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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.02 01-Mar-2010  Note that the PCRE 8.xx series (PCRE1) is now in a bugfix-only state. All
5    development is happening in the PCRE2 10.xx series.
6    
7    Version 8.38 xx-xxx-xxxx
8    ------------------------
9    
10    1.  If a group that contained a recursive back reference also contained a
11        forward reference subroutine call followed by a non-forward-reference
12        subroutine call, for example /.((?2)(?R)\1)()/, pcre2_compile() failed to
13        compile correct code, leading to undefined behaviour or an internally
14        detected error. This bug was discovered by the LLVM fuzzer.
15    
16    2.  Quantification of certain items (e.g. atomic back references) could cause
17        incorrect code to be compiled when recursive forward references were
18        involved. For example, in this pattern: /(?1)()((((((\1++))\x85)+)|))/.
19        This bug was discovered by the LLVM fuzzer.
20    
21    3.  A repeated conditional group whose condition was a reference by name caused
22        a buffer overflow if there was more than one group with the given name.
23        This bug was discovered by the LLVM fuzzer.
24    
25    4.  A recursive back reference by name within a group that had the same name as
26        another group caused a buffer overflow. For example:
27        /(?J)(?'d'(?'d'\g{d}))/. This bug was discovered by the LLVM fuzzer.
28    
29    5.  A forward reference by name to a group whose number is the same as the
30        current group, for example in this pattern: /(?|(\k'Pm')|(?'Pm'))/, caused
31        a buffer overflow at compile time. This bug was discovered by the LLVM
32        fuzzer.
33    
34    6.  A lookbehind assertion within a set of mutually recursive subpatterns could
35        provoke a buffer overflow. This bug was discovered by the LLVM fuzzer.
36    
37    7.  Another buffer overflow bug involved duplicate named groups with a
38        reference between their definition, with a group that reset capture
39        numbers, for example: /(?J:(?|(?'R')(\k'R')|((?'R'))))/. This has been
40        fixed by always allowing for more memory, even if not needed. (A proper fix
41        is implemented in PCRE2, but it involves more refactoring.)
42    
43    8.  There was no check for integer overflow in subroutine calls such as (?123).
44    
45    9.  The table entry for \l in EBCDIC environments was incorrect, leading to its
46        being treated as a literal 'l' instead of causing an error.
47    
48    10. There was a buffer overflow if pcre_exec() was called with an ovector of
49        size 1. This bug was found by american fuzzy lop.
50    
51    11. If a non-capturing group containing a conditional group that could match
52        an empty string was repeated, it was not identified as matching an empty
53        string itself. For example: /^(?:(?(1)x|)+)+$()/.
54    
55    12. In an EBCDIC environment, pcretest was mishandling the escape sequences
56        \a and \e in test subject lines.
57    
58    13. In an EBCDIC environment, \a in a pattern was converted to the ASCII
59        instead of the EBCDIC value.
60    
61    14. The handling of \c in an EBCDIC environment has been revised so that it is
62        now compatible with the specification in Perl's perlebcdic page.
63    
64    15. The EBCDIC character 0x41 is a non-breaking space, equivalent to 0xa0 in
65        ASCII/Unicode. This has now been added to the list of characters that are
66        recognized as white space in EBCDIC.
67    
68    16. When PCRE was compiled without UCP support, the use of \p and \P gave an
69        error (correctly) when used outside a class, but did not give an error
70        within a class.
71    
72    17. \h within a class was incorrectly compiled in EBCDIC environments.
73    
74    
75    Version 8.37 28-April-2015
76    --------------------------
77    
78    1.  When an (*ACCEPT) is triggered inside capturing parentheses, it arranges
79        for those parentheses to be closed with whatever has been captured so far.
80        However, it was failing to mark any other groups between the hightest
81        capture so far and the currrent group as "unset". Thus, the ovector for
82        those groups contained whatever was previously there. An example is the
83        pattern /(x)|((*ACCEPT))/ when matched against "abcd".
84    
85    2.  If an assertion condition was quantified with a minimum of zero (an odd
86        thing to do, but it happened), SIGSEGV or other misbehaviour could occur.
87    
88    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
89        unrecognized modifier, a crash could occur.
90    
91    4.  An attempt to do global matching in pcretest with a zero-length ovector
92        caused a crash.
93    
94    5.  Fixed a memory leak during matching that could occur for a subpattern
95        subroutine call (recursive or otherwise) if the number of captured groups
96        that had to be saved was greater than ten.
97    
98    6.  Catch a bad opcode during auto-possessification after compiling a bad UTF
99        string with NO_UTF_CHECK. This is a tidyup, not a bug fix, as passing bad
100        UTF with NO_UTF_CHECK is documented as having an undefined outcome.
101    
102    7.  A UTF pattern containing a "not" match of a non-ASCII character and a
103        subroutine reference could loop at compile time. Example: /[^\xff]((?1))/.
104    
105    8. When a pattern is compiled, it remembers the highest back reference so that
106       when matching, if the ovector is too small, extra memory can be obtained to
107       use instead. A conditional subpattern whose condition is a check on a
108       capture having happened, such as, for example in the pattern
109       /^(?:(a)|b)(?(1)A|B)/, is another kind of back reference, but it was not
110       setting the highest backreference number. This mattered only if pcre_exec()
111       was called with an ovector that was too small to hold the capture, and there
112       was no other kind of back reference (a situation which is probably quite
113       rare). The effect of the bug was that the condition was always treated as
114       FALSE when the capture could not be consulted, leading to a incorrect
115       behaviour by pcre_exec(). This bug has been fixed.
116    
117    9. A reference to a duplicated named group (either a back reference or a test
118       for being set in a conditional) that occurred in a part of the pattern where
119       PCRE_DUPNAMES was not set caused the amount of memory needed for the pattern
120       to be incorrectly calculated, leading to overwriting.
121    
122    10. A mutually recursive set of back references such as (\2)(\1) caused a
123        segfault at study time (while trying to find the minimum matching length).
124        The infinite loop is now broken (with the minimum length unset, that is,
125        zero).
