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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.13 02-Aug-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 and given the CVE number
85        CVE-2015-2325.
87    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
88        call within a group that also contained a recursive back reference caused
89        incorrect code to be compiled. This bug was reported as "heap overflow",
90        discovered by Kai Lu of Fortinet's FortiGuard Labs, and given the CVE
91        number CVE-2015-2326.
93    24. Computing the size of the JIT read-only data in advance has been a source
94        of various issues, and new ones are still appear unfortunately. To fix
95        existing and future issues, size computation is eliminated from the code,
96        and replaced by on-demand memory allocation.
98    25. A pattern such as /(?i)[A-`]/, where characters in the other case are
99        adjacent to the end of the range, and the range contained characters with
100        more than one other case, caused incorrect behaviour when compiled in UTF
101        mode. In that example, the range a-j was left out of the class.
103    26. Fix JIT compilation of conditional blocks, which assertion
104        is converted to (*FAIL). E.g: /(?(?!))/.
106    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
107        discovered by the LLVM fuzzer.
109    28. The assertion (?!) is optimized to (*FAIL). This was not handled correctly
110        when this assertion was used as a condition, for example (?(?!)a|b). In
111        pcre2_match() it worked by luck; in pcre2_dfa_match() it gave an incorrect
112        error about an unsupported item.
114    29. For some types of pattern, for example /Z*(|d*){216}/, the auto-
115        possessification code could take exponential time to complete. A recursion
116        depth limit of 1000 has been imposed to limit the resources used by this
117        optimization.
119    30. A pattern such as /(*UTF)[\S\V\H]/, which contains a negated special class
120        such as \S in non-UCP mode, explicit wide characters (> 255) can be ignored
121        because \S ensures they are all in the class. The code for doing this was
122        interacting badly with the code for computing the amount of space needed to
123        compile the pattern, leading to a buffer overflow. This bug was discovered
124        by the LLVM fuzzer.
126    31. A pattern such as /((?2)+)((?1))/ which has mutual recursion nested inside
127        other kinds of group caused stack overflow at compile time. This bug was
128        discovered by the LLVM fuzzer.
130    32. A pattern such as /(?1)(?#?'){8}(a)/ which had a parenthesized comment
131        between a subroutine call and its quantifier was incorrectly compiled,
132        leading to buffer overflow or other errors. This bug was discovered by the
133        LLVM fuzzer.
135    33. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an
136        assertion after (?(. The code was failing to check the character after
137        (?(?< for the ! or = that would indicate a lookbehind assertion. This bug
138        was discovered by the LLVM fuzzer.
140    34. A pattern such as /X((?2)()*+){2}+/ which has a possessive quantifier with
141        a fixed maximum following a group that contains a subroutine reference was
142        incorrectly compiled and could trigger buffer overflow. This bug was
143        discovered by the LLVM fuzzer.
146    Version 8.36 26-September-2014
147    ------------------------------
149    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
150        -Wmissing-field-initializers and -Wunused-parameter.
152    2.  The tests for quantifiers being too big (greater than 65535) were being
153        applied after reading the number, and stupidly assuming that integer
154        overflow would give a negative number. The tests are now applied as the
155        numbers are read.
157    3.  Tidy code in pcre_exec.c where two branches that used to be different are
158        now the same.
160    4.  The JIT compiler did not generate match limit checks for certain
161        bracketed expressions with quantifiers. This may lead to exponential
162        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
163        issue should be resolved now.
165    5.  Fixed an issue, which occures when nested alternatives are optimized
166        with table jumps.
168    6.  Inserted two casts and changed some ints to size_t in the light of some
169        reported 64-bit compiler warnings (Bugzilla 1477).
171    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
172        an empty string, which sometimes were behaving incorrectly in the
173        interpreter (though correctly in the JIT matcher). This pcretest input is
174        an example:
176          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
179        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
180        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
181        for an empty string was breaking the inner loop and carrying on at a lower
182        level, when possessive repeated groups should always return to a higher
183        level as they have no backtrack points in them. The empty string test now
184        occurs at the outer level.
186    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
187        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
189    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
190        doesn't).
192    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
193        to hold a pattern to be incorrectly computed (too small) when there were
194        named back references to duplicated names. This could cause "internal
195        error: code overflow" or "double free or corruption" or other memory
196        handling errors.
198    11. When named subpatterns had the same prefixes, back references could be
199        confused. For example, in this pattern:
201          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
203        the reference to 'Name' was incorrectly treated as a reference to a
204        duplicate name.
206    12. A pattern such as /^s?c/mi8 where the optional character has more than
207        one "other case" was incorrectly compiled such that it would only try to
208        match starting at "c".
210    13. When a pattern starting with \s was studied, VT was not included in the
211        list of possible starting characters; this should have been part of the
212        8.34/18 patch.
214    14. If a character class started [\Qx]... where x is any character, the class
215        was incorrectly terminated at the ].
217    15. If a pattern that started with a caseless match for a character with more
218        than one "other case" was studied, PCRE did not set up the starting code
219        unit bit map for the list of possible characters. Now it does. This is an
220        optimization improvement, not a bug fix.
222    16. The Unicode data tables have been updated to Unicode 7.0.0.
224    17. Fixed a number of memory leaks in pcregrep.
226    18. Avoid a compiler warning (from some compilers) for a function call with
227        a cast that removes "const" from an lvalue by using an intermediate
228        variable (to which the compiler does not object).
230    19. Incorrect code was compiled if a group that contained an internal recursive
231        back reference was optional (had quantifier with a minimum of zero). This
232        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
233        caused segmentation faults because of stack overflows at compile time.
