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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    11. If an assertion that was used as a condition was quantified with a minimum
57        of zero, matching went wrong. In particular, if the whole group had
58        unlimited repetition and could match an empty string, a segfault was
59        likely. The pattern (?(?=0)?)+ is an example that caused this. Perl allows
60        assertions to be quantified, but not if they are being used as conditions,
61        so the above pattern is faulted by Perl. PCRE has now been changed so that
62        it also rejects such patterns.
63    
64    12. A possessive capturing group such as (a)*+ with a minimum repeat of zero
65        failed to allow the zero-repeat case if pcre2_exec() was called with an
66        ovector too small to capture the group.
67    
68    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
69        Red Hat Product Security:
70    
71        (a) A crash if /K and /F were both set with the option to save the compiled
72        pattern.
73    
74        (b) Another crash if the option to print captured substrings in a callout
75        was combined with setting a null ovector, for example \O\C+ as a subject
76        string.
77    
78    14. A pattern such as "((?2){0,1999}())?", which has a group containing a
79        forward reference repeated a large (but limited) number of times within a
80        repeated outer group that has a zero minimum quantifier, caused incorrect
81        code to be compiled, leading to the error "internal error:
82        previously-checked referenced subpattern not found" when an incorrect
83        memory address was read. This bug was reported as "heap overflow",
84        discovered by Kai Lu of Fortinet's FortiGuard Labs and given the CVE number
85        CVE-2015-2325.
86    
87    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
88        call within a group that also contained a recursive back reference caused
89        incorrect code to be compiled. This bug was reported as "heap overflow",
90        discovered by Kai Lu of Fortinet's FortiGuard Labs, and given the CVE
91        number CVE-2015-2326.
92    
93    24. Computing the size of the JIT read-only data in advance has been a source
94        of various issues, and new ones are still appear unfortunately. To fix
95        existing and future issues, size computation is eliminated from the code,
96        and replaced by on-demand memory allocation.
97    
98    25. A pattern such as /(?i)[A-`]/, where characters in the other case are
99        adjacent to the end of the range, and the range contained characters with
100        more than one other case, caused incorrect behaviour when compiled in UTF
101        mode. In that example, the range a-j was left out of the class.
102    
103    26. Fix JIT compilation of conditional blocks, which assertion
104        is converted to (*FAIL). E.g: /(?(?!))/.
105    
106    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
107        discovered by the LLVM fuzzer.
108    
109    28. The assertion (?!) is optimized to (*FAIL). This was not handled correctly
110        when this assertion was used as a condition, for example (?(?!)a|b). In
111        pcre2_match() it worked by luck; in pcre2_dfa_match() it gave an incorrect
112        error about an unsupported item.
113    
114    29. For some types of pattern, for example /Z*(|d*){216}/, the auto-
115        possessification code could take exponential time to complete. A recursion
116        depth limit of 1000 has been imposed to limit the resources used by this
117        optimization.
118    
119    
120    Version 8.36 26-September-2014
121    ------------------------------
122    
123    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
124        -Wmissing-field-initializers and -Wunused-parameter.
125    
126    2.  The tests for quantifiers being too big (greater than 65535) were being
127        applied after reading the number, and stupidly assuming that integer
128        overflow would give a negative number. The tests are now applied as the
129        numbers are read.
130    
131    3.  Tidy code in pcre_exec.c where two branches that used to be different are
132        now the same.
133    
134    4.  The JIT compiler did not generate match limit checks for certain
135        bracketed expressions with quantifiers. This may lead to exponential
136        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
137        issue should be resolved now.
138    
139    5.  Fixed an issue, which occures when nested alternatives are optimized
140        with table jumps.
141    
142    6.  Inserted two casts and changed some ints to size_t in the light of some
143        reported 64-bit compiler warnings (Bugzilla 1477).
144    
145    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
146        an empty string, which sometimes were behaving incorrectly in the
147        interpreter (though correctly in the JIT matcher). This pcretest input is
148        an example:
149    
150          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
151          NON QUOTED "QUOT""ED" AFTER "NOT MATCHED
152    
153        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
154        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
155        for an empty string was breaking the inner loop and carrying on at a lower
156        level, when possessive repeated groups should always return to a higher
157        level as they have no backtrack points in them. The empty string test now
158        occurs at the outer level.
159    
160    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
161        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
162    
163    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
164        doesn't).
165    
166    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
167        to hold a pattern to be incorrectly computed (too small) when there were
168        named back references to duplicated names. This could cause "internal
169        error: code overflow" or "double free or corruption" or other memory
170        handling errors.
171    
172    11. When named subpatterns had the same prefixes, back references could be
173        confused. For example, in this pattern:
174    
175          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
176    
177        the reference to 'Name' was incorrectly treated as a reference to a
178        duplicate name.
179    
180    12. A pattern such as /^s?c/mi8 where the optional character has more than
181        one "other case" was incorrectly compiled such that it would only try to
182        match starting at "c".
183    
184    13. When a pattern starting with \s was studied, VT was not included in the
185        list of possible starting characters; this should have been part of the
186        8.34/18 patch.
187    
188    14. If a character class started [\Qx]... where x is any character, the class
189        was incorrectly terminated at the ].
190    
191    15. If a pattern that started with a caseless match for a character with more
192        than one "other case" was studied, PCRE did not set up the starting code
193        unit bit map for the list of possible characters. Now it does. This is an
194        optimization improvement, not a bug fix.
195    
196    16. The Unicode data tables have been updated to Unicode 7.0.0.
197    
198    17. Fixed a number of memory leaks in pcregrep.
199    
200    18. Avoid a compiler warning (from some compilers) for a function call with
201        a cast that removes "const" from an lvalue by using an intermediate
202        variable (to which the compiler does not object).
203    
204    19. Incorrect code was compiled if a group that contained an internal recursive
205        back reference was optional (had quantifier with a minimum of zero). This
206        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
207        caused segmentation faults because of stack overflows at compile time.
208    
209    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
210        group that is quantified with an indefinite repeat, caused a compile-time
211        loop which used up all the system stack and provoked a segmentation fault.
212        This was not the same bug as 19 above.
213    
214    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
215        Patch by Mike Frysinger.
216    
217    
218    Version 8.35 04-April-2014
219    --------------------------
220    
221    1.  A new flag is set, when property checks are present in an XCLASS.
222        When this flag is not set, PCRE can perform certain optimizations
223        such as studying these XCLASS-es.
224    
225    2.  The auto-possessification of character sets were improved: a normal
226        and an extended character set can be compared now. Furthermore
227        the JIT compiler optimizes more character set checks.
228    
229    3.  Got rid of some compiler warnings for potentially uninitialized variables
230        that show up only when compiled with -O2.
231    
232    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
233        of a match later then the end of the match. The pcretest program was not
234        handling the case sensibly - it was outputting from the start to the next
235        binary zero. It now reports this situation in a message, and outputs the
236        text from the end to the start.
237    
238    5.  Fast forward search is improved in JIT. Instead of the first three
239        characters, any three characters with fixed position can be searched.
240        Search order: first, last, middle.
241    
242    6.  Improve character range checks in JIT. Characters are read by an inprecise
243        function now, which returns with an unknown value if the character code is
244        above a certain threshold (e.g: 256). The only limitation is that the value
245        must be bigger than the threshold as well. This function is useful when
246        the characters above the threshold are handled in the same way.
247    
248    7.  The macros whose names start with RAWUCHAR are placeholders for a future
249        mode in which only the bottom 21 bits of 32-bit data items are used. To
250        make this more memorable for those maintaining the code, the names have
251        been changed to start with UCHAR21, and an extensive comment has been added
252        to their definition.
253    
254    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
255        to the export list in Makefile.am (they were accidentally omitted from the
256        8.34 tarball).
257    
258    9.  The informational output from pcretest used the phrase "starting byte set"
259        which is inappropriate for the 16-bit and 32-bit libraries. As the output
260        for "first char" and "need char" really means "non-UTF-char", I've changed
261        "byte" to "char", and slightly reworded the output. The documentation about
262        these values has also been (I hope) clarified.
263    
264    10. Another JIT related optimization: use table jumps for selecting the correct
265        backtracking path, when more than four alternatives are present inside a
266        bracket.
