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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.13 30-Apr-2011  Version 8.37 xx-xxx-2015
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.
20    4.  An attempt to do global matching in pcretest with a zero-length ovector
21        caused a crash.
23    5.  Fixed a memory leak during matching that could occur for a subpattern
24        subroutine call (recursive or otherwise) if the number of captured groups
25        that had to be saved was greater than ten.
27    6.  Catch a bad opcode during auto-possessification after compiling a bad UTF
28        string with NO_UTF_CHECK. This is a tidyup, not a bug fix, as passing bad
29        UTF with NO_UTF_CHECK is documented as having an undefined outcome.
31    7.  A UTF pattern containing a "not" match of a non-ASCII character and a
32        subroutine reference could loop at compile time. Example: /[^\xff]((?1))/.
34    8. When a pattern is compiled, it remembers the highest back reference so that
35       when matching, if the ovector is too small, extra memory can be obtained to
36       use instead. A conditional subpattern whose condition is a check on a
37       capture having happened, such as, for example in the pattern
38       /^(?:(a)|b)(?(1)A|B)/, is another kind of back reference, but it was not
39       setting the highest backreference number. This mattered only if pcre_exec()
40       was called with an ovector that was too small to hold the capture, and there
41       was no other kind of back reference (a situation which is probably quite
42       rare). The effect of the bug was that the condition was always treated as
43       FALSE when the capture could not be consulted, leading to a incorrect
44       behaviour by pcre2_match(). This bug has been fixed.
46    9. A reference to a duplicated named group (either a back reference or a test
47       for being set in a conditional) that occurred in a part of the pattern where
48       PCRE_DUPNAMES was not set caused the amount of memory needed for the pattern
49       to be incorrectly calculated, leading to overwriting.
51    10. A mutually recursive set of back references such as (\2)(\1) caused a
52        segfault at study time (while trying to find the minimum matching length).
53        The infinite loop is now broken (with the minimum length unset, that is,
54        zero).
56    11. If an assertion that was used as a condition was quantified with a minimum
57        of zero, matching went wrong. In particular, if the whole group had
58        unlimited repetition and could match an empty string, a segfault was
59        likely. The pattern (?(?=0)?)+ is an example that caused this. Perl allows
60        assertions to be quantified, but not if they are being used as conditions,
61        so the above pattern is faulted by Perl. PCRE has now been changed so that
62        it also rejects such patterns.
64    12. A possessive capturing group such as (a)*+ with a minimum repeat of zero
65        failed to allow the zero-repeat case if pcre2_exec() was called with an
66        ovector too small to capture the group.
68    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
69        Red Hat Product Security:
71        (a) A crash if /K and /F were both set with the option to save the compiled
72        pattern.
74        (b) Another crash if the option to print captured substrings in a callout
75        was combined with setting a null ovector, for example \O\C+ as a subject
76        string.
78    14. A pattern such as "((?2){0,1999}())?", which has a group containing a
79        forward reference repeated a large (but limited) number of times within a
80        repeated outer group that has a zero minimum quantifier, caused incorrect
81        code to be compiled, leading to the error "internal error:
82        previously-checked referenced subpattern not found" when an incorrect
83        memory address was read. This bug was reported as "heap overflow",
84        discovered by Kai Lu of Fortinet's FortiGuard Labs.
86    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
87        call within a group that also contained a recursive back reference caused
88        incorrect code to be compiled. This bug was reported as "heap overflow",
89        discovered by Kai Lu of Fortinet's FortiGuard Labs.
92    Version 8.36 26-September-2014
93    ------------------------------
95    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
96        -Wmissing-field-initializers and -Wunused-parameter.
98    2.  The tests for quantifiers being too big (greater than 65535) were being
99        applied after reading the number, and stupidly assuming that integer
100        overflow would give a negative number. The tests are now applied as the
101        numbers are read.
103    3.  Tidy code in pcre_exec.c where two branches that used to be different are
104        now the same.
106    4.  The JIT compiler did not generate match limit checks for certain
107        bracketed expressions with quantifiers. This may lead to exponential
108        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
109        issue should be resolved now.
111    5.  Fixed an issue, which occures when nested alternatives are optimized
112        with table jumps.
114    6.  Inserted two casts and changed some ints to size_t in the light of some
115        reported 64-bit compiler warnings (Bugzilla 1477).
117    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
118        an empty string, which sometimes were behaving incorrectly in the
119        interpreter (though correctly in the JIT matcher). This pcretest input is
120        an example:
122          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
125        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
126        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
127        for an empty string was breaking the inner loop and carrying on at a lower
128        level, when possessive repeated groups should always return to a higher
129        level as they have no backtrack points in them. The empty string test now
130        occurs at the outer level.
132    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
133        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
135    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
136        doesn't).
138    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
139        to hold a pattern to be incorrectly computed (too small) when there were
140        named back references to duplicated names. This could cause "internal
141        error: code overflow" or "double free or corruption" or other memory
142        handling errors.
144    11. When named subpatterns had the same prefixes, back references could be
145        confused. For example, in this pattern:
147          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
149        the reference to 'Name' was incorrectly treated as a reference to a
150        duplicate name.
152    12. A pattern such as /^s?c/mi8 where the optional character has more than
153        one "other case" was incorrectly compiled such that it would only try to
154        match starting at "c".
156    13. When a pattern starting with \s was studied, VT was not included in the
157        list of possible starting characters; this should have been part of the
158        8.34/18 patch.
160    14. If a character class started [\Qx]... where x is any character, the class
161        was incorrectly terminated at the ].
163    15. If a pattern that started with a caseless match for a character with more
164        than one "other case" was studied, PCRE did not set up the starting code
165        unit bit map for the list of possible characters. Now it does. This is an
166        optimization improvement, not a bug fix.
168    16. The Unicode data tables have been updated to Unicode 7.0.0.
170    17. Fixed a number of memory leaks in pcregrep.
172    18. Avoid a compiler warning (from some compilers) for a function call with
173        a cast that removes "const" from an lvalue by using an intermediate
174        variable (to which the compiler does not object).
176    19. Incorrect code was compiled if a group that contained an internal recursive
177        back reference was optional (had quantifier with a minimum of zero). This
178        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
179        caused segmentation faults because of stack overflows at compile time.
181    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
182        group that is quantified with an indefinite repeat, caused a compile-time
183        loop which used up all the system stack and provoked a segmentation fault.