126    
127    11. If an assertion that was used as a condition was quantified with a minimum
128        of zero, matching went wrong. In particular, if the whole group had
129        unlimited repetition and could match an empty string, a segfault was
130        likely. The pattern (?(?=0)?)+ is an example that caused this. Perl allows
131        assertions to be quantified, but not if they are being used as conditions,
132        so the above pattern is faulted by Perl. PCRE has now been changed so that
133        it also rejects such patterns.
134    
135    12. A possessive capturing group such as (a)*+ with a minimum repeat of zero
136        failed to allow the zero-repeat case if pcre2_exec() was called with an
137        ovector too small to capture the group.
138    
139    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
140        Red Hat Product Security:
141    
142        (a) A crash if /K and /F were both set with the option to save the compiled
143        pattern.
144    
145        (b) Another crash if the option to print captured substrings in a callout
146        was combined with setting a null ovector, for example \O\C+ as a subject
147        string.
148    
149    14. A pattern such as "((?2){0,1999}())?", which has a group containing a
150        forward reference repeated a large (but limited) number of times within a
151        repeated outer group that has a zero minimum quantifier, caused incorrect
152        code to be compiled, leading to the error "internal error:
153        previously-checked referenced subpattern not found" when an incorrect
154        memory address was read. This bug was reported as "heap overflow",
155        discovered by Kai Lu of Fortinet's FortiGuard Labs and given the CVE number
156        CVE-2015-2325.
157    
158    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
159        call within a group that also contained a recursive back reference caused
160        incorrect code to be compiled. This bug was reported as "heap overflow",
161        discovered by Kai Lu of Fortinet's FortiGuard Labs, and given the CVE
162        number CVE-2015-2326.
163    
164    24. Computing the size of the JIT read-only data in advance has been a source
165        of various issues, and new ones are still appear unfortunately. To fix
166        existing and future issues, size computation is eliminated from the code,
167        and replaced by on-demand memory allocation.
168    
169    25. A pattern such as /(?i)[A-`]/, where characters in the other case are
170        adjacent to the end of the range, and the range contained characters with
171        more than one other case, caused incorrect behaviour when compiled in UTF
172        mode. In that example, the range a-j was left out of the class.
173    
174    26. Fix JIT compilation of conditional blocks, which assertion
175        is converted to (*FAIL). E.g: /(?(?!))/.
176    
177    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
178        discovered by the LLVM fuzzer.
179    
180    28. The assertion (?!) is optimized to (*FAIL). This was not handled correctly
181        when this assertion was used as a condition, for example (?(?!)a|b). In
182        pcre2_match() it worked by luck; in pcre2_dfa_match() it gave an incorrect
183        error about an unsupported item.
184    
185    29. For some types of pattern, for example /Z*(|d*){216}/, the auto-
186        possessification code could take exponential time to complete. A recursion
187        depth limit of 1000 has been imposed to limit the resources used by this
188        optimization.
189    
190    30. A pattern such as /(*UTF)[\S\V\H]/, which contains a negated special class
191        such as \S in non-UCP mode, explicit wide characters (> 255) can be ignored
192        because \S ensures they are all in the class. The code for doing this was
193        interacting badly with the code for computing the amount of space needed to
194        compile the pattern, leading to a buffer overflow. This bug was discovered
195        by the LLVM fuzzer.
196    
197    31. A pattern such as /((?2)+)((?1))/ which has mutual recursion nested inside
198        other kinds of group caused stack overflow at compile time. This bug was
199        discovered by the LLVM fuzzer.
200    
201    32. A pattern such as /(?1)(?#?'){8}(a)/ which had a parenthesized comment
202        between a subroutine call and its quantifier was incorrectly compiled,
203        leading to buffer overflow or other errors. This bug was discovered by the
204        LLVM fuzzer.
205    
206    33. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an
207        assertion after (?(. The code was failing to check the character after
208        (?(?< for the ! or = that would indicate a lookbehind assertion. This bug
209        was discovered by the LLVM fuzzer.
210    
211    34. A pattern such as /X((?2)()*+){2}+/ which has a possessive quantifier with
212        a fixed maximum following a group that contains a subroutine reference was
213        incorrectly compiled and could trigger buffer overflow. This bug was
214        discovered by the LLVM fuzzer.
215    
216    35. A mutual recursion within a lookbehind assertion such as (?<=((?2))((?1)))
217        caused a stack overflow instead of the diagnosis of a non-fixed length
218        lookbehind assertion. This bug was discovered by the LLVM fuzzer.
219    
220    36. The use of \K in a positive lookbehind assertion in a non-anchored pattern
221        (e.g. /(?<=\Ka)/) could make pcregrep loop.
222    
223    37. There was a similar problem to 36 in pcretest for global matches.
224    
225    38. If a greedy quantified \X was preceded by \C in UTF mode (e.g. \C\X*),
226        and a subsequent item in the pattern caused a non-match, backtracking over
227        the repeated \X did not stop, but carried on past the start of the subject,
228        causing reference to random memory and/or a segfault. There were also some
229        other cases where backtracking after \C could crash. This set of bugs was
230        discovered by the LLVM fuzzer.
231    
232    39. The function for finding the minimum length of a matching string could take
233        a very long time if mutual recursion was present many times in a pattern,
234        for example, /((?2){73}(?2))((?1))/. A better mutual recursion detection
235        method has been implemented. This infelicity was discovered by the LLVM
236        fuzzer.
237    
238    40. Static linking against the PCRE library using the pkg-config module was
239        failing on missing pthread symbols.
240    
241    
242    Version 8.36 26-September-2014
243    ------------------------------
244    
245    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
246        -Wmissing-field-initializers and -Wunused-parameter.
247    
248    2.  The tests for quantifiers being too big (greater than 65535) were being
249        applied after reading the number, and stupidly assuming that integer
250        overflow would give a negative number. The tests are now applied as the
251        numbers are read.
252    
253    3.  Tidy code in pcre_exec.c where two branches that used to be different are
254        now the same.
255    
256    4.  The JIT compiler did not generate match limit checks for certain
257        bracketed expressions with quantifiers. This may lead to exponential
258        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
259        issue should be resolved now.
260    
261    5.  Fixed an issue, which occures when nested alternatives are optimized
262        with table jumps.