267    
268    11. Empty match is not possible, when the minimum length is greater than zero,
269        and there is no \K in the pattern. JIT should avoid empty match checks in
270        such cases.
271    
272    12. In a caseless character class with UCP support, when a character with more
273        than one alternative case was not the first character of a range, not all
274        the alternative cases were added to the class. For example, s and \x{17f}
275        are both alternative cases for S: the class [RST] was handled correctly,
276        but [R-T] was not.
277    
278    13. The configure.ac file always checked for pthread support when JIT was
279        enabled. This is not used in Windows, so I have put this test inside a
280        check for the presence of windows.h (which was already tested for).
281    
282    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
283        The algorithm provides a way to skip certain starting offsets, and usually
284        faster than linear prefix searches.
285    
286    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
287        as for 'fr_FR' and 'french'. For some reason, however, it then used the
288        Windows-specific input and output files, which have 'french' screwed in.
289        So this could never have worked. One of the problems with locales is that
290        they aren't always the same. I have now updated RunTest so that it checks
291        the output of the locale test (test 3) against three different output
292        files, and it allows the test to pass if any one of them matches. With luck
293        this should make the test pass on some versions of Solaris where it was
294        failing. Because of the uncertainty, the script did not used to stop if
295        test 3 failed; it now does. If further versions of a French locale ever
296        come to light, they can now easily be added.
297    
298    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
299        there was a message during ./configure, but it did not stop. This now
300        provokes an error. The invalid example in README has been corrected.
301        If a value less than the minimum is given, the minimum value has always
302        been used, but now a warning is given.
303    
304    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
305        was a bug in the test system, which is now fixed. Also, the list of various
306        configurations that are tested for each release did not have one with both
307        16/32 bits and --enable-bar-anycrlf. It now does.
308    
309    18. pcretest was missing "-C bsr" for displaying the \R default setting.
310    
311    19. Little endian PowerPC systems are supported now by the JIT compiler.
312    
313    20. The fast forward newline mechanism could enter to an infinite loop on
314        certain invalid UTF-8 input. Although we don't support these cases
315        this issue can be fixed by a performance optimization.
316    
317    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
318        not take account if existing stack usage. There is now a new global
319        variable called pcre_stack_guard that can be set to point to an external
320        function to check stack availability. It is called at the start of
321        processing every parenthesized group.
322    
323    22. A typo in the code meant that in ungreedy mode the max/min qualifier
324        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
325        not match "ab".
326    
327    23. When UTF was disabled, the JIT program reported some incorrect compile
328        errors. These messages are silenced now.
329    
330    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
331        compiler.
332    
333    25. Change all the temporary files used in RunGrepTest to be different to those
334        used by RunTest so that the tests can be run simultaneously, for example by
335        "make -j check".
336    
337    
338    Version 8.34 15-December-2013
339    -----------------------------
340    
341    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
342        executable memory. Patch inspired by Carsten Klein.
343    
344    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
345        this macro is never tested and has no effect, because the work to support
346        coverage involves only compiling and linking options and special targets in
347        the Makefile. The comment in config.h implied that defining the macro would
348        enable coverage support, which is totally false. There was also support for
349        setting this macro in the CMake files (my fault, I just copied it from
350        configure). SUPPORT_GCOV has now been removed.
351    
352    3.  Make a small performance improvement in strlen16() and strlen32() in
353        pcretest.
354    
355    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
356        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
357        these cases). There was also one in pcretest.c.
358    
359    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
360    
361    6.  In UTF mode, the code for checking whether a group could match an empty
362        string (which is used for indefinitely repeated groups to allow for
363        breaking an infinite loop) was broken when the group contained a repeated
364        negated single-character class with a character that occupied more than one
365        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
366        UTF-8 mode). The effect was undefined: the group might or might not be
367        deemed as matching an empty string, or the program might have crashed.
368    
369    7.  The code for checking whether a group could match an empty string was not
370        recognizing that \h, \H, \v, \V, and \R must match a character.
371    
372    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
373        an empty string. If it can, pcretest shows this in its information output.
374    
375    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
376        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
377        matched by pcre_exec() without using JIT:
378    
379        (a) If the rest of the pattern did not match after a maximal run of
380            grapheme clusters, the code for backing up to try with fewer of them
381            did not always back up over a full grapheme when characters that do not
382            have the modifier quality were involved, e.g. Hangul syllables.
383    
384        (b) If the match point in a subject started with modifier character, and
385            there was no match, the code could incorrectly back up beyond the match
386            point, and potentially beyond the first character in the subject,
387            leading to a segfault or an incorrect match result.
388    
389    10. A conditional group with an assertion condition could lead to PCRE
390        recording an incorrect first data item for a match if no other first data
391        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
392        first data item, and therefore matched "ca" after "c" instead of at the
393        start.
394    
395    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
396        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
397    
398    12. The source of pcregrep now includes z/OS-specific code so that it can be
399        compiled for z/OS as part of the special z/OS distribution.
400    
401    13. Added the -T and -TM options to pcretest.
402    
403    14. The code in pcre_compile.c for creating the table of named capturing groups
404        has been refactored. Instead of creating the table dynamically during the
405        actual compiling pass, the information is remembered during the pre-compile
406        pass (on the stack unless there are more than 20 named groups, in which
407        case malloc() is used) and the whole table is created before the actual
408        compile happens. This has simplified the code (it is now nearly 150 lines
409        shorter) and prepared the way for better handling of references to groups
410        with duplicate names.
411    
412    15. A back reference to a named subpattern when there is more than one of the
413        same name now checks them in the order in which they appear in the pattern.
414        The first one that is set is used for the reference. Previously only the
415        first one was inspected. This change makes PCRE more compatible with Perl.
416    
417    16. Unicode character properties were updated from Unicode 6.3.0.
418    
419    17. The compile-time code for auto-possessification has been refactored, based
420        on a patch by Zoltan Herczeg. It now happens after instead of during
421        compilation. The code is cleaner, and more cases are handled. The option
422        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
423        options in pcretest are provided to set it. It can also be set by
424        (*NO_AUTO_POSSESS) at the start of a pattern.
425    
426    18. The character VT has been added to the default ("C" locale) set of
427        characters that match \s and are generally treated as white space,
428        following this same change in Perl 5.18. There is now no difference between
429        "Perl space" and "POSIX space". Whether VT is treated as white space in
430        other locales depends on the locale.
431    
432    19. The code for checking named groups as conditions, either for being set or
433        for being recursed, has been refactored (this is related to 14 and 15
434        above). Processing unduplicated named groups should now be as fast at
435        numerical groups, and processing duplicated groups should be faster than
436        before.
437    
438    20. Two patches to the CMake build system, by Alexander Barkov:
439    
440          (1) Replace the "source" command by "." in CMakeLists.txt because
441              "source" is a bash-ism.
442    
443          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
444              without these the CMake build does not work on Solaris.
445    
446    21. Perl has changed its handling of \8 and \9. If there is no previously
447        encountered capturing group of those numbers, they are treated as the
448        literal characters 8 and 9 instead of a binary zero followed by the
449        literals. PCRE now does the same.
450    
451    22. Following Perl, added \o{} to specify codepoints in octal, making it
452        possible to specify values greater than 0777 and also making them
453        unambiguous.
454    
455    23. Perl now gives an error for missing closing braces after \x{... instead of
456        treating the string as literal. PCRE now does the same.
457    
458    24. RunTest used to grumble if an inappropriate test was selected explicitly,
459        but just skip it when running all tests. This make it awkward to run ranges
460        of tests when one of them was inappropriate. Now it just skips any
461        inappropriate tests, as it always did when running all tests.
462    
463    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
464        character types such as \d or \w, too many callouts were inserted, and the
465        data that they returned was rubbish.
466    
467    26. In UCP mode, \s was not matching two of the characters that Perl matches,
468        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
469        were matched by \h. The code has now been refactored so that the lists of
470        the horizontal and vertical whitespace characters used for \h and \v (which
471        are defined only in one place) are now also used for \s.
472    
473    27. Add JIT support for the 64 bit TileGX architecture.
474        Patch by Jiong Wang (Tilera Corporation).
475    
476    28. Possessive quantifiers for classes (both explicit and automatically
477        generated) now use special opcodes instead of wrapping in ONCE brackets.