235    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
236        group that is quantified with an indefinite repeat, caused a compile-time
237        loop which used up all the system stack and provoked a segmentation fault.
238        This was not the same bug as 19 above.
240    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
241        Patch by Mike Frysinger.
244    Version 8.35 04-April-2014
245    --------------------------
247    1.  A new flag is set, when property checks are present in an XCLASS.
248        When this flag is not set, PCRE can perform certain optimizations
249        such as studying these XCLASS-es.
251    2.  The auto-possessification of character sets were improved: a normal
252        and an extended character set can be compared now. Furthermore
253        the JIT compiler optimizes more character set checks.
255    3.  Got rid of some compiler warnings for potentially uninitialized variables
256        that show up only when compiled with -O2.
258    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
259        of a match later then the end of the match. The pcretest program was not
260        handling the case sensibly - it was outputting from the start to the next
261        binary zero. It now reports this situation in a message, and outputs the
262        text from the end to the start.
264    5.  Fast forward search is improved in JIT. Instead of the first three
265        characters, any three characters with fixed position can be searched.
266        Search order: first, last, middle.
268    6.  Improve character range checks in JIT. Characters are read by an inprecise
269        function now, which returns with an unknown value if the character code is
270        above a certain threshold (e.g: 256). The only limitation is that the value
271        must be bigger than the threshold as well. This function is useful when
272        the characters above the threshold are handled in the same way.
274    7.  The macros whose names start with RAWUCHAR are placeholders for a future
275        mode in which only the bottom 21 bits of 32-bit data items are used. To
276        make this more memorable for those maintaining the code, the names have
277        been changed to start with UCHAR21, and an extensive comment has been added
278        to their definition.
280    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
281        to the export list in Makefile.am (they were accidentally omitted from the
282        8.34 tarball).
284    9.  The informational output from pcretest used the phrase "starting byte set"
285        which is inappropriate for the 16-bit and 32-bit libraries. As the output
286        for "first char" and "need char" really means "non-UTF-char", I've changed
287        "byte" to "char", and slightly reworded the output. The documentation about
288        these values has also been (I hope) clarified.
290    10. Another JIT related optimization: use table jumps for selecting the correct
291        backtracking path, when more than four alternatives are present inside a
292        bracket.
294    11. Empty match is not possible, when the minimum length is greater than zero,
295        and there is no \K in the pattern. JIT should avoid empty match checks in
296        such cases.
298    12. In a caseless character class with UCP support, when a character with more
299        than one alternative case was not the first character of a range, not all
300        the alternative cases were added to the class. For example, s and \x{17f}
301        are both alternative cases for S: the class [RST] was handled correctly,
302        but [R-T] was not.
304    13. The configure.ac file always checked for pthread support when JIT was
305        enabled. This is not used in Windows, so I have put this test inside a
306        check for the presence of windows.h (which was already tested for).
308    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
309        The algorithm provides a way to skip certain starting offsets, and usually
310        faster than linear prefix searches.
312    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
313        as for 'fr_FR' and 'french'. For some reason, however, it then used the
314        Windows-specific input and output files, which have 'french' screwed in.
315        So this could never have worked. One of the problems with locales is that
316        they aren't always the same. I have now updated RunTest so that it checks
317        the output of the locale test (test 3) against three different output
318        files, and it allows the test to pass if any one of them matches. With luck
319        this should make the test pass on some versions of Solaris where it was
320        failing. Because of the uncertainty, the script did not used to stop if
321        test 3 failed; it now does. If further versions of a French locale ever
322        come to light, they can now easily be added.
324    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
325        there was a message during ./configure, but it did not stop. This now
326        provokes an error. The invalid example in README has been corrected.
327        If a value less than the minimum is given, the minimum value has always
328        been used, but now a warning is given.
330    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
331        was a bug in the test system, which is now fixed. Also, the list of various
332        configurations that are tested for each release did not have one with both
333        16/32 bits and --enable-bar-anycrlf. It now does.
335    18. pcretest was missing "-C bsr" for displaying the \R default setting.
337    19. Little endian PowerPC systems are supported now by the JIT compiler.
339    20. The fast forward newline mechanism could enter to an infinite loop on
340        certain invalid UTF-8 input. Although we don't support these cases
341        this issue can be fixed by a performance optimization.
343    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
344        not take account if existing stack usage. There is now a new global
345        variable called pcre_stack_guard that can be set to point to an external
346        function to check stack availability. It is called at the start of
347        processing every parenthesized group.
349    22. A typo in the code meant that in ungreedy mode the max/min qualifier
350        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
351        not match "ab".
353    23. When UTF was disabled, the JIT program reported some incorrect compile
354        errors. These messages are silenced now.
356    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
357        compiler.
359    25. Change all the temporary files used in RunGrepTest to be different to those
360        used by RunTest so that the tests can be run simultaneously, for example by
361        "make -j check".
364    Version 8.34 15-December-2013
365    -----------------------------
367    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
368        executable memory. Patch inspired by Carsten Klein.
370    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
371        this macro is never tested and has no effect, because the work to support
372        coverage involves only compiling and linking options and special targets in
373        the Makefile. The comment in config.h implied that defining the macro would
374        enable coverage support, which is totally false. There was also support for
375        setting this macro in the CMake files (my fault, I just copied it from
376        configure). SUPPORT_GCOV has now been removed.
378    3.  Make a small performance improvement in strlen16() and strlen32() in
379        pcretest.
381    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
382        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
383        these cases). There was also one in pcretest.c.