263    
264    6.  Inserted two casts and changed some ints to size_t in the light of some
265        reported 64-bit compiler warnings (Bugzilla 1477).
266    
267    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
268        an empty string, which sometimes were behaving incorrectly in the
269        interpreter (though correctly in the JIT matcher). This pcretest input is
270        an example:
271    
272          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
273          NON QUOTED "QUOT""ED" AFTER "NOT MATCHED
274    
275        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
276        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
277        for an empty string was breaking the inner loop and carrying on at a lower
278        level, when possessive repeated groups should always return to a higher
279        level as they have no backtrack points in them. The empty string test now
280        occurs at the outer level.
281    
282    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
283        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
284    
285    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
286        doesn't).
287    
288    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
289        to hold a pattern to be incorrectly computed (too small) when there were
290        named back references to duplicated names. This could cause "internal
291        error: code overflow" or "double free or corruption" or other memory
292        handling errors.
293    
294    11. When named subpatterns had the same prefixes, back references could be
295        confused. For example, in this pattern:
296    
297          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
298    
299        the reference to 'Name' was incorrectly treated as a reference to a
300        duplicate name.
301    
302    12. A pattern such as /^s?c/mi8 where the optional character has more than
303        one "other case" was incorrectly compiled such that it would only try to
304        match starting at "c".
305    
306    13. When a pattern starting with \s was studied, VT was not included in the
307        list of possible starting characters; this should have been part of the
308        8.34/18 patch.
309    
310    14. If a character class started [\Qx]... where x is any character, the class
311        was incorrectly terminated at the ].
312    
313    15. If a pattern that started with a caseless match for a character with more
314        than one "other case" was studied, PCRE did not set up the starting code
315        unit bit map for the list of possible characters. Now it does. This is an
316        optimization improvement, not a bug fix.
317    
318    16. The Unicode data tables have been updated to Unicode 7.0.0.
319    
320    17. Fixed a number of memory leaks in pcregrep.
321    
322    18. Avoid a compiler warning (from some compilers) for a function call with
323        a cast that removes "const" from an lvalue by using an intermediate
324        variable (to which the compiler does not object).
325    
326    19. Incorrect code was compiled if a group that contained an internal recursive
327        back reference was optional (had quantifier with a minimum of zero). This
328        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
329        caused segmentation faults because of stack overflows at compile time.
330    
331    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
332        group that is quantified with an indefinite repeat, caused a compile-time
333        loop which used up all the system stack and provoked a segmentation fault.
334        This was not the same bug as 19 above.
335    
336    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
337        Patch by Mike Frysinger.
338    
339    
340    Version 8.35 04-April-2014
341    --------------------------
342    
343    1.  A new flag is set, when property checks are present in an XCLASS.
344        When this flag is not set, PCRE can perform certain optimizations
345        such as studying these XCLASS-es.
346    
347    2.  The auto-possessification of character sets were improved: a normal
348        and an extended character set can be compared now. Furthermore
349        the JIT compiler optimizes more character set checks.
350    
351    3.  Got rid of some compiler warnings for potentially uninitialized variables
352        that show up only when compiled with -O2.
353    
354    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
355        of a match later then the end of the match. The pcretest program was not
356        handling the case sensibly - it was outputting from the start to the next
357        binary zero. It now reports this situation in a message, and outputs the
358        text from the end to the start.
359    
360    5.  Fast forward search is improved in JIT. Instead of the first three
361        characters, any three characters with fixed position can be searched.
362        Search order: first, last, middle.
363    
364    6.  Improve character range checks in JIT. Characters are read by an inprecise
365        function now, which returns with an unknown value if the character code is
366        above a certain threshold (e.g: 256). The only limitation is that the value
367        must be bigger than the threshold as well. This function is useful when
368        the characters above the threshold are handled in the same way.
369    
370    7.  The macros whose names start with RAWUCHAR are placeholders for a future
371        mode in which only the bottom 21 bits of 32-bit data items are used. To
372        make this more memorable for those maintaining the code, the names have
373        been changed to start with UCHAR21, and an extensive comment has been added
374        to their definition.
375    
376    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
377        to the export list in Makefile.am (they were accidentally omitted from the
378        8.34 tarball).
379    
380    9.  The informational output from pcretest used the phrase "starting byte set"
381        which is inappropriate for the 16-bit and 32-bit libraries. As the output
382        for "first char" and "need char" really means "non-UTF-char", I've changed
383        "byte" to "char", and slightly reworded the output. The documentation about
384        these values has also been (I hope) clarified.
385    
386    10. Another JIT related optimization: use table jumps for selecting the correct
387        backtracking path, when more than four alternatives are present inside a
388        bracket.
389    
390    11. Empty match is not possible, when the minimum length is greater than zero,
391        and there is no \K in the pattern. JIT should avoid empty match checks in
392        such cases.
393    
394    12. In a caseless character class with UCP support, when a character with more
395        than one alternative case was not the first character of a range, not all
396        the alternative cases were added to the class. For example, s and \x{17f}
397        are both alternative cases for S: the class [RST] was handled correctly,
398        but [R-T] was not.
399    
400    13. The configure.ac file always checked for pthread support when JIT was
401        enabled. This is not used in Windows, so I have put this test inside a
402        check for the presence of windows.h (which was already tested for).
403    
404    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
405        The algorithm provides a way to skip certain starting offsets, and usually
406        faster than linear prefix searches.
407    
408    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
409        as for 'fr_FR' and 'french'. For some reason, however, it then used the
410        Windows-specific input and output files, which have 'french' screwed in.
411        So this could never have worked. One of the problems with locales is that
412        they aren't always the same. I have now updated RunTest so that it checks
413        the output of the locale test (test 3) against three different output
414        files, and it allows the test to pass if any one of them matches. With luck
415        this should make the test pass on some versions of Solaris where it was
416        failing. Because of the uncertainty, the script did not used to stop if
417        test 3 failed; it now does. If further versions of a French locale ever
418        come to light, they can now easily be added.
419    
420    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
421        there was a message during ./configure, but it did not stop. This now
422        provokes an error. The invalid example in README has been corrected.
423        If a value less than the minimum is given, the minimum value has always
424        been used, but now a warning is given.