478    
479    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
480        (because it's meaningless), this was not happening when PCRE_CASELESS was
481        set. Not wrong, but inefficient.
482    
483    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
484        properties for \w, \d, etc) is present in a test regex. Otherwise if the
485        test contains no characters greater than 255, Perl doesn't realise it
486        should be using Unicode semantics.
487    
488    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
489        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
490        does in Unicode mode.
491    
492    32. Added the "forbid" facility to pcretest so that putting tests into the
493        wrong test files can sometimes be quickly detected.
494    
495    33. There is now a limit (default 250) on the depth of nesting of parentheses.
496        This limit is imposed to control the amount of system stack used at compile
497        time. It can be changed at build time by --with-parens-nest-limit=xxx or
498        the equivalent in CMake.
499    
500    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
501        errors. Perl warns for these when in warning mode, but PCRE has no facility
502        for giving warnings.
503    
504    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
505        However, this was not working for (?!) because it is optimized to (*FAIL),
506        for which PCRE does not allow quantifiers. The optimization is now disabled
507        when a quantifier follows (?!). I can't see any use for this, but it makes
508        things uniform.
509    
510    36. Perl no longer allows group names to start with digits, so I have made this
511        change also in PCRE. It simplifies the code a bit.
512    
513    37. In extended mode, Perl ignores spaces before a + that indicates a
514        possessive quantifier. PCRE allowed a space before the quantifier, but not
515        before the possessive +. It now does.
516    
517    38. The use of \K (reset reported match start) within a repeated possessive
518        group such as (a\Kb)*+ was not working.
519    
520    40. Document that the same character tables must be used at compile time and
521        run time, and that the facility to pass tables to pcre_exec() and
522        pcre_dfa_exec() is for use only with saved/restored patterns.
523    
524    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
525        features for Builds with MSVC:
526    
527        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
528           builds). The .rc files can be used to set FileDescription and many other
529           attributes.
530    
531        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
532           This allows higher-level build scripts which want .pdb files to avoid
533           hard-coding the exact files needed."
534    
535    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
536        mean "start of word" and "end of word", respectively, as a transition aid.
537    
538    43. A minimizing repeat of a class containing codepoints greater than 255 in
539        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
540        compiled to use the heap for recursion.
541    
542    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
543        is configured.
544    
545    
546    Version 8.33 28-May-2013
547    ------------------------
548    
549    1.  Added 'U' to some constants that are compared to unsigned integers, to
550        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
551        variables that are added to signed variables, to ensure the result is
552        signed and can be negated.
553    
554    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
555        CMake config files.
556    
557    3.  Revise the creation of config.h.generic so that all boolean macros are
558        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
559        overriding via -D on the command line possible.
560    
561    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
562        to unsigned int is reported to make a quite noticeable speed difference in
563        a specific Windows environment. Testing on Linux did also appear to show
564        some benefit (and it is clearly not harmful). Also fixed the definition of
565        Xop which should be unsigned.
566    
567    5.  Related to (4), changing the definition of the intermediate variable cc
568        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
569        improvements.
570    
571    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
572        unnecessary spaces.
573    
574    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
575        and later.
576    
577    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
578    
579    9.  Optimizing fast_forward_start_bits in JIT.
580    
581    10. Adding support for callouts in JIT, and fixing some issues revealed
582        during this work. Namely:
583    
584        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
585    
586        (b) Minimum length was not checked before the matching is started.
587    
588    11. The value of capture_last that is passed to callouts was incorrect in some
589        cases when there was a capture on one path that was subsequently abandoned
590        after a backtrack. Also, the capture_last value is now reset after a
591        recursion, since all captures are also reset in this case.
592    
593    12. The interpreter no longer returns the "too many substrings" error in the
594        case when an overflowing capture is in a branch that is subsequently
595        abandoned after a backtrack.
596    
597    13. In the pathological case when an offset vector of size 2 is used, pcretest
598        now prints out the matched string after a yield of 0 or 1.
599    
600    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
601        Only supported by the JIT compiler at the moment.
602    
603    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
604    
605    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
606        offset of the starting point of the matching process, provided the offsets
607        vector is large enough.
608    
609    17. The \A escape now records a lookbehind value of 1, though its execution
610        does not actually inspect the previous character. This is to ensure that,
611        in partial multi-segment matching, at least one character from the old
612        segment is retained when a new segment is processed. Otherwise, if there
613        are no lookbehinds in the pattern, \A might match incorrectly at the start
614        of a new segment.
615    
616    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
617    
618    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
619        gives some modest performance improvement in 8-bit mode.
620    
621    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
622        be expressed in certain programming languages using Universal Character
623        Names.
624    
625    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
626        which points out that "non characters" are not "characters that may not
627        appear in Unicode strings" but rather "characters that are reserved for
628        internal use and have only local meaning".
629    
630    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
631        there was a conditional group that depended on an assertion, if the
632        assertion was false, the callout that immediately followed the alternation
633        in the condition was skipped when pcre_exec() was used for matching.
634    
635    23. Allow an explicit callout to be inserted before an assertion that is the
636        condition for a conditional group, for compatibility with automatic
637        callouts, which always insert a callout at this point.
638    
639    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
640        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
641    
642    25. (*PRUNE) is now supported by the JIT compiler.
643    
644    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
645    
646    27. Fix the case where there are two or more SKIPs with arguments that may be
647        ignored.
648    
649    28. (*SKIP) is now supported by the JIT compiler.
650    
651    29. (*THEN) is now supported by the JIT compiler.
652    
653    30. Update RunTest with additional test selector options.
654    
655    31. The way PCRE handles backtracking verbs has been changed in two ways.
656    
657        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
658        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
659        backtracking. In some cases this makes it more Perl-compatible, but Perl's
660        rather obscure rules do not always do the same thing.
661    
662        (2) Previously, backtracking verbs were confined within assertions. This is
663        no longer the case for positive assertions, except for (*ACCEPT). Again,
664        this sometimes improves Perl compatibility, and sometimes does not.
665    
666    32. A number of tests that were in test 2 because Perl did things differently
667        have been moved to test 1, because either Perl or PCRE has changed, and
668        these tests are now compatible.
669    
670    32. Backtracking control verbs are now handled in the same way in JIT and
671        interpreter.
672    
673    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
674        contained a forward subroutine reference caused a compile error.
675    
676    34. Auto-detect and optimize limited repetitions in JIT.
677    
678    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
679        blocking (*UTF) etc.
680    
681    36. In the interpreter, maximizing pattern repetitions for characters and
682        character types now use tail recursion, which reduces stack usage.
683    
684    37. The value of the max lookbehind was not correctly preserved if a compiled
685        and saved regex was reloaded on a host of different endianness.
686    
687    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
688        of the compiled pattern block, expand the flags field from 16 to 32 bits
689        because it was almost full.
690    
691    39. Try madvise first before posix_madvise.
692    
693    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
694        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
695        original change locked out all matches of empty strings. This has been
696        changed so that one match of an empty string per line is recognized.
697        Subsequent searches on the same line (for colouring or for --only-matching,
698        for example) do not recognize empty strings.
699    
700    41. Applied a user patch to fix a number of spelling mistakes in comments.
701    
702    42. Data lines longer than 65536 caused pcretest to crash.
703    
704    43. Clarified the data type for length and startoffset arguments for pcre_exec
705        and pcre_dfa_exec in the function-specific man pages, where they were
706        explicitly stated to be in bytes, never having been updated. I also added
707        some clarification to the pcreapi man page.
708    
709    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
710        a segmentation fault.
711    
712    
713    Version 8.32 30-November-2012
714    -----------------------------
715    
716    1.  Improved JIT compiler optimizations for first character search and single
717        character iterators.
718    
719    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
720        Patch by Daniel Richard G.
721    
722    3.  Single character iterator optimizations in the JIT compiler.
723    
724    4.  Improved JIT compiler optimizations for character ranges.
725    
726    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
727        Reported by Giuseppe D'Angelo.
728    
729    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
730        of a line, was being set incorrectly in cases where .* appeared inside
731        atomic brackets at the start of a pattern, or where there was a subsequent
732        *PRUNE or *SKIP.