385    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
387    6.  In UTF mode, the code for checking whether a group could match an empty
388        string (which is used for indefinitely repeated groups to allow for
389        breaking an infinite loop) was broken when the group contained a repeated
390        negated single-character class with a character that occupied more than one
391        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
392        UTF-8 mode). The effect was undefined: the group might or might not be
393        deemed as matching an empty string, or the program might have crashed.
395    7.  The code for checking whether a group could match an empty string was not
396        recognizing that \h, \H, \v, \V, and \R must match a character.
398    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
399        an empty string. If it can, pcretest shows this in its information output.
401    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
402        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
403        matched by pcre_exec() without using JIT:
405        (a) If the rest of the pattern did not match after a maximal run of
406            grapheme clusters, the code for backing up to try with fewer of them
407            did not always back up over a full grapheme when characters that do not
408            have the modifier quality were involved, e.g. Hangul syllables.
410        (b) If the match point in a subject started with modifier character, and
411            there was no match, the code could incorrectly back up beyond the match
412            point, and potentially beyond the first character in the subject,
413            leading to a segfault or an incorrect match result.
415    10. A conditional group with an assertion condition could lead to PCRE
416        recording an incorrect first data item for a match if no other first data
417        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
418        first data item, and therefore matched "ca" after "c" instead of at the
419        start.
421    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
422        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
424    12. The source of pcregrep now includes z/OS-specific code so that it can be
425        compiled for z/OS as part of the special z/OS distribution.
427    13. Added the -T and -TM options to pcretest.
429    14. The code in pcre_compile.c for creating the table of named capturing groups
430        has been refactored. Instead of creating the table dynamically during the
431        actual compiling pass, the information is remembered during the pre-compile
432        pass (on the stack unless there are more than 20 named groups, in which
433        case malloc() is used) and the whole table is created before the actual
434        compile happens. This has simplified the code (it is now nearly 150 lines
435        shorter) and prepared the way for better handling of references to groups
436        with duplicate names.
438    15. A back reference to a named subpattern when there is more than one of the
439        same name now checks them in the order in which they appear in the pattern.
440        The first one that is set is used for the reference. Previously only the
441        first one was inspected. This change makes PCRE more compatible with Perl.
443    16. Unicode character properties were updated from Unicode 6.3.0.
445    17. The compile-time code for auto-possessification has been refactored, based
446        on a patch by Zoltan Herczeg. It now happens after instead of during
447        compilation. The code is cleaner, and more cases are handled. The option
448        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
449        options in pcretest are provided to set it. It can also be set by
450        (*NO_AUTO_POSSESS) at the start of a pattern.
452    18. The character VT has been added to the default ("C" locale) set of
453        characters that match \s and are generally treated as white space,
454        following this same change in Perl 5.18. There is now no difference between
455        "Perl space" and "POSIX space". Whether VT is treated as white space in
456        other locales depends on the locale.
458    19. The code for checking named groups as conditions, either for being set or
459        for being recursed, has been refactored (this is related to 14 and 15
460        above). Processing unduplicated named groups should now be as fast at
461        numerical groups, and processing duplicated groups should be faster than
462        before.
464    20. Two patches to the CMake build system, by Alexander Barkov:
466          (1) Replace the "source" command by "." in CMakeLists.txt because
467              "source" is a bash-ism.
469          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
470              without these the CMake build does not work on Solaris.
472    21. Perl has changed its handling of \8 and \9. If there is no previously
473        encountered capturing group of those numbers, they are treated as the
474        literal characters 8 and 9 instead of a binary zero followed by the
475        literals. PCRE now does the same.
477    22. Following Perl, added \o{} to specify codepoints in octal, making it
478        possible to specify values greater than 0777 and also making them
479        unambiguous.
481    23. Perl now gives an error for missing closing braces after \x{... instead of
482        treating the string as literal. PCRE now does the same.
484    24. RunTest used to grumble if an inappropriate test was selected explicitly,
485        but just skip it when running all tests. This make it awkward to run ranges
486        of tests when one of them was inappropriate. Now it just skips any
487        inappropriate tests, as it always did when running all tests.
489    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
490        character types such as \d or \w, too many callouts were inserted, and the
491        data that they returned was rubbish.
493    26. In UCP mode, \s was not matching two of the characters that Perl matches,
494        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
495        were matched by \h. The code has now been refactored so that the lists of
496        the horizontal and vertical whitespace characters used for \h and \v (which
497        are defined only in one place) are now also used for \s.
499    27. Add JIT support for the 64 bit TileGX architecture.
500        Patch by Jiong Wang (Tilera Corporation).
502    28. Possessive quantifiers for classes (both explicit and automatically
503        generated) now use special opcodes instead of wrapping in ONCE brackets.
505    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
506        (because it's meaningless), this was not happening when PCRE_CASELESS was
507        set. Not wrong, but inefficient.
509    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
510        properties for \w, \d, etc) is present in a test regex. Otherwise if the
511        test contains no characters greater than 255, Perl doesn't realise it
512        should be using Unicode semantics.
514    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
515        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
516        does in Unicode mode.
518    32. Added the "forbid" facility to pcretest so that putting tests into the
519        wrong test files can sometimes be quickly detected.
521    33. There is now a limit (default 250) on the depth of nesting of parentheses.
522        This limit is imposed to control the amount of system stack used at compile
523        time. It can be changed at build time by --with-parens-nest-limit=xxx or
524        the equivalent in CMake.
526    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
527        errors. Perl warns for these when in warning mode, but PCRE has no facility
528        for giving warnings.
530    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
531        However, this was not working for (?!) because it is optimized to (*FAIL),
532        for which PCRE does not allow quantifiers. The optimization is now disabled
533        when a quantifier follows (?!). I can't see any use for this, but it makes
534        things uniform.
