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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.37 14-April-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    30. A pattern such as /(*UTF)[\S\V\H]/, which contains a negated special class
120        such as \S in non-UCP mode, explicit wide characters (> 255) can be ignored
121        because \S ensures they are all in the class. The code for doing this was
122        interacting badly with the code for computing the amount of space needed to
123        compile the pattern, leading to a buffer overflow. This bug was discovered
124        by the LLVM fuzzer.
125    
126    31. A pattern such as /((?2)+)((?1))/ which has mutual recursion nested inside
127        other kinds of group caused stack overflow at compile time. This bug was
128        discovered by the LLVM fuzzer.
129    
130    32. A pattern such as /(?1)(?#?'){8}(a)/ which had a parenthesized comment
131        between a subroutine call and its quantifier was incorrectly compiled,
132        leading to buffer overflow or other errors. This bug was discovered by the
133        LLVM fuzzer.
134    
135    33. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an
136        assertion after (?(. The code was failing to check the character after
137        (?(?< for the ! or = that would indicate a lookbehind assertion. This bug
138        was discovered by the LLVM fuzzer.
139    
140    34. A pattern such as /X((?2)()*+){2}+/ which has a possessive quantifier with
141        a fixed maximum following a group that contains a subroutine reference was
142        incorrectly compiled and could trigger buffer overflow. This bug was
143        discovered by the LLVM fuzzer.
144    
145    35. A mutual recursion within a lookbehind assertion such as (?<=((?2))((?1)))
146        caused a stack overflow instead of the diagnosis of a non-fixed length
147        lookbehind assertion. This bug was discovered by the LLVM fuzzer.
148    
149    36. The use of \K in a positive lookbehind assertion in a non-anchored pattern
150        (e.g. /(?<=\Ka)/) could make pcregrep loop.
151    
152    37. There was a similar problem to 36 in pcretest for global matches.
153    
154    38. If a greedy quantified \X was preceded by \C in UTF mode (e.g. \C\X*),
155        and a subsequent item in the pattern caused a non-match, backtracking over
156        the repeated \X did not stop, but carried on past the start of the subject,
157        causing reference to random memory and/or a segfault. There were also some
158        other cases where backtracking after \C could crash. This set of bugs was
159        discovered by the LLVM fuzzer.
160    
161    39. The function for finding the minimum length of a matching string could take
162        a very long time if mutual recursion was present many times in a pattern,
163        for example, /((?2){73}(?2))((?1))/. A better mutual recursion detection
164        method has been implemented. This infelicity was discovered by the LLVM
165        fuzzer.
166    
167    
168    Version 8.36 26-September-2014
169    ------------------------------
170    
171    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
172        -Wmissing-field-initializers and -Wunused-parameter.
173    
174    2.  The tests for quantifiers being too big (greater than 65535) were being
175        applied after reading the number, and stupidly assuming that integer
176        overflow would give a negative number. The tests are now applied as the
177        numbers are read.
178    
179    3.  Tidy code in pcre_exec.c where two branches that used to be different are
180        now the same.
181    
182    4.  The JIT compiler did not generate match limit checks for certain
183        bracketed expressions with quantifiers. This may lead to exponential
184        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
185        issue should be resolved now.
186    
187    5.  Fixed an issue, which occures when nested alternatives are optimized
188        with table jumps.
189    
190    6.  Inserted two casts and changed some ints to size_t in the light of some
191        reported 64-bit compiler warnings (Bugzilla 1477).
192    
193    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
194        an empty string, which sometimes were behaving incorrectly in the
195        interpreter (though correctly in the JIT matcher). This pcretest input is
196        an example:
197    
198          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
199          NON QUOTED "QUOT""ED" AFTER "NOT MATCHED
200    
201        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
202        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
203        for an empty string was breaking the inner loop and carrying on at a lower
204        level, when possessive repeated groups should always return to a higher
205        level as they have no backtrack points in them. The empty string test now
206        occurs at the outer level.
207    
208    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
209        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
210    
211    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
212        doesn't).
213    
214    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
215        to hold a pattern to be incorrectly computed (too small) when there were
216        named back references to duplicated names. This could cause "internal
217        error: code overflow" or "double free or corruption" or other memory
218        handling errors.
219    
220    11. When named subpatterns had the same prefixes, back references could be
221        confused. For example, in this pattern:
222    
223          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
224    
225        the reference to 'Name' was incorrectly treated as a reference to a
226        duplicate name.
227    
228    12. A pattern such as /^s?c/mi8 where the optional character has more than
229        one "other case" was incorrectly compiled such that it would only try to
230        match starting at "c".
231    
232    13. When a pattern starting with \s was studied, VT was not included in the
233        list of possible starting characters; this should have been part of the
234        8.34/18 patch.
235    
236    14. If a character class started [\Qx]... where x is any character, the class
237        was incorrectly terminated at the ].
238    
239    15. If a pattern that started with a caseless match for a character with more
240        than one "other case" was studied, PCRE did not set up the starting code
241        unit bit map for the list of possible characters. Now it does. This is an
242        optimization improvement, not a bug fix.
243    
244    16. The Unicode data tables have been updated to Unicode 7.0.0.
245    
246    17. Fixed a number of memory leaks in pcregrep.
247    
248    18. Avoid a compiler warning (from some compilers) for a function call with
249        a cast that removes "const" from an lvalue by using an intermediate
250        variable (to which the compiler does not object).
251    
252    19. Incorrect code was compiled if a group that contained an internal recursive
253        back reference was optional (had quantifier with a minimum of zero). This
254        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
255        caused segmentation faults because of stack overflows at compile time.
256    
257    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
258        group that is quantified with an indefinite repeat, caused a compile-time
259        loop which used up all the system stack and provoked a segmentation fault.
260        This was not the same bug as 19 above.
261    
262    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
263        Patch by Mike Frysinger.
264    
265    
266    Version 8.35 04-April-2014
267    --------------------------
268    
269    1.  A new flag is set, when property checks are present in an XCLASS.
270        When this flag is not set, PCRE can perform certain optimizations
271        such as studying these XCLASS-es.
272    
273    2.  The auto-possessification of character sets were improved: a normal
274        and an extended character set can be compared now. Furthermore
275        the JIT compiler optimizes more character set checks.
276    
277    3.  Got rid of some compiler warnings for potentially uninitialized variables
278        that show up only when compiled with -O2.
279    
280    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
281        of a match later then the end of the match. The pcretest program was not
282        handling the case sensibly - it was outputting from the start to the next
283        binary zero. It now reports this situation in a message, and outputs the
284        text from the end to the start.
285    
286    5.  Fast forward search is improved in JIT. Instead of the first three
287        characters, any three characters with fixed position can be searched.
