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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.02 01-Mar-2010  Version 8.37 xx-xxx-2015
5    ------------------------
6    
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".
13    
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.
16    
17    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
18        unrecognized modifier, a crash could occur.
19    
20    4.  An attempt to do global matching in pcretest with a zero-length ovector
21        caused a crash.
22    
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.
26    
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.
30    
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))/.
33    
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.
45    
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.
50    
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).
55    
56    
57    Version 8.36 26-September-2014
58    ------------------------------
59    
60    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
61        -Wmissing-field-initializers and -Wunused-parameter.
62    
63    2.  The tests for quantifiers being too big (greater than 65535) were being
64        applied after reading the number, and stupidly assuming that integer
65        overflow would give a negative number. The tests are now applied as the
66        numbers are read.
67    
68    3.  Tidy code in pcre_exec.c where two branches that used to be different are
69        now the same.
70    
71    4.  The JIT compiler did not generate match limit checks for certain
72        bracketed expressions with quantifiers. This may lead to exponential
73        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
74        issue should be resolved now.
75    
76    5.  Fixed an issue, which occures when nested alternatives are optimized
77        with table jumps.
78    
79    6.  Inserted two casts and changed some ints to size_t in the light of some
80        reported 64-bit compiler warnings (Bugzilla 1477).
81    
82    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
83        an empty string, which sometimes were behaving incorrectly in the
84        interpreter (though correctly in the JIT matcher). This pcretest input is
85        an example:
86    
87          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
88          NON QUOTED "QUOT""ED" AFTER "NOT MATCHED
89    
90        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
91        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
92        for an empty string was breaking the inner loop and carrying on at a lower
93        level, when possessive repeated groups should always return to a higher
94        level as they have no backtrack points in them. The empty string test now
95        occurs at the outer level.
96    
97    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
98        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
99    
100    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
101        doesn't).
102    
103    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
104        to hold a pattern to be incorrectly computed (too small) when there were
105        named back references to duplicated names. This could cause "internal
106        error: code overflow" or "double free or corruption" or other memory
107        handling errors.
108    
109    11. When named subpatterns had the same prefixes, back references could be
110        confused. For example, in this pattern:
111    
112          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
113    
114        the reference to 'Name' was incorrectly treated as a reference to a
115        duplicate name.
116    
117    12. A pattern such as /^s?c/mi8 where the optional character has more than
118        one "other case" was incorrectly compiled such that it would only try to
119        match starting at "c".
120    
121    13. When a pattern starting with \s was studied, VT was not included in the
122        list of possible starting characters; this should have been part of the
123        8.34/18 patch.
124    
125    14. If a character class started [\Qx]... where x is any character, the class
126        was incorrectly terminated at the ].
127    
128    15. If a pattern that started with a caseless match for a character with more
129        than one "other case" was studied, PCRE did not set up the starting code
130        unit bit map for the list of possible characters. Now it does. This is an
131        optimization improvement, not a bug fix.
132    
133    16. The Unicode data tables have been updated to Unicode 7.0.0.
134    
135    17. Fixed a number of memory leaks in pcregrep.
136    
137    18. Avoid a compiler warning (from some compilers) for a function call with
138        a cast that removes "const" from an lvalue by using an intermediate
139        variable (to which the compiler does not object).
140    
141    19. Incorrect code was compiled if a group that contained an internal recursive
142        back reference was optional (had quantifier with a minimum of zero). This
143        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
144        caused segmentation faults because of stack overflows at compile time.
145    
146    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
147        group that is quantified with an indefinite repeat, caused a compile-time
148        loop which used up all the system stack and provoked a segmentation fault.
149        This was not the same bug as 19 above.
150    
151    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
152        Patch by Mike Frysinger.
153    
154    
155    Version 8.35 04-April-2014
156    --------------------------
157    
158    1.  A new flag is set, when property checks are present in an XCLASS.
159        When this flag is not set, PCRE can perform certain optimizations
160        such as studying these XCLASS-es.
161    
162    2.  The auto-possessification of character sets were improved: a normal
163        and an extended character set can be compared now. Furthermore
164        the JIT compiler optimizes more character set checks.
165    
166    3.  Got rid of some compiler warnings for potentially uninitialized variables
167        that show up only when compiled with -O2.
168    
169    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
170        of a match later then the end of the match. The pcretest program was not
171        handling the case sensibly - it was outputting from the start to the next
172        binary zero. It now reports this situation in a message, and outputs the
173        text from the end to the start.
174    
175    5.  Fast forward search is improved in JIT. Instead of the first three
176        characters, any three characters with fixed position can be searched.
177        Search order: first, last, middle.
178    
179    6.  Improve character range checks in JIT. Characters are read by an inprecise
180        function now, which returns with an unknown value if the character code is
181        above a certain threshold (e.g: 256). The only limitation is that the value
182        must be bigger than the threshold as well. This function is useful when
183        the characters above the threshold are handled in the same way.
184    
185    7.  The macros whose names start with RAWUCHAR are placeholders for a future
186        mode in which only the bottom 21 bits of 32-bit data items are used. To
187        make this more memorable for those maintaining the code, the names have
188        been changed to start with UCHAR21, and an extensive comment has been added
189        to their definition.
190    
191    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
192        to the export list in Makefile.am (they were accidentally omitted from the
193        8.34 tarball).
194    
195    9.  The informational output from pcretest used the phrase "starting byte set"
196        which is inappropriate for the 16-bit and 32-bit libraries. As the output
197        for "first char" and "need char" really means "non-UTF-char", I've changed
198        "byte" to "char", and slightly reworded the output. The documentation about
199        these values has also been (I hope) clarified.
200    
201    10. Another JIT related optimization: use table jumps for selecting the correct
202        backtracking path, when more than four alternatives are present inside a
203        bracket.
204    
205    11. Empty match is not possible, when the minimum length is greater than zero,
206        and there is no \K in the pattern. JIT should avoid empty match checks in
207        such cases.
208    
209    12. In a caseless character class with UCP support, when a character with more
210        than one alternative case was not the first character of a range, not all
211        the alternative cases were added to the class. For example, s and \x{17f}
212        are both alternative cases for S: the class [RST] was handled correctly,
213        but [R-T] was not.
214    
215    13. The configure.ac file always checked for pthread support when JIT was
216        enabled. This is not used in Windows, so I have put this test inside a
217        check for the presence of windows.h (which was already tested for).
218    
219    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
220        The algorithm provides a way to skip certain starting offsets, and usually
221        faster than linear prefix searches.
222    
223    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
224        as for 'fr_FR' and 'french'. For some reason, however, it then used the
225        Windows-specific input and output files, which have 'french' screwed in.
226        So this could never have worked. One of the problems with locales is that
227        they aren't always the same. I have now updated RunTest so that it checks
228        the output of the locale test (test 3) against three different output
229        files, and it allows the test to pass if any one of them matches. With luck
230        this should make the test pass on some versions of Solaris where it was
231        failing. Because of the uncertainty, the script did not used to stop if
232        test 3 failed; it now does. If further versions of a French locale ever
233        come to light, they can now easily be added.
234    
235    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
236        there was a message during ./configure, but it did not stop. This now
237        provokes an error. The invalid example in README has been corrected.
238        If a value less than the minimum is given, the minimum value has always
239        been used, but now a warning is given.
240    
241    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
242        was a bug in the test system, which is now fixed. Also, the list of various
243        configurations that are tested for each release did not have one with both
244        16/32 bits and --enable-bar-anycrlf. It now does.
245    
246    18. pcretest was missing "-C bsr" for displaying the \R default setting.
247    
248    19. Little endian PowerPC systems are supported now by the JIT compiler.
249    
250    20. The fast forward newline mechanism could enter to an infinite loop on
251        certain invalid UTF-8 input. Although we don't support these cases
252        this issue can be fixed by a performance optimization.
253    
254    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
255        not take account if existing stack usage. There is now a new global
256        variable called pcre_stack_guard that can be set to point to an external
257        function to check stack availability. It is called at the start of
258        processing every parenthesized group.
259    
260    22. A typo in the code meant that in ungreedy mode the max/min qualifier
261        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
262        not match "ab".
