moment.
505    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
507    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
508        offset of the starting point of the matching process, provided the offsets
509        vector is large enough.
511    17. The \A escape now records a lookbehind value of 1, though its execution
512        does not actually inspect the previous character. This is to ensure that,
513        in partial multi-segment matching, at least one character from the old
514        segment is retained when a new segment is processed. Otherwise, if there
515        are no lookbehinds in the pattern, \A might match incorrectly at the start
516        of a new segment.
518    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
520    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
521        gives some modest performance improvement in 8-bit mode.
523    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
524        be expressed in certain programming languages using Universal Character
525        Names.
527    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
528        which points out that "non characters" are not "characters that may not
529        appear in Unicode strings" but rather "characters that are reserved for
530        internal use and have only local meaning".
532    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
533        there was a conditional group that depended on an assertion, if the
534        assertion was false, the callout that immediately followed the alternation
535        in the condition was skipped when pcre_exec() was used for matching.
537    23. Allow an explicit callout to be inserted before an assertion that is the
538        condition for a conditional group, for compatibility with automatic
539        callouts, which always insert a callout at this point.
541    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
542        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
544    25. (*PRUNE) is now supported by the JIT compiler.
546    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
548    27. Fix the case where there are two or more SKIPs with arguments that may be
549        ignored.
551    28. (*SKIP) is now supported by the JIT compiler.
553    29. (*THEN) is now supported by the JIT compiler.
555    30. Update RunTest with additional test selector options.
557    31. The way PCRE handles backtracking verbs has been changed in two ways.
559        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
560        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
561        backtracking. In some cases this makes it more Perl-compatible, but Perl's
562        rather obscure rules do not always do the same thing.
564        (2) Previously, backtracking verbs were confined within assertions. This is
565        no longer the case for positive assertions, except for (*ACCEPT). Again,
566        this sometimes improves Perl compatibility, and sometimes does not.
568    32. A number of tests that were in test 2 because Perl did things differently
569        have been moved to test 1, because either Perl or PCRE has changed, and
570        these tests are now compatible.
572    32. Backtracking control verbs are now handled in the same way in JIT and
573        interpreter.
575    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
576        contained a forward subroutine reference caused a compile error.
578    34. Auto-detect and optimize limited repetitions in JIT.
580    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
581        blocking (*UTF) etc.
583    36. In the interpreter, maximizing pattern repetitions for characters and
584        character types now use tail recursion, which reduces stack usage.
586    37. The value of the max lookbehind was not correctly preserved if a compiled
587        and saved regex was reloaded on a host of different endianness.
589    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
590        of the compiled pattern block, expand the flags field from 16 to 32 bits
591        because it was almost full.
593    39. Try madvise first before posix_madvise.
595    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
596        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
597        original change locked out all matches of empty strings. This has been
598        changed so that one match of an empty string per line is recognized.
599        Subsequent searches on the same line (for colouring or for --only-matching,
600        for example) do not recognize empty strings.
602    41. Applied a user patch to fix a number of spelling mistakes in comments.
604    42. Data lines longer than 65536 caused pcretest to crash.
606    43. Clarified the data type for length and startoffset arguments for pcre_exec
607        and pcre_dfa_exec in the function-specific man pages, where they were
608        explicitly stated to be in bytes, never having been updated. I also added
609        some clarification to the pcreapi man page.
611    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
612        a segmentation fault.
615    Version 8.32 30-November-2012
616    -----------------------------
618    1.  Improved JIT compiler optimizations for first character search and single
619        character iterators.
621    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
622        Patch by Daniel Richard G.
624    3.  Single character iterator optimizations in the JIT compiler.
626    4.  Improved JIT compiler optimizations for character ranges.
628    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
629        Reported by Giuseppe D'Angelo.
631    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
632        of a line, was being set incorrectly in cases where .* appeared inside
633        atomic brackets at the start of a pattern, or where there was a subsequent
634        *PRUNE or *SKIP.
636    7.  Improved instruction cache flush for POWER/PowerPC.