536    36. Perl no longer allows group names to start with digits, so I have made this
537        change also in PCRE. It simplifies the code a bit.
539    37. In extended mode, Perl ignores spaces before a + that indicates a
540        possessive quantifier. PCRE allowed a space before the quantifier, but not
541        before the possessive +. It now does.
543    38. The use of \K (reset reported match start) within a repeated possessive
544        group such as (a\Kb)*+ was not working.
546    40. Document that the same character tables must be used at compile time and
547        run time, and that the facility to pass tables to pcre_exec() and
548        pcre_dfa_exec() is for use only with saved/restored patterns.
550    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
551        features for Builds with MSVC:
553        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
554           builds). The .rc files can be used to set FileDescription and many other
555           attributes.
557        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
558           This allows higher-level build scripts which want .pdb files to avoid
559           hard-coding the exact files needed."
561    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
562        mean "start of word" and "end of word", respectively, as a transition aid.
564    43. A minimizing repeat of a class containing codepoints greater than 255 in
565        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
566        compiled to use the heap for recursion.
568    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
569        is configured.
572    Version 8.33 28-May-2013
573    ------------------------
575    1.  Added 'U' to some constants that are compared to unsigned integers, to
576        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
577        variables that are added to signed variables, to ensure the result is
578        signed and can be negated.
580    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
581        CMake config files.
583    3.  Revise the creation of config.h.generic so that all boolean macros are
584        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
585        overriding via -D on the command line possible.
587    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
588        to unsigned int is reported to make a quite noticeable speed difference in
589        a specific Windows environment. Testing on Linux did also appear to show
590        some benefit (and it is clearly not harmful). Also fixed the definition of
591        Xop which should be unsigned.
593    5.  Related to (4), changing the definition of the intermediate variable cc
594        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
595        improvements.
597    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
598        unnecessary spaces.
600    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
601        and later.
603    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
605    9.  Optimizing fast_forward_start_bits in JIT.
607    10. Adding support for callouts in JIT, and fixing some issues revealed
608        during this work. Namely:
610        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
612        (b) Minimum length was not checked before the matching is started.
614    11. The value of capture_last that is passed to callouts was incorrect in some
615        cases when there was a capture on one path that was subsequently abandoned
616        after a backtrack. Also, the capture_last value is now reset after a
617        recursion, since all captures are also reset in this case.
619    12. The interpreter no longer returns the "too many substrings" error in the
620        case when an overflowing capture is in a branch that is subsequently
621        abandoned after a backtrack.
623    13. In the pathological case when an offset vector of size 2 is used, pcretest
624        now prints out the matched string after a yield of 0 or 1.
626    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
627        Only supported by the JIT compiler at the moment.
629    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
631    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
632        offset of the starting point of the matching process, provided the offsets
633        vector is large enough.
635    17. The \A escape now records a lookbehind value of 1, though its execution
636        does not actually inspect the previous character. This is to ensure that,
637        in partial multi-segment matching, at least one character from the old
638        segment is retained when a new segment is processed. Otherwise, if there
639        are no lookbehinds in the pattern, \A might match incorrectly at the start
640        of a new segment.
642    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
644    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
645        gives some modest performance improvement in 8-bit mode.
647    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
648        be expressed in certain programming languages using Universal Character
649        Names.
651    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
652        which points out that "non characters" are not "characters that may not
653        appear in Unicode strings" but rather "characters that are reserved for
654        internal use and have only local meaning".
656    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
657        there was a conditional group that depended on an assertion, if the
658        assertion was false, the callout that immediately followed the alternation
659        in the condition was skipped when pcre_exec() was used for matching.
661    23. Allow an explicit callout to be inserted before an assertion that is the
662        condition for a conditional group, for compatibility with automatic
663        callouts, which always insert a callout at this point.
665    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
666        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
668    25. (*PRUNE) is now supported by the JIT compiler.
670    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
672    27. Fix the case where there are two or more SKIPs with arguments that may be
673        ignored.
675    28. (*SKIP) is now supported by the JIT compiler.
677    29. (*THEN) is now supported by the JIT compiler.
679    30. Update RunTest with additional test selector options.
681    31. The way PCRE handles backtracking verbs has been changed in two ways.
683        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
684        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
685        backtracking. In some cases this makes it more Perl-compatible, but Perl's
686        rather obscure rules do not always do the same thing.
688        (2) Previously, backtracking verbs were confined within assertions. This is
689        no longer the case for positive assertions, except for (*ACCEPT). Again,
690        this sometimes improves Perl compatibility, and sometimes does not.
692    32. A number of tests that were in test 2 because Perl did things differently
693        have been moved to test 1, because either Perl or PCRE has changed, and
694        these tests are now compatible.
696    32. Backtracking control verbs are now handled in the same way in JIT and
697        interpreter.
699    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
700        contained a forward subroutine reference caused a compile error.
702    34. Auto-detect and optimize limited repetitions in JIT.
704    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
705        blocking (*UTF) etc.
707    36. In the interpreter, maximizing pattern repetitions for characters and
708        character types now use tail recursion, which reduces stack usage.
710    37. The value of the max lookbehind was not correctly preserved if a compiled
711        and saved regex was reloaded on a host of different endianness.
713    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
714        of the compiled pattern block, expand the flags field from 16 to 32 bits
715        because it was almost full.
717    39. Try madvise first before posix_madvise.
719    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
720        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
721        original change locked out all matches of empty strings. This has been
722        changed so that one match of an empty string per line is recognized.