263    
264    23. When UTF was disabled, the JIT program reported some incorrect compile
265        errors. These messages are silenced now.
266    
267    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
268        compiler.
269    
270    25. Change all the temporary files used in RunGrepTest to be different to those
271        used by RunTest so that the tests can be run simultaneously, for example by
272        "make -j check".
273    
274    
275    Version 8.34 15-December-2013
276    -----------------------------
277    
278    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
279        executable memory. Patch inspired by Carsten Klein.
280    
281    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
282        this macro is never tested and has no effect, because the work to support
283        coverage involves only compiling and linking options and special targets in
284        the Makefile. The comment in config.h implied that defining the macro would
285        enable coverage support, which is totally false. There was also support for
286        setting this macro in the CMake files (my fault, I just copied it from
287        configure). SUPPORT_GCOV has now been removed.
288    
289    3.  Make a small performance improvement in strlen16() and strlen32() in
290        pcretest.
291    
292    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
293        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
294        these cases). There was also one in pcretest.c.
295    
296    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
297    
298    6.  In UTF mode, the code for checking whether a group could match an empty
299        string (which is used for indefinitely repeated groups to allow for
300        breaking an infinite loop) was broken when the group contained a repeated
301        negated single-character class with a character that occupied more than one
302        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
303        UTF-8 mode). The effect was undefined: the group might or might not be
304        deemed as matching an empty string, or the program might have crashed.
305    
306    7.  The code for checking whether a group could match an empty string was not
307        recognizing that \h, \H, \v, \V, and \R must match a character.
308    
309    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
310        an empty string. If it can, pcretest shows this in its information output.
311    
312    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
313        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
314        matched by pcre_exec() without using JIT:
315    
316        (a) If the rest of the pattern did not match after a maximal run of
317            grapheme clusters, the code for backing up to try with fewer of them
318            did not always back up over a full grapheme when characters that do not
319            have the modifier quality were involved, e.g. Hangul syllables.
320    
321        (b) If the match point in a subject started with modifier character, and
322            there was no match, the code could incorrectly back up beyond the match
323            point, and potentially beyond the first character in the subject,
324            leading to a segfault or an incorrect match result.
325    
326    10. A conditional group with an assertion condition could lead to PCRE
327        recording an incorrect first data item for a match if no other first data
328        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
329        first data item, and therefore matched "ca" after "c" instead of at the
330        start.
331    
332    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
333        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
334    
335    12. The source of pcregrep now includes z/OS-specific code so that it can be
336        compiled for z/OS as part of the special z/OS distribution.
337    
338    13. Added the -T and -TM options to pcretest.
339    
340    14. The code in pcre_compile.c for creating the table of named capturing groups
341        has been refactored. Instead of creating the table dynamically during the
342        actual compiling pass, the information is remembered during the pre-compile
343        pass (on the stack unless there are more than 20 named groups, in which
344        case malloc() is used) and the whole table is created before the actual
345        compile happens. This has simplified the code (it is now nearly 150 lines
346        shorter) and prepared the way for better handling of references to groups
347        with duplicate names.
348    
349    15. A back reference to a named subpattern when there is more than one of the
350        same name now checks them in the order in which they appear in the pattern.
351        The first one that is set is used for the reference. Previously only the
352        first one was inspected. This change makes PCRE more compatible with Perl.
353    
354    16. Unicode character properties were updated from Unicode 6.3.0.
355    
356    17. The compile-time code for auto-possessification has been refactored, based
357        on a patch by Zoltan Herczeg. It now happens after instead of during
358        compilation. The code is cleaner, and more cases are handled. The option
359        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
360        options in pcretest are provided to set it. It can also be set by
361        (*NO_AUTO_POSSESS) at the start of a pattern.
362    
363    18. The character VT has been added to the default ("C" locale) set of
364        characters that match \s and are generally treated as white space,
365        following this same change in Perl 5.18. There is now no difference between
366        "Perl space" and "POSIX space". Whether VT is treated as white space in
367        other locales depends on the locale.
368    
369    19. The code for checking named groups as conditions, either for being set or
370        for being recursed, has been refactored (this is related to 14 and 15
371        above). Processing unduplicated named groups should now be as fast at
372        numerical groups, and processing duplicated groups should be faster than
373        before.
374    
375    20. Two patches to the CMake build system, by Alexander Barkov:
376    
377          (1) Replace the "source" command by "." in CMakeLists.txt because
378              "source" is a bash-ism.
379    
380          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
381              without these the CMake build does not work on Solaris.
382    
383    21. Perl has changed its handling of \8 and \9. If there is no previously
384        encountered capturing group of those numbers, they are treated as the
385        literal characters 8 and 9 instead of a binary zero followed by the
386        literals. PCRE now does the same.
387    
388    22. Following Perl, added \o{} to specify codepoints in octal, making it
389        possible to specify values greater than 0777 and also making them
390        unambiguous.
391    
392    23. Perl now gives an error for missing closing braces after \x{... instead of
393        treating the string as literal. PCRE now does the same.
394    
395    24. RunTest used to grumble if an inappropriate test was selected explicitly,
396        but just skip it when running all tests. This make it awkward to run ranges
397        of tests when one of them was inappropriate. Now it just skips any
398        inappropriate tests, as it always did when running all tests.
399    
400    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
401        character types such as \d or \w, too many callouts were inserted, and the
402        data that they returned was rubbish.
403    
404    26. In UCP mode, \s was not matching two of the characters that Perl matches,
405        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
406        were matched by \h. The code has now been refactored so that the lists of
407        the horizontal and vertical whitespace characters used for \h and \v (which
408        are defined only in one place) are now also used for \s.
409    
410    27. Add JIT support for the 64 bit TileGX architecture.
411        Patch by Jiong Wang (Tilera Corporation).
412    
413    28. Possessive quantifiers for classes (both explicit and automatically
414        generated) now use special opcodes instead of wrapping in ONCE brackets.
415    
416    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
417        (because it's meaningless), this was not happening when PCRE_CASELESS was
418        set. Not wrong, but inefficient.
419    
420    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
421        properties for \w, \d, etc) is present in a test regex. Otherwise if the
422        test contains no characters greater than 255, Perl doesn't realise it
423        should be using Unicode semantics.
424    
425    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
426        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
427        does in Unicode mode.
428    
429    32. Added the "forbid" facility to pcretest so that putting tests into the
430        wrong test files can sometimes be quickly detected.
431    
432    33. There is now a limit (default 250) on the depth of nesting of parentheses.
433        This limit is imposed to control the amount of system stack used at compile
434        time. It can be changed at build time by --with-parens-nest-limit=xxx or
435        the equivalent in CMake.
436    
437    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
438        errors. Perl warns for these when in warning mode, but PCRE has no facility
439        for giving warnings.
440    
441    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
442        However, this was not working for (?!) because it is optimized to (*FAIL),
443        for which PCRE does not allow quantifiers. The optimization is now disabled
444        when a quantifier follows (?!). I can't see any use for this, but it makes
445        things uniform.
446    
447    36. Perl no longer allows group names to start with digits, so I have made this
448        change also in PCRE. It simplifies the code a bit.
449    
450    37. In extended mode, Perl ignores spaces before a + that indicates a
451        possessive quantifier. PCRE allowed a space before the quantifier, but not
452        before the possessive +. It now does.
453    
454    38. The use of \K (reset reported match start) within a repeated possessive
455        group such as (a\Kb)*+ was not working.
456    
457    40. Document that the same character tables must be used at compile time and
458        run time, and that the facility to pass tables to pcre_exec() and
459        pcre_dfa_exec() is for use only with saved/restored patterns.
460    
461    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
462        features for Builds with MSVC:
463    
464        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
465           builds). The .rc files can be used to set FileDescription and many other
466           attributes.
467    
468        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
469           This allows higher-level build scripts which want .pdb files to avoid
470           hard-coding the exact files needed."
471    
472    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
473        mean "start of word" and "end of word", respectively, as a transition aid.
474    
475    43. A minimizing repeat of a class containing codepoints greater than 255 in
476        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
477        compiled to use the heap for recursion.
478    
479    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
480        is configured.