733    
734    7.  Improved instruction cache flush for POWER/PowerPC.
735        Patch by Daniel Richard G.
736    
737    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
738        grep:
739    
740        (a) There is now no limit to the number of patterns to be matched.
741    
742        (b) An error is given if a pattern is too long.
743    
744        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
745            are now supported.
746    
747        (d) --exclude-from and --include-from (multiple use) have been added.
748    
749        (e) Exclusions and inclusions now apply to all files and directories, not
750            just to those obtained from scanning a directory recursively.
751    
752        (f) Multiple uses of -f and --file-list are now supported.
753    
754        (g) In a Windows environment, the default for -d has been changed from
755            "read" (the GNU grep default) to "skip", because otherwise the presence
756            of a directory in the file list provokes an error.
757    
758        (h) The documentation has been revised and clarified in places.
759    
760    9.  Improve the matching speed of capturing brackets.
761    
762    10. Changed the meaning of \X so that it now matches a Unicode extended
763        grapheme cluster.
764    
765    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
766        out POSIX threads when JIT support is configured.
767    
768    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
769    
770    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
771        structure could go wrong in environments where size_t is not the same size
772        as int.
773    
774    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
775        set.
776    
777    15. The EBCDIC support had decayed; later updates to the code had included
778        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
779        general tidy up of EBCDIC-related issues, and the documentation was also
780        not quite right. There is now a test that can be run on ASCII systems to
781        check some of the EBCDIC-related things (but is it not a full test).
782    
783    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
784        in a small tidy to the code.
785    
786    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
787    
788    18. If the --only-matching (-o) option in pcregrep is specified multiple
789        times, each one causes appropriate output. For example, -o1 -o2 outputs the
790        substrings matched by the 1st and 2nd capturing parentheses. A separating
791        string can be specified by --om-separator (default empty).
792    
793    19. Improving the first n character searches.
794    
795    20. Turn case lists for horizontal and vertical white space into macros so that
796        they are defined only once.
797    
798    21. This set of changes together give more compatible Unicode case-folding
799        behaviour for characters that have more than one other case when UCP
800        support is available.
801    
802        (a) The Unicode property table now has offsets into a new table of sets of
803            three or more characters that are case-equivalent. The MultiStage2.py
804            script that generates these tables (the pcre_ucd.c file) now scans
805            CaseFolding.txt instead of UnicodeData.txt for character case
806            information.
807    
808        (b) The code for adding characters or ranges of characters to a character
809            class has been abstracted into a generalized function that also handles
810            case-independence. In UTF-mode with UCP support, this uses the new data
811            to handle characters with more than one other case.
812    
813        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
814            whose other case is greater than 256 are now correctly matched
815            caselessly. Previously, the high codepoint matched the low one, but not
816            vice versa.
817    
818        (d) The processing of \h, \H, \v, and \ in character classes now makes use
819            of the new class addition function, using character lists defined as
820            macros alongside the case definitions of 20 above.
821    
822        (e) Caseless back references now work with characters that have more than
823            one other case.
824    
825        (f) General caseless matching of characters with more than one other case
826            is supported.
827    
828    22. Unicode character properties were updated from Unicode 6.2.0
829    
830    23. Improved CMake support under Windows. Patch by Daniel Richard G.
831    
832    24. Add support for 32-bit character strings, and UTF-32
833    
834    25. Major JIT compiler update (code refactoring and bugfixing).
835        Experimental Sparc 32 support is added.
836    
837    26. Applied a modified version of Daniel Richard G's patch to create
838        pcre.h.generic and config.h.generic by "make" instead of in the
839        PrepareRelease script.
840    
841    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
842        pcre_compile.c when checking for a zero character.
843    
844    28. Introducing a native interface for JIT. Through this interface, the compiled
845        machine code can be directly executed. The purpose of this interface is to
846        provide fast pattern matching, so several sanity checks are not performed.
847        However, feature tests are still performed. The new interface provides
848        1.4x speedup compared to the old one.
849    
850    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
851        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
852        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
853    
854    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
855        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
856        the "old" RFC 2279). Instead, it ended up passing a negative length to
857        pcre_exec().
858    
859    31. Add support for GCC's visibility feature to hide internal functions.
860    
861    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
862        "unknown -C option" after outputting 0 or 1.
863    
864    33. There is now support for generating a code coverage report for the test
865        suite in environments where gcc is the compiler and lcov is installed. This
866        is mainly for the benefit of the developers.
867    
868    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
869        unaddressable using valgrind annotations, allowing valgrind to detect
870        invalid memory accesses. This is mainly for the benefit of the developers.
871    
872    25. (*UTF) can now be used to start a pattern in any of the three libraries.
873    
874    26. Give configure error if --enable-cpp but no C++ compiler found.
875    
876    
877    Version 8.31 06-July-2012
878    -------------------------
879    
880    1.  Fixing a wrong JIT test case and some compiler warnings.
881    
882    2.  Removed a bashism from the RunTest script.
883    
884    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
885        to unsigned type, result still unsigned" that was given by an MS compiler
886        on encountering the code "-sizeof(xxx)".
887    
888    4.  Partial matching support is added to the JIT compiler.
889    
890    5.  Fixed several bugs concerned with partial matching of items that consist
891        of more than one character:
892    
893        (a) /^(..)\1/ did not partially match "aba" because checking references was
894            done on an "all or nothing" basis. This also applied to repeated
895            references.
896    
897        (b) \R did not give a hard partial match if \r was found at the end of the
898            subject.
899    
900        (c) \X did not give a hard partial match after matching one or more
901            characters at the end of the subject.
902    
903        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
904            a partial match for the string "\r".
905    
906        (e) When newline was set to CRLF, the metacharacter "." did not recognize
907            a partial match for a CR character at the end of the subject string.
908    
909    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
910        running pcretest, the text "(JIT)" added to the output whenever JIT is
911        actually used to run the match.
912    
913    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
914        or /S+[+] with a digit between 1 and 7.
915    
916    8.  OP_NOT now supports any UTF character not just single-byte ones.
917    
918    9.  (*MARK) control verb is now supported by the JIT compiler.
919    
920    10. The command "./RunTest list" lists the available tests without actually
921        running any of them. (Because I keep forgetting what they all are.)
922    
923    11. Add PCRE_INFO_MAXLOOKBEHIND.
924    
925    12. Applied a (slightly modified) user-supplied patch that improves performance
926        when the heap is used for recursion (compiled with --disable-stack-for-
927        recursion). Instead of malloc and free for each heap frame each time a
928        logical recursion happens, frames are retained on a chain and re-used where
929        possible. This sometimes gives as much as 30% improvement.
930    
931    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
932        call.
933    
934    14. As documented, (*COMMIT) is now confined to within a positive assertion.
935    
936    15. It is now possible to link pcretest with libedit as an alternative to
937        libreadline.
938    
939    16. (*COMMIT) control verb is now supported by the JIT compiler.
940    
941    17. The Unicode data tables have been updated to Unicode 6.1.0.
942    
943    18. Added --file-list option to pcregrep.
944    
945    19. Added binary file support to pcregrep, including the -a, --binary-files,
946        -I, and --text options.
947    
948    20. The madvise function is renamed for posix_madvise for QNX compatibility
949        reasons. Fixed by Giuseppe D'Angelo.
950    
951    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
952    
953    22. Changed the option for creating symbolic links for 16-bit man pages from
954        -s to -sf so that re-installing does not cause issues.
955    
956    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
957    
958    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
959        matches in certain environments (the workspace was not being correctly
960        retained). Also added to pcre_dfa_exec() a simple plausibility check on
961        some of the workspace data at the beginning of a restart.
962    
963    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
964        was not doing so when it should - probably a typo introduced by SVN 528
965        (change 8.10/14).
966    
967    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
968        \w+ when the character tables indicated that \x{c4} was a word character.
969        There were several related cases, all because the tests for doing a table
970        lookup were testing for characters less than 127 instead of 255.
971    
972    27. If a pattern contains capturing parentheses that are not used in a match,
973        their slots in the ovector are set to -1. For those that are higher than
974        any matched groups, this happens at the end of processing. In the case when
975        there were back references that the ovector was too small to contain
976        (causing temporary malloc'd memory to be used during matching), and the
977        highest capturing number was not used, memory off the end of the ovector
978        was incorrectly being set to -1. (It was using the size of the temporary
979        memory instead of the true size.)