425    
426    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
427        was a bug in the test system, which is now fixed. Also, the list of various
428        configurations that are tested for each release did not have one with both
429        16/32 bits and --enable-bar-anycrlf. It now does.
430    
431    18. pcretest was missing "-C bsr" for displaying the \R default setting.
432    
433    19. Little endian PowerPC systems are supported now by the JIT compiler.
434    
435    20. The fast forward newline mechanism could enter to an infinite loop on
436        certain invalid UTF-8 input. Although we don't support these cases
437        this issue can be fixed by a performance optimization.
438    
439    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
440        not take account if existing stack usage. There is now a new global
441        variable called pcre_stack_guard that can be set to point to an external
442        function to check stack availability. It is called at the start of
443        processing every parenthesized group.
444    
445    22. A typo in the code meant that in ungreedy mode the max/min qualifier
446        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
447        not match "ab".
448    
449    23. When UTF was disabled, the JIT program reported some incorrect compile
450        errors. These messages are silenced now.
451    
452    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
453        compiler.
454    
455    25. Change all the temporary files used in RunGrepTest to be different to those
456        used by RunTest so that the tests can be run simultaneously, for example by
457        "make -j check".
458    
459    
460    Version 8.34 15-December-2013
461    -----------------------------
462    
463    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
464        executable memory. Patch inspired by Carsten Klein.
465    
466    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
467        this macro is never tested and has no effect, because the work to support
468        coverage involves only compiling and linking options and special targets in
469        the Makefile. The comment in config.h implied that defining the macro would
470        enable coverage support, which is totally false. There was also support for
471        setting this macro in the CMake files (my fault, I just copied it from
472        configure). SUPPORT_GCOV has now been removed.
473    
474    3.  Make a small performance improvement in strlen16() and strlen32() in
475        pcretest.
476    
477    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
478        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
479        these cases). There was also one in pcretest.c.
480    
481    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
482    
483    6.  In UTF mode, the code for checking whether a group could match an empty
484        string (which is used for indefinitely repeated groups to allow for
485        breaking an infinite loop) was broken when the group contained a repeated
486        negated single-character class with a character that occupied more than one
487        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
488        UTF-8 mode). The effect was undefined: the group might or might not be
489        deemed as matching an empty string, or the program might have crashed.
490    
491    7.  The code for checking whether a group could match an empty string was not
492        recognizing that \h, \H, \v, \V, and \R must match a character.
493    
494    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
495        an empty string. If it can, pcretest shows this in its information output.
496    
497    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
498        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
499        matched by pcre_exec() without using JIT:
500    
501        (a) If the rest of the pattern did not match after a maximal run of
502            grapheme clusters, the code for backing up to try with fewer of them
503            did not always back up over a full grapheme when characters that do not
504            have the modifier quality were involved, e.g. Hangul syllables.
505    
506        (b) If the match point in a subject started with modifier character, and
507            there was no match, the code could incorrectly back up beyond the match
508            point, and potentially beyond the first character in the subject,
509            leading to a segfault or an incorrect match result.
510    
511    10. A conditional group with an assertion condition could lead to PCRE
512        recording an incorrect first data item for a match if no other first data
513        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
514        first data item, and therefore matched "ca" after "c" instead of at the
515        start.
516    
517    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
518        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
519    
520    12. The source of pcregrep now includes z/OS-specific code so that it can be
521        compiled for z/OS as part of the special z/OS distribution.
522    
523    13. Added the -T and -TM options to pcretest.
524    
525    14. The code in pcre_compile.c for creating the table of named capturing groups
526        has been refactored. Instead of creating the table dynamically during the
527        actual compiling pass, the information is remembered during the pre-compile
528        pass (on the stack unless there are more than 20 named groups, in which
529        case malloc() is used) and the whole table is created before the actual
530        compile happens. This has simplified the code (it is now nearly 150 lines
531        shorter) and prepared the way for better handling of references to groups
532        with duplicate names.
533    
534    15. A back reference to a named subpattern when there is more than one of the
535        same name now checks them in the order in which they appear in the pattern.
536        The first one that is set is used for the reference. Previously only the
537        first one was inspected. This change makes PCRE more compatible with Perl.
538    
539    16. Unicode character properties were updated from Unicode 6.3.0.
540    
541    17. The compile-time code for auto-possessification has been refactored, based
542        on a patch by Zoltan Herczeg. It now happens after instead of during
543        compilation. The code is cleaner, and more cases are handled. The option
544        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
545        options in pcretest are provided to set it. It can also be set by
546        (*NO_AUTO_POSSESS) at the start of a pattern.
547    
548    18. The character VT has been added to the default ("C" locale) set of
549        characters that match \s and are generally treated as white space,
550        following this same change in Perl 5.18. There is now no difference between
551        "Perl space" and "POSIX space". Whether VT is treated as white space in
552        other locales depends on the locale.
553    
554    19. The code for checking named groups as conditions, either for being set or
555        for being recursed, has been refactored (this is related to 14 and 15
556        above). Processing unduplicated named groups should now be as fast at
557        numerical groups, and processing duplicated groups should be faster than
558        before.
559    
560    20. Two patches to the CMake build system, by Alexander Barkov:
561    
562          (1) Replace the "source" command by "." in CMakeLists.txt because
563              "source" is a bash-ism.
564    
565          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
566              without these the CMake build does not work on Solaris.
567    
568    21. Perl has changed its handling of \8 and \9. If there is no previously
569        encountered capturing group of those numbers, they are treated as the
570        literal characters 8 and 9 instead of a binary zero followed by the
571        literals. PCRE now does the same.
572    
573    22. Following Perl, added \o{} to specify codepoints in octal, making it
574        possible to specify values greater than 0777 and also making them
575        unambiguous.
576    
577    23. Perl now gives an error for missing closing braces after \x{... instead of
578        treating the string as literal. PCRE now does the same.
579    
580    24. RunTest used to grumble if an inappropriate test was selected explicitly,
581        but just skip it when running all tests. This make it awkward to run ranges
582        of tests when one of them was inappropriate. Now it just skips any
583        inappropriate tests, as it always did when running all tests.