481    
482    
483    Version 8.33 28-May-2013
484    ------------------------
485    
486    1.  Added 'U' to some constants that are compared to unsigned integers, to
487        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
488        variables that are added to signed variables, to ensure the result is
489        signed and can be negated.
490    
491    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
492        CMake config files.
493    
494    3.  Revise the creation of config.h.generic so that all boolean macros are
495        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
496        overriding via -D on the command line possible.
497    
498    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
499        to unsigned int is reported to make a quite noticeable speed difference in
500        a specific Windows environment. Testing on Linux did also appear to show
501        some benefit (and it is clearly not harmful). Also fixed the definition of
502        Xop which should be unsigned.
503    
504    5.  Related to (4), changing the definition of the intermediate variable cc
505        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
506        improvements.
507    
508    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
509        unnecessary spaces.
510    
511    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
512        and later.
513    
514    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
515    
516    9.  Optimizing fast_forward_start_bits in JIT.
517    
518    10. Adding support for callouts in JIT, and fixing some issues revealed
519        during this work. Namely:
520    
521        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
522    
523        (b) Minimum length was not checked before the matching is started.
524    
525    11. The value of capture_last that is passed to callouts was incorrect in some
526        cases when there was a capture on one path that was subsequently abandoned
527        after a backtrack. Also, the capture_last value is now reset after a
528        recursion, since all captures are also reset in this case.
529    
530    12. The interpreter no longer returns the "too many substrings" error in the
531        case when an overflowing capture is in a branch that is subsequently
532        abandoned after a backtrack.
533    
534    13. In the pathological case when an offset vector of size 2 is used, pcretest
535        now prints out the matched string after a yield of 0 or 1.
536    
537    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
538        Only supported by the JIT compiler at the moment.
539    
540    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
541    
542    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
543        offset of the starting point of the matching process, provided the offsets
544        vector is large enough.
545    
546    17. The \A escape now records a lookbehind value of 1, though its execution
547        does not actually inspect the previous character. This is to ensure that,
548        in partial multi-segment matching, at least one character from the old
549        segment is retained when a new segment is processed. Otherwise, if there
550        are no lookbehinds in the pattern, \A might match incorrectly at the start
551        of a new segment.
552    
553    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
554    
555    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
556        gives some modest performance improvement in 8-bit mode.
557    
558    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
559        be expressed in certain programming languages using Universal Character
560        Names.
561    
562    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
563        which points out that "non characters" are not "characters that may not
564        appear in Unicode strings" but rather "characters that are reserved for
565        internal use and have only local meaning".
566    
567    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
568        there was a conditional group that depended on an assertion, if the
569        assertion was false, the callout that immediately followed the alternation
570        in the condition was skipped when pcre_exec() was used for matching.
571    
572    23. Allow an explicit callout to be inserted before an assertion that is the
573        condition for a conditional group, for compatibility with automatic
574        callouts, which always insert a callout at this point.
575    
576    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
577        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
578    
579    25. (*PRUNE) is now supported by the JIT compiler.
580    
581    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
582    
583    27. Fix the case where there are two or more SKIPs with arguments that may be
584        ignored.
585    
586    28. (*SKIP) is now supported by the JIT compiler.
587    
588    29. (*THEN) is now supported by the JIT compiler.
589    
590    30. Update RunTest with additional test selector options.
591    
592    31. The way PCRE handles backtracking verbs has been changed in two ways.
593    
594        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
595        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
596        backtracking. In some cases this makes it more Perl-compatible, but Perl's
597        rather obscure rules do not always do the same thing.
598    
599        (2) Previously, backtracking verbs were confined within assertions. This is
600        no longer the case for positive assertions, except for (*ACCEPT). Again,
601        this sometimes improves Perl compatibility, and sometimes does not.
602    
603    32. A number of tests that were in test 2 because Perl did things differently
604        have been moved to test 1, because either Perl or PCRE has changed, and
605        these tests are now compatible.
606    
607    32. Backtracking control verbs are now handled in the same way in JIT and
608        interpreter.
609    
610    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
611        contained a forward subroutine reference caused a compile error.
612    
613    34. Auto-detect and optimize limited repetitions in JIT.
614    
615    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
616        blocking (*UTF) etc.
617    
618    36. In the interpreter, maximizing pattern repetitions for characters and
619        character types now use tail recursion, which reduces stack usage.
620    
621    37. The value of the max lookbehind was not correctly preserved if a compiled
622        and saved regex was reloaded on a host of different endianness.
623    
624    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
625        of the compiled pattern block, expand the flags field from 16 to 32 bits
626        because it was almost full.
627    
628    39. Try madvise first before posix_madvise.
629    
630    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
631        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
632        original change locked out all matches of empty strings. This has been
633        changed so that one match of an empty string per line is recognized.
634        Subsequent searches on the same line (for colouring or for --only-matching,
635        for example) do not recognize empty strings.
636    
637    41. Applied a user patch to fix a number of spelling mistakes in comments.
638    
639    42. Data lines longer than 65536 caused pcretest to crash.
640    
641    43. Clarified the data type for length and startoffset arguments for pcre_exec
642        and pcre_dfa_exec in the function-specific man pages, where they were
643        explicitly stated to be in bytes, never having been updated. I also added
644        some clarification to the pcreapi man page.
645    
646    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
647        a segmentation fault.
648    
649    
650    Version 8.32 30-November-2012
651    -----------------------------
652    
653    1.  Improved JIT compiler optimizations for first character search and single
654        character iterators.
655    
656    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
657        Patch by Daniel Richard G.
658    
659    3.  Single character iterator optimizations in the JIT compiler.
660    
661    4.  Improved JIT compiler optimizations for character ranges.
662    
663    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
664        Reported by Giuseppe D'Angelo.
665    
666    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
667        of a line, was being set incorrectly in cases where .* appeared inside
668        atomic brackets at the start of a pattern, or where there was a subsequent
669        *PRUNE or *SKIP.
670    
671    7.  Improved instruction cache flush for POWER/PowerPC.
672        Patch by Daniel Richard G.
673    
674    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
675        grep:
676    
677        (a) There is now no limit to the number of patterns to be matched.
678    
679        (b) An error is given if a pattern is too long.
680    
681        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
682            are now supported.
683    
684        (d) --exclude-from and --include-from (multiple use) have been added.
685    
686        (e) Exclusions and inclusions now apply to all files and directories, not
687            just to those obtained from scanning a directory recursively.
688    
689        (f) Multiple uses of -f and --file-list are now supported.
690    
691        (g) In a Windows environment, the default for -d has been changed from
692            "read" (the GNU grep default) to "skip", because otherwise the presence
693            of a directory in the file list provokes an error.
694    
695        (h) The documentation has been revised and clarified in places.
696    
697    9.  Improve the matching speed of capturing brackets.
698    
699    10. Changed the meaning of \X so that it now matches a Unicode extended
700        grapheme cluster.
701    
702    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
703        out POSIX threads when JIT support is configured.
704    
705    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
706    
707    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
708        structure could go wrong in environments where size_t is not the same size
709        as int.
710    
711    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
712        set.
713    
714    15. The EBCDIC support had decayed; later updates to the code had included
715        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
716        general tidy up of EBCDIC-related issues, and the documentation was also
717        not quite right. There is now a test that can be run on ASCII systems to
718        check some of the EBCDIC-related things (but is it not a full test).
719    
720    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
721        in a small tidy to the code.
722    
723    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
724    
725    18. If the --only-matching (-o) option in pcregrep is specified multiple
726        times, each one causes appropriate output. For example, -o1 -o2 outputs the
727        substrings matched by the 1st and 2nd capturing parentheses. A separating
728        string can be specified by --om-separator (default empty).
729    
730    19. Improving the first n character searches.
731    
732    20. Turn case lists for horizontal and vertical white space into macros so that
733        they are defined only once.
734    
735    21. This set of changes together give more compatible Unicode case-folding
736        behaviour for characters that have more than one other case when UCP
737        support is available.
738    
739        (a) The Unicode property table now has offsets into a new table of sets of
740            three or more characters that are case-equivalent. The MultiStage2.py
741            script that generates these tables (the pcre_ucd.c file) now scans
742            CaseFolding.txt instead of UnicodeData.txt for character case
743            information.