980    
981    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
982        ovector size, it uses memory at the end of the block that it has got.
983    
984    29. Check for an overlong MARK name and give an error at compile time. The
985        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
986    
987    30. JIT compiler update.
988    
989    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
990        Rill for the patch.
991    
992    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
993    
994    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
995    
996    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
997        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
998        was enabled.
999    
1000    35. Improve JIT code generation for greedy plus quantifier.
1001    
1002    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
1003        1 to "aa" instead of to an empty string. The bug affected repeated groups
1004        that could potentially match an empty string.
1005    
1006    37. Optimizing single character iterators in JIT.
1007    
1008    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
1009        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
1010        codepoints that are too big for the mode are faulted, and in a UTF mode,
1011        disallowed codepoints are also faulted.
1012    
1013    39. If PCRE was compiled with UTF support, in three places in the DFA
1014        matcher there was code that should only have been obeyed in UTF mode, but
1015        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
1016        processing when bytes with values greater than 127 were present. In 16-bit
1017        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
1018        both cases the values are those that cannot be the first data item in a UTF
1019        character. The three items that might have provoked this were recursions,
1020        possessively repeated groups, and atomic groups.
1021    
1022    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
1023        and pcregrep, because some OS require shared objects to be explicitly
1024        passed to ld, causing the link step to fail if they are not.
1025    
1026    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
1027        mode, patterns that started with \h* or \R* might be incorrectly matched.
1028    
1029    
1030    Version 8.30 04-February-2012
1031    -----------------------------
1032    
1033    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
1034        name is defined in ctype.h.
1035    
1036    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
1037        only in quite long subpatterns.
1038    
1039    3.  Removed the function pcre_info(), which has been obsolete and deprecated
1040        since it was replaced by pcre_fullinfo() in February 2000.
1041    
1042    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
1043        match a (*MARK), and the match failed at the start of the subject, a
1044        reference to memory before the start of the subject could occur. This bug
1045        was introduced by fix 17 of release 8.21.
1046    
1047    5.  A reference to an unset group with zero minimum repetition was giving
1048        totally wrong answers (in non-JavaScript-compatibility mode). For example,
1049        /(another)?(\1?)test/ matched against "hello world test". This bug was
1050        introduced in release 8.13.
1051    
1052    6.  Add support for 16-bit character strings (a large amount of work involving
1053        many changes and refactorings).
1054    
1055    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
1056        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
1057        from a file.
1058    
1059    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
1060        rounding is not applied in this particular case).
1061    
1062    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
1063        if they appear, or are escaped, in patterns.
1064    
1065    10. Get rid of a number of -Wunused-but-set-variable warnings.
1066    
1067    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
1068        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
1069        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
1070        also returns the mark "x". This bug applied to capturing parentheses,
1071        non-capturing parentheses, and atomic parentheses. It also applied to some
1072        assertions.
1073    
1074    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
1075        information out of configure.ac instead of relying on pcre.h.generic, which
1076        is not stored in the repository.
1077    
1078    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
1079        -lreadline.
1080    
1081    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
1082    
1083    15. Applied Graycode's patch to put the top-level frame on the stack rather
1084        than the heap when not using the stack for recursion. This gives a
1085        performance improvement in many cases when recursion is not deep.
1086    
1087    16. Experimental code added to "pcretest -C" to output the stack frame size.
1088    
1089    
1090    Version 8.21 12-Dec-2011
1091    ------------------------
1092    
1093    1.  Updating the JIT compiler.
1094    
1095    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1096        are added as well.
1097    
1098    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1099        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1100        calling _pcre_jit_exec. Some extra comments are added.
1101    
1102    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1103        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1104        was introduced by change 18 for 8.20.
1105    
1106    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1107        ECMA-262 standard.
1108    
1109    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1110        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1111        This bug was probably introduced by change 9 of 8.13.
1112    
1113    7.  While fixing 6 above, I noticed that a number of other items were being
1114        incorrectly rejected as "not fixed length". This arose partly because newer
1115        opcodes had not been added to the fixed-length checking code. I have (a)
1116        corrected the bug and added tests for these items, and (b) arranged for an
1117        error to occur if an unknown opcode is encountered while checking for fixed
1118        length instead of just assuming "not fixed length". The items that were
1119        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1120        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1121        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1122    
1123    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1124        being incorrectly compiled and would have given unpredicatble results.
1125    
1126    9.  A possessively repeated subpattern with minimum repeat count greater than
1127        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1128        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1129        the first (A) could occur when it should not.
1130    
1131    10. Add a cast and remove a redundant test from the code.
1132    
1133    11. JIT should use pcre_malloc/pcre_free for allocation.
1134    
1135    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1136        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1137        is anything other than /usr, -L is still shown).
1138    
1139    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1140    
1141    14. Perl does not support \N without a following name in a [] class; PCRE now
1142        also gives an error.
1143    
1144    15. If a forward reference was repeated with an upper limit of around 2000,
1145        it caused the error "internal error: overran compiling workspace". The
1146        maximum number of forward references (including repeats) was limited by the
1147        internal workspace, and dependent on the LINK_SIZE. The code has been
1148        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1149        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1150        of around 200,000 forward references. While doing this, I also speeded up
1151        the filling in of repeated forward references.
1152    
1153    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1154        incorrectly expecting the subject to contain another "a" after the start.
1155    
1156    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1157        in the match, the SKIP should be ignored. This was not happening; instead
1158        the SKIP was being treated as NOMATCH. For patterns such as
1159        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1160        tested.
1161    
1162    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1163        now much more compatible with Perl, in particular in cases where the result
1164        is a non-match for a non-anchored pattern. For example, if
1165        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1166        "m", where previously it did not return a name. A side effect of this
1167        change is that for partial matches, the last encountered mark name is
1168        returned, as for non matches. A number of tests that were previously not
1169        Perl-compatible have been moved into the Perl-compatible test files. The
1170        refactoring has had the pleasing side effect of removing one argument from
1171        the match() function, thus reducing its stack requirements.
1172    
1173    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1174        subsequent uses of /S (without +) incorrectly behaved like /S+.
1175    
1176    21. Retrieve executable code size support for the JIT compiler and fixing
1177        some warnings.
1178    
1179    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1180        not work when the shorter character appeared right at the end of the
1181        subject string.
1182    
1183    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1184        systems.
1185    
1186    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1187        output it when the /M option is used in pcretest.
1188    
1189    25. The CheckMan script was not being included in the distribution. Also, added
1190        an explicit "perl" to run Perl scripts from the PrepareRelease script
1191        because this is reportedly needed in Windows.
1192    
1193    26. If study data was being save in a file and studying had not found a set of
1194        "starts with" bytes for the pattern, the data written to the file (though
1195        never used) was taken from uninitialized memory and so caused valgrind to
1196        complain.
1197    
1198    27. Updated RunTest.bat as provided by Sheri Pierce.
1199    
1200    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1201    
1202    29. Computation of memory usage for the table of capturing group names was
1203        giving an unnecessarily large value.
1204    
1205    
1206    Version 8.20 21-Oct-2011
1207    ------------------------
1208    
1209    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1210        a POSIX class. After further experiments with Perl, which convinced me that
1211        Perl has bugs and confusions, a closing square bracket is no longer allowed
1212        in a POSIX name. This bug also affected patterns with classes that started
1213        with full stops.
1214    
1215    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1216        captured substring, but while checking the failing first alternative,
1217        substring 1 is temporarily captured. If the output vector supplied to
1218        pcre_exec() was not big enough for this capture, the yield of the function
1219        was still zero ("insufficient space for captured substrings"). This cannot
1220        be totally fixed without adding another stack variable, which seems a lot
1221        of expense for a edge case. However, I have improved the situation in cases
1222        such as /(a)(b)x|abc/ matched against "abc", where the return code
1223        indicates that fewer than the maximum number of slots in the ovector have
1224        been set.
1225    
1226    3.  Related to (2) above: when there are more back references in a pattern than
1227        slots in the output vector, pcre_exec() uses temporary memory during
1228        matching, and copies in the captures as far as possible afterwards. It was
1229        using the entire output vector, but this conflicts with the specification
1230        that only 2/3 is used for passing back captured substrings. Now it uses
1231        only the first 2/3, for compatibility. This is, of course, another edge
1232        case.