584    
585    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
586        character types such as \d or \w, too many callouts were inserted, and the
587        data that they returned was rubbish.
588    
589    26. In UCP mode, \s was not matching two of the characters that Perl matches,
590        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
591        were matched by \h. The code has now been refactored so that the lists of
592        the horizontal and vertical whitespace characters used for \h and \v (which
593        are defined only in one place) are now also used for \s.
594    
595    27. Add JIT support for the 64 bit TileGX architecture.
596        Patch by Jiong Wang (Tilera Corporation).
597    
598    28. Possessive quantifiers for classes (both explicit and automatically
599        generated) now use special opcodes instead of wrapping in ONCE brackets.
600    
601    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
602        (because it's meaningless), this was not happening when PCRE_CASELESS was
603        set. Not wrong, but inefficient.
604    
605    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
606        properties for \w, \d, etc) is present in a test regex. Otherwise if the
607        test contains no characters greater than 255, Perl doesn't realise it
608        should be using Unicode semantics.
609    
610    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
611        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
612        does in Unicode mode.
613    
614    32. Added the "forbid" facility to pcretest so that putting tests into the
615        wrong test files can sometimes be quickly detected.
616    
617    33. There is now a limit (default 250) on the depth of nesting of parentheses.
618        This limit is imposed to control the amount of system stack used at compile
619        time. It can be changed at build time by --with-parens-nest-limit=xxx or
620        the equivalent in CMake.
621    
622    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
623        errors. Perl warns for these when in warning mode, but PCRE has no facility
624        for giving warnings.
625    
626    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
627        However, this was not working for (?!) because it is optimized to (*FAIL),
628        for which PCRE does not allow quantifiers. The optimization is now disabled
629        when a quantifier follows (?!). I can't see any use for this, but it makes
630        things uniform.
631    
632    36. Perl no longer allows group names to start with digits, so I have made this
633        change also in PCRE. It simplifies the code a bit.
634    
635    37. In extended mode, Perl ignores spaces before a + that indicates a
636        possessive quantifier. PCRE allowed a space before the quantifier, but not
637        before the possessive +. It now does.
638    
639    38. The use of \K (reset reported match start) within a repeated possessive
640        group such as (a\Kb)*+ was not working.
641    
642    40. Document that the same character tables must be used at compile time and
643        run time, and that the facility to pass tables to pcre_exec() and
644        pcre_dfa_exec() is for use only with saved/restored patterns.
645    
646    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
647        features for Builds with MSVC:
648    
649        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
650           builds). The .rc files can be used to set FileDescription and many other
651           attributes.
652    
653        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
654           This allows higher-level build scripts which want .pdb files to avoid
655           hard-coding the exact files needed."
656    
657    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
658        mean "start of word" and "end of word", respectively, as a transition aid.
659    
660    43. A minimizing repeat of a class containing codepoints greater than 255 in
661        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
662        compiled to use the heap for recursion.
663    
664    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
665        is configured.
666    
667    
668    Version 8.33 28-May-2013
669    ------------------------
670    
671    1.  Added 'U' to some constants that are compared to unsigned integers, to
672        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
673        variables that are added to signed variables, to ensure the result is
674        signed and can be negated.
675    
676    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
677        CMake config files.
678    
679    3.  Revise the creation of config.h.generic so that all boolean macros are
680        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
681        overriding via -D on the command line possible.
682    
683    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
684        to unsigned int is reported to make a quite noticeable speed difference in
685        a specific Windows environment. Testing on Linux did also appear to show
686        some benefit (and it is clearly not harmful). Also fixed the definition of
687        Xop which should be unsigned.
688    
689    5.  Related to (4), changing the definition of the intermediate variable cc
690        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
691        improvements.
692    
693    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
694        unnecessary spaces.
695    
696    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
697        and later.
698    
699    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
700    
701    9.  Optimizing fast_forward_start_bits in JIT.
702    
703    10. Adding support for callouts in JIT, and fixing some issues revealed
704        during this work. Namely:
705    
706        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
707    
708        (b) Minimum length was not checked before the matching is started.
709    
710    11. The value of capture_last that is passed to callouts was incorrect in some
711        cases when there was a capture on one path that was subsequently abandoned
712        after a backtrack. Also, the capture_last value is now reset after a
713        recursion, since all captures are also reset in this case.
714    
715    12. The interpreter no longer returns the "too many substrings" error in the
716        case when an overflowing capture is in a branch that is subsequently
717        abandoned after a backtrack.
718    
719    13. In the pathological case when an offset vector of size 2 is used, pcretest
720        now prints out the matched string after a yield of 0 or 1.
721    
722    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
723        Only supported by the JIT compiler at the moment.
724    
725    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
726    
727    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
728        offset of the starting point of the matching process, provided the offsets
729        vector is large enough.
730    
731    17. The \A escape now records a lookbehind value of 1, though its execution
732        does not actually inspect the previous character. This is to ensure that,
733        in partial multi-segment matching, at least one character from the old
734        segment is retained when a new segment is processed. Otherwise, if there
735        are no lookbehinds in the pattern, \A might match incorrectly at the start
736        of a new segment.
737    
738    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
739    
740    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
741        gives some modest performance improvement in 8-bit mode.
742    
743    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
744        be expressed in certain programming languages using Universal Character
745        Names.
746    
747    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
748        which points out that "non characters" are not "characters that may not
749        appear in Unicode strings" but rather "characters that are reserved for
750        internal use and have only local meaning".
751    
752    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
753        there was a conditional group that depended on an assertion, if the
754        assertion was false, the callout that immediately followed the alternation
755        in the condition was skipped when pcre_exec() was used for matching.
756    
757    23. Allow an explicit callout to be inserted before an assertion that is the
758        condition for a conditional group, for compatibility with automatic
759        callouts, which always insert a callout at this point.
760    
761    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
762        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
763    
764    25. (*PRUNE) is now supported by the JIT compiler.
765    
766    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
767    
768    27. Fix the case where there are two or more SKIPs with arguments that may be
769        ignored.
770    
771    28. (*SKIP) is now supported by the JIT compiler.
772    
773    29. (*THEN) is now supported by the JIT compiler.
774    
775    30. Update RunTest with additional test selector options.