637        Patch by Daniel Richard G.
639    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
640        grep:
642        (a) There is now no limit to the number of patterns to be matched.
644        (b) An error is given if a pattern is too long.
646        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
647            are now supported.
649        (d) --exclude-from and --include-from (multiple use) have been added.
651        (e) Exclusions and inclusions now apply to all files and directories, not
652            just to those obtained from scanning a directory recursively.
654        (f) Multiple uses of -f and --file-list are now supported.
656        (g) In a Windows environment, the default for -d has been changed from
657            "read" (the GNU grep default) to "skip", because otherwise the presence
658            of a directory in the file list provokes an error.
660        (h) The documentation has been revised and clarified in places.
662    9.  Improve the matching speed of capturing brackets.
664    10. Changed the meaning of \X so that it now matches a Unicode extended
665        grapheme cluster.
667    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
668        out POSIX threads when JIT support is configured.
670    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
672    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
673        structure could go wrong in environments where size_t is not the same size
674        as int.
676    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
677        set.
679    15. The EBCDIC support had decayed; later updates to the code had included
680        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
681        general tidy up of EBCDIC-related issues, and the documentation was also
682        not quite right. There is now a test that can be run on ASCII systems to
683        check some of the EBCDIC-related things (but is it not a full test).
685    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
686        in a small tidy to the code.
688    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
690    18. If the --only-matching (-o) option in pcregrep is specified multiple
691        times, each one causes appropriate output. For example, -o1 -o2 outputs the
692        substrings matched by the 1st and 2nd capturing parentheses. A separating
693        string can be specified by --om-separator (default empty).
695    19. Improving the first n character searches.
697    20. Turn case lists for horizontal and vertical white space into macros so that
698        they are defined only once.
700    21. This set of changes together give more compatible Unicode case-folding
701        behaviour for characters that have more than one other case when UCP
702        support is available.
704        (a) The Unicode property table now has offsets into a new table of sets of
705            three or more characters that are case-equivalent. The MultiStage2.py
706            script that generates these tables (the pcre_ucd.c file) now scans
707            CaseFolding.txt instead of UnicodeData.txt for character case
708            information.
710        (b) The code for adding characters or ranges of characters to a character
711            class has been abstracted into a generalized function that also handles
712            case-independence. In UTF-mode with UCP support, this uses the new data
713            to handle characters with more than one other case.
715        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
716            whose other case is greater than 256 are now correctly matched
717            caselessly. Previously, the high codepoint matched the low one, but not
718            vice versa.
720        (d) The processing of \h, \H, \v, and \ in character classes now makes use
721            of the new class addition function, using character lists defined as
722            macros alongside the case definitions of 20 above.
724        (e) Caseless back references now work with characters that have more than
725            one other case.
727        (f) General caseless matching of characters with more than one other case
728            is supported.
730    22. Unicode character properties were updated from Unicode 6.2.0
732    23. Improved CMake support under Windows. Patch by Daniel Richard G.
734    24. Add support for 32-bit character strings, and UTF-32
736    25. Major JIT compiler update (code refactoring and bugfixing).
737        Experimental Sparc 32 support is added.
739    26. Applied a modified version of Daniel Richard G's patch to create
740        pcre.h.generic and config.h.generic by "make" instead of in the
741        PrepareRelease script.
743    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
744        pcre_compile.c when checking for a zero character.
746    28. Introducing a native interface for JIT. Through this interface, the compiled
747        machine code can be directly executed. The purpose of this interface is to
748        provide fast pattern matching, so several sanity checks are not performed.
749        However, feature tests are still performed. The new interface provides
750        1.4x speedup compared to the old one.
752    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
753        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
754        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
756    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
757        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
758        the "old" RFC 2279). Instead, it ended up passing a negative length to
759        pcre_exec().
761    31. Add support for GCC's visibility feature to hide internal functions.
763    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
764        "unknown -C option" after outputting 0 or 1.
766    33. There is now support for generating a code coverage report for the test
767        suite in environments where gcc is the compiler and lcov is installed. This
768        is mainly for the benefit of the developers.