288        Search order: first, last, middle.
289    
290    6.  Improve character range checks in JIT. Characters are read by an inprecise
291        function now, which returns with an unknown value if the character code is
292        above a certain threshold (e.g: 256). The only limitation is that the value
293        must be bigger than the threshold as well. This function is useful when
294        the characters above the threshold are handled in the same way.
295    
296    7.  The macros whose names start with RAWUCHAR are placeholders for a future
297        mode in which only the bottom 21 bits of 32-bit data items are used. To
298        make this more memorable for those maintaining the code, the names have
299        been changed to start with UCHAR21, and an extensive comment has been added
300        to their definition.
301    
302    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
303        to the export list in Makefile.am (they were accidentally omitted from the
304        8.34 tarball).
305    
306    9.  The informational output from pcretest used the phrase "starting byte set"
307        which is inappropriate for the 16-bit and 32-bit libraries. As the output
308        for "first char" and "need char" really means "non-UTF-char", I've changed
309        "byte" to "char", and slightly reworded the output. The documentation about
310        these values has also been (I hope) clarified.
311    
312    10. Another JIT related optimization: use table jumps for selecting the correct
313        backtracking path, when more than four alternatives are present inside a
314        bracket.
315    
316    11. Empty match is not possible, when the minimum length is greater than zero,
317        and there is no \K in the pattern. JIT should avoid empty match checks in
318        such cases.
319    
320    12. In a caseless character class with UCP support, when a character with more
321        than one alternative case was not the first character of a range, not all
322        the alternative cases were added to the class. For example, s and \x{17f}
323        are both alternative cases for S: the class [RST] was handled correctly,
324        but [R-T] was not.
325    
326    13. The configure.ac file always checked for pthread support when JIT was
327        enabled. This is not used in Windows, so I have put this test inside a
328        check for the presence of windows.h (which was already tested for).
329    
330    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
331        The algorithm provides a way to skip certain starting offsets, and usually
332        faster than linear prefix searches.
333    
334    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
335        as for 'fr_FR' and 'french'. For some reason, however, it then used the
336        Windows-specific input and output files, which have 'french' screwed in.
337        So this could never have worked. One of the problems with locales is that
338        they aren't always the same. I have now updated RunTest so that it checks
339        the output of the locale test (test 3) against three different output
340        files, and it allows the test to pass if any one of them matches. With luck
341        this should make the test pass on some versions of Solaris where it was
342        failing. Because of the uncertainty, the script did not used to stop if
343        test 3 failed; it now does. If further versions of a French locale ever
344        come to light, they can now easily be added.
345    
346    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
347        there was a message during ./configure, but it did not stop. This now
348        provokes an error. The invalid example in README has been corrected.
349        If a value less than the minimum is given, the minimum value has always
350        been used, but now a warning is given.
351    
352    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
353        was a bug in the test system, which is now fixed. Also, the list of various
354        configurations that are tested for each release did not have one with both
355        16/32 bits and --enable-bar-anycrlf. It now does.
356    
357    18. pcretest was missing "-C bsr" for displaying the \R default setting.
358    
359    19. Little endian PowerPC systems are supported now by the JIT compiler.
360    
361    20. The fast forward newline mechanism could enter to an infinite loop on
362        certain invalid UTF-8 input. Although we don't support these cases
363        this issue can be fixed by a performance optimization.
364    
365    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
366        not take account if existing stack usage. There is now a new global
367        variable called pcre_stack_guard that can be set to point to an external
368        function to check stack availability. It is called at the start of
369        processing every parenthesized group.
370    
371    22. A typo in the code meant that in ungreedy mode the max/min qualifier
372        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
373        not match "ab".
374    
375    23. When UTF was disabled, the JIT program reported some incorrect compile
376        errors. These messages are silenced now.
377    
378    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
379        compiler.
380    
381    25. Change all the temporary files used in RunGrepTest to be different to those
382        used by RunTest so that the tests can be run simultaneously, for example by
383        "make -j check".
384    
385    
386    Version 8.34 15-December-2013
387    -----------------------------
388    
389    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
390        executable memory. Patch inspired by Carsten Klein.
391    
392    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
393        this macro is never tested and has no effect, because the work to support
394        coverage involves only compiling and linking options and special targets in
395        the Makefile. The comment in config.h implied that defining the macro would
396        enable coverage support, which is totally false. There was also support for
397        setting this macro in the CMake files (my fault, I just copied it from
398        configure). SUPPORT_GCOV has now been removed.
399    
400    3.  Make a small performance improvement in strlen16() and strlen32() in
401        pcretest.
402    
403    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
404        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
405        these cases). There was also one in pcretest.c.
406    
407    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
408    
409    6.  In UTF mode, the code for checking whether a group could match an empty
410        string (which is used for indefinitely repeated groups to allow for
411        breaking an infinite loop) was broken when the group contained a repeated
412        negated single-character class with a character that occupied more than one
413        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
414        UTF-8 mode). The effect was undefined: the group might or might not be
415        deemed as matching an empty string, or the program might have crashed.
416    
417    7.  The code for checking whether a group could match an empty string was not
418        recognizing that \h, \H, \v, \V, and \R must match a character.
419    
420    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
421        an empty string. If it can, pcretest shows this in its information output.
422    
423    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
424        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
425        matched by pcre_exec() without using JIT:
426    
427        (a) If the rest of the pattern did not match after a maximal run of
428            grapheme clusters, the code for backing up to try with fewer of them
429            did not always back up over a full grapheme when characters that do not
430            have the modifier quality were involved, e.g. Hangul syllables.
431    
432        (b) If the match point in a subject started with modifier character, and
433            there was no match, the code could incorrectly back up beyond the match
434            point, and potentially beyond the first character in the subject,
435            leading to a segfault or an incorrect match result.
436    
437    10. A conditional group with an assertion condition could lead to PCRE
438        recording an incorrect first data item for a match if no other first data
439        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
440        first data item, and therefore matched "ca" after "c" instead of at the
441        start.
442    
443    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
444        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
445    
446    12. The source of pcregrep now includes z/OS-specific code so that it can be
447        compiled for z/OS as part of the special z/OS distribution.
448    
449    13. Added the -T and -TM options to pcretest.
450    
451    14. The code in pcre_compile.c for creating the table of named capturing groups
452        has been refactored. Instead of creating the table dynamically during the
453        actual compiling pass, the information is remembered during the pre-compile
454        pass (on the stack unless there are more than 20 named groups, in which
455        case malloc() is used) and the whole table is created before the actual
456        compile happens. This has simplified the code (it is now nearly 150 lines
457        shorter) and prepared the way for better handling of references to groups
458        with duplicate names.
459    
460    15. A back reference to a named subpattern when there is more than one of the
461        same name now checks them in the order in which they appear in the pattern.
462        The first one that is set is used for the reference. Previously only the
463        first one was inspected. This change makes PCRE more compatible with Perl.
464    
465    16. Unicode character properties were updated from Unicode 6.3.0.