723        Subsequent searches on the same line (for colouring or for --only-matching,
724        for example) do not recognize empty strings.
726    41. Applied a user patch to fix a number of spelling mistakes in comments.
728    42. Data lines longer than 65536 caused pcretest to crash.
730    43. Clarified the data type for length and startoffset arguments for pcre_exec
731        and pcre_dfa_exec in the function-specific man pages, where they were
732        explicitly stated to be in bytes, never having been updated. I also added
733        some clarification to the pcreapi man page.
735    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
736        a segmentation fault.
739    Version 8.32 30-November-2012
740    -----------------------------
742    1.  Improved JIT compiler optimizations for first character search and single
743        character iterators.
745    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
746        Patch by Daniel Richard G.
748    3.  Single character iterator optimizations in the JIT compiler.
750    4.  Improved JIT compiler optimizations for character ranges.
752    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
753        Reported by Giuseppe D'Angelo.
755    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
756        of a line, was being set incorrectly in cases where .* appeared inside
757        atomic brackets at the start of a pattern, or where there was a subsequent
758        *PRUNE or *SKIP.
760    7.  Improved instruction cache flush for POWER/PowerPC.
761        Patch by Daniel Richard G.
763    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
764        grep:
766        (a) There is now no limit to the number of patterns to be matched.
768        (b) An error is given if a pattern is too long.
770        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
771            are now supported.
773        (d) --exclude-from and --include-from (multiple use) have been added.
775        (e) Exclusions and inclusions now apply to all files and directories, not
776            just to those obtained from scanning a directory recursively.
778        (f) Multiple uses of -f and --file-list are now supported.
780        (g) In a Windows environment, the default for -d has been changed from
781            "read" (the GNU grep default) to "skip", because otherwise the presence
782            of a directory in the file list provokes an error.
784        (h) The documentation has been revised and clarified in places.
786    9.  Improve the matching speed of capturing brackets.
788    10. Changed the meaning of \X so that it now matches a Unicode extended
789        grapheme cluster.
791    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
792        out POSIX threads when JIT support is configured.
794    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
796    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
797        structure could go wrong in environments where size_t is not the same size
798        as int.
800    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
801        set.
803    15. The EBCDIC support had decayed; later updates to the code had included
804        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
805        general tidy up of EBCDIC-related issues, and the documentation was also
806        not quite right. There is now a test that can be run on ASCII systems to
807        check some of the EBCDIC-related things (but is it not a full test).
809    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
810        in a small tidy to the code.
812    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
814    18. If the --only-matching (-o) option in pcregrep is specified multiple
815        times, each one causes appropriate output. For example, -o1 -o2 outputs the
816        substrings matched by the 1st and 2nd capturing parentheses. A separating
817        string can be specified by --om-separator (default empty).
819    19. Improving the first n character searches.
821    20. Turn case lists for horizontal and vertical white space into macros so that
822        they are defined only once.
824    21. This set of changes together give more compatible Unicode case-folding
825        behaviour for characters that have more than one other case when UCP
826        support is available.
828        (a) The Unicode property table now has offsets into a new table of sets of
829            three or more characters that are case-equivalent. The MultiStage2.py
830            script that generates these tables (the pcre_ucd.c file) now scans
831            CaseFolding.txt instead of UnicodeData.txt for character case
832            information.
834        (b) The code for adding characters or ranges of characters to a character
835            class has been abstracted into a generalized function that also handles
836            case-independence. In UTF-mode with UCP support, this uses the new data
837            to handle characters with more than one other case.
839        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
840            whose other case is greater than 256 are now correctly matched
841            caselessly. Previously, the high codepoint matched the low one, but not
842            vice versa.
844        (d) The processing of \h, \H, \v, and \ in character classes now makes use
845            of the new class addition function, using character lists defined as
846            macros alongside the case definitions of 20 above.
848        (e) Caseless back references now work with characters that have more than
849            one other case.
851        (f) General caseless matching of characters with more than one other case
852            is supported.
854    22. Unicode character properties were updated from Unicode 6.2.0
856    23. Improved CMake support under Windows. Patch by Daniel Richard G.
858    24. Add support for 32-bit character strings, and UTF-32
860    25. Major JIT compiler update (code refactoring and bugfixing).
861        Experimental Sparc 32 support is added.
863    26. Applied a modified version of Daniel Richard G's patch to create
864        pcre.h.generic and config.h.generic by "make" instead of in the
865        PrepareRelease script.
867    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
868        pcre_compile.c when checking for a zero character.
870    28. Introducing a native interface for JIT. Through this interface, the compiled
871        machine code can be directly executed. The purpose of this interface is to
872        provide fast pattern matching, so several sanity checks are not performed.
873        However, feature tests are still performed. The new interface provides
874        1.4x speedup compared to the old one.
876    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
877        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
878        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
880    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
881        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
882        the "old" RFC 2279). Instead, it ended up passing a negative length to
883        pcre_exec().
885    31. Add support for GCC's visibility feature to hide internal functions.
887    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
888        "unknown -C option" after outputting 0 or 1.
890    33. There is now support for generating a code coverage report for the test
891        suite in environments where gcc is the compiler and lcov is installed. This
892        is mainly for the benefit of the developers.
894    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
895        unaddressable using valgrind annotations, allowing valgrind to detect
896        invalid memory accesses. This is mainly for the benefit of the developers.
898    25. (*UTF) can now be used to start a pattern in any of the three libraries.
900    26. Give configure error if --enable-cpp but no C++ compiler found.
903    Version 8.31 06-July-2012
904    -------------------------
906    1.  Fixing a wrong JIT test case and some compiler warnings.
908    2.  Removed a bashism from the RunTest script.