770    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
771        unaddressable using valgrind annotations, allowing valgrind to detect
772        invalid memory accesses. This is mainly for the benefit of the developers.
774    25. (*UTF) can now be used to start a pattern in any of the three libraries.
776    26. Give configure error if --enable-cpp but no C++ compiler found.
779    Version 8.31 06-July-2012
780    -------------------------
782    1.  Fixing a wrong JIT test case and some compiler warnings.
784    2.  Removed a bashism from the RunTest script.
786    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
787        to unsigned type, result still unsigned" that was given by an MS compiler
788        on encountering the code "-sizeof(xxx)".
790    4.  Partial matching support is added to the JIT compiler.
792    5.  Fixed several bugs concerned with partial matching of items that consist
793        of more than one character:
795        (a) /^(..)\1/ did not partially match "aba" because checking references was
796            done on an "all or nothing" basis. This also applied to repeated
797            references.
799        (b) \R did not give a hard partial match if \r was found at the end of the
800            subject.
802        (c) \X did not give a hard partial match after matching one or more
803            characters at the end of the subject.
805        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
806            a partial match for the string "\r".
808        (e) When newline was set to CRLF, the metacharacter "." did not recognize
809            a partial match for a CR character at the end of the subject string.
811    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
812        running pcretest, the text "(JIT)" added to the output whenever JIT is
813        actually used to run the match.
815    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
816        or /S+[+] with a digit between 1 and 7.
818    8.  OP_NOT now supports any UTF character not just single-byte ones.
820    9.  (*MARK) control verb is now supported by the JIT compiler.
822    10. The command "./RunTest list" lists the available tests without actually
823        running any of them. (Because I keep forgetting what they all are.)
827    12. Applied a (slightly modified) user-supplied patch that improves performance
828        when the heap is used for recursion (compiled with --disable-stack-for-
829        recursion). Instead of malloc and free for each heap frame each time a
830        logical recursion happens, frames are retained on a chain and re-used where
831        possible. This sometimes gives as much as 30% improvement.
833    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
834        call.
836    14. As documented, (*COMMIT) is now confined to within a positive assertion.
838    15. It is now possible to link pcretest with libedit as an alternative to
839        libreadline.
841    16. (*COMMIT) control verb is now supported by the JIT compiler.
843    17. The Unicode data tables have been updated to Unicode 6.1.0.
845    18. Added --file-list option to pcregrep.
847    19. Added binary file support to pcregrep, including the -a, --binary-files,
848        -I, and --text options.
850    20. The madvise function is renamed for posix_madvise for QNX compatibility
851        reasons. Fixed by Giuseppe D'Angelo.
853    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
855    22. Changed the option for creating symbolic links for 16-bit man pages from
856        -s to -sf so that re-installing does not cause issues.
858    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
860    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
861        matches in certain environments (the workspace was not being correctly
862        retained). Also added to pcre_dfa_exec() a simple plausibility check on
863        some of the workspace data at the beginning of a restart.
865    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
866        was not doing so when it should - probably a typo introduced by SVN 528
867        (change 8.10/14).
869    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
870        \w+ when the character tables indicated that \x{c4} was a word character.
871        There were several related cases, all because the tests for doing a table
872        lookup were testing for characters less than 127 instead of 255.
874    27. If a pattern contains capturing parentheses that are not used in a match,
875        their slots in the ovector are set to -1. For those that are higher than
876        any matched groups, this happens at the end of processing. In the case when
877        there were back references that the ovector was too small to contain
878        (causing temporary malloc'd memory to be used during matching), and the
879        highest capturing number was not used, memory off the end of the ovector
880        was incorrectly being set to -1. (It was using the size of the temporary
881        memory instead of the true size.)
883    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
884        ovector size, it uses memory at the end of the block that it has got.
886    29. Check for an overlong MARK name and give an error at compile time. The
887        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
889    30. JIT compiler update.
891    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
892        Rill for the patch.
894    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
896    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
898    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
899        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
900        was enabled.