1233    
1234    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1235        main code base, and can be used by building with --enable-jit. When this is
1236        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1237        runtime --no-jit option is given.
1238    
1239    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1240        ovector, the return from the function was zero, implying that there were
1241        other matches that did not fit. The correct "exactly full" value is now
1242        returned.
1243    
1244    6.  If a subpattern that was called recursively or as a subroutine contained
1245        (*PRUNE) or any other control that caused it to give a non-standard return,
1246        invalid errors such as "Error -26 (nested recursion at the same subject
1247        position)" or even infinite loops could occur.
1248    
1249    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1250        computing the minimum length on reaching *ACCEPT, and so ended up with the
1251        wrong value of 1 rather than 0. Further investigation indicates that
1252        computing a minimum subject length in the presence of *ACCEPT is difficult
1253        (think back references, subroutine calls), and so I have changed the code
1254        so that no minimum is registered for a pattern that contains *ACCEPT.
1255    
1256    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1257        it was not handled as intended. [But see 16 below.]
1258    
1259    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1260        Sheri Pierce.
1261    
1262    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1263        the first byte in a match must be "a".
1264    
1265    11. Change 17 for 8.13 increased the recursion depth for patterns like
1266        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1267        pattern contains any instances of (*THEN). If it does not, the old
1268        optimizations are restored. It would be nice to do this on a per-group
1269        basis, but at the moment that is not feasible.
1270    
1271    12. In some environments, the output of pcretest -C is CRLF terminated. This
1272        broke RunTest's code that checks for the link size. A single white space
1273        character after the value is now allowed for.
1274    
1275    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1276        For "fr", it uses the Windows-specific input and output files.
1277    
1278    14. If (*THEN) appeared in a group that was called recursively or as a
1279        subroutine, it did not work as intended. [But see next item.]
1280    
1281    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1282        pattern fragments (but not containing any | characters). If A and B are
1283        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1284        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1285        D. In other words, Perl considers parentheses that do not contain any |
1286        characters to be part of a surrounding alternative, whereas PCRE was
1287        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1288        differently. PCRE now behaves in the same way as Perl, except in the case
1289        of subroutine/recursion calls such as (?1) which have in any case always
1290        been different (but PCRE had them first :-).
1291    
1292    16. Related to 15 above: Perl does not treat the | in a conditional group as
1293        creating alternatives. Such a group is treated in the same way as an
1294        ordinary group without any | characters when processing (*THEN). PCRE has
1295        been changed to match Perl's behaviour.
1296    
1297    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1298        RunGrepTest script failed.
1299    
1300    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1301        inevitable for groups that contain captures, but it can lead to a lot of
1302        stack use in large patterns. The old behaviour has been restored for atomic
1303        groups that do not contain any capturing parentheses.
1304    
1305    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1306        suppress the check for a minimum subject length at run time. (If it was
1307        given to pcre_exec() or pcre_dfa_exec() it did work.)
1308    
1309    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1310        fail to work when decoding hex characters in data strings in EBCDIC
1311        environments.
1312    
1313    21. It appears that in at least one Mac OS environment, the isxdigit() function
1314        is implemented as a macro that evaluates to its argument more than once,
1315        contravening the C 90 Standard (I haven't checked a later standard). There
1316        was an instance in pcretest which caused it to go wrong when processing
1317        \x{...} escapes in subject strings. The has been rewritten to avoid using
1318        things like p++ in the argument of isxdigit().
1319    
1320    
1321    Version 8.13 16-Aug-2011
1322    ------------------------
1323    
1324    1.  The Unicode data tables have been updated to Unicode 6.0.0.
1325    
1326    2.  Two minor typos in pcre_internal.h have been fixed.
1327    
1328    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
1329        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
1330        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
1331    
1332    4.  There were a number of related bugs in the code for matching backrefences
1333        caselessly in UTF-8 mode when codes for the characters concerned were
1334        different numbers of bytes. For example, U+023A and U+2C65 are an upper
1335        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
1336        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
1337        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1338        2-byte code at the end of the subject (it thought there wasn't enough data
1339        left).
1340    
1341    5.  Comprehensive information about what went wrong is now returned by
1342        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1343        as the output vector has at least 2 elements. The offset of the start of
1344        the failing character and a reason code are placed in the vector.
1345    
1346    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1347        now returned is for the first byte of the failing character, instead of the
1348        last byte inspected. This is an incompatible change, but I hope it is small
1349        enough not to be a problem. It makes the returned offset consistent with
1350        pcre_exec() and pcre_dfa_exec().
1351    
1352    7.  pcretest now gives a text phrase as well as the error number when
1353        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1354        failure, the offset and reason code are output.
1355    
1356    8.  When \R was used with a maximizing quantifier it failed to skip backwards
1357        over a \r\n pair if the subsequent match failed. Instead, it just skipped
1358        back over a single character (\n). This seems wrong (because it treated the
1359        two characters as a single entity when going forwards), conflicts with the
1360        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1361        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1362        has been changed.
1363    
1364    9.  Some internal refactoring has changed the processing so that the handling
1365        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1366        time (the PCRE_DOTALL option was changed this way some time ago: version
1367        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1368        which was always a bit of a fudge. It also means that there is one less
1369        argument for the match() function, which reduces its stack requirements
1370        slightly. This change also fixes an incompatibility with Perl: the pattern
1371        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1372    
1373    10. More internal refactoring has drastically reduced the number of recursive
1374        calls to match() for possessively repeated groups such as (abc)++ when
1375        using pcre_exec().
1376    
1377    11. While implementing 10, a number of bugs in the handling of groups were
1378        discovered and fixed:
1379    
1380        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1381        (a|)*(?1) gave a compile-time internal error.
1382        ((a|)+)+  did not notice that the outer group could match an empty string.
1383        (^a|^)+   was not marked as anchored.
1384        (.*a|.*)+ was not marked as matching at start or after a newline.
1385    
1386    12. Yet more internal refactoring has removed another argument from the match()
1387        function. Special calls to this function are now indicated by setting a
1388        value in a variable in the "match data" data block.
1389    
1390    13. Be more explicit in pcre_study() instead of relying on "default" for
1391        opcodes that mean there is no starting character; this means that when new
1392        ones are added and accidentally left out of pcre_study(), testing should
1393        pick them up.
1394    
1395    14. The -s option of pcretest has been documented for ages as being an old
1396        synonym of -m (show memory usage). I have changed it to mean "force study
1397        for every regex", that is, assume /S for every regex. This is similar to -i
1398        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1399        using it. It makes it easier to run collections of tests with and without
1400        study enabled, and thereby test pcre_study() more easily. All the standard
1401        tests are now run with and without -s (but some patterns can be marked as
1402        "never study" - see 20 below).
1403    
1404    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1405        restoration of the capturing data to the outer values was not happening
1406        correctly.
1407    
1408    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1409        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1410        pattern had matched an empty string, and so incorrectly returned a no
1411        match.
1412    
1413    17. There was optimizing code for the last branch of non-capturing parentheses,
1414        and also for the obeyed branch of a conditional subexpression, which used
1415        tail recursion to cut down on stack usage. Unfortunately, now that there is
1416        the possibility of (*THEN) occurring in these branches, tail recursion is
1417        no longer possible because the return has to be checked for (*THEN). These
1418        two optimizations have therefore been removed. [But see 8.20/11 above.]
1419    
1420    18. If a pattern containing \R was studied, it was assumed that \R always
1421        matched two bytes, thus causing the minimum subject length to be
1422        incorrectly computed because \R can also match just one byte.
1423    
1424    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1425        was incorrectly computed.
1426    
1427    20. If /S is present twice on a test pattern in pcretest input, it now
1428        *disables* studying, thereby overriding the use of -s on the command line
1429        (see 14 above). This is necessary for one or two tests to keep the output
1430        identical in both cases.