776    
777    31. The way PCRE handles backtracking verbs has been changed in two ways.
778    
779        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
780        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
781        backtracking. In some cases this makes it more Perl-compatible, but Perl's
782        rather obscure rules do not always do the same thing.
783    
784        (2) Previously, backtracking verbs were confined within assertions. This is
785        no longer the case for positive assertions, except for (*ACCEPT). Again,
786        this sometimes improves Perl compatibility, and sometimes does not.
787    
788    32. A number of tests that were in test 2 because Perl did things differently
789        have been moved to test 1, because either Perl or PCRE has changed, and
790        these tests are now compatible.
791    
792    32. Backtracking control verbs are now handled in the same way in JIT and
793        interpreter.
794    
795    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
796        contained a forward subroutine reference caused a compile error.
797    
798    34. Auto-detect and optimize limited repetitions in JIT.
799    
800    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
801        blocking (*UTF) etc.
802    
803    36. In the interpreter, maximizing pattern repetitions for characters and
804        character types now use tail recursion, which reduces stack usage.
805    
806    37. The value of the max lookbehind was not correctly preserved if a compiled
807        and saved regex was reloaded on a host of different endianness.
808    
809    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
810        of the compiled pattern block, expand the flags field from 16 to 32 bits
811        because it was almost full.
812    
813    39. Try madvise first before posix_madvise.
814    
815    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
816        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
817        original change locked out all matches of empty strings. This has been
818        changed so that one match of an empty string per line is recognized.
819        Subsequent searches on the same line (for colouring or for --only-matching,
820        for example) do not recognize empty strings.
821    
822    41. Applied a user patch to fix a number of spelling mistakes in comments.
823    
824    42. Data lines longer than 65536 caused pcretest to crash.
825    
826    43. Clarified the data type for length and startoffset arguments for pcre_exec
827        and pcre_dfa_exec in the function-specific man pages, where they were
828        explicitly stated to be in bytes, never having been updated. I also added
829        some clarification to the pcreapi man page.
830    
831    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
832        a segmentation fault.
833    
834    
835    Version 8.32 30-November-2012
836    -----------------------------
837    
838    1.  Improved JIT compiler optimizations for first character search and single
839        character iterators.
840    
841    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
842        Patch by Daniel Richard G.
843    
844    3.  Single character iterator optimizations in the JIT compiler.
845    
846    4.  Improved JIT compiler optimizations for character ranges.
847    
848    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
849        Reported by Giuseppe D'Angelo.
850    
851    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
852        of a line, was being set incorrectly in cases where .* appeared inside
853        atomic brackets at the start of a pattern, or where there was a subsequent
854        *PRUNE or *SKIP.
855    
856    7.  Improved instruction cache flush for POWER/PowerPC.
857        Patch by Daniel Richard G.
858    
859    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
860        grep:
861    
862        (a) There is now no limit to the number of patterns to be matched.
863    
864        (b) An error is given if a pattern is too long.
865    
866        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
867            are now supported.
868    
869        (d) --exclude-from and --include-from (multiple use) have been added.
870    
871        (e) Exclusions and inclusions now apply to all files and directories, not
872            just to those obtained from scanning a directory recursively.
873    
874        (f) Multiple uses of -f and --file-list are now supported.
875    
876        (g) In a Windows environment, the default for -d has been changed from
877            "read" (the GNU grep default) to "skip", because otherwise the presence
878            of a directory in the file list provokes an error.
879    
880        (h) The documentation has been revised and clarified in places.
881    
882    9.  Improve the matching speed of capturing brackets.
883    
884    10. Changed the meaning of \X so that it now matches a Unicode extended
885        grapheme cluster.
886    
887    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
888        out POSIX threads when JIT support is configured.
889    
890    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
891    
892    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
893        structure could go wrong in environments where size_t is not the same size
894        as int.
895    
896    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
897        set.
898    
899    15. The EBCDIC support had decayed; later updates to the code had included
900        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
901        general tidy up of EBCDIC-related issues, and the documentation was also
902        not quite right. There is now a test that can be run on ASCII systems to
903        check some of the EBCDIC-related things (but is it not a full test).
904    
905    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
906        in a small tidy to the code.
907    
908    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
909    
910    18. If the --only-matching (-o) option in pcregrep is specified multiple
911        times, each one causes appropriate output. For example, -o1 -o2 outputs the
912        substrings matched by the 1st and 2nd capturing parentheses. A separating
913        string can be specified by --om-separator (default empty).
914    
915    19. Improving the first n character searches.
916    
917    20. Turn case lists for horizontal and vertical white space into macros so that
918        they are defined only once.
919    
920    21. This set of changes together give more compatible Unicode case-folding
921        behaviour for characters that have more than one other case when UCP
922        support is available.
923    
924        (a) The Unicode property table now has offsets into a new table of sets of
925            three or more characters that are case-equivalent. The MultiStage2.py
926            script that generates these tables (the pcre_ucd.c file) now scans
927            CaseFolding.txt instead of UnicodeData.txt for character case
928            information.
929    
930        (b) The code for adding characters or ranges of characters to a character
931            class has been abstracted into a generalized function that also handles
932            case-independence. In UTF-mode with UCP support, this uses the new data
933            to handle characters with more than one other case.
934    
935        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
936            whose other case is greater than 256 are now correctly matched
937            caselessly. Previously, the high codepoint matched the low one, but not
938            vice versa.
939    
940        (d) The processing of \h, \H, \v, and \ in character classes now makes use
941            of the new class addition function, using character lists defined as
942            macros alongside the case definitions of 20 above.
943    
944        (e) Caseless back references now work with characters that have more than
945            one other case.
946    
947        (f) General caseless matching of characters with more than one other case
948            is supported.
949    
950    22. Unicode character properties were updated from Unicode 6.2.0
951    
952    23. Improved CMake support under Windows. Patch by Daniel Richard G.
953    
954    24. Add support for 32-bit character strings, and UTF-32
955    
956    25. Major JIT compiler update (code refactoring and bugfixing).
957        Experimental Sparc 32 support is added.
958    
959    26. Applied a modified version of Daniel Richard G's patch to create
960        pcre.h.generic and config.h.generic by "make" instead of in the
961        PrepareRelease script.
962    
963    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
964        pcre_compile.c when checking for a zero character.