744    
745        (b) The code for adding characters or ranges of characters to a character
746            class has been abstracted into a generalized function that also handles
747            case-independence. In UTF-mode with UCP support, this uses the new data
748            to handle characters with more than one other case.
749    
750        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
751            whose other case is greater than 256 are now correctly matched
752            caselessly. Previously, the high codepoint matched the low one, but not
753            vice versa.
754    
755        (d) The processing of \h, \H, \v, and \ in character classes now makes use
756            of the new class addition function, using character lists defined as
757            macros alongside the case definitions of 20 above.
758    
759        (e) Caseless back references now work with characters that have more than
760            one other case.
761    
762        (f) General caseless matching of characters with more than one other case
763            is supported.
764    
765    22. Unicode character properties were updated from Unicode 6.2.0
766    
767    23. Improved CMake support under Windows. Patch by Daniel Richard G.
768    
769    24. Add support for 32-bit character strings, and UTF-32
770    
771    25. Major JIT compiler update (code refactoring and bugfixing).
772        Experimental Sparc 32 support is added.
773    
774    26. Applied a modified version of Daniel Richard G's patch to create
775        pcre.h.generic and config.h.generic by "make" instead of in the
776        PrepareRelease script.
777    
778    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
779        pcre_compile.c when checking for a zero character.
780    
781    28. Introducing a native interface for JIT. Through this interface, the compiled
782        machine code can be directly executed. The purpose of this interface is to
783        provide fast pattern matching, so several sanity checks are not performed.
784        However, feature tests are still performed. The new interface provides
785        1.4x speedup compared to the old one.
786    
787    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
788        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
789        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
790    
791    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
792        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
793        the "old" RFC 2279). Instead, it ended up passing a negative length to
794        pcre_exec().
795    
796    31. Add support for GCC's visibility feature to hide internal functions.
797    
798    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
799        "unknown -C option" after outputting 0 or 1.
800    
801    33. There is now support for generating a code coverage report for the test
802        suite in environments where gcc is the compiler and lcov is installed. This
803        is mainly for the benefit of the developers.
804    
805    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
806        unaddressable using valgrind annotations, allowing valgrind to detect
807        invalid memory accesses. This is mainly for the benefit of the developers.
808    
809    25. (*UTF) can now be used to start a pattern in any of the three libraries.
810    
811    26. Give configure error if --enable-cpp but no C++ compiler found.
812    
813    
814    Version 8.31 06-July-2012
815    -------------------------
816    
817    1.  Fixing a wrong JIT test case and some compiler warnings.
818    
819    2.  Removed a bashism from the RunTest script.
820    
821    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
822        to unsigned type, result still unsigned" that was given by an MS compiler
823        on encountering the code "-sizeof(xxx)".
824    
825    4.  Partial matching support is added to the JIT compiler.
826    
827    5.  Fixed several bugs concerned with partial matching of items that consist
828        of more than one character:
829    
830        (a) /^(..)\1/ did not partially match "aba" because checking references was
831            done on an "all or nothing" basis. This also applied to repeated
832            references.
833    
834        (b) \R did not give a hard partial match if \r was found at the end of the
835            subject.
836    
837        (c) \X did not give a hard partial match after matching one or more
838            characters at the end of the subject.
839    
840        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
841            a partial match for the string "\r".
842    
843        (e) When newline was set to CRLF, the metacharacter "." did not recognize
844            a partial match for a CR character at the end of the subject string.
845    
846    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
847        running pcretest, the text "(JIT)" added to the output whenever JIT is
848        actually used to run the match.
849    
850    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
851        or /S+[+] with a digit between 1 and 7.
852    
853    8.  OP_NOT now supports any UTF character not just single-byte ones.
854    
855    9.  (*MARK) control verb is now supported by the JIT compiler.
856    
857    10. The command "./RunTest list" lists the available tests without actually
858        running any of them. (Because I keep forgetting what they all are.)
859    
860    11. Add PCRE_INFO_MAXLOOKBEHIND.
861    
862    12. Applied a (slightly modified) user-supplied patch that improves performance
863        when the heap is used for recursion (compiled with --disable-stack-for-
864        recursion). Instead of malloc and free for each heap frame each time a
865        logical recursion happens, frames are retained on a chain and re-used where
866        possible. This sometimes gives as much as 30% improvement.
867    
868    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
869        call.
870    
871    14. As documented, (*COMMIT) is now confined to within a positive assertion.
872    
873    15. It is now possible to link pcretest with libedit as an alternative to
874        libreadline.
875    
876    16. (*COMMIT) control verb is now supported by the JIT compiler.
877    
878    17. The Unicode data tables have been updated to Unicode 6.1.0.
879    
880    18. Added --file-list option to pcregrep.
881    
882    19. Added binary file support to pcregrep, including the -a, --binary-files,
883        -I, and --text options.
884    
885    20. The madvise function is renamed for posix_madvise for QNX compatibility
886        reasons. Fixed by Giuseppe D'Angelo.
887    
888    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
889    
890    22. Changed the option for creating symbolic links for 16-bit man pages from
891        -s to -sf so that re-installing does not cause issues.
892    
893    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
894    
895    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
896        matches in certain environments (the workspace was not being correctly
897        retained). Also added to pcre_dfa_exec() a simple plausibility check on
898        some of the workspace data at the beginning of a restart.
899    
900    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
901        was not doing so when it should - probably a typo introduced by SVN 528
902        (change 8.10/14).
903    
904    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
905        \w+ when the character tables indicated that \x{c4} was a word character.
906        There were several related cases, all because the tests for doing a table
907        lookup were testing for characters less than 127 instead of 255.
908    
909    27. If a pattern contains capturing parentheses that are not used in a match,
910        their slots in the ovector are set to -1. For those that are higher than
911        any matched groups, this happens at the end of processing. In the case when
912        there were back references that the ovector was too small to contain
913        (causing temporary malloc'd memory to be used during matching), and the
914        highest capturing number was not used, memory off the end of the ovector
915        was incorrectly being set to -1. (It was using the size of the temporary
916        memory instead of the true size.)
917    
918    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
919        ovector size, it uses memory at the end of the block that it has got.
920    
921    29. Check for an overlong MARK name and give an error at compile time. The
922        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
923    
924    30. JIT compiler update.
925    
926    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
927        Rill for the patch.
928    
929    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
930    
931    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
932    
933    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
934        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
935        was enabled.
936    
937    35. Improve JIT code generation for greedy plus quantifier.
938    
939    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
940        1 to "aa" instead of to an empty string. The bug affected repeated groups
941        that could potentially match an empty string.
942    
943    37. Optimizing single character iterators in JIT.
944    
945    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
946        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
947        codepoints that are too big for the mode are faulted, and in a UTF mode,
948        disallowed codepoints are also faulted.
949    
950    39. If PCRE was compiled with UTF support, in three places in the DFA
951        matcher there was code that should only have been obeyed in UTF mode, but
952        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
953        processing when bytes with values greater than 127 were present. In 16-bit
954        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
955        both cases the values are those that cannot be the first data item in a UTF
956        character. The three items that might have provoked this were recursions,
957        possessively repeated groups, and atomic groups.
958    
959    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
960        and pcregrep, because some OS require shared objects to be explicitly
961        passed to ld, causing the link step to fail if they are not.
962    
963    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
964        mode, patterns that started with \h* or \R* might be incorrectly matched.
965    
966    
967    Version 8.30 04-February-2012
968    -----------------------------
969    
970    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
971        name is defined in ctype.h.
972    
973    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
974        only in quite long subpatterns.
975    
976    3.  Removed the function pcre_info(), which has been obsolete and deprecated
977        since it was replaced by pcre_fullinfo() in February 2000.
978    
979    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
980        match a (*MARK), and the match failed at the start of the subject, a
981        reference to memory before the start of the subject could occur. This bug
982        was introduced by fix 17 of release 8.21.
983    
984    5.  A reference to an unset group with zero minimum repetition was giving
985        totally wrong answers (in non-JavaScript-compatibility mode). For example,
986        /(another)?(\1?)test/ matched against "hello world test". This bug was
987        introduced in release 8.13.