1431    
1432    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1433        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1434    
1435    22. When an atomic group that contained a capturing parenthesis was
1436        successfully matched, but the branch in which it appeared failed, the
1437        capturing was not being forgotten if a higher numbered group was later
1438        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1439        group 1 to "a", when in fact it should be unset. This applied to multi-
1440        branched capturing and non-capturing groups, repeated or not, and also to
1441        positive assertions (capturing in negative assertions does not happen
1442        in PCRE) and also to nested atomic groups.
1443    
1444    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1445        subject after a captured substring, to make it easier to tell which of a
1446        number of identical substrings has been captured.
1447    
1448    24. The way atomic groups are processed by pcre_exec() has been changed so that
1449        if they are repeated, backtracking one repetition now resets captured
1450        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1451        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1452        "aaa". Previously, it would have been "a". As part of this code
1453        refactoring, the way recursive calls are handled has also been changed.
1454    
1455    25. If an assertion condition captured any substrings, they were not passed
1456        back unless some other capturing happened later. For example, if
1457        (?(?=(a))a) was matched against "a", no capturing was returned.
1458    
1459    26. When studying a pattern that contained subroutine calls or assertions,
1460        the code for finding the minimum length of a possible match was handling
1461        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1462        group 1 called group 2 while simultaneously a separate group 2 called group
1463        1). A stack overflow occurred in this case. I have fixed this by limiting
1464        the recursion depth to 10.
1465    
1466    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1467        Fortmann. This supports explicit test numbers on the command line, and has
1468        argument validation and error reporting.
1469    
1470    28. An instance of \X with an unlimited repeat could fail if at any point the
1471        first character it looked at was a mark character.
1472    
1473    29. Some minor code refactoring concerning Unicode properties and scripts
1474        should reduce the stack requirement of match() slightly.
1475    
1476    30. Added the '=' option to pcretest to check the setting of unused capturing
1477        slots at the end of the pattern, which are documented as being -1, but are
1478        not included in the return count.
1479    
1480    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1481        compiled something random. Now it gives a compile-time error (as does
1482        Perl).
1483    
1484    32. A *MARK encountered during the processing of a positive assertion is now
1485        recorded and passed back (compatible with Perl).
1486    
1487    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1488        had alternative anchored branches, the search for a second match in a line
1489        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1490        matched the line "0102" twice. The same bug affected patterns that started
1491        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1492        twice.
1493    
1494    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1495        does, and because of capturing effects, quantifying parenthesized
1496        assertions may at times be useful. Quantifiers are now allowed for
1497        parenthesized assertions.
1498    
1499    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1500    
1501    36. \g was being checked for fancy things in a character class, when it should
1502        just be a literal "g".
1503    
1504    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1505        appearance of a nested POSIX class supersedes an apparent external class.
1506        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1507        unescaped square brackets may also appear as part of class names. For
1508        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1509        more like Perl. (But see 8.20/1 above.)
1510    
1511    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1512        was because it thought it was \N{name}, which is not supported).
1513    
1514    39. Add minix to OS list not supporting the -S option in pcretest.
1515    
1516    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1517        cannot analyze patterns in sufficient detail to catch mutual recursions
1518        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1519        subgroup is called recursively as a subpattern for a second time at the
1520        same position in the subject string. In previous releases this might have
1521        been caught by the recursion limit, or it might have run out of stack.
1522    
1523    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1524        happen only once. PCRE was, however incorrectly giving a compile time error
1525        "recursive call could loop indefinitely" because it cannot analyze the
1526        pattern in sufficient detail. The compile time test no longer happens when
1527        PCRE is compiling a conditional subpattern, but actual runaway loops are
1528        now caught at runtime (see 40 above).
1529    
1530    42. It seems that Perl allows any characters other than a closing parenthesis
1531        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1532        has been changed to be the same.
1533    
1534    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1535        as not to get warnings when autogen.sh is called. Also changed
1536        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1537    
1538    44. To help people who use pcregrep to scan files containing exceedingly long
1539        lines, the following changes have been made:
1540    
1541        (a) The default value of the buffer size parameter has been increased from
1542            8K to 20K. (The actual buffer used is three times this size.)
1543    
1544        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1545            PCRE is built.
1546    
1547        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1548            to be set at run time.
1549    
1550        (d) Numerical values in pcregrep options can be followed by K or M, for
1551            example --buffer-size=50K.
1552    
1553        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1554            given and the return code is set to 2.
1555    
1556    45. Add a pointer to the latest mark to the callout data block.
1557    
1558    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1559        partial match of an empty string instead of no match. This was specific to
1560        the use of ".".
1561    
1562    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1563        complete match instead of a partial match. This bug was dependent on both
1564        the PCRE_UTF8 and PCRE_DOTALL options being set.
1565    
1566    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1567        starting byte set, because \b was not being ignored.
1568    
1569    
1570    Version 8.12 15-Jan-2011
1571    ------------------------
1572    
1573    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1574        checks for such things as part of the documentation building process.
1575    
1576    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1577        --match-limit and --recursion-limit options (added for 8.11). In
1578        particular, this made one of the standard tests fail. (The integer value
1579        went into the wrong half of a long int.)
1580    
1581    3.  If the --colour option was given to pcregrep with -v (invert match), it
1582        did strange things, either producing crazy output, or crashing. It should,
1583        of course, ignore a request for colour when reporting lines that do not
1584        match.
1585    
1586    4.  Another pcregrep bug caused similar problems if --colour was specified with
1587        -M (multiline) and the pattern match finished with a line ending.
1588    
1589    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1590        matched in multiline mode, the following line was shown as part of the
1591        match. This seems wrong, so I have changed it.
1592    
1593    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1594        the check for further matches in the same line (so they could be coloured)
1595        to overrun the end of the current line. If another match was found, it was
1596        incorrectly shown (and then shown again when found in the next line).
1597    
1598    7.  If pcregrep was compiled under Windows, there was a reference to the
1599        function pcregrep_exit() before it was defined. I am assuming this was
1600        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1601        reported by a user. I've moved the definition above the reference.
1602    
1603    
1604    Version 8.11 10-Dec-2010
1605    ------------------------
1606    
1607    1.  (*THEN) was not working properly if there were untried alternatives prior
1608        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1609        backtracked to try for "b" instead of moving to the next alternative branch
1610        at the same level (in this case, to look for "c"). The Perl documentation
1611        is clear that when (*THEN) is backtracked onto, it goes to the "next
1612        alternative in the innermost enclosing group".
1613    
1614    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1615        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1616        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1617        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1618        (*THEN).
1619    
1620    3.  If \s appeared in a character class, it removed the VT character from
1621        the class, even if it had been included by some previous item, for example
1622        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1623        of \s, but is part of the POSIX "space" class.)
1624    
1625    4.  A partial match never returns an empty string (because you can always
1626        match an empty string at the end of the subject); however the checking for
1627        an empty string was starting at the "start of match" point. This has been
1628        changed to the "earliest inspected character" point, because the returned
1629        data for a partial match starts at this character. This means that, for
1630        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1631        (previously it gave "no match").
1632    
1633    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1634        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1635        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1636        has an implication that the given string is incomplete (because a partial
1637        match is preferred over a full match). For this reason, these items now
1638        give a partial match in this situation. [Aside: previously, the one case
1639        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1640        match rather than a full match, which was wrong by the old rules, but is
1641        now correct.]
1642    
1643    6.  There was a bug in the handling of #-introduced comments, recognized when
1644        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1645        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1646        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1647        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1648        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1649        places in pcre_compile().
1650    
1651    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1652        comments when looking ahead for named forward references to subpatterns,
1653        the only newline sequence it recognized was NL. It now handles newlines
1654        according to the set newline convention.
1655    
1656    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1657        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1658        cater for a lack of strerror(). These oversights have been fixed.
1659    
1660    9.  Added --match-limit and --recursion-limit to pcregrep.
1661    
1662    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1663    
1664    11. When the -o option was used, pcregrep was setting a return code of 1, even
1665        when matches were found, and --line-buffered was not being honoured.
1666    
1667    12. Added an optional parentheses number to the -o and --only-matching options
1668        of pcregrep.
1669    
1670    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1671        can match an empty string. The code to do it in pcretest and pcredemo
1672        needed fixing:
1673    
1674        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1675            only one byte after an empty string match just before CRLF (this case
1676            just got forgotten; "any" and "anycrlf" were OK).