466    
467    17. The compile-time code for auto-possessification has been refactored, based
468        on a patch by Zoltan Herczeg. It now happens after instead of during
469        compilation. The code is cleaner, and more cases are handled. The option
470        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
471        options in pcretest are provided to set it. It can also be set by
472        (*NO_AUTO_POSSESS) at the start of a pattern.
473    
474    18. The character VT has been added to the default ("C" locale) set of
475        characters that match \s and are generally treated as white space,
476        following this same change in Perl 5.18. There is now no difference between
477        "Perl space" and "POSIX space". Whether VT is treated as white space in
478        other locales depends on the locale.
479    
480    19. The code for checking named groups as conditions, either for being set or
481        for being recursed, has been refactored (this is related to 14 and 15
482        above). Processing unduplicated named groups should now be as fast at
483        numerical groups, and processing duplicated groups should be faster than
484        before.
485    
486    20. Two patches to the CMake build system, by Alexander Barkov:
487    
488          (1) Replace the "source" command by "." in CMakeLists.txt because
489              "source" is a bash-ism.
490    
491          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
492              without these the CMake build does not work on Solaris.
493    
494    21. Perl has changed its handling of \8 and \9. If there is no previously
495        encountered capturing group of those numbers, they are treated as the
496        literal characters 8 and 9 instead of a binary zero followed by the
497        literals. PCRE now does the same.
498    
499    22. Following Perl, added \o{} to specify codepoints in octal, making it
500        possible to specify values greater than 0777 and also making them
501        unambiguous.
502    
503    23. Perl now gives an error for missing closing braces after \x{... instead of
504        treating the string as literal. PCRE now does the same.
505    
506    24. RunTest used to grumble if an inappropriate test was selected explicitly,
507        but just skip it when running all tests. This make it awkward to run ranges
508        of tests when one of them was inappropriate. Now it just skips any
509        inappropriate tests, as it always did when running all tests.
510    
511    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
512        character types such as \d or \w, too many callouts were inserted, and the
513        data that they returned was rubbish.
514    
515    26. In UCP mode, \s was not matching two of the characters that Perl matches,
516        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
517        were matched by \h. The code has now been refactored so that the lists of
518        the horizontal and vertical whitespace characters used for \h and \v (which
519        are defined only in one place) are now also used for \s.
520    
521    27. Add JIT support for the 64 bit TileGX architecture.
522        Patch by Jiong Wang (Tilera Corporation).
523    
524    28. Possessive quantifiers for classes (both explicit and automatically
525        generated) now use special opcodes instead of wrapping in ONCE brackets.
526    
527    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
528        (because it's meaningless), this was not happening when PCRE_CASELESS was
529        set. Not wrong, but inefficient.
530    
531    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
532        properties for \w, \d, etc) is present in a test regex. Otherwise if the
533        test contains no characters greater than 255, Perl doesn't realise it
534        should be using Unicode semantics.
535    
536    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
537        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
538        does in Unicode mode.
539    
540    32. Added the "forbid" facility to pcretest so that putting tests into the
541        wrong test files can sometimes be quickly detected.
542    
543    33. There is now a limit (default 250) on the depth of nesting of parentheses.
544        This limit is imposed to control the amount of system stack used at compile
545        time. It can be changed at build time by --with-parens-nest-limit=xxx or
546        the equivalent in CMake.
547    
548    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
549        errors. Perl warns for these when in warning mode, but PCRE has no facility
550        for giving warnings.
551    
552    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
553        However, this was not working for (?!) because it is optimized to (*FAIL),
554        for which PCRE does not allow quantifiers. The optimization is now disabled
555        when a quantifier follows (?!). I can't see any use for this, but it makes
556        things uniform.
557    
558    36. Perl no longer allows group names to start with digits, so I have made this
559        change also in PCRE. It simplifies the code a bit.
560    
561    37. In extended mode, Perl ignores spaces before a + that indicates a
562        possessive quantifier. PCRE allowed a space before the quantifier, but not
563        before the possessive +. It now does.
564    
565    38. The use of \K (reset reported match start) within a repeated possessive
566        group such as (a\Kb)*+ was not working.
567    
568    40. Document that the same character tables must be used at compile time and
569        run time, and that the facility to pass tables to pcre_exec() and
570        pcre_dfa_exec() is for use only with saved/restored patterns.
571    
572    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
573        features for Builds with MSVC:
574    
575        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
576           builds). The .rc files can be used to set FileDescription and many other
577           attributes.
578    
579        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
580           This allows higher-level build scripts which want .pdb files to avoid
581           hard-coding the exact files needed."
582    
583    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
584        mean "start of word" and "end of word", respectively, as a transition aid.
585    
586    43. A minimizing repeat of a class containing codepoints greater than 255 in
587        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
588        compiled to use the heap for recursion.
589    
590    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
591        is configured.
592    
593    
594    Version 8.33 28-May-2013
595    ------------------------
596    
597    1.  Added 'U' to some constants that are compared to unsigned integers, to
598        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
599        variables that are added to signed variables, to ensure the result is
600        signed and can be negated.
601    
602    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
603        CMake config files.
604    
605    3.  Revise the creation of config.h.generic so that all boolean macros are
606        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
607        overriding via -D on the command line possible.
608    
609    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
610        to unsigned int is reported to make a quite noticeable speed difference in
611        a specific Windows environment. Testing on Linux did also appear to show
612        some benefit (and it is clearly not harmful). Also fixed the definition of
613        Xop which should be unsigned.
614    
615    5.  Related to (4), changing the definition of the intermediate variable cc
616        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
617        improvements.
618    
619    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
620        unnecessary spaces.
621    
622    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
623        and later.
624    
625    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
626    
627    9.  Optimizing fast_forward_start_bits in JIT.
628    
629    10. Adding support for callouts in JIT, and fixing some issues revealed
630        during this work. Namely:
631    
632        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
633    
634        (b) Minimum length was not checked before the matching is started.
635    
636    11. The value of capture_last that is passed to callouts was incorrect in some
637        cases when there was a capture on one path that was subsequently abandoned
638        after a backtrack. Also, the capture_last value is now reset after a
639        recursion, since all captures are also reset in this case.
640    
641    12. The interpreter no longer returns the "too many substrings" error in the
642        case when an overflowing capture is in a branch that is subsequently
643        abandoned after a backtrack.
644    
645    13. In the pathological case when an offset vector of size 2 is used, pcretest
646        now prints out the matched string after a yield of 0 or 1.
647    
648    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
649        Only supported by the JIT compiler at the moment.
650    
651    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
652    
653    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
654        offset of the starting point of the matching process, provided the offsets
655        vector is large enough.