902    35. Improve JIT code generation for greedy plus quantifier.
904    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
905        1 to "aa" instead of to an empty string. The bug affected repeated groups
906        that could potentially match an empty string.
908    37. Optimizing single character iterators in JIT.
910    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
911        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
912        codepoints that are too big for the mode are faulted, and in a UTF mode,
913        disallowed codepoints are also faulted.
915    39. If PCRE was compiled with UTF support, in three places in the DFA
916        matcher there was code that should only have been obeyed in UTF mode, but
917        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
918        processing when bytes with values greater than 127 were present. In 16-bit
919        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
920        both cases the values are those that cannot be the first data item in a UTF
921        character. The three items that might have provoked this were recursions,
922        possessively repeated groups, and atomic groups.
924    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
925        and pcregrep, because some OS require shared objects to be explicitly
926        passed to ld, causing the link step to fail if they are not.
928    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
929        mode, patterns that started with \h* or \R* might be incorrectly matched.
932    Version 8.30 04-February-2012
933    -----------------------------
935    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
936        name is defined in ctype.h.
938    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
939        only in quite long subpatterns.
941    3.  Removed the function pcre_info(), which has been obsolete and deprecated
942        since it was replaced by pcre_fullinfo() in February 2000.
944    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
945        match a (*MARK), and the match failed at the start of the subject, a
946        reference to memory before the start of the subject could occur. This bug
947        was introduced by fix 17 of release 8.21.
949    5.  A reference to an unset group with zero minimum repetition was giving
950        totally wrong answers (in non-JavaScript-compatibility mode). For example,
951        /(another)?(\1?)test/ matched against "hello world test". This bug was
952        introduced in release 8.13.
954    6.  Add support for 16-bit character strings (a large amount of work involving
955        many changes and refactorings).
957    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
958        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
959        from a file.
961    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
962        rounding is not applied in this particular case).
964    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
965        if they appear, or are escaped, in patterns.
967    10. Get rid of a number of -Wunused-but-set-variable warnings.
969    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
970        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
971        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
972        also returns the mark "x". This bug applied to capturing parentheses,
973        non-capturing parentheses, and atomic parentheses. It also applied to some
974        assertions.
976    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
977        information out of configure.ac instead of relying on pcre.h.generic, which
978        is not stored in the repository.
980    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
981        -lreadline.
983    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
985    15. Applied Graycode's patch to put the top-level frame on the stack rather
986        than the heap when not using the stack for recursion. This gives a
987        performance improvement in many cases when recursion is not deep.
989    16. Experimental code added to "pcretest -C" to output the stack frame size.
992    Version 8.21 12-Dec-2011
993    ------------------------
995    1.  Updating the JIT compiler.
997    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
998        are added as well.
1000    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1001        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1002        calling _pcre_jit_exec. Some extra comments are added.
1004    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1005        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1006        was introduced by change 18 for 8.20.
1008    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1009        ECMA-262 standard.
1011    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1012        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1013        This bug was probably introduced by change 9 of 8.13.
1015    7.  While fixing 6 above, I noticed that a number of other items were being
1016        incorrectly rejected as "not fixed length". This arose partly because newer
1017        opcodes had not been added to the fixed-length checking code. I have (a)
1018        corrected the bug and added tests for these items, and (b) arranged for an
1019        error to occur if an unknown opcode is encountered while checking for fixed
1020        length instead of just assuming "not fixed length". The items that were
1021        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1022        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1023        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1025    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1026        being incorrectly compiled and would have given unpredicatble results.
1028    9.  A possessively repeated subpattern with minimum repeat count greater than
1029        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1030        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1031        the first (A) could occur when it should not.
1033    10. Add a cast and remove a redundant test from the code.
1035    11. JIT should use pcre_malloc/pcre_free for allocation.
1037    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1038        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1039        is anything other than /usr, -L is still shown).
1041    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1043    14. Perl does not support \N without a following name in a [] class; PCRE now
1044        also gives an error.