184        This was not the same bug as 19 above.
186    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
187        Patch by Mike Frysinger.
190    Version 8.35 04-April-2014
191    --------------------------
193    1.  A new flag is set, when property checks are present in an XCLASS.
194        When this flag is not set, PCRE can perform certain optimizations
195        such as studying these XCLASS-es.
197    2.  The auto-possessification of character sets were improved: a normal
198        and an extended character set can be compared now. Furthermore
199        the JIT compiler optimizes more character set checks.
201    3.  Got rid of some compiler warnings for potentially uninitialized variables
202        that show up only when compiled with -O2.
204    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
205        of a match later then the end of the match. The pcretest program was not
206        handling the case sensibly - it was outputting from the start to the next
207        binary zero. It now reports this situation in a message, and outputs the
208        text from the end to the start.
210    5.  Fast forward search is improved in JIT. Instead of the first three
211        characters, any three characters with fixed position can be searched.
212        Search order: first, last, middle.
214    6.  Improve character range checks in JIT. Characters are read by an inprecise
215        function now, which returns with an unknown value if the character code is
216        above a certain threshold (e.g: 256). The only limitation is that the value
217        must be bigger than the threshold as well. This function is useful when
218        the characters above the threshold are handled in the same way.
220    7.  The macros whose names start with RAWUCHAR are placeholders for a future
221        mode in which only the bottom 21 bits of 32-bit data items are used. To
222        make this more memorable for those maintaining the code, the names have
223        been changed to start with UCHAR21, and an extensive comment has been added
224        to their definition.
226    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
227        to the export list in Makefile.am (they were accidentally omitted from the
228        8.34 tarball).
230    9.  The informational output from pcretest used the phrase "starting byte set"
231        which is inappropriate for the 16-bit and 32-bit libraries. As the output
232        for "first char" and "need char" really means "non-UTF-char", I've changed
233        "byte" to "char", and slightly reworded the output. The documentation about
234        these values has also been (I hope) clarified.
236    10. Another JIT related optimization: use table jumps for selecting the correct
237        backtracking path, when more than four alternatives are present inside a
238        bracket.
240    11. Empty match is not possible, when the minimum length is greater than zero,
241        and there is no \K in the pattern. JIT should avoid empty match checks in
242        such cases.
244    12. In a caseless character class with UCP support, when a character with more
245        than one alternative case was not the first character of a range, not all
246        the alternative cases were added to the class. For example, s and \x{17f}
247        are both alternative cases for S: the class [RST] was handled correctly,
248        but [R-T] was not.
250    13. The configure.ac file always checked for pthread support when JIT was
251        enabled. This is not used in Windows, so I have put this test inside a
252        check for the presence of windows.h (which was already tested for).
254    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
255        The algorithm provides a way to skip certain starting offsets, and usually
256        faster than linear prefix searches.
258    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
259        as for 'fr_FR' and 'french'. For some reason, however, it then used the
260        Windows-specific input and output files, which have 'french' screwed in.
261        So this could never have worked. One of the problems with locales is that
262        they aren't always the same. I have now updated RunTest so that it checks
263        the output of the locale test (test 3) against three different output
264        files, and it allows the test to pass if any one of them matches. With luck
265        this should make the test pass on some versions of Solaris where it was
266        failing. Because of the uncertainty, the script did not used to stop if
267        test 3 failed; it now does. If further versions of a French locale ever
268        come to light, they can now easily be added.
270    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
271        there was a message during ./configure, but it did not stop. This now
272        provokes an error. The invalid example in README has been corrected.
273        If a value less than the minimum is given, the minimum value has always
274        been used, but now a warning is given.
276    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
277        was a bug in the test system, which is now fixed. Also, the list of various
278        configurations that are tested for each release did not have one with both
279        16/32 bits and --enable-bar-anycrlf. It now does.
281    18. pcretest was missing "-C bsr" for displaying the \R default setting.
283    19. Little endian PowerPC systems are supported now by the JIT compiler.
285    20. The fast forward newline mechanism could enter to an infinite loop on
286        certain invalid UTF-8 input. Although we don't support these cases
287        this issue can be fixed by a performance optimization.
289    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
290        not take account if existing stack usage. There is now a new global
291        variable called pcre_stack_guard that can be set to point to an external
292        function to check stack availability. It is called at the start of
293        processing every parenthesized group.
295    22. A typo in the code meant that in ungreedy mode the max/min qualifier
296        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
297        not match "ab".
299    23. When UTF was disabled, the JIT program reported some incorrect compile
300        errors. These messages are silenced now.
302    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
303        compiler.
305    25. Change all the temporary files used in RunGrepTest to be different to those
306        used by RunTest so that the tests can be run simultaneously, for example by
307        "make -j check".
310    Version 8.34 15-December-2013
311    -----------------------------
313    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
314        executable memory. Patch inspired by Carsten Klein.
316    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
317        this macro is never tested and has no effect, because the work to support
318        coverage involves only compiling and linking options and special targets in
319        the Makefile. The comment in config.h implied that defining the macro would
320        enable coverage support, which is totally false. There was also support for
321        setting this macro in the CMake files (my fault, I just copied it from
322        configure). SUPPORT_GCOV has now been removed.
324    3.  Make a small performance improvement in strlen16() and strlen32() in
325        pcretest.
327    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
328        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
329        these cases). There was also one in pcretest.c.
331    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
333    6.  In UTF mode, the code for checking whether a group could match an empty
334        string (which is used for indefinitely repeated groups to allow for
335        breaking an infinite loop) was broken when the group contained a repeated
336        negated single-character class with a character that occupied more than one
337        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
338        UTF-8 mode). The effect was undefined: the group might or might not be
339        deemed as matching an empty string, or the program might have crashed.
341    7.  The code for checking whether a group could match an empty string was not
342        recognizing that \h, \H, \v, \V, and \R must match a character.
344    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
345        an empty string. If it can, pcretest shows this in its information output.
347    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
348        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
349        matched by pcre_exec() without using JIT:
351        (a) If the rest of the pattern did not match after a maximal run of
352            grapheme clusters, the code for backing up to try with fewer of them
353            did not always back up over a full grapheme when characters that do not
354            have the modifier quality were involved, e.g. Hangul syllables.