656    
657    17. The \A escape now records a lookbehind value of 1, though its execution
658        does not actually inspect the previous character. This is to ensure that,
659        in partial multi-segment matching, at least one character from the old
660        segment is retained when a new segment is processed. Otherwise, if there
661        are no lookbehinds in the pattern, \A might match incorrectly at the start
662        of a new segment.
663    
664    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
665    
666    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
667        gives some modest performance improvement in 8-bit mode.
668    
669    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
670        be expressed in certain programming languages using Universal Character
671        Names.
672    
673    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
674        which points out that "non characters" are not "characters that may not
675        appear in Unicode strings" but rather "characters that are reserved for
676        internal use and have only local meaning".
677    
678    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
679        there was a conditional group that depended on an assertion, if the
680        assertion was false, the callout that immediately followed the alternation
681        in the condition was skipped when pcre_exec() was used for matching.
682    
683    23. Allow an explicit callout to be inserted before an assertion that is the
684        condition for a conditional group, for compatibility with automatic
685        callouts, which always insert a callout at this point.
686    
687    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
688        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
689    
690    25. (*PRUNE) is now supported by the JIT compiler.
691    
692    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
693    
694    27. Fix the case where there are two or more SKIPs with arguments that may be
695        ignored.
696    
697    28. (*SKIP) is now supported by the JIT compiler.
698    
699    29. (*THEN) is now supported by the JIT compiler.
700    
701    30. Update RunTest with additional test selector options.
702    
703    31. The way PCRE handles backtracking verbs has been changed in two ways.
704    
705        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
706        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
707        backtracking. In some cases this makes it more Perl-compatible, but Perl's
708        rather obscure rules do not always do the same thing.
709    
710        (2) Previously, backtracking verbs were confined within assertions. This is
711        no longer the case for positive assertions, except for (*ACCEPT). Again,
712        this sometimes improves Perl compatibility, and sometimes does not.
713    
714    32. A number of tests that were in test 2 because Perl did things differently
715        have been moved to test 1, because either Perl or PCRE has changed, and
716        these tests are now compatible.
717    
718    32. Backtracking control verbs are now handled in the same way in JIT and
719        interpreter.
720    
721    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
722        contained a forward subroutine reference caused a compile error.
723    
724    34. Auto-detect and optimize limited repetitions in JIT.
725    
726    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
727        blocking (*UTF) etc.
728    
729    36. In the interpreter, maximizing pattern repetitions for characters and
730        character types now use tail recursion, which reduces stack usage.
731    
732    37. The value of the max lookbehind was not correctly preserved if a compiled
733        and saved regex was reloaded on a host of different endianness.
734    
735    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
736        of the compiled pattern block, expand the flags field from 16 to 32 bits
737        because it was almost full.
738    
739    39. Try madvise first before posix_madvise.
740    
741    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
742        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
743        original change locked out all matches of empty strings. This has been
744        changed so that one match of an empty string per line is recognized.
745        Subsequent searches on the same line (for colouring or for --only-matching,
746        for example) do not recognize empty strings.
747    
748    41. Applied a user patch to fix a number of spelling mistakes in comments.
749    
750    42. Data lines longer than 65536 caused pcretest to crash.
751    
752    43. Clarified the data type for length and startoffset arguments for pcre_exec
753        and pcre_dfa_exec in the function-specific man pages, where they were
754        explicitly stated to be in bytes, never having been updated. I also added
755        some clarification to the pcreapi man page.
756    
757    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
758        a segmentation fault.
759    
760    
761    Version 8.32 30-November-2012
762    -----------------------------
763    
764    1.  Improved JIT compiler optimizations for first character search and single
765        character iterators.
766    
767    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
768        Patch by Daniel Richard G.
769    
770    3.  Single character iterator optimizations in the JIT compiler.
771    
772    4.  Improved JIT compiler optimizations for character ranges.
773    
774    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
775        Reported by Giuseppe D'Angelo.
776    
777    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
778        of a line, was being set incorrectly in cases where .* appeared inside
779        atomic brackets at the start of a pattern, or where there was a subsequent
780        *PRUNE or *SKIP.
781    
782    7.  Improved instruction cache flush for POWER/PowerPC.
783        Patch by Daniel Richard G.
784    
785    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
786        grep:
787    
788        (a) There is now no limit to the number of patterns to be matched.
789    
790        (b) An error is given if a pattern is too long.
791    
792        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
793            are now supported.
794    
795        (d) --exclude-from and --include-from (multiple use) have been added.
796    
797        (e) Exclusions and inclusions now apply to all files and directories, not
798            just to those obtained from scanning a directory recursively.
799    
800        (f) Multiple uses of -f and --file-list are now supported.
801    
802        (g) In a Windows environment, the default for -d has been changed from
803            "read" (the GNU grep default) to "skip", because otherwise the presence
804            of a directory in the file list provokes an error.
805    
806        (h) The documentation has been revised and clarified in places.
807    
808    9.  Improve the matching speed of capturing brackets.
809    
810    10. Changed the meaning of \X so that it now matches a Unicode extended
811        grapheme cluster.
812    
813    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
814        out POSIX threads when JIT support is configured.
815    
816    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
817    
818    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
819        structure could go wrong in environments where size_t is not the same size
820        as int.
821    
822    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
823        set.
824    
825    15. The EBCDIC support had decayed; later updates to the code had included
826        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
827        general tidy up of EBCDIC-related issues, and the documentation was also
828        not quite right. There is now a test that can be run on ASCII systems to
829        check some of the EBCDIC-related things (but is it not a full test).
830    
831    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
832        in a small tidy to the code.
833    
834    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
835    
836    18. If the --only-matching (-o) option in pcregrep is specified multiple
837        times, each one causes appropriate output. For example, -o1 -o2 outputs the
838        substrings matched by the 1st and 2nd capturing parentheses. A separating
839        string can be specified by --om-separator (default empty).
840    
841    19. Improving the first n character searches.
842    
843    20. Turn case lists for horizontal and vertical white space into macros so that
844        they are defined only once.
845    
846    21. This set of changes together give more compatible Unicode case-folding
847        behaviour for characters that have more than one other case when UCP
848        support is available.
849    
850        (a) The Unicode property table now has offsets into a new table of sets of
851            three or more characters that are case-equivalent. The MultiStage2.py
852            script that generates these tables (the pcre_ucd.c file) now scans
853            CaseFolding.txt instead of UnicodeData.txt for character case
854            information.
855    
856        (b) The code for adding characters or ranges of characters to a character
857            class has been abstracted into a generalized function that also handles
858            case-independence. In UTF-mode with UCP support, this uses the new data
859            to handle characters with more than one other case.
860    
861        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
862            whose other case is greater than 256 are now correctly matched
863            caselessly. Previously, the high codepoint matched the low one, but not
864            vice versa.
865    
866        (d) The processing of \h, \H, \v, and \ in character classes now makes use
867            of the new class addition function, using character lists defined as
868            macros alongside the case definitions of 20 above.