1046    15. If a forward reference was repeated with an upper limit of around 2000,
1047        it caused the error "internal error: overran compiling workspace". The
1048        maximum number of forward references (including repeats) was limited by the
1049        internal workspace, and dependent on the LINK_SIZE. The code has been
1050        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1051        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1052        of around 200,000 forward references. While doing this, I also speeded up
1053        the filling in of repeated forward references.
1055    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1056        incorrectly expecting the subject to contain another "a" after the start.
1058    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1059        in the match, the SKIP should be ignored. This was not happening; instead
1060        the SKIP was being treated as NOMATCH. For patterns such as
1061        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1062        tested.
1064    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1065        now much more compatible with Perl, in particular in cases where the result
1066        is a non-match for a non-anchored pattern. For example, if
1067        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1068        "m", where previously it did not return a name. A side effect of this
1069        change is that for partial matches, the last encountered mark name is
1070        returned, as for non matches. A number of tests that were previously not
1071        Perl-compatible have been moved into the Perl-compatible test files. The
1072        refactoring has had the pleasing side effect of removing one argument from
1073        the match() function, thus reducing its stack requirements.
1075    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1076        subsequent uses of /S (without +) incorrectly behaved like /S+.
1078    21. Retrieve executable code size support for the JIT compiler and fixing
1079        some warnings.
1081    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1082        not work when the shorter character appeared right at the end of the
1083        subject string.
1085    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1086        systems.
1088    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1089        output it when the /M option is used in pcretest.
1091    25. The CheckMan script was not being included in the distribution. Also, added
1092        an explicit "perl" to run Perl scripts from the PrepareRelease script
1093        because this is reportedly needed in Windows.
1095    26. If study data was being save in a file and studying had not found a set of
1096        "starts with" bytes for the pattern, the data written to the file (though
1097        never used) was taken from uninitialized memory and so caused valgrind to
1098        complain.
1100    27. Updated RunTest.bat as provided by Sheri Pierce.
1102    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1104    29. Computation of memory usage for the table of capturing group names was
1105        giving an unnecessarily large value.
1108    Version 8.20 21-Oct-2011
1109    ------------------------
1111    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1112        a POSIX class. After further experiments with Perl, which convinced me that
1113        Perl has bugs and confusions, a closing square bracket is no longer allowed
1114        in a POSIX name. This bug also affected patterns with classes that started
1115        with full stops.
1117    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1118        captured substring, but while checking the failing first alternative,
1119        substring 1 is temporarily captured. If the output vector supplied to
1120        pcre_exec() was not big enough for this capture, the yield of the function
1121        was still zero ("insufficient space for captured substrings"). This cannot
1122        be totally fixed without adding another stack variable, which seems a lot
1123        of expense for a edge case. However, I have improved the situation in cases
1124        such as /(a)(b)x|abc/ matched against "abc", where the return code
1125        indicates that fewer than the maximum number of slots in the ovector have
1126        been set.
1128    3.  Related to (2) above: when there are more back references in a pattern than
1129        slots in the output vector, pcre_exec() uses temporary memory during
1130        matching, and copies in the captures as far as possible afterwards. It was
1131        using the entire output vector, but this conflicts with the specification
1132        that only 2/3 is used for passing back captured substrings. Now it uses
1133        only the first 2/3, for compatibility. This is, of course, another edge
1134        case.
1136    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1137        main code base, and can be used by building with --enable-jit. When this is
1138        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1139        runtime --no-jit option is given.
1141    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1142        ovector, the return from the function was zero, implying that there were
1143        other matches that did not fit. The correct "exactly full" value is now
1144        returned.
1146    6.  If a subpattern that was called recursively or as a subroutine contained
1147        (*PRUNE) or any other control that caused it to give a non-standard return,
1148        invalid errors such as "Error -26 (nested recursion at the same subject
1149        position)" or even infinite loops could occur.