356        (b) If the match point in a subject started with modifier character, and
357            there was no match, the code could incorrectly back up beyond the match
358            point, and potentially beyond the first character in the subject,
359            leading to a segfault or an incorrect match result.
361    10. A conditional group with an assertion condition could lead to PCRE
362        recording an incorrect first data item for a match if no other first data
363        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
364        first data item, and therefore matched "ca" after "c" instead of at the
365        start.
367    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
368        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
370    12. The source of pcregrep now includes z/OS-specific code so that it can be
371        compiled for z/OS as part of the special z/OS distribution.
373    13. Added the -T and -TM options to pcretest.
375    14. The code in pcre_compile.c for creating the table of named capturing groups
376        has been refactored. Instead of creating the table dynamically during the
377        actual compiling pass, the information is remembered during the pre-compile
378        pass (on the stack unless there are more than 20 named groups, in which
379        case malloc() is used) and the whole table is created before the actual
380        compile happens. This has simplified the code (it is now nearly 150 lines
381        shorter) and prepared the way for better handling of references to groups
382        with duplicate names.
384    15. A back reference to a named subpattern when there is more than one of the
385        same name now checks them in the order in which they appear in the pattern.
386        The first one that is set is used for the reference. Previously only the
387        first one was inspected. This change makes PCRE more compatible with Perl.
389    16. Unicode character properties were updated from Unicode 6.3.0.
391    17. The compile-time code for auto-possessification has been refactored, based
392        on a patch by Zoltan Herczeg. It now happens after instead of during
393        compilation. The code is cleaner, and more cases are handled. The option
394        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
395        options in pcretest are provided to set it. It can also be set by
396        (*NO_AUTO_POSSESS) at the start of a pattern.
398    18. The character VT has been added to the default ("C" locale) set of
399        characters that match \s and are generally treated as white space,
400        following this same change in Perl 5.18. There is now no difference between
401        "Perl space" and "POSIX space". Whether VT is treated as white space in
402        other locales depends on the locale.
404    19. The code for checking named groups as conditions, either for being set or
405        for being recursed, has been refactored (this is related to 14 and 15
406        above). Processing unduplicated named groups should now be as fast at
407        numerical groups, and processing duplicated groups should be faster than
408        before.
410    20. Two patches to the CMake build system, by Alexander Barkov:
412          (1) Replace the "source" command by "." in CMakeLists.txt because
413              "source" is a bash-ism.
415          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
416              without these the CMake build does not work on Solaris.
418    21. Perl has changed its handling of \8 and \9. If there is no previously
419        encountered capturing group of those numbers, they are treated as the
420        literal characters 8 and 9 instead of a binary zero followed by the
421        literals. PCRE now does the same.
423    22. Following Perl, added \o{} to specify codepoints in octal, making it
424        possible to specify values greater than 0777 and also making them
425        unambiguous.
427    23. Perl now gives an error for missing closing braces after \x{... instead of
428        treating the string as literal. PCRE now does the same.
430    24. RunTest used to grumble if an inappropriate test was selected explicitly,
431        but just skip it when running all tests. This make it awkward to run ranges
432        of tests when one of them was inappropriate. Now it just skips any
433        inappropriate tests, as it always did when running all tests.
435    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
436        character types such as \d or \w, too many callouts were inserted, and the
437        data that they returned was rubbish.
439    26. In UCP mode, \s was not matching two of the characters that Perl matches,
440        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
441        were matched by \h. The code has now been refactored so that the lists of
442        the horizontal and vertical whitespace characters used for \h and \v (which
443        are defined only in one place) are now also used for \s.
445    27. Add JIT support for the 64 bit TileGX architecture.
446        Patch by Jiong Wang (Tilera Corporation).
448    28. Possessive quantifiers for classes (both explicit and automatically
449        generated) now use special opcodes instead of wrapping in ONCE brackets.
451    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
452        (because it's meaningless), this was not happening when PCRE_CASELESS was
453        set. Not wrong, but inefficient.
455    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
456        properties for \w, \d, etc) is present in a test regex. Otherwise if the
457        test contains no characters greater than 255, Perl doesn't realise it
458        should be using Unicode semantics.
460    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
461        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
462        does in Unicode mode.
464    32. Added the "forbid" facility to pcretest so that putting tests into the
465        wrong test files can sometimes be quickly detected.
467    33. There is now a limit (default 250) on the depth of nesting of parentheses.
468        This limit is imposed to control the amount of system stack used at compile
469        time. It can be changed at build time by --with-parens-nest-limit=xxx or
470        the equivalent in CMake.
472    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
473        errors. Perl warns for these when in warning mode, but PCRE has no facility
474        for giving warnings.
476    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
477        However, this was not working for (?!) because it is optimized to (*FAIL),
478        for which PCRE does not allow quantifiers. The optimization is now disabled
479        when a quantifier follows (?!). I can't see any use for this, but it makes
480        things uniform.
482    36. Perl no longer allows group names to start with digits, so I have made this
483        change also in PCRE. It simplifies the code a bit.
485    37. In extended mode, Perl ignores spaces before a + that indicates a
486        possessive quantifier. PCRE allowed a space before the quantifier, but not
487        before the possessive +. It now does.
489    38. The use of \K (reset reported match start) within a repeated possessive
490        group such as (a\Kb)*+ was not working.
492    40. Document that the same character tables must be used at compile time and
493        run time, and that the facility to pass tables to pcre_exec() and
494        pcre_dfa_exec() is for use only with saved/restored patterns.
496    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
497        features for Builds with MSVC:
499        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
500           builds). The .rc files can be used to set FileDescription and many other
501           attributes.
503        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
504           This allows higher-level build scripts which want .pdb files to avoid
505           hard-coding the exact files needed."
507    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
508        mean "start of word" and "end of word", respectively, as a transition aid.
510    43. A minimizing repeat of a class containing codepoints greater than 255 in
511        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
512        compiled to use the heap for recursion.
514    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
515        is configured.
518    Version 8.33 28-May-2013
519    ------------------------
521    1.  Added 'U' to some constants that are compared to unsigned integers, to
522        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
523        variables that are added to signed variables, to ensure the result is
524        signed and can be negated.
526    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
527        CMake config files.
529    3.  Revise the creation of config.h.generic so that all boolean macros are
530        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
531        overriding via -D on the command line possible.