869    
870        (e) Caseless back references now work with characters that have more than
871            one other case.
872    
873        (f) General caseless matching of characters with more than one other case
874            is supported.
875    
876    22. Unicode character properties were updated from Unicode 6.2.0
877    
878    23. Improved CMake support under Windows. Patch by Daniel Richard G.
879    
880    24. Add support for 32-bit character strings, and UTF-32
881    
882    25. Major JIT compiler update (code refactoring and bugfixing).
883        Experimental Sparc 32 support is added.
884    
885    26. Applied a modified version of Daniel Richard G's patch to create
886        pcre.h.generic and config.h.generic by "make" instead of in the
887        PrepareRelease script.
888    
889    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
890        pcre_compile.c when checking for a zero character.
891    
892    28. Introducing a native interface for JIT. Through this interface, the compiled
893        machine code can be directly executed. The purpose of this interface is to
894        provide fast pattern matching, so several sanity checks are not performed.
895        However, feature tests are still performed. The new interface provides
896        1.4x speedup compared to the old one.
897    
898    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
899        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
900        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
901    
902    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
903        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
904        the "old" RFC 2279). Instead, it ended up passing a negative length to
905        pcre_exec().
906    
907    31. Add support for GCC's visibility feature to hide internal functions.
908    
909    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
910        "unknown -C option" after outputting 0 or 1.
911    
912    33. There is now support for generating a code coverage report for the test
913        suite in environments where gcc is the compiler and lcov is installed. This
914        is mainly for the benefit of the developers.
915    
916    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
917        unaddressable using valgrind annotations, allowing valgrind to detect
918        invalid memory accesses. This is mainly for the benefit of the developers.
919    
920    25. (*UTF) can now be used to start a pattern in any of the three libraries.
921    
922    26. Give configure error if --enable-cpp but no C++ compiler found.
923    
924    
925    Version 8.31 06-July-2012
926    -------------------------
927    
928    1.  Fixing a wrong JIT test case and some compiler warnings.
929    
930    2.  Removed a bashism from the RunTest script.
931    
932    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
933        to unsigned type, result still unsigned" that was given by an MS compiler
934        on encountering the code "-sizeof(xxx)".
935    
936    4.  Partial matching support is added to the JIT compiler.
937    
938    5.  Fixed several bugs concerned with partial matching of items that consist
939        of more than one character:
940    
941        (a) /^(..)\1/ did not partially match "aba" because checking references was
942            done on an "all or nothing" basis. This also applied to repeated
943            references.
944    
945        (b) \R did not give a hard partial match if \r was found at the end of the
946            subject.
947    
948        (c) \X did not give a hard partial match after matching one or more
949            characters at the end of the subject.
950    
951        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
952            a partial match for the string "\r".
953    
954        (e) When newline was set to CRLF, the metacharacter "." did not recognize
955            a partial match for a CR character at the end of the subject string.
956    
957    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
958        running pcretest, the text "(JIT)" added to the output whenever JIT is
959        actually used to run the match.
960    
961    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
962        or /S+[+] with a digit between 1 and 7.
963    
964    8.  OP_NOT now supports any UTF character not just single-byte ones.
965    
966    9.  (*MARK) control verb is now supported by the JIT compiler.
967    
968    10. The command "./RunTest list" lists the available tests without actually
969        running any of them. (Because I keep forgetting what they all are.)
970    
971    11. Add PCRE_INFO_MAXLOOKBEHIND.
972    
973    12. Applied a (slightly modified) user-supplied patch that improves performance
974        when the heap is used for recursion (compiled with --disable-stack-for-
975        recursion). Instead of malloc and free for each heap frame each time a
976        logical recursion happens, frames are retained on a chain and re-used where
977        possible. This sometimes gives as much as 30% improvement.
978    
979    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
980        call.
981    
982    14. As documented, (*COMMIT) is now confined to within a positive assertion.
983    
984    15. It is now possible to link pcretest with libedit as an alternative to
985        libreadline.
986    
987    16. (*COMMIT) control verb is now supported by the JIT compiler.
988    
989    17. The Unicode data tables have been updated to Unicode 6.1.0.
990    
991    18. Added --file-list option to pcregrep.
992    
993    19. Added binary file support to pcregrep, including the -a, --binary-files,
994        -I, and --text options.
995    
996    20. The madvise function is renamed for posix_madvise for QNX compatibility
997        reasons. Fixed by Giuseppe D'Angelo.
998    
999    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
1000    
1001    22. Changed the option for creating symbolic links for 16-bit man pages from
1002        -s to -sf so that re-installing does not cause issues.
1003    
1004    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
1005    
1006    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
1007        matches in certain environments (the workspace was not being correctly
1008        retained). Also added to pcre_dfa_exec() a simple plausibility check on
1009        some of the workspace data at the beginning of a restart.
1010    
1011    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
1012        was not doing so when it should - probably a typo introduced by SVN 528
1013        (change 8.10/14).
1014    
1015    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
1016        \w+ when the character tables indicated that \x{c4} was a word character.
1017        There were several related cases, all because the tests for doing a table
1018        lookup were testing for characters less than 127 instead of 255.
1019    
1020    27. If a pattern contains capturing parentheses that are not used in a match,
1021        their slots in the ovector are set to -1. For those that are higher than
1022        any matched groups, this happens at the end of processing. In the case when
1023        there were back references that the ovector was too small to contain
1024        (causing temporary malloc'd memory to be used during matching), and the
1025        highest capturing number was not used, memory off the end of the ovector
1026        was incorrectly being set to -1. (It was using the size of the temporary
1027        memory instead of the true size.)
1028    
1029    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
1030        ovector size, it uses memory at the end of the block that it has got.
1031    
1032    29. Check for an overlong MARK name and give an error at compile time. The
1033        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
1034    
1035    30. JIT compiler update.
1036    
1037    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
1038        Rill for the patch.
1039    
1040    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
1041    
1042    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
1043    
1044    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
1045        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
1046        was enabled.
1047    
1048    35. Improve JIT code generation for greedy plus quantifier.
1049    
1050    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
1051        1 to "aa" instead of to an empty string. The bug affected repeated groups
1052        that could potentially match an empty string.
1053    
1054    37. Optimizing single character iterators in JIT.
1055    
1056    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
1057        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
1058        codepoints that are too big for the mode are faulted, and in a UTF mode,
1059        disallowed codepoints are also faulted.
1060    
1061    39. If PCRE was compiled with UTF support, in three places in the DFA
1062        matcher there was code that should only have been obeyed in UTF mode, but
1063        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
1064        processing when bytes with values greater than 127 were present. In 16-bit
1065        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
1066        both cases the values are those that cannot be the first data item in a UTF
1067        character. The three items that might have provoked this were recursions,
1068        possessively repeated groups, and atomic groups.