1677    
1678        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1679            mode when an empty string match preceded an ASCII character followed by
1680            a non-ASCII character. (The code for advancing by one character rather
1681            than one byte was nonsense.)
1682    
1683        (c) The pcredemo.c sample program did not have any code at all to handle
1684            the cases when CRLF is a valid newline sequence.
1685    
1686    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1687        as a starting offset was within the subject string. There is now a new
1688        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1689        negative or greater than the length of the string. In order to test this,
1690        pcretest is extended to allow the setting of negative starting offsets.
1691    
1692    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1693        starting offset points to the beginning of a UTF-8 character was
1694        unnecessarily clumsy. I tidied it up.
1695    
1696    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1697        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1698    
1699    17. Nobody had reported that the --include_dir option, which was added in
1700        release 7.7 should have been called --include-dir (hyphen, not underscore)
1701        for compatibility with GNU grep. I have changed it to --include-dir, but
1702        left --include_dir as an undocumented synonym, and the same for
1703        --exclude-dir, though that is not available in GNU grep, at least as of
1704        release 2.5.4.
1705    
1706    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1707        characters from a string of bytes) have been redefined so as not to use
1708        loops, in order to improve performance in some environments. At the same
1709        time, I abstracted some of the common code into auxiliary macros to save
1710        repetition (this should not affect the compiled code).
1711    
1712    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1713        compile-time error is now given if \c is not followed by an ASCII
1714        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1715        different, and any byte value is allowed.)
1716    
1717    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1718        START_OPTIMIZE option, which is now allowed at compile time - but just
1719        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1720        to pcregrep and other applications that have no direct access to PCRE
1721        options. The new /Y option in pcretest sets this option when calling
1722        pcre_compile().
1723    
1724    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1725        back references. Groups containing recursive back references were forced to
1726        be atomic by that change, but in the case of named groups, the amount of
1727        memory required was incorrectly computed, leading to "Failed: internal
1728        error: code overflow". This has been fixed.
1729    
1730    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1731        pcretest.c, to avoid build problems in some Borland environments.
1732    
1733    
1734    Version 8.10 25-Jun-2010
1735    ------------------------
1736    
1737    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1738        THEN.
1739    
1740    2.  (*ACCEPT) was not working when inside an atomic group.
1741    
1742    3.  Inside a character class, \B is treated as a literal by default, but
1743        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1744        causes the error). The code is unchanged, but I tidied the documentation.
1745    
1746    4.  Inside a character class, PCRE always treated \R and \X as literals,
1747        whereas Perl faults them if its -w option is set. I have changed PCRE so
1748        that it faults them when PCRE_EXTRA is set.
1749    
1750    5.  Added support for \N, which always matches any character other than
1751        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1752    
1753    6.  When compiling pcregrep with newer versions of gcc which may have
1754        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1755        declared with attribute warn_unused_result" were given. Just casting the
1756        result to (void) does not stop the warnings; a more elaborate fudge is
1757        needed. I've used a macro to implement this.
1758    
1759    7.  Minor change to pcretest.c to avoid a compiler warning.
1760    
1761    8.  Added four artifical Unicode properties to help with an option to make
1762        \s etc use properties (see next item). The new properties are: Xan
1763        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1764    
1765    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1766        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1767        this option. Modified pcretest to add /W to test this facility. Added
1768        REG_UCP to make it available via the POSIX interface.
1769    
1770    10. Added --line-buffered to pcregrep.
1771    
1772    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1773        studied, and the match started with a letter with a code point greater than
1774        127 whose first byte was different to the first byte of the other case of
1775        the letter, the other case of this starting letter was not recognized
1776        (#976).
1777    
1778    12. If a pattern that was studied started with a repeated Unicode property
1779        test, for example, \p{Nd}+, there was the theoretical possibility of
1780        setting up an incorrect bitmap of starting bytes, but fortunately it could
1781        not have actually happened in practice until change 8 above was made (it
1782        added property types that matched character-matching opcodes).
1783    
1784    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1785        possible starting bytes for non-anchored patterns.
1786    
1787    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1788        \R, and also a number of cases that involve Unicode properties, both
1789        explicit and implicit when PCRE_UCP is set.
1790    
1791    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1792        input, it could crash or give wrong results if characters with values
1793        greater than 0xc0 were present in the subject string. (Detail: it assumed
1794        UTF-8 input when processing these items.)
1795    
1796    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1797        size_t is 64-bit (#991).
1798    
1799    17. Added a check for running out of memory when PCRE is compiled with
1800        --disable-stack-for-recursion (#990).
1801    
1802    18. If the last data line in a file for pcretest does not have a newline on
1803        the end, a newline was missing in the output.
1804    
1805    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1806        less than 128) in its various bitmaps. However, there is a facility for
1807        generating tables according to the current locale when PCRE is compiled. It
1808        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1809        characters, are recognized by isspace() and therefore were getting set in
1810        these tables, and indeed these tables seem to approximate to ISO 8859. This
1811        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1812        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1813        which of course cannot start UTF-8 characters. I have changed the code so
1814        that only real ASCII characters (less than 128) and the correct starting
1815        bytes for UTF-8 encodings are set for characters greater than 127 when in
1816        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1817        altogether.)
1818    
1819    20. Added the /T option to pcretest so as to be able to run tests with non-
1820        standard character tables, thus making it possible to include the tests
1821        used for 19 above in the standard set of tests.
1822    
1823    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1824        reference to a subpattern the other side of a comment that contains an
1825        opening parenthesis caused either an internal compiling error, or a
1826        reference to the wrong subpattern.
1827    
1828    
1829    Version 8.02 19-Mar-2010
1830  ------------------------  ------------------------
1831    
1832  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.
1833    
1834    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1835        configured.
1836    
1837    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1838        original author of that file, following a query about its status.
1839    
1840    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1841        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1842    
1843    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1844        quantifier applied to a forward-referencing subroutine call, could compile
1845        incorrect code or give the error "internal error: previously-checked
1846        referenced subpattern not found".
1847    
1848    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1849        variables to point to external functions. For these systems, therefore,
1850        pcre_malloc etc. are now initialized to local functions that call the
1851        relevant global functions.
1852    
1853    7.  There were two entries missing in the vectors called coptable and poptable
1854        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1855        I've fixed the data, and added a kludgy way of testing at compile time that
1856        the lengths are correct (equal to the number of opcodes).
1857    
1858    8.  Following on from 7, I added a similar kludge to check the length of the
1859        eint vector in pcreposix.c.
1860    
1861    9.  Error texts for pcre_compile() are held as one long string to avoid too
1862        much relocation at load time. To find a text, the string is searched,
1863        counting zeros. There was no check for running off the end of the string,
1864        which could happen if a new error number was added without updating the
1865        string.
1866    
1867    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1868    
1869    11. \K was not working if it appeared in an atomic group or in a group that
1870        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1871        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1872        the assertion is positive, but not if it is negative.
1873    
1874    12. Change 11 fortuitously reduced the size of the stack frame used in the
1875        "match()" function of pcre_exec.c by one pointer. Forthcoming
1876        implementation of support for (*MARK) will need an extra pointer on the
1877        stack; I have reserved it now, so that the stack frame size does not
1878        decrease.
1879    
1880    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1881        item in branch that calls a recursion is a subroutine call - as in the
1882        second branch in the above example - was incorrectly given the compile-
1883        time error "recursive call could loop indefinitely" because pcre_compile()
1884        was not correctly checking the subroutine for matching a non-empty string.
1885    
1886    14. The checks for overrunning compiling workspace could trigger after an
1887        overrun had occurred. This is a "should never occur" error, but it can be
1888        triggered by pathological patterns such as hundreds of nested parentheses.
1889        The checks now trigger 100 bytes before the end of the workspace.
1890    
1891    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1892    
1893    
1894  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
1895  ------------------------  ------------------------
# Line 333  Version 7.9 11-Apr-09 Line 2217  Version 7.9 11-Apr-09
2217  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
2218      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
2219      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2220      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2221        8.33.]
2222    
2223  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
2224      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 576  Version 7.7 07-May-08 Line 2461  Version 7.7 07-May-08
2461      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2462      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2463      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2464      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2465      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2466      was subsequently set up correctly.)      was subsequently set up correctly.)
2467    

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