988    
989    6.  Add support for 16-bit character strings (a large amount of work involving
990        many changes and refactorings).
991    
992    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
993        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
994        from a file.
995    
996    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
997        rounding is not applied in this particular case).
998    
999    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
1000        if they appear, or are escaped, in patterns.
1001    
1002    10. Get rid of a number of -Wunused-but-set-variable warnings.
1003    
1004    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
1005        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
1006        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
1007        also returns the mark "x". This bug applied to capturing parentheses,
1008        non-capturing parentheses, and atomic parentheses. It also applied to some
1009        assertions.
1010    
1011    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
1012        information out of configure.ac instead of relying on pcre.h.generic, which
1013        is not stored in the repository.
1014    
1015    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
1016        -lreadline.
1017    
1018    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
1019    
1020    15. Applied Graycode's patch to put the top-level frame on the stack rather
1021        than the heap when not using the stack for recursion. This gives a
1022        performance improvement in many cases when recursion is not deep.
1023    
1024    16. Experimental code added to "pcretest -C" to output the stack frame size.
1025    
1026    
1027    Version 8.21 12-Dec-2011
1028    ------------------------
1029    
1030    1.  Updating the JIT compiler.
1031    
1032    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1033        are added as well.
1034    
1035    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1036        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1037        calling _pcre_jit_exec. Some extra comments are added.
1038    
1039    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1040        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1041        was introduced by change 18 for 8.20.
1042    
1043    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1044        ECMA-262 standard.
1045    
1046    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1047        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1048        This bug was probably introduced by change 9 of 8.13.
1049    
1050    7.  While fixing 6 above, I noticed that a number of other items were being
1051        incorrectly rejected as "not fixed length". This arose partly because newer
1052        opcodes had not been added to the fixed-length checking code. I have (a)
1053        corrected the bug and added tests for these items, and (b) arranged for an
1054        error to occur if an unknown opcode is encountered while checking for fixed
1055        length instead of just assuming "not fixed length". The items that were
1056        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1057        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1058        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1059    
1060    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1061        being incorrectly compiled and would have given unpredicatble results.
1062    
1063    9.  A possessively repeated subpattern with minimum repeat count greater than
1064        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1065        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1066        the first (A) could occur when it should not.
1067    
1068    10. Add a cast and remove a redundant test from the code.
1069    
1070    11. JIT should use pcre_malloc/pcre_free for allocation.
1071    
1072    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1073        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1074        is anything other than /usr, -L is still shown).
1075    
1076    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1077    
1078    14. Perl does not support \N without a following name in a [] class; PCRE now
1079        also gives an error.
1080    
1081    15. If a forward reference was repeated with an upper limit of around 2000,
1082        it caused the error "internal error: overran compiling workspace". The
1083        maximum number of forward references (including repeats) was limited by the
1084        internal workspace, and dependent on the LINK_SIZE. The code has been
1085        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1086        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1087        of around 200,000 forward references. While doing this, I also speeded up
1088        the filling in of repeated forward references.
1089    
1090    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1091        incorrectly expecting the subject to contain another "a" after the start.
1092    
1093    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1094        in the match, the SKIP should be ignored. This was not happening; instead
1095        the SKIP was being treated as NOMATCH. For patterns such as
1096        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1097        tested.
1098    
1099    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1100        now much more compatible with Perl, in particular in cases where the result
1101        is a non-match for a non-anchored pattern. For example, if
1102        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1103        "m", where previously it did not return a name. A side effect of this
1104        change is that for partial matches, the last encountered mark name is
1105        returned, as for non matches. A number of tests that were previously not
1106        Perl-compatible have been moved into the Perl-compatible test files. The
1107        refactoring has had the pleasing side effect of removing one argument from
1108        the match() function, thus reducing its stack requirements.
1109    
1110    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1111        subsequent uses of /S (without +) incorrectly behaved like /S+.
1112    
1113    21. Retrieve executable code size support for the JIT compiler and fixing
1114        some warnings.
1115    
1116    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1117        not work when the shorter character appeared right at the end of the
1118        subject string.
1119    
1120    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1121        systems.
1122    
1123    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1124        output it when the /M option is used in pcretest.
1125    
1126    25. The CheckMan script was not being included in the distribution. Also, added
1127        an explicit "perl" to run Perl scripts from the PrepareRelease script
1128        because this is reportedly needed in Windows.
1129    
1130    26. If study data was being save in a file and studying had not found a set of
1131        "starts with" bytes for the pattern, the data written to the file (though
1132        never used) was taken from uninitialized memory and so caused valgrind to
1133        complain.
1134    
1135    27. Updated RunTest.bat as provided by Sheri Pierce.
1136    
1137    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1138    
1139    29. Computation of memory usage for the table of capturing group names was
1140        giving an unnecessarily large value.
1141    
1142    
1143    Version 8.20 21-Oct-2011
1144    ------------------------
1145    
1146    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1147        a POSIX class. After further experiments with Perl, which convinced me that
1148        Perl has bugs and confusions, a closing square bracket is no longer allowed
1149        in a POSIX name. This bug also affected patterns with classes that started
1150        with full stops.
1151    
1152    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1153        captured substring, but while checking the failing first alternative,
1154        substring 1 is temporarily captured. If the output vector supplied to
1155        pcre_exec() was not big enough for this capture, the yield of the function
1156        was still zero ("insufficient space for captured substrings"). This cannot
1157        be totally fixed without adding another stack variable, which seems a lot
1158        of expense for a edge case. However, I have improved the situation in cases
1159        such as /(a)(b)x|abc/ matched against "abc", where the return code
1160        indicates that fewer than the maximum number of slots in the ovector have
1161        been set.
1162    
1163    3.  Related to (2) above: when there are more back references in a pattern than
1164        slots in the output vector, pcre_exec() uses temporary memory during
1165        matching, and copies in the captures as far as possible afterwards. It was
1166        using the entire output vector, but this conflicts with the specification
1167        that only 2/3 is used for passing back captured substrings. Now it uses
1168        only the first 2/3, for compatibility. This is, of course, another edge
1169        case.
1170    
1171    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1172        main code base, and can be used by building with --enable-jit. When this is
1173        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1174        runtime --no-jit option is given.
1175    
1176    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1177        ovector, the return from the function was zero, implying that there were
1178        other matches that did not fit. The correct "exactly full" value is now
1179        returned.
1180    
1181    6.  If a subpattern that was called recursively or as a subroutine contained
1182        (*PRUNE) or any other control that caused it to give a non-standard return,
1183        invalid errors such as "Error -26 (nested recursion at the same subject
1184        position)" or even infinite loops could occur.
1185    
1186    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1187        computing the minimum length on reaching *ACCEPT, and so ended up with the
1188        wrong value of 1 rather than 0. Further investigation indicates that
1189        computing a minimum subject length in the presence of *ACCEPT is difficult
1190        (think back references, subroutine calls), and so I have changed the code
1191        so that no minimum is registered for a pattern that contains *ACCEPT.
1192    
1193    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1194        it was not handled as intended. [But see 16 below.]
1195    
1196    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1197        Sheri Pierce.
1198    
1199    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1200        the first byte in a match must be "a".
1201    
1202    11. Change 17 for 8.13 increased the recursion depth for patterns like
1203        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1204        pattern contains any instances of (*THEN). If it does not, the old
1205        optimizations are restored. It would be nice to do this on a per-group
1206        basis, but at the moment that is not feasible.
1207    
1208    12. In some environments, the output of pcretest -C is CRLF terminated. This
1209        broke RunTest's code that checks for the link size. A single white space
1210        character after the value is now allowed for.
1211    
1212    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1213        For "fr", it uses the Windows-specific input and output files.
1214    
1215    14. If (*THEN) appeared in a group that was called recursively or as a
1216        subroutine, it did not work as intended. [But see next item.]
1217    
1218    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1219        pattern fragments (but not containing any | characters). If A and B are
1220        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1221        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1222        D. In other words, Perl considers parentheses that do not contain any |
1223        characters to be part of a surrounding alternative, whereas PCRE was
1224        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1225        differently. PCRE now behaves in the same way as Perl, except in the case
1226        of subroutine/recursion calls such as (?1) which have in any case always
1227        been different (but PCRE had them first :-).