533    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
534        to unsigned int is reported to make a quite noticeable speed difference in
535        a specific Windows environment. Testing on Linux did also appear to show
536        some benefit (and it is clearly not harmful). Also fixed the definition of
537        Xop which should be unsigned.
539    5.  Related to (4), changing the definition of the intermediate variable cc
540        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
541        improvements.
543    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
544        unnecessary spaces.
546    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
547        and later.
549    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
551    9.  Optimizing fast_forward_start_bits in JIT.
553    10. Adding support for callouts in JIT, and fixing some issues revealed
554        during this work. Namely:
556        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
558        (b) Minimum length was not checked before the matching is started.
560    11. The value of capture_last that is passed to callouts was incorrect in some
561        cases when there was a capture on one path that was subsequently abandoned
562        after a backtrack. Also, the capture_last value is now reset after a
563        recursion, since all captures are also reset in this case.
565    12. The interpreter no longer returns the "too many substrings" error in the
566        case when an overflowing capture is in a branch that is subsequently
567        abandoned after a backtrack.
569    13. In the pathological case when an offset vector of size 2 is used, pcretest
570        now prints out the matched string after a yield of 0 or 1.
572    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
573        Only supported by the JIT compiler at the moment.
575    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
577    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
578        offset of the starting point of the matching process, provided the offsets
579        vector is large enough.
581    17. The \A escape now records a lookbehind value of 1, though its execution
582        does not actually inspect the previous character. This is to ensure that,
583        in partial multi-segment matching, at least one character from the old
584        segment is retained when a new segment is processed. Otherwise, if there
585        are no lookbehinds in the pattern, \A might match incorrectly at the start
586        of a new segment.
588    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
590    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
591        gives some modest performance improvement in 8-bit mode.
593    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
594        be expressed in certain programming languages using Universal Character
595        Names.
597    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
598        which points out that "non characters" are not "characters that may not
599        appear in Unicode strings" but rather "characters that are reserved for
600        internal use and have only local meaning".
602    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
603        there was a conditional group that depended on an assertion, if the
604        assertion was false, the callout that immediately followed the alternation
605        in the condition was skipped when pcre_exec() was used for matching.
607    23. Allow an explicit callout to be inserted before an assertion that is the
608        condition for a conditional group, for compatibility with automatic
609        callouts, which always insert a callout at this point.
611    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
612        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
614    25. (*PRUNE) is now supported by the JIT compiler.
616    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
618    27. Fix the case where there are two or more SKIPs with arguments that may be
619        ignored.
621    28. (*SKIP) is now supported by the JIT compiler.
623    29. (*THEN) is now supported by the JIT compiler.
625    30. Update RunTest with additional test selector options.
627    31. The way PCRE handles backtracking verbs has been changed in two ways.
629        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
630        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
631        backtracking. In some cases this makes it more Perl-compatible, but Perl's
632        rather obscure rules do not always do the same thing.
634        (2) Previously, backtracking verbs were confined within assertions. This is
635        no longer the case for positive assertions, except for (*ACCEPT). Again,
636        this sometimes improves Perl compatibility, and sometimes does not.
638    32. A number of tests that were in test 2 because Perl did things differently
639        have been moved to test 1, because either Perl or PCRE has changed, and
640        these tests are now compatible.
642    32. Backtracking control verbs are now handled in the same way in JIT and
643        interpreter.
645    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
646        contained a forward subroutine reference caused a compile error.
648    34. Auto-detect and optimize limited repetitions in JIT.
650    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
651        blocking (*UTF) etc.
653    36. In the interpreter, maximizing pattern repetitions for characters and
654        character types now use tail recursion, which reduces stack usage.
656    37. The value of the max lookbehind was not correctly preserved if a compiled
657        and saved regex was reloaded on a host of different endianness.
659    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
660        of the compiled pattern block, expand the flags field from 16 to 32 bits
661        because it was almost full.
663    39. Try madvise first before posix_madvise.
665    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
666        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
667        original change locked out all matches of empty strings. This has been
668        changed so that one match of an empty string per line is recognized.
669        Subsequent searches on the same line (for colouring or for --only-matching,
670        for example) do not recognize empty strings.
672    41. Applied a user patch to fix a number of spelling mistakes in comments.
674    42. Data lines longer than 65536 caused pcretest to crash.
676    43. Clarified the data type for length and startoffset arguments for pcre_exec
677        and pcre_dfa_exec in the function-specific man pages, where they were
678        explicitly stated to be in bytes, never having been updated. I also added
679        some clarification to the pcreapi man page.
681    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
682        a segmentation fault.
685    Version 8.32 30-November-2012
686    -----------------------------
688    1.  Improved JIT compiler optimizations for first character search and single
689        character iterators.
691    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
692        Patch by Daniel Richard G.
694    3.  Single character iterator optimizations in the JIT compiler.
696    4.  Improved JIT compiler optimizations for character ranges.
698    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
699        Reported by Giuseppe D'Angelo.
701    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
702        of a line, was being set incorrectly in cases where .* appeared inside
703        atomic brackets at the start of a pattern, or where there was a subsequent
704        *PRUNE or *SKIP.
706    7.  Improved instruction cache flush for POWER/PowerPC.
707        Patch by Daniel Richard G.
709    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
710        grep:
712        (a) There is now no limit to the number of patterns to be matched.
714        (b) An error is given if a pattern is too long.
716        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
717            are now supported.
719        (d) --exclude-from and --include-from (multiple use) have been added.
721        (e) Exclusions and inclusions now apply to all files and directories, not
722            just to those obtained from scanning a directory recursively.
724        (f) Multiple uses of -f and --file-list are now supported.
726        (g) In a Windows environment, the default for -d has been changed from
727            "read" (the GNU grep default) to "skip", because otherwise the presence
728            of a directory in the file list provokes an error.
730        (h) The documentation has been revised and clarified in places.
732    9.  Improve the matching speed of capturing brackets.
734    10. Changed the meaning of \X so that it now matches a Unicode extended
735        grapheme cluster.
737    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
738        out POSIX threads when JIT support is configured.
740    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
742    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
743        structure could go wrong in environments where size_t is not the same size
744        as int.
746    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
747        set.
749    15. The EBCDIC support had decayed; later updates to the code had included
750        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
751        general tidy up of EBCDIC-related issues, and the documentation was also
752        not quite right. There is now a test that can be run on ASCII systems to
753        check some of the EBCDIC-related things (but is it not a full test).
755    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
756        in a small tidy to the code.