965    
966    28. Introducing a native interface for JIT. Through this interface, the compiled
967        machine code can be directly executed. The purpose of this interface is to
968        provide fast pattern matching, so several sanity checks are not performed.
969        However, feature tests are still performed. The new interface provides
970        1.4x speedup compared to the old one.
971    
972    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
973        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
974        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
975    
976    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
977        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
978        the "old" RFC 2279). Instead, it ended up passing a negative length to
979        pcre_exec().
980    
981    31. Add support for GCC's visibility feature to hide internal functions.
982    
983    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
984        "unknown -C option" after outputting 0 or 1.
985    
986    33. There is now support for generating a code coverage report for the test
987        suite in environments where gcc is the compiler and lcov is installed. This
988        is mainly for the benefit of the developers.
989    
990    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
991        unaddressable using valgrind annotations, allowing valgrind to detect
992        invalid memory accesses. This is mainly for the benefit of the developers.
993    
994    25. (*UTF) can now be used to start a pattern in any of the three libraries.
995    
996    26. Give configure error if --enable-cpp but no C++ compiler found.
997    
998    
999    Version 8.31 06-July-2012
1000    -------------------------
1001    
1002    1.  Fixing a wrong JIT test case and some compiler warnings.
1003    
1004    2.  Removed a bashism from the RunTest script.
1005    
1006    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
1007        to unsigned type, result still unsigned" that was given by an MS compiler
1008        on encountering the code "-sizeof(xxx)".
1009    
1010    4.  Partial matching support is added to the JIT compiler.
1011    
1012    5.  Fixed several bugs concerned with partial matching of items that consist
1013        of more than one character:
1014    
1015        (a) /^(..)\1/ did not partially match "aba" because checking references was
1016            done on an "all or nothing" basis. This also applied to repeated
1017            references.
1018    
1019        (b) \R did not give a hard partial match if \r was found at the end of the
1020            subject.
1021    
1022        (c) \X did not give a hard partial match after matching one or more
1023            characters at the end of the subject.
1024    
1025        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
1026            a partial match for the string "\r".
1027    
1028        (e) When newline was set to CRLF, the metacharacter "." did not recognize
1029            a partial match for a CR character at the end of the subject string.
1030    
1031    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
1032        running pcretest, the text "(JIT)" added to the output whenever JIT is
1033        actually used to run the match.
1034    
1035    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
1036        or /S+[+] with a digit between 1 and 7.
1037    
1038    8.  OP_NOT now supports any UTF character not just single-byte ones.
1039    
1040    9.  (*MARK) control verb is now supported by the JIT compiler.
1041    
1042    10. The command "./RunTest list" lists the available tests without actually
1043        running any of them. (Because I keep forgetting what they all are.)
1044    
1045    11. Add PCRE_INFO_MAXLOOKBEHIND.
1046    
1047    12. Applied a (slightly modified) user-supplied patch that improves performance
1048        when the heap is used for recursion (compiled with --disable-stack-for-
1049        recursion). Instead of malloc and free for each heap frame each time a
1050        logical recursion happens, frames are retained on a chain and re-used where
1051        possible. This sometimes gives as much as 30% improvement.
1052    
1053    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
1054        call.
1055    
1056    14. As documented, (*COMMIT) is now confined to within a positive assertion.
1057    
1058    15. It is now possible to link pcretest with libedit as an alternative to
1059        libreadline.
1060    
1061    16. (*COMMIT) control verb is now supported by the JIT compiler.
1062    
1063    17. The Unicode data tables have been updated to Unicode 6.1.0.
1064    
1065    18. Added --file-list option to pcregrep.
1066    
1067    19. Added binary file support to pcregrep, including the -a, --binary-files,
1068        -I, and --text options.
1069    
1070    20. The madvise function is renamed for posix_madvise for QNX compatibility
1071        reasons. Fixed by Giuseppe D'Angelo.
1072    
1073    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
1074    
1075    22. Changed the option for creating symbolic links for 16-bit man pages from
1076        -s to -sf so that re-installing does not cause issues.
1077    
1078    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
1079    
1080    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
1081        matches in certain environments (the workspace was not being correctly
1082        retained). Also added to pcre_dfa_exec() a simple plausibility check on
1083        some of the workspace data at the beginning of a restart.
1084    
1085    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
1086        was not doing so when it should - probably a typo introduced by SVN 528
1087        (change 8.10/14).
1088    
1089    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
1090        \w+ when the character tables indicated that \x{c4} was a word character.
1091        There were several related cases, all because the tests for doing a table
1092        lookup were testing for characters less than 127 instead of 255.
1093    
1094    27. If a pattern contains capturing parentheses that are not used in a match,
1095        their slots in the ovector are set to -1. For those that are higher than
1096        any matched groups, this happens at the end of processing. In the case when
1097        there were back references that the ovector was too small to contain
1098        (causing temporary malloc'd memory to be used during matching), and the
1099        highest capturing number was not used, memory off the end of the ovector
1100        was incorrectly being set to -1. (It was using the size of the temporary
1101        memory instead of the true size.)
1102    
1103    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
1104        ovector size, it uses memory at the end of the block that it has got.
1105    
1106    29. Check for an overlong MARK name and give an error at compile time. The
1107        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
1108    
1109    30. JIT compiler update.
1110    
1111    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
1112        Rill for the patch.
1113    
1114    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
1115    
1116    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
1117    
1118    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
1119        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
1120        was enabled.
1121    
1122    35. Improve JIT code generation for greedy plus quantifier.
1123    
1124    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
1125        1 to "aa" instead of to an empty string. The bug affected repeated groups
1126        that could potentially match an empty string.
1127    
1128    37. Optimizing single character iterators in JIT.
1129    
1130    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
1131        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
1132        codepoints that are too big for the mode are faulted, and in a UTF mode,
1133        disallowed codepoints are also faulted.
1134    
1135    39. If PCRE was compiled with UTF support, in three places in the DFA
1136        matcher there was code that should only have been obeyed in UTF mode, but
1137        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
1138        processing when bytes with values greater than 127 were present. In 16-bit
1139        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
1140        both cases the values are those that cannot be the first data item in a UTF
1141        character. The three items that might have provoked this were recursions,
1142        possessively repeated groups, and atomic groups.