910    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
911        to unsigned type, result still unsigned" that was given by an MS compiler
912        on encountering the code "-sizeof(xxx)".
914    4.  Partial matching support is added to the JIT compiler.
916    5.  Fixed several bugs concerned with partial matching of items that consist
917        of more than one character:
919        (a) /^(..)\1/ did not partially match "aba" because checking references was
920            done on an "all or nothing" basis. This also applied to repeated
921            references.
923        (b) \R did not give a hard partial match if \r was found at the end of the
924            subject.
926        (c) \X did not give a hard partial match after matching one or more
927            characters at the end of the subject.
929        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
930            a partial match for the string "\r".
932        (e) When newline was set to CRLF, the metacharacter "." did not recognize
933            a partial match for a CR character at the end of the subject string.
935    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
936        running pcretest, the text "(JIT)" added to the output whenever JIT is
937        actually used to run the match.
939    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
940        or /S+[+] with a digit between 1 and 7.
942    8.  OP_NOT now supports any UTF character not just single-byte ones.
944    9.  (*MARK) control verb is now supported by the JIT compiler.
946    10. The command "./RunTest list" lists the available tests without actually
947        running any of them. (Because I keep forgetting what they all are.)
951    12. Applied a (slightly modified) user-supplied patch that improves performance
952        when the heap is used for recursion (compiled with --disable-stack-for-
953        recursion). Instead of malloc and free for each heap frame each time a
954        logical recursion happens, frames are retained on a chain and re-used where
955        possible. This sometimes gives as much as 30% improvement.
957    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
958        call.
960    14. As documented, (*COMMIT) is now confined to within a positive assertion.
962    15. It is now possible to link pcretest with libedit as an alternative to
963        libreadline.
965    16. (*COMMIT) control verb is now supported by the JIT compiler.
967    17. The Unicode data tables have been updated to Unicode 6.1.0.
969    18. Added --file-list option to pcregrep.
971    19. Added binary file support to pcregrep, including the -a, --binary-files,
972        -I, and --text options.
974    20. The madvise function is renamed for posix_madvise for QNX compatibility
975        reasons. Fixed by Giuseppe D'Angelo.
977    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
979    22. Changed the option for creating symbolic links for 16-bit man pages from
980        -s to -sf so that re-installing does not cause issues.
982    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
984    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
985        matches in certain environments (the workspace was not being correctly
986        retained). Also added to pcre_dfa_exec() a simple plausibility check on
987        some of the workspace data at the beginning of a restart.
989    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
990        was not doing so when it should - probably a typo introduced by SVN 528
991        (change 8.10/14).
993    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
994        \w+ when the character tables indicated that \x{c4} was a word character.
995        There were several related cases, all because the tests for doing a table
996        lookup were testing for characters less than 127 instead of 255.
998    27. If a pattern contains capturing parentheses that are not used in a match,
999        their slots in the ovector are set to -1. For those that are higher than
1000        any matched groups, this happens at the end of processing. In the case when
1001        there were back references that the ovector was too small to contain
1002        (causing temporary malloc'd memory to be used during matching), and the
1003        highest capturing number was not used, memory off the end of the ovector
1004        was incorrectly being set to -1. (It was using the size of the temporary
1005        memory instead of the true size.)
1007    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
1008        ovector size, it uses memory at the end of the block that it has got.
1010    29. Check for an overlong MARK name and give an error at compile time. The
1011        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
1013    30. JIT compiler update.
1015    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
1016        Rill for the patch.
1018    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
1020    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
1022    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
1023        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
1024        was enabled.
1026    35. Improve JIT code generation for greedy plus quantifier.
1028    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
1029        1 to "aa" instead of to an empty string. The bug affected repeated groups
1030        that could potentially match an empty string.
1032    37. Optimizing single character iterators in JIT.
1034    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
1035        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
1036        codepoints that are too big for the mode are faulted, and in a UTF mode,
1037        disallowed codepoints are also faulted.
1039    39. If PCRE was compiled with UTF support, in three places in the DFA
1040        matcher there was code that should only have been obeyed in UTF mode, but
1041        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
1042        processing when bytes with values greater than 127 were present. In 16-bit
1043        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
1044        both cases the values are those that cannot be the first data item in a UTF
1045        character. The three items that might have provoked this were recursions,
1046        possessively repeated groups, and atomic groups.
1048    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
1049        and pcregrep, because some OS require shared objects to be explicitly
1050        passed to ld, causing the link step to fail if they are not.
1052    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
1053        mode, patterns that started with \h* or \R* might be incorrectly matched.
1056    Version 8.30 04-February-2012
1057    -----------------------------
1059    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
1060        name is defined in ctype.h.
1062    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
1063        only in quite long subpatterns.
1065    3.  Removed the function pcre_info(), which has been obsolete and deprecated
1066        since it was replaced by pcre_fullinfo() in February 2000.
1068    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
1069        match a (*MARK), and the match failed at the start of the subject, a
1070        reference to memory before the start of the subject could occur. This bug
1071        was introduced by fix 17 of release 8.21.
1073    5.  A reference to an unset group with zero minimum repetition was giving
1074        totally wrong answers (in non-JavaScript-compatibility mode). For example,
1075        /(another)?(\1?)test/ matched against "hello world test". This bug was
1076        introduced in release 8.13.
1078    6.  Add support for 16-bit character strings (a large amount of work involving
1079        many changes and refactorings).
1081    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
1082        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
1083        from a file.
1085    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
1086        rounding is not applied in this particular case).
1088    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
1089        if they appear, or are escaped, in patterns.