1069    
1070    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
1071        and pcregrep, because some OS require shared objects to be explicitly
1072        passed to ld, causing the link step to fail if they are not.
1073    
1074    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
1075        mode, patterns that started with \h* or \R* might be incorrectly matched.
1076    
1077    
1078    Version 8.30 04-February-2012
1079    -----------------------------
1080    
1081    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
1082        name is defined in ctype.h.
1083    
1084    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
1085        only in quite long subpatterns.
1086    
1087    3.  Removed the function pcre_info(), which has been obsolete and deprecated
1088        since it was replaced by pcre_fullinfo() in February 2000.
1089    
1090    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
1091        match a (*MARK), and the match failed at the start of the subject, a
1092        reference to memory before the start of the subject could occur. This bug
1093        was introduced by fix 17 of release 8.21.
1094    
1095    5.  A reference to an unset group with zero minimum repetition was giving
1096        totally wrong answers (in non-JavaScript-compatibility mode). For example,
1097        /(another)?(\1?)test/ matched against "hello world test". This bug was
1098        introduced in release 8.13.
1099    
1100    6.  Add support for 16-bit character strings (a large amount of work involving
1101        many changes and refactorings).
1102    
1103    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
1104        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
1105        from a file.
1106    
1107    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
1108        rounding is not applied in this particular case).
1109    
1110    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
1111        if they appear, or are escaped, in patterns.
1112    
1113    10. Get rid of a number of -Wunused-but-set-variable warnings.
1114    
1115    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
1116        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
1117        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
1118        also returns the mark "x". This bug applied to capturing parentheses,
1119        non-capturing parentheses, and atomic parentheses. It also applied to some
1120        assertions.
1121    
1122    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
1123        information out of configure.ac instead of relying on pcre.h.generic, which
1124        is not stored in the repository.
1125    
1126    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
1127        -lreadline.
1128    
1129    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
1130    
1131    15. Applied Graycode's patch to put the top-level frame on the stack rather
1132        than the heap when not using the stack for recursion. This gives a
1133        performance improvement in many cases when recursion is not deep.
1134    
1135    16. Experimental code added to "pcretest -C" to output the stack frame size.
1136    
1137    
1138    Version 8.21 12-Dec-2011
1139    ------------------------
1140    
1141    1.  Updating the JIT compiler.
1142    
1143    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1144        are added as well.
1145    
1146    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1147        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1148        calling _pcre_jit_exec. Some extra comments are added.
1149    
1150    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1151        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1152        was introduced by change 18 for 8.20.
1153    
1154    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1155        ECMA-262 standard.
1156    
1157    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1158        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1159        This bug was probably introduced by change 9 of 8.13.
1160    
1161    7.  While fixing 6 above, I noticed that a number of other items were being
1162        incorrectly rejected as "not fixed length". This arose partly because newer
1163        opcodes had not been added to the fixed-length checking code. I have (a)
1164        corrected the bug and added tests for these items, and (b) arranged for an
1165        error to occur if an unknown opcode is encountered while checking for fixed
1166        length instead of just assuming "not fixed length". The items that were
1167        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1168        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1169        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1170    
1171    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1172        being incorrectly compiled and would have given unpredicatble results.
1173    
1174    9.  A possessively repeated subpattern with minimum repeat count greater than
1175        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1176        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1177        the first (A) could occur when it should not.
1178    
1179    10. Add a cast and remove a redundant test from the code.
1180    
1181    11. JIT should use pcre_malloc/pcre_free for allocation.
1182    
1183    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1184        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1185        is anything other than /usr, -L is still shown).
1186    
1187    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1188    
1189    14. Perl does not support \N without a following name in a [] class; PCRE now
1190        also gives an error.
1191    
1192    15. If a forward reference was repeated with an upper limit of around 2000,
1193        it caused the error "internal error: overran compiling workspace". The
1194        maximum number of forward references (including repeats) was limited by the
1195        internal workspace, and dependent on the LINK_SIZE. The code has been
1196        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1197        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1198        of around 200,000 forward references. While doing this, I also speeded up
1199        the filling in of repeated forward references.
1200    
1201    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1202        incorrectly expecting the subject to contain another "a" after the start.
1203    
1204    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1205        in the match, the SKIP should be ignored. This was not happening; instead
1206        the SKIP was being treated as NOMATCH. For patterns such as
1207        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1208        tested.
1209    
1210    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1211        now much more compatible with Perl, in particular in cases where the result
1212        is a non-match for a non-anchored pattern. For example, if
1213        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1214        "m", where previously it did not return a name. A side effect of this
1215        change is that for partial matches, the last encountered mark name is
1216        returned, as for non matches. A number of tests that were previously not
1217        Perl-compatible have been moved into the Perl-compatible test files. The
1218        refactoring has had the pleasing side effect of removing one argument from
1219        the match() function, thus reducing its stack requirements.
1220    
1221    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1222        subsequent uses of /S (without +) incorrectly behaved like /S+.
1223    
1224    21. Retrieve executable code size support for the JIT compiler and fixing
1225        some warnings.
1226    
1227    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1228        not work when the shorter character appeared right at the end of the
1229        subject string.
1230    
1231    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1232        systems.
1233    
1234    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1235        output it when the /M option is used in pcretest.
1236    
1237    25. The CheckMan script was not being included in the distribution. Also, added
1238        an explicit "perl" to run Perl scripts from the PrepareRelease script
1239        because this is reportedly needed in Windows.
1240    
1241    26. If study data was being save in a file and studying had not found a set of
1242        "starts with" bytes for the pattern, the data written to the file (though
1243        never used) was taken from uninitialized memory and so caused valgrind to
1244        complain.
1245    
1246    27. Updated RunTest.bat as provided by Sheri Pierce.
1247    
1248    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1249    
1250    29. Computation of memory usage for the table of capturing group names was
1251        giving an unnecessarily large value.
1252    
1253    
1254    Version 8.20 21-Oct-2011
1255    ------------------------
1256    
1257    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1258        a POSIX class. After further experiments with Perl, which convinced me that
1259        Perl has bugs and confusions, a closing square bracket is no longer allowed
1260        in a POSIX name. This bug also affected patterns with classes that started
1261        with full stops.
1262    
1263    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1264        captured substring, but while checking the failing first alternative,
1265        substring 1 is temporarily captured. If the output vector supplied to
1266        pcre_exec() was not big enough for this capture, the yield of the function
1267        was still zero ("insufficient space for captured substrings"). This cannot
1268        be totally fixed without adding another stack variable, which seems a lot
1269        of expense for a edge case. However, I have improved the situation in cases
1270        such as /(a)(b)x|abc/ matched against "abc", where the return code
1271        indicates that fewer than the maximum number of slots in the ovector have
1272        been set.