758    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
760    18. If the --only-matching (-o) option in pcregrep is specified multiple
761        times, each one causes appropriate output. For example, -o1 -o2 outputs the
762        substrings matched by the 1st and 2nd capturing parentheses. A separating
763        string can be specified by --om-separator (default empty).
765    19. Improving the first n character searches.
767    20. Turn case lists for horizontal and vertical white space into macros so that
768        they are defined only once.
770    21. This set of changes together give more compatible Unicode case-folding
771        behaviour for characters that have more than one other case when UCP
772        support is available.
774        (a) The Unicode property table now has offsets into a new table of sets of
775            three or more characters that are case-equivalent. The MultiStage2.py
776            script that generates these tables (the pcre_ucd.c file) now scans
777            CaseFolding.txt instead of UnicodeData.txt for character case
778            information.
780        (b) The code for adding characters or ranges of characters to a character
781            class has been abstracted into a generalized function that also handles
782            case-independence. In UTF-mode with UCP support, this uses the new data
783            to handle characters with more than one other case.
785        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
786            whose other case is greater than 256 are now correctly matched
787            caselessly. Previously, the high codepoint matched the low one, but not
788            vice versa.
790        (d) The processing of \h, \H, \v, and \ in character classes now makes use
791            of the new class addition function, using character lists defined as
792            macros alongside the case definitions of 20 above.
794        (e) Caseless back references now work with characters that have more than
795            one other case.
797        (f) General caseless matching of characters with more than one other case
798            is supported.
800    22. Unicode character properties were updated from Unicode 6.2.0
802    23. Improved CMake support under Windows. Patch by Daniel Richard G.
804    24. Add support for 32-bit character strings, and UTF-32
806    25. Major JIT compiler update (code refactoring and bugfixing).
807        Experimental Sparc 32 support is added.
809    26. Applied a modified version of Daniel Richard G's patch to create
810        pcre.h.generic and config.h.generic by "make" instead of in the
811        PrepareRelease script.
813    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
814        pcre_compile.c when checking for a zero character.
816    28. Introducing a native interface for JIT. Through this interface, the compiled
817        machine code can be directly executed. The purpose of this interface is to
818        provide fast pattern matching, so several sanity checks are not performed.
819        However, feature tests are still performed. The new interface provides
820        1.4x speedup compared to the old one.
822    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
823        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
824        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
826    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
827        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
828        the "old" RFC 2279). Instead, it ended up passing a negative length to
829        pcre_exec().
831    31. Add support for GCC's visibility feature to hide internal functions.
833    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
834        "unknown -C option" after outputting 0 or 1.
836    33. There is now support for generating a code coverage report for the test
837        suite in environments where gcc is the compiler and lcov is installed. This
838        is mainly for the benefit of the developers.
840    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
841        unaddressable using valgrind annotations, allowing valgrind to detect
842        invalid memory accesses. This is mainly for the benefit of the developers.
844    25. (*UTF) can now be used to start a pattern in any of the three libraries.
846    26. Give configure error if --enable-cpp but no C++ compiler found.
849    Version 8.31 06-July-2012
850    -------------------------
852    1.  Fixing a wrong JIT test case and some compiler warnings.
854    2.  Removed a bashism from the RunTest script.
856    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
857        to unsigned type, result still unsigned" that was given by an MS compiler
858        on encountering the code "-sizeof(xxx)".
860    4.  Partial matching support is added to the JIT compiler.
862    5.  Fixed several bugs concerned with partial matching of items that consist
863        of more than one character:
865        (a) /^(..)\1/ did not partially match "aba" because checking references was
866            done on an "all or nothing" basis. This also applied to repeated
867            references.
869        (b) \R did not give a hard partial match if \r was found at the end of the
870            subject.
872        (c) \X did not give a hard partial match after matching one or more
873            characters at the end of the subject.
875        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
876            a partial match for the string "\r".
878        (e) When newline was set to CRLF, the metacharacter "." did not recognize
879            a partial match for a CR character at the end of the subject string.
881    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
882        running pcretest, the text "(JIT)" added to the output whenever JIT is
883        actually used to run the match.
885    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
886        or /S+[+] with a digit between 1 and 7.
888    8.  OP_NOT now supports any UTF character not just single-byte ones.
890    9.  (*MARK) control verb is now supported by the JIT compiler.
892    10. The command "./RunTest list" lists the available tests without actually
893        running any of them. (Because I keep forgetting what they all are.)
897    12. Applied a (slightly modified) user-supplied patch that improves performance
898        when the heap is used for recursion (compiled with --disable-stack-for-
899        recursion). Instead of malloc and free for each heap frame each time a
900        logical recursion happens, frames are retained on a chain and re-used where
901        possible. This sometimes gives as much as 30% improvement.
903    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
904        call.
906    14. As documented, (*COMMIT) is now confined to within a positive assertion.
908    15. It is now possible to link pcretest with libedit as an alternative to
909        libreadline.
911    16. (*COMMIT) control verb is now supported by the JIT compiler.
913    17. The Unicode data tables have been updated to Unicode 6.1.0.
915    18. Added --file-list option to pcregrep.
917    19. Added binary file support to pcregrep, including the -a, --binary-files,
918        -I, and --text options.
920    20. The madvise function is renamed for posix_madvise for QNX compatibility
921        reasons. Fixed by Giuseppe D'Angelo.
923    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
925    22. Changed the option for creating symbolic links for 16-bit man pages from
926        -s to -sf so that re-installing does not cause issues.
928    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
930    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
931        matches in certain environments (the workspace was not being correctly
932        retained). Also added to pcre_dfa_exec() a simple plausibility check on
933        some of the workspace data at the beginning of a restart.
935    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
936        was not doing so when it should - probably a typo introduced by SVN 528
937        (change 8.10/14).
939    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
940        \w+ when the character tables indicated that \x{c4} was a word character.
941        There were several related cases, all because the tests for doing a table
942        lookup were testing for characters less than 127 instead of 255.
944    27. If a pattern contains capturing parentheses that are not used in a match,
945        their slots in the ovector are set to -1. For those that are higher than
946        any matched groups, this happens at the end of processing. In the case when
947        there were back references that the ovector was too small to contain
948        (causing temporary malloc'd memory to be used during matching), and the
949        highest capturing number was not used, memory off the end of the ovector
950        was incorrectly being set to -1. (It was using the size of the temporary
951        memory instead of the true size.)