1151    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1152        computing the minimum length on reaching *ACCEPT, and so ended up with the
1153        wrong value of 1 rather than 0. Further investigation indicates that
1154        computing a minimum subject length in the presence of *ACCEPT is difficult
1155        (think back references, subroutine calls), and so I have changed the code
1156        so that no minimum is registered for a pattern that contains *ACCEPT.
1158    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1159        it was not handled as intended. [But see 16 below.]
1161    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1162        Sheri Pierce.
1164    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1165        the first byte in a match must be "a".
1167    11. Change 17 for 8.13 increased the recursion depth for patterns like
1168        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1169        pattern contains any instances of (*THEN). If it does not, the old
1170        optimizations are restored. It would be nice to do this on a per-group
1171        basis, but at the moment that is not feasible.
1173    12. In some environments, the output of pcretest -C is CRLF terminated. This
1174        broke RunTest's code that checks for the link size. A single white space
1175        character after the value is now allowed for.
1177    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1178        For "fr", it uses the Windows-specific input and output files.
1180    14. If (*THEN) appeared in a group that was called recursively or as a
1181        subroutine, it did not work as intended. [But see next item.]
1183    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1184        pattern fragments (but not containing any | characters). If A and B are
1185        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1186        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1187        D. In other words, Perl considers parentheses that do not contain any |
1188        characters to be part of a surrounding alternative, whereas PCRE was
1189        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1190        differently. PCRE now behaves in the same way as Perl, except in the case
1191        of subroutine/recursion calls such as (?1) which have in any case always
1192        been different (but PCRE had them first :-).
1194    16. Related to 15 above: Perl does not treat the | in a conditional group as
1195        creating alternatives. Such a group is treated in the same way as an
1196        ordinary group without any | characters when processing (*THEN). PCRE has
1197        been changed to match Perl's behaviour.
1199    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1200        RunGrepTest script failed.
1202    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1203        inevitable for groups that contain captures, but it can lead to a lot of
1204        stack use in large patterns. The old behaviour has been restored for atomic
1205        groups that do not contain any capturing parentheses.
1207    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1208        suppress the check for a minimum subject length at run time. (If it was
1209        given to pcre_exec() or pcre_dfa_exec() it did work.)
1211    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1212        fail to work when decoding hex characters in data strings in EBCDIC
1213        environments.
1215    21. It appears that in at least one Mac OS environment, the isxdigit() function
1216        is implemented as a macro that evaluates to its argument more than once,
1217        contravening the C 90 Standard (I haven't checked a later standard). There
1218        was an instance in pcretest which caused it to go wrong when processing
1219        \x{...} escapes in subject strings. The has been rewritten to avoid using
1220        things like p++ in the argument of isxdigit().
1223    Version 8.13 16-Aug-2011
1224  ------------------------  ------------------------
1226  1.  The Unicode data tables have been updated to Unicode 6.0.0.  1.  The Unicode data tables have been updated to Unicode 6.0.0.
# Line 20  Version 8.13 30-Apr-2011 Line 1239  Version 8.13 30-Apr-2011
1239      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1240      2-byte code at the end of the subject (it thought there wasn't enough data      2-byte code at the end of the subject (it thought there wasn't enough data
1241      left).      left).
1243  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
1244      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1245      as the output vector has at least 2 elements. The offset of the start of      as the output vector has at least 2 elements. The offset of the start of
1246      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
1248  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1249      now returned is for the first byte of the failing character, instead of the      now returned is for the first byte of the failing character, instead of the
1250      last byte inspected. This is an incompatible change, but I hope it is small      last byte inspected. This is an incompatible change, but I hope it is small
1251      enough not to be a problem. It makes the returned offset consistent with      enough not to be a problem. It makes the returned offset consistent with
1252      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
1254  7.  pcretest now gives a text phrase as well as the error number when  7.  pcretest now gives a text phrase as well as the error number when
1255      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1256      failure, the offset and reason code are output.      failure, the offset and reason code are output.