1228    
1229    16. Related to 15 above: Perl does not treat the | in a conditional group as
1230        creating alternatives. Such a group is treated in the same way as an
1231        ordinary group without any | characters when processing (*THEN). PCRE has
1232        been changed to match Perl's behaviour.
1233    
1234    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1235        RunGrepTest script failed.
1236    
1237    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1238        inevitable for groups that contain captures, but it can lead to a lot of
1239        stack use in large patterns. The old behaviour has been restored for atomic
1240        groups that do not contain any capturing parentheses.
1241    
1242    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1243        suppress the check for a minimum subject length at run time. (If it was
1244        given to pcre_exec() or pcre_dfa_exec() it did work.)
1245    
1246    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1247        fail to work when decoding hex characters in data strings in EBCDIC
1248        environments.
1249    
1250    21. It appears that in at least one Mac OS environment, the isxdigit() function
1251        is implemented as a macro that evaluates to its argument more than once,
1252        contravening the C 90 Standard (I haven't checked a later standard). There
1253        was an instance in pcretest which caused it to go wrong when processing
1254        \x{...} escapes in subject strings. The has been rewritten to avoid using
1255        things like p++ in the argument of isxdigit().
1256    
1257    
1258    Version 8.13 16-Aug-2011
1259    ------------------------
1260    
1261    1.  The Unicode data tables have been updated to Unicode 6.0.0.
1262    
1263    2.  Two minor typos in pcre_internal.h have been fixed.
1264    
1265    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
1266        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
1267        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
1268    
1269    4.  There were a number of related bugs in the code for matching backrefences
1270        caselessly in UTF-8 mode when codes for the characters concerned were
1271        different numbers of bytes. For example, U+023A and U+2C65 are an upper
1272        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
1273        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
1274        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1275        2-byte code at the end of the subject (it thought there wasn't enough data
1276        left).
1277    
1278    5.  Comprehensive information about what went wrong is now returned by
1279        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1280        as the output vector has at least 2 elements. The offset of the start of
1281        the failing character and a reason code are placed in the vector.
1282    
1283    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1284        now returned is for the first byte of the failing character, instead of the
1285        last byte inspected. This is an incompatible change, but I hope it is small
1286        enough not to be a problem. It makes the returned offset consistent with
1287        pcre_exec() and pcre_dfa_exec().
1288    
1289    7.  pcretest now gives a text phrase as well as the error number when
1290        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1291        failure, the offset and reason code are output.
1292    
1293    8.  When \R was used with a maximizing quantifier it failed to skip backwards
1294        over a \r\n pair if the subsequent match failed. Instead, it just skipped
1295        back over a single character (\n). This seems wrong (because it treated the
1296        two characters as a single entity when going forwards), conflicts with the
1297        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1298        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1299        has been changed.
1300    
1301    9.  Some internal refactoring has changed the processing so that the handling
1302        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1303        time (the PCRE_DOTALL option was changed this way some time ago: version
1304        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1305        which was always a bit of a fudge. It also means that there is one less
1306        argument for the match() function, which reduces its stack requirements
1307        slightly. This change also fixes an incompatibility with Perl: the pattern
1308        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1309    
1310    10. More internal refactoring has drastically reduced the number of recursive
1311        calls to match() for possessively repeated groups such as (abc)++ when
1312        using pcre_exec().
1313    
1314    11. While implementing 10, a number of bugs in the handling of groups were
1315        discovered and fixed:
1316    
1317        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1318        (a|)*(?1) gave a compile-time internal error.
1319        ((a|)+)+  did not notice that the outer group could match an empty string.
1320        (^a|^)+   was not marked as anchored.
1321        (.*a|.*)+ was not marked as matching at start or after a newline.
1322    
1323    12. Yet more internal refactoring has removed another argument from the match()
1324        function. Special calls to this function are now indicated by setting a
1325        value in a variable in the "match data" data block.
1326    
1327    13. Be more explicit in pcre_study() instead of relying on "default" for
1328        opcodes that mean there is no starting character; this means that when new
1329        ones are added and accidentally left out of pcre_study(), testing should
1330        pick them up.
1331    
1332    14. The -s option of pcretest has been documented for ages as being an old
1333        synonym of -m (show memory usage). I have changed it to mean "force study
1334        for every regex", that is, assume /S for every regex. This is similar to -i
1335        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1336        using it. It makes it easier to run collections of tests with and without
1337        study enabled, and thereby test pcre_study() more easily. All the standard
1338        tests are now run with and without -s (but some patterns can be marked as
1339        "never study" - see 20 below).
1340    
1341    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1342        restoration of the capturing data to the outer values was not happening
1343        correctly.
1344    
1345    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1346        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1347        pattern had matched an empty string, and so incorrectly returned a no
1348        match.
1349    
1350    17. There was optimizing code for the last branch of non-capturing parentheses,
1351        and also for the obeyed branch of a conditional subexpression, which used
1352        tail recursion to cut down on stack usage. Unfortunately, now that there is
1353        the possibility of (*THEN) occurring in these branches, tail recursion is
1354        no longer possible because the return has to be checked for (*THEN). These
1355        two optimizations have therefore been removed. [But see 8.20/11 above.]
1356    
1357    18. If a pattern containing \R was studied, it was assumed that \R always
1358        matched two bytes, thus causing the minimum subject length to be
1359        incorrectly computed because \R can also match just one byte.
1360    
1361    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1362        was incorrectly computed.
1363    
1364    20. If /S is present twice on a test pattern in pcretest input, it now
1365        *disables* studying, thereby overriding the use of -s on the command line
1366        (see 14 above). This is necessary for one or two tests to keep the output
1367        identical in both cases.
1368    
1369    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1370        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1371    
1372    22. When an atomic group that contained a capturing parenthesis was
1373        successfully matched, but the branch in which it appeared failed, the
1374        capturing was not being forgotten if a higher numbered group was later
1375        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1376        group 1 to "a", when in fact it should be unset. This applied to multi-
1377        branched capturing and non-capturing groups, repeated or not, and also to
1378        positive assertions (capturing in negative assertions does not happen
1379        in PCRE) and also to nested atomic groups.
1380    
1381    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1382        subject after a captured substring, to make it easier to tell which of a
1383        number of identical substrings has been captured.
1384    
1385    24. The way atomic groups are processed by pcre_exec() has been changed so that
1386        if they are repeated, backtracking one repetition now resets captured
1387        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1388        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1389        "aaa". Previously, it would have been "a". As part of this code
1390        refactoring, the way recursive calls are handled has also been changed.
1391    
1392    25. If an assertion condition captured any substrings, they were not passed
1393        back unless some other capturing happened later. For example, if
1394        (?(?=(a))a) was matched against "a", no capturing was returned.
1395    
1396    26. When studying a pattern that contained subroutine calls or assertions,
1397        the code for finding the minimum length of a possible match was handling
1398        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1399        group 1 called group 2 while simultaneously a separate group 2 called group
1400        1). A stack overflow occurred in this case. I have fixed this by limiting
1401        the recursion depth to 10.
1402    
1403    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1404        Fortmann. This supports explicit test numbers on the command line, and has
1405        argument validation and error reporting.
1406    
1407    28. An instance of \X with an unlimited repeat could fail if at any point the
1408        first character it looked at was a mark character.
1409    
1410    29. Some minor code refactoring concerning Unicode properties and scripts
1411        should reduce the stack requirement of match() slightly.
1412    
1413    30. Added the '=' option to pcretest to check the setting of unused capturing
1414        slots at the end of the pattern, which are documented as being -1, but are
1415        not included in the return count.
1416    
1417    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1418        compiled something random. Now it gives a compile-time error (as does
1419        Perl).
1420    
1421    32. A *MARK encountered during the processing of a positive assertion is now
1422        recorded and passed back (compatible with Perl).
1423    
1424    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1425        had alternative anchored branches, the search for a second match in a line
1426        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1427        matched the line "0102" twice. The same bug affected patterns that started
1428        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1429        twice.