1273    
1274    3.  Related to (2) above: when there are more back references in a pattern than
1275        slots in the output vector, pcre_exec() uses temporary memory during
1276        matching, and copies in the captures as far as possible afterwards. It was
1277        using the entire output vector, but this conflicts with the specification
1278        that only 2/3 is used for passing back captured substrings. Now it uses
1279        only the first 2/3, for compatibility. This is, of course, another edge
1280        case.
1281    
1282    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1283        main code base, and can be used by building with --enable-jit. When this is
1284        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1285        runtime --no-jit option is given.
1286    
1287    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1288        ovector, the return from the function was zero, implying that there were
1289        other matches that did not fit. The correct "exactly full" value is now
1290        returned.
1291    
1292    6.  If a subpattern that was called recursively or as a subroutine contained
1293        (*PRUNE) or any other control that caused it to give a non-standard return,
1294        invalid errors such as "Error -26 (nested recursion at the same subject
1295        position)" or even infinite loops could occur.
1296    
1297    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1298        computing the minimum length on reaching *ACCEPT, and so ended up with the
1299        wrong value of 1 rather than 0. Further investigation indicates that
1300        computing a minimum subject length in the presence of *ACCEPT is difficult
1301        (think back references, subroutine calls), and so I have changed the code
1302        so that no minimum is registered for a pattern that contains *ACCEPT.
1303    
1304    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1305        it was not handled as intended. [But see 16 below.]
1306    
1307    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1308        Sheri Pierce.
1309    
1310    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1311        the first byte in a match must be "a".
1312    
1313    11. Change 17 for 8.13 increased the recursion depth for patterns like
1314        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1315        pattern contains any instances of (*THEN). If it does not, the old
1316        optimizations are restored. It would be nice to do this on a per-group
1317        basis, but at the moment that is not feasible.
1318    
1319    12. In some environments, the output of pcretest -C is CRLF terminated. This
1320        broke RunTest's code that checks for the link size. A single white space
1321        character after the value is now allowed for.
1322    
1323    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1324        For "fr", it uses the Windows-specific input and output files.
1325    
1326    14. If (*THEN) appeared in a group that was called recursively or as a
1327        subroutine, it did not work as intended. [But see next item.]
1328    
1329    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1330        pattern fragments (but not containing any | characters). If A and B are
1331        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1332        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1333        D. In other words, Perl considers parentheses that do not contain any |
1334        characters to be part of a surrounding alternative, whereas PCRE was
1335        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1336        differently. PCRE now behaves in the same way as Perl, except in the case
1337        of subroutine/recursion calls such as (?1) which have in any case always
1338        been different (but PCRE had them first :-).
1339    
1340    16. Related to 15 above: Perl does not treat the | in a conditional group as
1341        creating alternatives. Such a group is treated in the same way as an
1342        ordinary group without any | characters when processing (*THEN). PCRE has
1343        been changed to match Perl's behaviour.
1344    
1345    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1346        RunGrepTest script failed.
1347    
1348    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1349        inevitable for groups that contain captures, but it can lead to a lot of
1350        stack use in large patterns. The old behaviour has been restored for atomic
1351        groups that do not contain any capturing parentheses.
1352    
1353    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1354        suppress the check for a minimum subject length at run time. (If it was
1355        given to pcre_exec() or pcre_dfa_exec() it did work.)
1356    
1357    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1358        fail to work when decoding hex characters in data strings in EBCDIC
1359        environments.
1360    
1361    21. It appears that in at least one Mac OS environment, the isxdigit() function
1362        is implemented as a macro that evaluates to its argument more than once,
1363        contravening the C 90 Standard (I haven't checked a later standard). There
1364        was an instance in pcretest which caused it to go wrong when processing
1365        \x{...} escapes in subject strings. The has been rewritten to avoid using
1366        things like p++ in the argument of isxdigit().
1367    
1368    
1369    Version 8.13 16-Aug-2011
1370  ------------------------  ------------------------
1371    
1372  1.  The Unicode data tables have been updated to Unicode 6.0.0.  1.  The Unicode data tables have been updated to Unicode 6.0.0.
# Line 20  Version 8.13 30-Apr-2011 Line 1385  Version 8.13 30-Apr-2011
1385      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1386      2-byte code at the end of the subject (it thought there wasn't enough data      2-byte code at the end of the subject (it thought there wasn't enough data
1387      left).      left).
1388    
1389  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
1390      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1391      as the output vector has at least 2 elements. The offset of the start of      as the output vector has at least 2 elements. The offset of the start of
1392      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
1393    
1394  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1395      now returned is for the first byte of the failing character, instead of the      now returned is for the first byte of the failing character, instead of the
1396      last byte inspected. This is an incompatible change, but I hope it is small      last byte inspected. This is an incompatible change, but I hope it is small
1397      enough not to be a problem. It makes the returned offset consistent with      enough not to be a problem. It makes the returned offset consistent with
1398      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
1399    
1400  7.  pcretest now gives a text phrase as well as the error number when  7.  pcretest now gives a text phrase as well as the error number when
1401      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1402      failure, the offset and reason code are output.      failure, the offset and reason code are output.
1403    
1404  8.  When \R was used with a maximizing quantifier it failed to skip backwards  8.  When \R was used with a maximizing quantifier it failed to skip backwards
1405      over a \r\n pair if the subsequent match failed. Instead, it just skipped      over a \r\n pair if the subsequent match failed. Instead, it just skipped
1406      back over a single character (\n). This seems wrong (because it treated the      back over a single character (\n). This seems wrong (because it treated the
1407      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
1408      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1409      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1410      has been changed.      has been changed.
1411    
1412    9.  Some internal refactoring has changed the processing so that the handling
1413        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1414        time (the PCRE_DOTALL option was changed this way some time ago: version
1415        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1416        which was always a bit of a fudge. It also means that there is one less
1417        argument for the match() function, which reduces its stack requirements
1418        slightly. This change also fixes an incompatibility with Perl: the pattern
1419        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1420    
1421    10. More internal refactoring has drastically reduced the number of recursive
1422        calls to match() for possessively repeated groups such as (abc)++ when
1423        using pcre_exec().
1424    
1425    11. While implementing 10, a number of bugs in the handling of groups were
1426        discovered and fixed:
1427    
1428        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1429        (a|)*(?1) gave a compile-time internal error.
1430        ((a|)+)+  did not notice that the outer group could match an empty string.
1431        (^a|^)+   was not marked as anchored.
1432        (.*a|.*)+ was not marked as matching at start or after a newline.
1433    
1434    12. Yet more internal refactoring has removed another argument from the match()
1435        function. Special calls to this function are now indicated by setting a
1436        value in a variable in the "match data" data block.
1437    
1438    13. Be more explicit in pcre_study() instead of relying on "default" for
1439        opcodes that mean there is no starting character; this means that when new
1440        ones are added and accidentally left out of pcre_study(), testing should
1441        pick them up.