1091    10. Get rid of a number of -Wunused-but-set-variable warnings.
1093    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
1094        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
1095        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
1096        also returns the mark "x". This bug applied to capturing parentheses,
1097        non-capturing parentheses, and atomic parentheses. It also applied to some
1098        assertions.
1100    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
1101        information out of configure.ac instead of relying on pcre.h.generic, which
1102        is not stored in the repository.
1104    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
1105        -lreadline.
1107    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
1109    15. Applied Graycode's patch to put the top-level frame on the stack rather
1110        than the heap when not using the stack for recursion. This gives a
1111        performance improvement in many cases when recursion is not deep.
1113    16. Experimental code added to "pcretest -C" to output the stack frame size.
1116    Version 8.21 12-Dec-2011
1117    ------------------------
1119    1.  Updating the JIT compiler.
1121    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1122        are added as well.
1124    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1125        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1126        calling _pcre_jit_exec. Some extra comments are added.
1128    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1129        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1130        was introduced by change 18 for 8.20.
1132    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1133        ECMA-262 standard.
1135    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1136        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1137        This bug was probably introduced by change 9 of 8.13.
1139    7.  While fixing 6 above, I noticed that a number of other items were being
1140        incorrectly rejected as "not fixed length". This arose partly because newer
1141        opcodes had not been added to the fixed-length checking code. I have (a)
1142        corrected the bug and added tests for these items, and (b) arranged for an
1143        error to occur if an unknown opcode is encountered while checking for fixed
1144        length instead of just assuming "not fixed length". The items that were
1145        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1146        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1147        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1149    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1150        being incorrectly compiled and would have given unpredicatble results.
1152    9.  A possessively repeated subpattern with minimum repeat count greater than
1153        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1154        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1155        the first (A) could occur when it should not.
1157    10. Add a cast and remove a redundant test from the code.
1159    11. JIT should use pcre_malloc/pcre_free for allocation.
1161    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1162        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1163        is anything other than /usr, -L is still shown).
1165    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1167    14. Perl does not support \N without a following name in a [] class; PCRE now
1168        also gives an error.
1170    15. If a forward reference was repeated with an upper limit of around 2000,
1171        it caused the error "internal error: overran compiling workspace". The
1172        maximum number of forward references (including repeats) was limited by the
1173        internal workspace, and dependent on the LINK_SIZE. The code has been
1174        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1175        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1176        of around 200,000 forward references. While doing this, I also speeded up
1177        the filling in of repeated forward references.
1179    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1180        incorrectly expecting the subject to contain another "a" after the start.
1182    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1183        in the match, the SKIP should be ignored. This was not happening; instead
1184        the SKIP was being treated as NOMATCH. For patterns such as
1185        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1186        tested.
1188    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1189        now much more compatible with Perl, in particular in cases where the result
1190        is a non-match for a non-anchored pattern. For example, if
1191        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1192        "m", where previously it did not return a name. A side effect of this
1193        change is that for partial matches, the last encountered mark name is
1194        returned, as for non matches. A number of tests that were previously not
1195        Perl-compatible have been moved into the Perl-compatible test files. The
1196        refactoring has had the pleasing side effect of removing one argument from
1197        the match() function, thus reducing its stack requirements.
1199    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1200        subsequent uses of /S (without +) incorrectly behaved like /S+.
1202    21. Retrieve executable code size support for the JIT compiler and fixing
1203        some warnings.
1205    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1206        not work when the shorter character appeared right at the end of the
1207        subject string.
1209    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1210        systems.
1212    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1213        output it when the /M option is used in pcretest.
1215    25. The CheckMan script was not being included in the distribution. Also, added
1216        an explicit "perl" to run Perl scripts from the PrepareRelease script
1217        because this is reportedly needed in Windows.
1219    26. If study data was being save in a file and studying had not found a set of
1220        "starts with" bytes for the pattern, the data written to the file (though
1221        never used) was taken from uninitialized memory and so caused valgrind to
1222        complain.
1224    27. Updated RunTest.bat as provided by Sheri Pierce.
1226    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1228    29. Computation of memory usage for the table of capturing group names was
1229        giving an unnecessarily large value.
1232    Version 8.20 21-Oct-2011
1233    ------------------------
1235    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1236        a POSIX class. After further experiments with Perl, which convinced me that
1237        Perl has bugs and confusions, a closing square bracket is no longer allowed
1238        in a POSIX name. This bug also affected patterns with classes that started
1239        with full stops.
1241    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1242        captured substring, but while checking the failing first alternative,
1243        substring 1 is temporarily captured. If the output vector supplied to
1244        pcre_exec() was not big enough for this capture, the yield of the function
1245        was still zero ("insufficient space for captured substrings"). This cannot
1246        be totally fixed without adding another stack variable, which seems a lot
1247        of expense for a edge case. However, I have improved the situation in cases
1248        such as /(a)(b)x|abc/ matched against "abc", where the return code
1249        indicates that fewer than the maximum number of slots in the ovector have
1250        been set.
1252    3.  Related to (2) above: when there are more back references in a pattern than
1253        slots in the output vector, pcre_exec() uses temporary memory during
1254        matching, and copies in the captures as far as possible afterwards. It was
1255        using the entire output vector, but this conflicts with the specification
1256        that only 2/3 is used for passing back captured substrings. Now it uses
1257        only the first 2/3, for compatibility. This is, of course, another edge
1258        case.
1260    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1261        main code base, and can be used by building with --enable-jit. When this is
1262        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1263        runtime --no-jit option is given.
1265    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1266        ovector, the return from the function was zero, implying that there were
1267        other matches that did not fit. The correct "exactly full" value is now
1268        returned.