1258  8.  When \R was used with a maximizing quantifier it failed to skip backwards  8.  When \R was used with a maximizing quantifier it failed to skip backwards
1259      over a \r\n pair if the subsequent match failed. Instead, it just skipped      over a \r\n pair if the subsequent match failed. Instead, it just skipped
1260      back over a single character (\n). This seems wrong (because it treated the      back over a single character (\n). This seems wrong (because it treated the
1261      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
1262      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1263      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1264      has been changed.      has been changed.
1266    9.  Some internal refactoring has changed the processing so that the handling
1267        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1268        time (the PCRE_DOTALL option was changed this way some time ago: version
1269        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1270        which was always a bit of a fudge. It also means that there is one less
1271        argument for the match() function, which reduces its stack requirements
1272        slightly. This change also fixes an incompatibility with Perl: the pattern
1273        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1275    10. More internal refactoring has drastically reduced the number of recursive
1276        calls to match() for possessively repeated groups such as (abc)++ when
1277        using pcre_exec().
1279    11. While implementing 10, a number of bugs in the handling of groups were
1280        discovered and fixed:
1282        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1283        (a|)*(?1) gave a compile-time internal error.
1284        ((a|)+)+  did not notice that the outer group could match an empty string.
1285        (^a|^)+   was not marked as anchored.
1286        (.*a|.*)+ was not marked as matching at start or after a newline.
1288    12. Yet more internal refactoring has removed another argument from the match()
1289        function. Special calls to this function are now indicated by setting a
1290        value in a variable in the "match data" data block.
1292    13. Be more explicit in pcre_study() instead of relying on "default" for
1293        opcodes that mean there is no starting character; this means that when new
1294        ones are added and accidentally left out of pcre_study(), testing should
1295        pick them up.
1297    14. The -s option of pcretest has been documented for ages as being an old
1298        synonym of -m (show memory usage). I have changed it to mean "force study
1299        for every regex", that is, assume /S for every regex. This is similar to -i
1300        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1301        using it. It makes it easier to run collections of tests with and without
1302        study enabled, and thereby test pcre_study() more easily. All the standard
1303        tests are now run with and without -s (but some patterns can be marked as
1304        "never study" - see 20 below).
1306    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1307        restoration of the capturing data to the outer values was not happening
1308        correctly.
1310    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1311        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1312        pattern had matched an empty string, and so incorrectly returned a no
1313        match.
1315    17. There was optimizing code for the last branch of non-capturing parentheses,
1316        and also for the obeyed branch of a conditional subexpression, which used
1317        tail recursion to cut down on stack usage. Unfortunately, now that there is
1318        the possibility of (*THEN) occurring in these branches, tail recursion is
1319        no longer possible because the return has to be checked for (*THEN). These
1320        two optimizations have therefore been removed. [But see 8.20/11 above.]
1322    18. If a pattern containing \R was studied, it was assumed that \R always
1323        matched two bytes, thus causing the minimum subject length to be
1324        incorrectly computed because \R can also match just one byte.
1326    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1327        was incorrectly computed.
1329    20. If /S is present twice on a test pattern in pcretest input, it now
1330        *disables* studying, thereby overriding the use of -s on the command line
1331        (see 14 above). This is necessary for one or two tests to keep the output
1332        identical in both cases.
1334    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1335        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1337    22. When an atomic group that contained a capturing parenthesis was
1338        successfully matched, but the branch in which it appeared failed, the
1339        capturing was not being forgotten if a higher numbered group was later
1340        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1341        group 1 to "a", when in fact it should be unset. This applied to multi-
1342        branched capturing and non-capturing groups, repeated or not, and also to
1343        positive assertions (capturing in negative assertions does not happen
1344        in PCRE) and also to nested atomic groups.
1346    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1347        subject after a captured substring, to make it easier to tell which of a
1348        number of identical substrings has been captured.
1350    24. The way atomic groups are processed by pcre_exec() has been changed so that
1351        if they are repeated, backtracking one repetition now resets captured
1352        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1353        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1354        "aaa". Previously, it would have been "a". As part of this code
1355        refactoring, the way recursive calls are handled has also been changed.
1357    25. If an assertion condition captured any substrings, they were not passed
1358        back unless some other capturing happened later. For example, if
1359        (?(?=(a))a) was matched against "a", no capturing was returned.