1442    
1443    14. The -s option of pcretest has been documented for ages as being an old
1444        synonym of -m (show memory usage). I have changed it to mean "force study
1445        for every regex", that is, assume /S for every regex. This is similar to -i
1446        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1447        using it. It makes it easier to run collections of tests with and without
1448        study enabled, and thereby test pcre_study() more easily. All the standard
1449        tests are now run with and without -s (but some patterns can be marked as
1450        "never study" - see 20 below).
1451    
1452    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1453        restoration of the capturing data to the outer values was not happening
1454        correctly.
1455    
1456    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1457        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1458        pattern had matched an empty string, and so incorrectly returned a no
1459        match.
1460    
1461    17. There was optimizing code for the last branch of non-capturing parentheses,
1462        and also for the obeyed branch of a conditional subexpression, which used
1463        tail recursion to cut down on stack usage. Unfortunately, now that there is
1464        the possibility of (*THEN) occurring in these branches, tail recursion is
1465        no longer possible because the return has to be checked for (*THEN). These
1466        two optimizations have therefore been removed. [But see 8.20/11 above.]
1467    
1468    18. If a pattern containing \R was studied, it was assumed that \R always
1469        matched two bytes, thus causing the minimum subject length to be
1470        incorrectly computed because \R can also match just one byte.
1471    
1472    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1473        was incorrectly computed.
1474    
1475    20. If /S is present twice on a test pattern in pcretest input, it now
1476        *disables* studying, thereby overriding the use of -s on the command line
1477        (see 14 above). This is necessary for one or two tests to keep the output
1478        identical in both cases.
1479    
1480    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1481        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1482    
1483    22. When an atomic group that contained a capturing parenthesis was
1484        successfully matched, but the branch in which it appeared failed, the
1485        capturing was not being forgotten if a higher numbered group was later
1486        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1487        group 1 to "a", when in fact it should be unset. This applied to multi-
1488        branched capturing and non-capturing groups, repeated or not, and also to
1489        positive assertions (capturing in negative assertions does not happen
1490        in PCRE) and also to nested atomic groups.
1491    
1492    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1493        subject after a captured substring, to make it easier to tell which of a
1494        number of identical substrings has been captured.
1495    
1496    24. The way atomic groups are processed by pcre_exec() has been changed so that
1497        if they are repeated, backtracking one repetition now resets captured
1498        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1499        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1500        "aaa". Previously, it would have been "a". As part of this code
1501        refactoring, the way recursive calls are handled has also been changed.
1502    
1503    25. If an assertion condition captured any substrings, they were not passed
1504        back unless some other capturing happened later. For example, if
1505        (?(?=(a))a) was matched against "a", no capturing was returned.
1506    
1507    26. When studying a pattern that contained subroutine calls or assertions,
1508        the code for finding the minimum length of a possible match was handling
1509        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1510        group 1 called group 2 while simultaneously a separate group 2 called group
1511        1). A stack overflow occurred in this case. I have fixed this by limiting
1512        the recursion depth to 10.
1513    
1514    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1515        Fortmann. This supports explicit test numbers on the command line, and has
1516        argument validation and error reporting.
1517    
1518    28. An instance of \X with an unlimited repeat could fail if at any point the
1519        first character it looked at was a mark character.
1520    
1521    29. Some minor code refactoring concerning Unicode properties and scripts
1522        should reduce the stack requirement of match() slightly.
1523    
1524    30. Added the '=' option to pcretest to check the setting of unused capturing
1525        slots at the end of the pattern, which are documented as being -1, but are
1526        not included in the return count.
1527    
1528    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1529        compiled something random. Now it gives a compile-time error (as does
1530        Perl).
1531    
1532    32. A *MARK encountered during the processing of a positive assertion is now
1533        recorded and passed back (compatible with Perl).
1534    
1535    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1536        had alternative anchored branches, the search for a second match in a line
1537        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1538        matched the line "0102" twice. The same bug affected patterns that started
1539        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1540        twice.
1541    
1542    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1543        does, and because of capturing effects, quantifying parenthesized
1544        assertions may at times be useful. Quantifiers are now allowed for
1545        parenthesized assertions.
1546    
1547    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1548    
1549    36. \g was being checked for fancy things in a character class, when it should
1550        just be a literal "g".
1551    
1552    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1553        appearance of a nested POSIX class supersedes an apparent external class.
1554        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1555        unescaped square brackets may also appear as part of class names. For
1556        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1557        more like Perl. (But see 8.20/1 above.)
1558    
1559    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1560        was because it thought it was \N{name}, which is not supported).
1561    
1562    39. Add minix to OS list not supporting the -S option in pcretest.
1563    
1564    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1565        cannot analyze patterns in sufficient detail to catch mutual recursions
1566        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1567        subgroup is called recursively as a subpattern for a second time at the
1568        same position in the subject string. In previous releases this might have
1569        been caught by the recursion limit, or it might have run out of stack.
1570    
1571    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1572        happen only once. PCRE was, however incorrectly giving a compile time error
1573        "recursive call could loop indefinitely" because it cannot analyze the
1574        pattern in sufficient detail. The compile time test no longer happens when
1575        PCRE is compiling a conditional subpattern, but actual runaway loops are
1576        now caught at runtime (see 40 above).
1577    
1578    42. It seems that Perl allows any characters other than a closing parenthesis
1579        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1580        has been changed to be the same.
1581    
1582    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1583        as not to get warnings when autogen.sh is called. Also changed
1584        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1585    
1586    44. To help people who use pcregrep to scan files containing exceedingly long
1587        lines, the following changes have been made:
1588    
1589        (a) The default value of the buffer size parameter has been increased from
1590            8K to 20K. (The actual buffer used is three times this size.)
1591    
1592        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1593            PCRE is built.
1594    
1595        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1596            to be set at run time.
1597    
1598        (d) Numerical values in pcregrep options can be followed by K or M, for
1599            example --buffer-size=50K.
1600    
1601        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1602            given and the return code is set to 2.
1603    
1604    45. Add a pointer to the latest mark to the callout data block.
1605    
1606    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1607        partial match of an empty string instead of no match. This was specific to
1608        the use of ".".
1609    
1610    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1611        complete match instead of a partial match. This bug was dependent on both
1612        the PCRE_UTF8 and PCRE_DOTALL options being set.
1613    
1614    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1615        starting byte set, because \b was not being ignored.
1616    
1617    
1618  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
1619  ------------------------  ------------------------
# Line 695  Version 7.9 11-Apr-09 Line 2265  Version 7.9 11-Apr-09
2265  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
2266      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
2267      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2268      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2269        8.33.]
2270    
2271  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
2272      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 938  Version 7.7 07-May-08 Line 2509  Version 7.7 07-May-08
2509      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2510      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2511      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2512      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2513      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2514      was subsequently set up correctly.)      was subsequently set up correctly.)
2515    

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