1270    6.  If a subpattern that was called recursively or as a subroutine contained
1271        (*PRUNE) or any other control that caused it to give a non-standard return,
1272        invalid errors such as "Error -26 (nested recursion at the same subject
1273        position)" or even infinite loops could occur.
1275    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1276        computing the minimum length on reaching *ACCEPT, and so ended up with the
1277        wrong value of 1 rather than 0. Further investigation indicates that
1278        computing a minimum subject length in the presence of *ACCEPT is difficult
1279        (think back references, subroutine calls), and so I have changed the code
1280        so that no minimum is registered for a pattern that contains *ACCEPT.
1282    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1283        it was not handled as intended. [But see 16 below.]
1285    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1286        Sheri Pierce.
1288    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1289        the first byte in a match must be "a".
1291    11. Change 17 for 8.13 increased the recursion depth for patterns like
1292        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1293        pattern contains any instances of (*THEN). If it does not, the old
1294        optimizations are restored. It would be nice to do this on a per-group
1295        basis, but at the moment that is not feasible.
1297    12. In some environments, the output of pcretest -C is CRLF terminated. This
1298        broke RunTest's code that checks for the link size. A single white space
1299        character after the value is now allowed for.
1301    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1302        For "fr", it uses the Windows-specific input and output files.
1304    14. If (*THEN) appeared in a group that was called recursively or as a
1305        subroutine, it did not work as intended. [But see next item.]
1307    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1308        pattern fragments (but not containing any | characters). If A and B are
1309        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1310        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1311        D. In other words, Perl considers parentheses that do not contain any |
1312        characters to be part of a surrounding alternative, whereas PCRE was
1313        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1314        differently. PCRE now behaves in the same way as Perl, except in the case
1315        of subroutine/recursion calls such as (?1) which have in any case always
1316        been different (but PCRE had them first :-).
1318    16. Related to 15 above: Perl does not treat the | in a conditional group as
1319        creating alternatives. Such a group is treated in the same way as an
1320        ordinary group without any | characters when processing (*THEN). PCRE has
1321        been changed to match Perl's behaviour.
1323    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1324        RunGrepTest script failed.
1326    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1327        inevitable for groups that contain captures, but it can lead to a lot of
1328        stack use in large patterns. The old behaviour has been restored for atomic
1329        groups that do not contain any capturing parentheses.
1331    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1332        suppress the check for a minimum subject length at run time. (If it was
1333        given to pcre_exec() or pcre_dfa_exec() it did work.)
1335    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1336        fail to work when decoding hex characters in data strings in EBCDIC
1337        environments.
1339    21. It appears that in at least one Mac OS environment, the isxdigit() function
1340        is implemented as a macro that evaluates to its argument more than once,
1341        contravening the C 90 Standard (I haven't checked a later standard). There
1342        was an instance in pcretest which caused it to go wrong when processing
1343        \x{...} escapes in subject strings. The has been rewritten to avoid using
1344        things like p++ in the argument of isxdigit().
1347    Version 8.13 16-Aug-2011
1348  ------------------------  ------------------------
1350  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 98  Version 8.13 02-Aug-2011 Line 1441  Version 8.13 02-Aug-2011
1441      tail recursion to cut down on stack usage. Unfortunately, now that there is      tail recursion to cut down on stack usage. Unfortunately, now that there is
1442      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
1443      no longer possible because the return has to be checked for (*THEN). These      no longer possible because the return has to be checked for (*THEN). These
1444      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
1446  18. If a pattern containing \R was studied, it was assumed that \R always  18. If a pattern containing \R was studied, it was assumed that \R always
1447      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
# Line 189  Version 8.13 02-Aug-2011 Line 1532  Version 8.13 02-Aug-2011
1532      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1533      unescaped square brackets may also appear as part of class names. For      unescaped square brackets may also appear as part of class names. For
1534      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1535      more like Perl.      more like Perl. (But see 8.20/1 above.)
1537  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1538      was because it thought it was \N{name}, which is not supported).      was because it thought it was \N{name}, which is not supported).
# Line 224  Version 8.13 02-Aug-2011 Line 1567  Version 8.13 02-Aug-2011
1567      (a) The default value of the buffer size parameter has been increased from      (a) The default value of the buffer size parameter has been increased from
1568          8K to 20K. (The actual buffer used is three times this size.)          8K to 20K. (The actual buffer used is three times this size.)
1570      (b) The default can be changed by ./configure --with-pcregrep-bufsiz when      (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1571          PCRE is built.          PCRE is built.
1573      (c) A --buffer-size=n option has been added to pcregrep, to allow the size      (c) A --buffer-size=n option has been added to pcregrep, to allow the size
# Line 245  Version 8.13 02-Aug-2011 Line 1588  Version 8.13 02-Aug-2011
1588  47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a  47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1589      complete match instead of a partial match. This bug was dependent on both      complete match instead of a partial match. This bug was dependent on both
1590      the PCRE_UTF8 and PCRE_DOTALL options being set.      the PCRE_UTF8 and PCRE_DOTALL options being set.
1592  48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the  48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1593      starting byte set, because \b was not being ignored.      starting byte set, because \b was not being ignored.
1596  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
# Line 900  Version 7.9 11-Apr-09 Line 2243  Version 7.9 11-Apr-09
2243  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
2244      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
2245      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2246      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2247        8.33.]
2249  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
2250      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 1143  Version 7.7 07-May-08 Line 2487  Version 7.7 07-May-08
2487      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2488      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2489      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2490      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2491      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2492      was subsequently set up correctly.)      was subsequently set up correctly.)

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