953    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
954        ovector size, it uses memory at the end of the block that it has got.
956    29. Check for an overlong MARK name and give an error at compile time. The
957        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
959    30. JIT compiler update.
961    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
962        Rill for the patch.
964    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
966    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
968    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
969        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
970        was enabled.
972    35. Improve JIT code generation for greedy plus quantifier.
974    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
975        1 to "aa" instead of to an empty string. The bug affected repeated groups
976        that could potentially match an empty string.
978    37. Optimizing single character iterators in JIT.
980    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
981        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
982        codepoints that are too big for the mode are faulted, and in a UTF mode,
983        disallowed codepoints are also faulted.
985    39. If PCRE was compiled with UTF support, in three places in the DFA
986        matcher there was code that should only have been obeyed in UTF mode, but
987        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
988        processing when bytes with values greater than 127 were present. In 16-bit
989        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
990        both cases the values are those that cannot be the first data item in a UTF
991        character. The three items that might have provoked this were recursions,
992        possessively repeated groups, and atomic groups.
994    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
995        and pcregrep, because some OS require shared objects to be explicitly
996        passed to ld, causing the link step to fail if they are not.
998    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
999        mode, patterns that started with \h* or \R* might be incorrectly matched.
1002    Version 8.30 04-February-2012
1003    -----------------------------
1005    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
1006        name is defined in ctype.h.
1008    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
1009        only in quite long subpatterns.
1011    3.  Removed the function pcre_info(), which has been obsolete and deprecated
1012        since it was replaced by pcre_fullinfo() in February 2000.
1014    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
1015        match a (*MARK), and the match failed at the start of the subject, a
1016        reference to memory before the start of the subject could occur. This bug
1017        was introduced by fix 17 of release 8.21.
1019    5.  A reference to an unset group with zero minimum repetition was giving
1020        totally wrong answers (in non-JavaScript-compatibility mode). For example,
1021        /(another)?(\1?)test/ matched against "hello world test". This bug was
1022        introduced in release 8.13.
1024    6.  Add support for 16-bit character strings (a large amount of work involving
1025        many changes and refactorings).
1027    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
1028        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
1029        from a file.
1031    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
1032        rounding is not applied in this particular case).
1034    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
1035        if they appear, or are escaped, in patterns.
1037    10. Get rid of a number of -Wunused-but-set-variable warnings.
1039    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
1040        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
1041        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
1042        also returns the mark "x". This bug applied to capturing parentheses,
1043        non-capturing parentheses, and atomic parentheses. It also applied to some
1044        assertions.
1046    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
1047        information out of configure.ac instead of relying on pcre.h.generic, which
1048        is not stored in the repository.
1050    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
1051        -lreadline.
1053    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
1055    15. Applied Graycode's patch to put the top-level frame on the stack rather
1056        than the heap when not using the stack for recursion. This gives a
1057        performance improvement in many cases when recursion is not deep.
1059    16. Experimental code added to "pcretest -C" to output the stack frame size.
1062    Version 8.21 12-Dec-2011
1063    ------------------------
1065    1.  Updating the JIT compiler.
1067    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1068        are added as well.
1070    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1071        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1072        calling _pcre_jit_exec. Some extra comments are added.
1074    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1075        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1076        was introduced by change 18 for 8.20.
1078    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1079        ECMA-262 standard.
1081    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1082        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1083        This bug was probably introduced by change 9 of 8.13.
1085    7.  While fixing 6 above, I noticed that a number of other items were being
1086        incorrectly rejected as "not fixed length". This arose partly because newer
1087        opcodes had not been added to the fixed-length checking code. I have (a)
1088        corrected the bug and added tests for these items, and (b) arranged for an
1089        error to occur if an unknown opcode is encountered while checking for fixed
1090        length instead of just assuming "not fixed length". The items that were
1091        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1092        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1093        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1095    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1096        being incorrectly compiled and would have given unpredicatble results.
1098    9.  A possessively repeated subpattern with minimum repeat count greater than
1099        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1100        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1101        the first (A) could occur when it should not.
1103    10. Add a cast and remove a redundant test from the code.
1105    11. JIT should use pcre_malloc/pcre_free for allocation.
1107    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1108        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1109        is anything other than /usr, -L is still shown).
1111    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1113    14. Perl does not support \N without a following name in a [] class; PCRE now
1114        also gives an error.
1116    15. If a forward reference was repeated with an upper limit of around 2000,
1117        it caused the error "internal error: overran compiling workspace". The
1118        maximum number of forward references (including repeats) was limited by the
1119        internal workspace, and dependent on the LINK_SIZE. The code has been
1120        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1121        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1122        of around 200,000 forward references. While doing this, I also speeded up
1123        the filling in of repeated forward references.
1125    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1126        incorrectly expecting the subject to contain another "a" after the start.
1128    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1129        in the match, the SKIP should be ignored. This was not happening; instead
1130        the SKIP was being treated as NOMATCH. For patterns such as
1131        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1132        tested.
1134    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1135        now much more compatible with Perl, in particular in cases where the result
1136        is a non-match for a non-anchored pattern. For example, if
1137        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1138        "m", where previously it did not return a name. A side effect of this
1139        change is that for partial matches, the last encountered mark name is
1140        returned, as for non matches. A number of tests that were previously not
1141        Perl-compatible have been moved into the Perl-compatible test files. The
1142        refactoring has had the pleasing side effect of removing one argument from
1143        the match() function, thus reducing its stack requirements.
1145    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1146        subsequent uses of /S (without +) incorrectly behaved like /S+.
1148    21. Retrieve executable code size support for the JIT compiler and fixing
1149        some warnings.
1151    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1152        not work when the shorter character appeared right at the end of the
1153        subject string.
1155    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1156        systems.
1158    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1159        output it when the /M option is used in pcretest.
1161    25. The CheckMan script was not being included in the distribution. Also, added
1162        an explicit "perl" to run Perl scripts from the PrepareRelease script
1163        because this is reportedly needed in Windows.
1165    26. If study data was being save in a file and studying had not found a set of
1166        "starts with" bytes for the pattern, the data written to the file (though
1167        never used) was taken from uninitialized memory and so caused valgrind to
1168        complain.
1170    27. Updated RunTest.bat as provided by Sheri Pierce.