1430    
1431    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1432        does, and because of capturing effects, quantifying parenthesized
1433        assertions may at times be useful. Quantifiers are now allowed for
1434        parenthesized assertions.
1435    
1436    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1437    
1438    36. \g was being checked for fancy things in a character class, when it should
1439        just be a literal "g".
1440    
1441    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1442        appearance of a nested POSIX class supersedes an apparent external class.
1443        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1444        unescaped square brackets may also appear as part of class names. For
1445        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1446        more like Perl. (But see 8.20/1 above.)
1447    
1448    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1449        was because it thought it was \N{name}, which is not supported).
1450    
1451    39. Add minix to OS list not supporting the -S option in pcretest.
1452    
1453    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1454        cannot analyze patterns in sufficient detail to catch mutual recursions
1455        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1456        subgroup is called recursively as a subpattern for a second time at the
1457        same position in the subject string. In previous releases this might have
1458        been caught by the recursion limit, or it might have run out of stack.
1459    
1460    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1461        happen only once. PCRE was, however incorrectly giving a compile time error
1462        "recursive call could loop indefinitely" because it cannot analyze the
1463        pattern in sufficient detail. The compile time test no longer happens when
1464        PCRE is compiling a conditional subpattern, but actual runaway loops are
1465        now caught at runtime (see 40 above).
1466    
1467    42. It seems that Perl allows any characters other than a closing parenthesis
1468        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1469        has been changed to be the same.
1470    
1471    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1472        as not to get warnings when autogen.sh is called. Also changed
1473        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1474    
1475    44. To help people who use pcregrep to scan files containing exceedingly long
1476        lines, the following changes have been made:
1477    
1478        (a) The default value of the buffer size parameter has been increased from
1479            8K to 20K. (The actual buffer used is three times this size.)
1480    
1481        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1482            PCRE is built.
1483    
1484        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1485            to be set at run time.
1486    
1487        (d) Numerical values in pcregrep options can be followed by K or M, for
1488            example --buffer-size=50K.
1489    
1490        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1491            given and the return code is set to 2.
1492    
1493    45. Add a pointer to the latest mark to the callout data block.
1494    
1495    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1496        partial match of an empty string instead of no match. This was specific to
1497        the use of ".".
1498    
1499    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1500        complete match instead of a partial match. This bug was dependent on both
1501        the PCRE_UTF8 and PCRE_DOTALL options being set.
1502    
1503    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1504        starting byte set, because \b was not being ignored.
1505    
1506    
1507    Version 8.12 15-Jan-2011
1508    ------------------------
1509    
1510    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1511        checks for such things as part of the documentation building process.
1512    
1513    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1514        --match-limit and --recursion-limit options (added for 8.11). In
1515        particular, this made one of the standard tests fail. (The integer value
1516        went into the wrong half of a long int.)
1517    
1518    3.  If the --colour option was given to pcregrep with -v (invert match), it
1519        did strange things, either producing crazy output, or crashing. It should,
1520        of course, ignore a request for colour when reporting lines that do not
1521        match.
1522    
1523    4.  Another pcregrep bug caused similar problems if --colour was specified with
1524        -M (multiline) and the pattern match finished with a line ending.
1525    
1526    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1527        matched in multiline mode, the following line was shown as part of the
1528        match. This seems wrong, so I have changed it.
1529    
1530    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1531        the check for further matches in the same line (so they could be coloured)
1532        to overrun the end of the current line. If another match was found, it was
1533        incorrectly shown (and then shown again when found in the next line).
1534    
1535    7.  If pcregrep was compiled under Windows, there was a reference to the
1536        function pcregrep_exit() before it was defined. I am assuming this was
1537        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1538        reported by a user. I've moved the definition above the reference.
1539    
1540    
1541    Version 8.11 10-Dec-2010
1542    ------------------------
1543    
1544    1.  (*THEN) was not working properly if there were untried alternatives prior
1545        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1546        backtracked to try for "b" instead of moving to the next alternative branch
1547        at the same level (in this case, to look for "c"). The Perl documentation
1548        is clear that when (*THEN) is backtracked onto, it goes to the "next
1549        alternative in the innermost enclosing group".
1550    
1551    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1552        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1553        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1554        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1555        (*THEN).
1556    
1557    3.  If \s appeared in a character class, it removed the VT character from
1558        the class, even if it had been included by some previous item, for example
1559        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1560        of \s, but is part of the POSIX "space" class.)
1561    
1562    4.  A partial match never returns an empty string (because you can always
1563        match an empty string at the end of the subject); however the checking for
1564        an empty string was starting at the "start of match" point. This has been
1565        changed to the "earliest inspected character" point, because the returned
1566        data for a partial match starts at this character. This means that, for
1567        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1568        (previously it gave "no match").
1569    
1570    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1571        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1572        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1573        has an implication that the given string is incomplete (because a partial
1574        match is preferred over a full match). For this reason, these items now
1575        give a partial match in this situation. [Aside: previously, the one case
1576        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1577        match rather than a full match, which was wrong by the old rules, but is
1578        now correct.]
1579    
1580    6.  There was a bug in the handling of #-introduced comments, recognized when
1581        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1582        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1583        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1584        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1585        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1586        places in pcre_compile().
1587    
1588    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1589        comments when looking ahead for named forward references to subpatterns,
1590        the only newline sequence it recognized was NL. It now handles newlines
1591        according to the set newline convention.
1592    
1593    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1594        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1595        cater for a lack of strerror(). These oversights have been fixed.
1596    
1597    9.  Added --match-limit and --recursion-limit to pcregrep.
1598    
1599    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1600    
1601    11. When the -o option was used, pcregrep was setting a return code of 1, even
1602        when matches were found, and --line-buffered was not being honoured.
1603    
1604    12. Added an optional parentheses number to the -o and --only-matching options
1605        of pcregrep.
1606    
1607    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1608        can match an empty string. The code to do it in pcretest and pcredemo
1609        needed fixing:
1610    
1611        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1612            only one byte after an empty string match just before CRLF (this case
1613            just got forgotten; "any" and "anycrlf" were OK).
1614    
1615        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1616            mode when an empty string match preceded an ASCII character followed by
1617            a non-ASCII character. (The code for advancing by one character rather
1618            than one byte was nonsense.)
1619    
1620        (c) The pcredemo.c sample program did not have any code at all to handle
1621            the cases when CRLF is a valid newline sequence.
1622    
1623    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1624        as a starting offset was within the subject string. There is now a new
1625        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1626        negative or greater than the length of the string. In order to test this,
1627        pcretest is extended to allow the setting of negative starting offsets.
1628    
1629    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1630        starting offset points to the beginning of a UTF-8 character was
1631        unnecessarily clumsy. I tidied it up.
1632    
1633    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1634        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1635    
1636    17. Nobody had reported that the --include_dir option, which was added in
1637        release 7.7 should have been called --include-dir (hyphen, not underscore)
1638        for compatibility with GNU grep. I have changed it to --include-dir, but
1639        left --include_dir as an undocumented synonym, and the same for
1640        --exclude-dir, though that is not available in GNU grep, at least as of
1641        release 2.5.4.
1642    
1643    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1644        characters from a string of bytes) have been redefined so as not to use
1645        loops, in order to improve performance in some environments. At the same
1646        time, I abstracted some of the common code into auxiliary macros to save
1647        repetition (this should not affect the compiled code).
1648    
1649    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1650        compile-time error is now given if \c is not followed by an ASCII
1651        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1652        different, and any byte value is allowed.)
1653    
1654    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1655        START_OPTIMIZE option, which is now allowed at compile time - but just
1656        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1657        to pcregrep and other applications that have no direct access to PCRE
1658        options. The new /Y option in pcretest sets this option when calling
1659        pcre_compile().
1660    
1661    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1662        back references. Groups containing recursive back references were forced to
1663        be atomic by that change, but in the case of named groups, the amount of
1664        memory required was incorrectly computed, leading to "Failed: internal
1665        error: code overflow". This has been fixed.
1666    
1667    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1668        pcretest.c, to avoid build problems in some Borland environments.
1669    
1670    
1671    Version 8.10 25-Jun-2010
1672    ------------------------
1673    
1674    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1675        THEN.