1361    26. When studying a pattern that contained subroutine calls or assertions,
1362        the code for finding the minimum length of a possible match was handling
1363        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1364        group 1 called group 2 while simultaneously a separate group 2 called group
1365        1). A stack overflow occurred in this case. I have fixed this by limiting
1366        the recursion depth to 10.
1368    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1369        Fortmann. This supports explicit test numbers on the command line, and has
1370        argument validation and error reporting.
1372    28. An instance of \X with an unlimited repeat could fail if at any point the
1373        first character it looked at was a mark character.
1375    29. Some minor code refactoring concerning Unicode properties and scripts
1376        should reduce the stack requirement of match() slightly.
1378    30. Added the '=' option to pcretest to check the setting of unused capturing
1379        slots at the end of the pattern, which are documented as being -1, but are
1380        not included in the return count.
1382    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1383        compiled something random. Now it gives a compile-time error (as does
1384        Perl).
1386    32. A *MARK encountered during the processing of a positive assertion is now
1387        recorded and passed back (compatible with Perl).
1389    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1390        had alternative anchored branches, the search for a second match in a line
1391        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1392        matched the line "0102" twice. The same bug affected patterns that started
1393        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1394        twice.
1396    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1397        does, and because of capturing effects, quantifying parenthesized
1398        assertions may at times be useful. Quantifiers are now allowed for
1399        parenthesized assertions.
1401    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1403    36. \g was being checked for fancy things in a character class, when it should
1404        just be a literal "g".
1406    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1407        appearance of a nested POSIX class supersedes an apparent external class.
1408        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1409        unescaped square brackets may also appear as part of class names. For
1410        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1411        more like Perl. (But see 8.20/1 above.)
1413    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1414        was because it thought it was \N{name}, which is not supported).
1416    39. Add minix to OS list not supporting the -S option in pcretest.
1418    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1419        cannot analyze patterns in sufficient detail to catch mutual recursions
1420        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1421        subgroup is called recursively as a subpattern for a second time at the
1422        same position in the subject string. In previous releases this might have
1423        been caught by the recursion limit, or it might have run out of stack.
1425    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1426        happen only once. PCRE was, however incorrectly giving a compile time error
1427        "recursive call could loop indefinitely" because it cannot analyze the
1428        pattern in sufficient detail. The compile time test no longer happens when
1429        PCRE is compiling a conditional subpattern, but actual runaway loops are
1430        now caught at runtime (see 40 above).
1432    42. It seems that Perl allows any characters other than a closing parenthesis
1433        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1434        has been changed to be the same.
1436    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1437        as not to get warnings when autogen.sh is called. Also changed
1438        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1440    44. To help people who use pcregrep to scan files containing exceedingly long
1441        lines, the following changes have been made:
1443        (a) The default value of the buffer size parameter has been increased from
1444            8K to 20K. (The actual buffer used is three times this size.)
1446        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1447            PCRE is built.
1449        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1450            to be set at run time.
1452        (d) Numerical values in pcregrep options can be followed by K or M, for
1453            example --buffer-size=50K.
1455        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1456            given and the return code is set to 2.
1458    45. Add a pointer to the latest mark to the callout data block.
1460    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1461        partial match of an empty string instead of no match. This was specific to
1462        the use of ".".
1464    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1465        complete match instead of a partial match. This bug was dependent on both
1466        the PCRE_UTF8 and PCRE_DOTALL options being set.
1468    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1469        starting byte set, because \b was not being ignored.
1472  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
1473  ------------------------  ------------------------
# Line 695  Version 7.9 11-Apr-09 Line 2119  Version 7.9 11-Apr-09
2119  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
2120      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
2121      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2122      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2123        8.33.]
2125  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
2126      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 938  Version 7.7 07-May-08 Line 2363  Version 7.7 07-May-08
2363      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2364      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2365      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2366      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2367      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2368      was subsequently set up correctly.)      was subsequently set up correctly.)

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