1172    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1174    29. Computation of memory usage for the table of capturing group names was
1175        giving an unnecessarily large value.
1178    Version 8.20 21-Oct-2011
1179    ------------------------
1181    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1182        a POSIX class. After further experiments with Perl, which convinced me that
1183        Perl has bugs and confusions, a closing square bracket is no longer allowed
1184        in a POSIX name. This bug also affected patterns with classes that started
1185        with full stops.
1187    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1188        captured substring, but while checking the failing first alternative,
1189        substring 1 is temporarily captured. If the output vector supplied to
1190        pcre_exec() was not big enough for this capture, the yield of the function
1191        was still zero ("insufficient space for captured substrings"). This cannot
1192        be totally fixed without adding another stack variable, which seems a lot
1193        of expense for a edge case. However, I have improved the situation in cases
1194        such as /(a)(b)x|abc/ matched against "abc", where the return code
1195        indicates that fewer than the maximum number of slots in the ovector have
1196        been set.
1198    3.  Related to (2) above: when there are more back references in a pattern than
1199        slots in the output vector, pcre_exec() uses temporary memory during
1200        matching, and copies in the captures as far as possible afterwards. It was
1201        using the entire output vector, but this conflicts with the specification
1202        that only 2/3 is used for passing back captured substrings. Now it uses
1203        only the first 2/3, for compatibility. This is, of course, another edge
1204        case.
1206    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1207        main code base, and can be used by building with --enable-jit. When this is
1208        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1209        runtime --no-jit option is given.
1211    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1212        ovector, the return from the function was zero, implying that there were
1213        other matches that did not fit. The correct "exactly full" value is now
1214        returned.
1216    6.  If a subpattern that was called recursively or as a subroutine contained
1217        (*PRUNE) or any other control that caused it to give a non-standard return,
1218        invalid errors such as "Error -26 (nested recursion at the same subject
1219        position)" or even infinite loops could occur.
1221    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1222        computing the minimum length on reaching *ACCEPT, and so ended up with the
1223        wrong value of 1 rather than 0. Further investigation indicates that
1224        computing a minimum subject length in the presence of *ACCEPT is difficult
1225        (think back references, subroutine calls), and so I have changed the code
1226        so that no minimum is registered for a pattern that contains *ACCEPT.
1228    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1229        it was not handled as intended. [But see 16 below.]
1231    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1232        Sheri Pierce.
1234    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1235        the first byte in a match must be "a".
1237    11. Change 17 for 8.13 increased the recursion depth for patterns like
1238        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1239        pattern contains any instances of (*THEN). If it does not, the old
1240        optimizations are restored. It would be nice to do this on a per-group
1241        basis, but at the moment that is not feasible.
1243    12. In some environments, the output of pcretest -C is CRLF terminated. This
1244        broke RunTest's code that checks for the link size. A single white space
1245        character after the value is now allowed for.
1247    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1248        For "fr", it uses the Windows-specific input and output files.
1250    14. If (*THEN) appeared in a group that was called recursively or as a
1251        subroutine, it did not work as intended. [But see next item.]
1253    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1254        pattern fragments (but not containing any | characters). If A and B are
1255        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1256        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1257        D. In other words, Perl considers parentheses that do not contain any |
1258        characters to be part of a surrounding alternative, whereas PCRE was
1259        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1260        differently. PCRE now behaves in the same way as Perl, except in the case
1261        of subroutine/recursion calls such as (?1) which have in any case always
1262        been different (but PCRE had them first :-).
1264    16. Related to 15 above: Perl does not treat the | in a conditional group as
1265        creating alternatives. Such a group is treated in the same way as an
1266        ordinary group without any | characters when processing (*THEN). PCRE has
1267        been changed to match Perl's behaviour.
1269    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1270        RunGrepTest script failed.
1272    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1273        inevitable for groups that contain captures, but it can lead to a lot of
1274        stack use in large patterns. The old behaviour has been restored for atomic
1275        groups that do not contain any capturing parentheses.
1277    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1278        suppress the check for a minimum subject length at run time. (If it was
1279        given to pcre_exec() or pcre_dfa_exec() it did work.)
1281    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1282        fail to work when decoding hex characters in data strings in EBCDIC
1283        environments.
1285    21. It appears that in at least one Mac OS environment, the isxdigit() function
1286        is implemented as a macro that evaluates to its argument more than once,
1287        contravening the C 90 Standard (I haven't checked a later standard). There
1288        was an instance in pcretest which caused it to go wrong when processing
1289        \x{...} escapes in subject strings. The has been rewritten to avoid using
1290        things like p++ in the argument of isxdigit().
1293    Version 8.13 16-Aug-2011
1294  ------------------------  ------------------------
1296  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 1309  Version 8.13 30-Apr-2011
1309      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
1310      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
1311      left).      left).
1313  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
1314      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
1315      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
1316      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
1318  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
1319      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
1320      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
1321      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
1322      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
1324  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
1325      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
1326      failure, the offset and reason code are output.      failure, the offset and reason code are output.
1328  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
1329      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
1330      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
1331      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
1332      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
1333      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1334      has been changed.      has been changed.
1336    9.  Some internal refactoring has changed the processing so that the handling
1337        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1338        time (the PCRE_DOTALL option was changed this way some time ago: version
1339        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1340        which was always a bit of a fudge. It also means that there is one less
1341        argument for the match() function, which reduces its stack requirements
1342        slightly. This change also fixes an incompatibility with Perl: the pattern
1343        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1345    10. More internal refactoring has drastically reduced the number of recursive
1346        calls to match() for possessively repeated groups such as (abc)++ when
1347        using pcre_exec().
1349    11. While implementing 10, a number of bugs in the handling of groups were
1350        discovered and fixed:
1352        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1353        (a|)*(?1) gave a compile-time internal error.
1354        ((a|)+)+  did not notice that the outer group could match an empty string.
1355        (^a|^)+   was not marked as anchored.
1356        (.*a|.*)+ was not marked as matching at start or after a newline.
1358    12. Yet more internal refactoring has removed another argument from the match()
1359        function. Special calls to this function are now indicated by setting a
1360        value in a variable in the "match data" data block.
1362    13. Be more explicit in pcre_study() instead of relying on "default" for
1363        opcodes that mean there is no starting character; this means that when new
1364        ones are added and accidentally left out of pcre_study(), testing should
1365        pick them up.