1676    
1677    2.  (*ACCEPT) was not working when inside an atomic group.
1678    
1679    3.  Inside a character class, \B is treated as a literal by default, but
1680        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1681        causes the error). The code is unchanged, but I tidied the documentation.
1682    
1683    4.  Inside a character class, PCRE always treated \R and \X as literals,
1684        whereas Perl faults them if its -w option is set. I have changed PCRE so
1685        that it faults them when PCRE_EXTRA is set.
1686    
1687    5.  Added support for \N, which always matches any character other than
1688        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1689    
1690    6.  When compiling pcregrep with newer versions of gcc which may have
1691        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1692        declared with attribute warn_unused_result" were given. Just casting the
1693        result to (void) does not stop the warnings; a more elaborate fudge is
1694        needed. I've used a macro to implement this.
1695    
1696    7.  Minor change to pcretest.c to avoid a compiler warning.
1697    
1698    8.  Added four artifical Unicode properties to help with an option to make
1699        \s etc use properties (see next item). The new properties are: Xan
1700        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1701    
1702    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1703        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1704        this option. Modified pcretest to add /W to test this facility. Added
1705        REG_UCP to make it available via the POSIX interface.
1706    
1707    10. Added --line-buffered to pcregrep.
1708    
1709    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1710        studied, and the match started with a letter with a code point greater than
1711        127 whose first byte was different to the first byte of the other case of
1712        the letter, the other case of this starting letter was not recognized
1713        (#976).
1714    
1715    12. If a pattern that was studied started with a repeated Unicode property
1716        test, for example, \p{Nd}+, there was the theoretical possibility of
1717        setting up an incorrect bitmap of starting bytes, but fortunately it could
1718        not have actually happened in practice until change 8 above was made (it
1719        added property types that matched character-matching opcodes).
1720    
1721    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1722        possible starting bytes for non-anchored patterns.
1723    
1724    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1725        \R, and also a number of cases that involve Unicode properties, both
1726        explicit and implicit when PCRE_UCP is set.
1727    
1728    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1729        input, it could crash or give wrong results if characters with values
1730        greater than 0xc0 were present in the subject string. (Detail: it assumed
1731        UTF-8 input when processing these items.)
1732    
1733    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1734        size_t is 64-bit (#991).
1735    
1736    17. Added a check for running out of memory when PCRE is compiled with
1737        --disable-stack-for-recursion (#990).
1738    
1739    18. If the last data line in a file for pcretest does not have a newline on
1740        the end, a newline was missing in the output.
1741    
1742    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1743        less than 128) in its various bitmaps. However, there is a facility for
1744        generating tables according to the current locale when PCRE is compiled. It
1745        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1746        characters, are recognized by isspace() and therefore were getting set in
1747        these tables, and indeed these tables seem to approximate to ISO 8859. This
1748        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1749        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1750        which of course cannot start UTF-8 characters. I have changed the code so
1751        that only real ASCII characters (less than 128) and the correct starting
1752        bytes for UTF-8 encodings are set for characters greater than 127 when in
1753        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1754        altogether.)
1755    
1756    20. Added the /T option to pcretest so as to be able to run tests with non-
1757        standard character tables, thus making it possible to include the tests
1758        used for 19 above in the standard set of tests.
1759    
1760    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1761        reference to a subpattern the other side of a comment that contains an
1762        opening parenthesis caused either an internal compiling error, or a
1763        reference to the wrong subpattern.
1764    
1765    
1766    Version 8.02 19-Mar-2010
1767  ------------------------  ------------------------
1768    
1769  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
1770    
1771  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1772      configured.      configured.
1773    
1774  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1775      original author of that file, following a query about its status.      original author of that file, following a query about its status.
1776    
1777  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1778      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1779    
1780  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1781      quantifier applied to a forward-referencing subroutine call, could compile      quantifier applied to a forward-referencing subroutine call, could compile
1782      incorrect code or give the error "internal error: previously-checked      incorrect code or give the error "internal error: previously-checked
1783      referenced subpattern not found".      referenced subpattern not found".
1784    
1785  6.  Both MS Visual Studio and Symbian OS have problems with initializing  6.  Both MS Visual Studio and Symbian OS have problems with initializing
1786      variables to point to external functions. For these systems, therefore,      variables to point to external functions. For these systems, therefore,
1787      pcre_malloc etc. are now initialized to local functions that call the      pcre_malloc etc. are now initialized to local functions that call the
1788      relevant global functions.      relevant global functions.
1789    
1790  7.  There were two entries missing in the vectors called coptable and poptable  7.  There were two entries missing in the vectors called coptable and poptable
1791      in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.      in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1792      I've fixed the data, and added a kludgy way of testing at compile time that      I've fixed the data, and added a kludgy way of testing at compile time that
1793      the lengths are correct (equal to the number of opcodes).      the lengths are correct (equal to the number of opcodes).
1794    
1795  8.  Following on from 7, I added a similar kludge to check the length of the  8.  Following on from 7, I added a similar kludge to check the length of the
1796      eint vector in pcreposix.c.      eint vector in pcreposix.c.
1797    
1798  9.  Error texts for pcre_compile() are held as one long string to avoid too  9.  Error texts for pcre_compile() are held as one long string to avoid too
1799      much relocation at load time. To find a text, the string is searched,      much relocation at load time. To find a text, the string is searched,
1800      counting zeros. There was no check for running off the end of the string,      counting zeros. There was no check for running off the end of the string,
1801      which could happen if a new error number was added without updating the      which could happen if a new error number was added without updating the
1802      string.      string.
1803    
1804  10. \K gave a compile-time error if it appeared in a lookbehind assersion.  10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1805    
1806  11. \K was not working if it appeared in an atomic group or in a group that  11. \K was not working if it appeared in an atomic group or in a group that
1807      was called as a "subroutine", or in an assertion. Perl 5.11 documents that      was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1808      \K is "not well defined" if used in an assertion. PCRE now accepts it if      \K is "not well defined" if used in an assertion. PCRE now accepts it if
1809      the assertion is positive, but not if it is negative.      the assertion is positive, but not if it is negative.
1810    
1811  12. Change 11 fortuitously reduced the size of the stack frame used in the  12. Change 11 fortuitously reduced the size of the stack frame used in the
1812      "match()" function of pcre_exec.c by one pointer. Forthcoming      "match()" function of pcre_exec.c by one pointer. Forthcoming
1813      implementation of support for (*MARK) will need an extra pointer on the      implementation of support for (*MARK) will need an extra pointer on the
1814      stack; I have reserved it now, so that the stack frame size does not      stack; I have reserved it now, so that the stack frame size does not
1815      decrease.      decrease.
1816    
1817  13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other  13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1818      item in branch that calls a recursion is a subroutine call - as in the      item in branch that calls a recursion is a subroutine call - as in the
1819      second branch in the above example - was incorrectly given the compile-      second branch in the above example - was incorrectly given the compile-
1820      time error "recursive call could loop indefinitely" because pcre_compile()      time error "recursive call could loop indefinitely" because pcre_compile()
1821      was not correctly checking the subroutine for matching a non-empty string.      was not correctly checking the subroutine for matching a non-empty string.
1822    
1823  14. The checks for overrunning compiling workspace could trigger after an  14. The checks for overrunning compiling workspace could trigger after an
1824      overrun had occurred. This is a "should never occur" error, but it can be      overrun had occurred. This is a "should never occur" error, but it can be
1825      triggered by pathological patterns such as hundreds of nested parentheses.      triggered by pathological patterns such as hundreds of nested parentheses.
1826      The checks now trigger 100 bytes before the end of the workspace.      The checks now trigger 100 bytes before the end of the workspace.
1827    
1828    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1829    
1830    
1831  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
# Line 390  Version 7.9 11-Apr-09 Line 2154  Version 7.9 11-Apr-09
2154  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
2155      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
2156      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2157      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2158        8.33.]
2159    
2160  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
2161      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 633  Version 7.7 07-May-08 Line 2398  Version 7.7 07-May-08
2398      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2399      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2400      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2401      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2402      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2403      was subsequently set up correctly.)      was subsequently set up correctly.)
2404    

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