1367    14. The -s option of pcretest has been documented for ages as being an old
1368        synonym of -m (show memory usage). I have changed it to mean "force study
1369        for every regex", that is, assume /S for every regex. This is similar to -i
1370        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1371        using it. It makes it easier to run collections of tests with and without
1372        study enabled, and thereby test pcre_study() more easily. All the standard
1373        tests are now run with and without -s (but some patterns can be marked as
1374        "never study" - see 20 below).
1376    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1377        restoration of the capturing data to the outer values was not happening
1378        correctly.
1380    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1381        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1382        pattern had matched an empty string, and so incorrectly returned a no
1383        match.
1385    17. There was optimizing code for the last branch of non-capturing parentheses,
1386        and also for the obeyed branch of a conditional subexpression, which used
1387        tail recursion to cut down on stack usage. Unfortunately, now that there is
1388        the possibility of (*THEN) occurring in these branches, tail recursion is
1389        no longer possible because the return has to be checked for (*THEN). These
1390        two optimizations have therefore been removed. [But see 8.20/11 above.]
1392    18. If a pattern containing \R was studied, it was assumed that \R always
1393        matched two bytes, thus causing the minimum subject length to be
1394        incorrectly computed because \R can also match just one byte.
1396    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1397        was incorrectly computed.
1399    20. If /S is present twice on a test pattern in pcretest input, it now
1400        *disables* studying, thereby overriding the use of -s on the command line
1401        (see 14 above). This is necessary for one or two tests to keep the output
1402        identical in both cases.
1404    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1405        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1407    22. When an atomic group that contained a capturing parenthesis was
1408        successfully matched, but the branch in which it appeared failed, the
1409        capturing was not being forgotten if a higher numbered group was later
1410        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1411        group 1 to "a", when in fact it should be unset. This applied to multi-
1412        branched capturing and non-capturing groups, repeated or not, and also to
1413        positive assertions (capturing in negative assertions does not happen
1414        in PCRE) and also to nested atomic groups.
1416    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1417        subject after a captured substring, to make it easier to tell which of a
1418        number of identical substrings has been captured.
1420    24. The way atomic groups are processed by pcre_exec() has been changed so that
1421        if they are repeated, backtracking one repetition now resets captured
1422        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1423        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1424        "aaa". Previously, it would have been "a". As part of this code
1425        refactoring, the way recursive calls are handled has also been changed.
1427    25. If an assertion condition captured any substrings, they were not passed
1428        back unless some other capturing happened later. For example, if
1429        (?(?=(a))a) was matched against "a", no capturing was returned.
1431    26. When studying a pattern that contained subroutine calls or assertions,
1432        the code for finding the minimum length of a possible match was handling
1433        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1434        group 1 called group 2 while simultaneously a separate group 2 called group
1435        1). A stack overflow occurred in this case. I have fixed this by limiting
1436        the recursion depth to 10.
1438    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1439        Fortmann. This supports explicit test numbers on the command line, and has
1440        argument validation and error reporting.
1442    28. An instance of \X with an unlimited repeat could fail if at any point the
1443        first character it looked at was a mark character.
1445    29. Some minor code refactoring concerning Unicode properties and scripts
1446        should reduce the stack requirement of match() slightly.
1448    30. Added the '=' option to pcretest to check the setting of unused capturing
1449        slots at the end of the pattern, which are documented as being -1, but are
1450        not included in the return count.
1452    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1453        compiled something random. Now it gives a compile-time error (as does
1454        Perl).
1456    32. A *MARK encountered during the processing of a positive assertion is now
1457        recorded and passed back (compatible with Perl).
1459    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1460        had alternative anchored branches, the search for a second match in a line
1461        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1462        matched the line "0102" twice. The same bug affected patterns that started
1463        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1464        twice.
1466    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1467        does, and because of capturing effects, quantifying parenthesized
1468        assertions may at times be useful. Quantifiers are now allowed for
1469        parenthesized assertions.
1471    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1473    36. \g was being checked for fancy things in a character class, when it should
1474        just be a literal "g".
1476    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1477        appearance of a nested POSIX class supersedes an apparent external class.
1478        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1479        unescaped square brackets may also appear as part of class names. For
1480        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1481        more like Perl. (But see 8.20/1 above.)
1483    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1484        was because it thought it was \N{name}, which is not supported).
1486    39. Add minix to OS list not supporting the -S option in pcretest.
1488    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1489        cannot analyze patterns in sufficient detail to catch mutual recursions
1490        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1491        subgroup is called recursively as a subpattern for a second time at the
1492        same position in the subject string. In previous releases this might have
1493        been caught by the recursion limit, or it might have run out of stack.
1495    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1496        happen only once. PCRE was, however incorrectly giving a compile time error
1497        "recursive call could loop indefinitely" because it cannot analyze the
1498        pattern in sufficient detail. The compile time test no longer happens when
1499        PCRE is compiling a conditional subpattern, but actual runaway loops are
1500        now caught at runtime (see 40 above).
1502    42. It seems that Perl allows any characters other than a closing parenthesis
1503        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1504        has been changed to be the same.
1506    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1507        as not to get warnings when autogen.sh is called. Also changed
1508        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1510    44. To help people who use pcregrep to scan files containing exceedingly long
1511        lines, the following changes have been made:
1513        (a) The default value of the buffer size parameter has been increased from
1514            8K to 20K. (The actual buffer used is three times this size.)
1516        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1517            PCRE is built.
1519        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1520            to be set at run time.
1522        (d) Numerical values in pcregrep options can be followed by K or M, for
1523            example --buffer-size=50K.
1525        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1526            given and the return code is set to 2.
1528    45. Add a pointer to the latest mark to the callout data block.
1530    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1531        partial match of an empty string instead of no match. This was specific to
1532        the use of ".".
1534    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1535        complete match instead of a partial match. This bug was dependent on both
1536        the PCRE_UTF8 and PCRE_DOTALL options being set.
1538    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1539        starting byte set, because \b was not being ignored.
1542  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
1543  ------------------------  ------------------------
# Line 695  Version 7.9 11-Apr-09 Line 2189  Version 7.9 11-Apr-09
2189  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
2190      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
2191      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2192      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2193        8.33.]
2195  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
2196      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 2433  Version 7.7 07-May-08
2433      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2434      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2435      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2436      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2437      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2438      was subsequently set up correctly.)      was subsequently set up correctly.)

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