1143    
1144    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
1145        and pcregrep, because some OS require shared objects to be explicitly
1146        passed to ld, causing the link step to fail if they are not.
1147    
1148    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
1149        mode, patterns that started with \h* or \R* might be incorrectly matched.
1150    
1151    
1152    Version 8.30 04-February-2012
1153    -----------------------------
1154    
1155    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
1156        name is defined in ctype.h.
1157    
1158    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
1159        only in quite long subpatterns.
1160    
1161    3.  Removed the function pcre_info(), which has been obsolete and deprecated
1162        since it was replaced by pcre_fullinfo() in February 2000.
1163    
1164    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
1165        match a (*MARK), and the match failed at the start of the subject, a
1166        reference to memory before the start of the subject could occur. This bug
1167        was introduced by fix 17 of release 8.21.
1168    
1169    5.  A reference to an unset group with zero minimum repetition was giving
1170        totally wrong answers (in non-JavaScript-compatibility mode). For example,
1171        /(another)?(\1?)test/ matched against "hello world test". This bug was
1172        introduced in release 8.13.
1173    
1174    6.  Add support for 16-bit character strings (a large amount of work involving
1175        many changes and refactorings).
1176    
1177    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
1178        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
1179        from a file.
1180    
1181    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
1182        rounding is not applied in this particular case).
1183    
1184    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
1185        if they appear, or are escaped, in patterns.
1186    
1187    10. Get rid of a number of -Wunused-but-set-variable warnings.
1188    
1189    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
1190        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
1191        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
1192        also returns the mark "x". This bug applied to capturing parentheses,
1193        non-capturing parentheses, and atomic parentheses. It also applied to some
1194        assertions.
1195    
1196    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
1197        information out of configure.ac instead of relying on pcre.h.generic, which
1198        is not stored in the repository.
1199    
1200    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
1201        -lreadline.
1202    
1203    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
1204    
1205    15. Applied Graycode's patch to put the top-level frame on the stack rather
1206        than the heap when not using the stack for recursion. This gives a
1207        performance improvement in many cases when recursion is not deep.
1208    
1209    16. Experimental code added to "pcretest -C" to output the stack frame size.
1210    
1211    
1212    Version 8.21 12-Dec-2011
1213    ------------------------
1214    
1215    1.  Updating the JIT compiler.
1216    
1217    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1218        are added as well.
1219    
1220    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1221        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1222        calling _pcre_jit_exec. Some extra comments are added.
1223    
1224    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1225        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1226        was introduced by change 18 for 8.20.
1227    
1228    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1229        ECMA-262 standard.
1230    
1231    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1232        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1233        This bug was probably introduced by change 9 of 8.13.
1234    
1235    7.  While fixing 6 above, I noticed that a number of other items were being
1236        incorrectly rejected as "not fixed length". This arose partly because newer
1237        opcodes had not been added to the fixed-length checking code. I have (a)
1238        corrected the bug and added tests for these items, and (b) arranged for an
1239        error to occur if an unknown opcode is encountered while checking for fixed
1240        length instead of just assuming "not fixed length". The items that were
1241        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1242        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1243        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1244    
1245    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1246        being incorrectly compiled and would have given unpredicatble results.
1247    
1248    9.  A possessively repeated subpattern with minimum repeat count greater than
1249        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1250        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1251        the first (A) could occur when it should not.
1252    
1253    10. Add a cast and remove a redundant test from the code.
1254    
1255    11. JIT should use pcre_malloc/pcre_free for allocation.
1256    
1257    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1258        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1259        is anything other than /usr, -L is still shown).
1260    
1261    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1262    
1263    14. Perl does not support \N without a following name in a [] class; PCRE now
1264        also gives an error.
1265    
1266    15. If a forward reference was repeated with an upper limit of around 2000,
1267        it caused the error "internal error: overran compiling workspace". The
1268        maximum number of forward references (including repeats) was limited by the
1269        internal workspace, and dependent on the LINK_SIZE. The code has been
1270        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1271        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1272        of around 200,000 forward references. While doing this, I also speeded up
1273        the filling in of repeated forward references.
1274    
1275    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1276        incorrectly expecting the subject to contain another "a" after the start.
1277    
1278    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1279        in the match, the SKIP should be ignored. This was not happening; instead
1280        the SKIP was being treated as NOMATCH. For patterns such as
1281        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1282        tested.
1283    
1284    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1285        now much more compatible with Perl, in particular in cases where the result
1286        is a non-match for a non-anchored pattern. For example, if
1287        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1288        "m", where previously it did not return a name. A side effect of this
1289        change is that for partial matches, the last encountered mark name is
1290        returned, as for non matches. A number of tests that were previously not
1291        Perl-compatible have been moved into the Perl-compatible test files. The
1292        refactoring has had the pleasing side effect of removing one argument from
1293        the match() function, thus reducing its stack requirements.
1294    
1295    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1296        subsequent uses of /S (without +) incorrectly behaved like /S+.
1297    
1298    21. Retrieve executable code size support for the JIT compiler and fixing
1299        some warnings.
1300    
1301    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1302        not work when the shorter character appeared right at the end of the
1303        subject string.
1304    
1305    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1306        systems.
1307    
1308    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1309        output it when the /M option is used in pcretest.
1310    
1311    25. The CheckMan script was not being included in the distribution. Also, added
1312        an explicit "perl" to run Perl scripts from the PrepareRelease script
1313        because this is reportedly needed in Windows.
1314    
1315    26. If study data was being save in a file and studying had not found a set of
1316        "starts with" bytes for the pattern, the data written to the file (though
1317        never used) was taken from uninitialized memory and so caused valgrind to
1318        complain.
1319    
1320    27. Updated RunTest.bat as provided by Sheri Pierce.
1321    
1322    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1323    
1324    29. Computation of memory usage for the table of capturing group names was
1325        giving an unnecessarily large value.
1326    
1327    
1328    Version 8.20 21-Oct-2011
1329    ------------------------
1330    
1331    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1332        a POSIX class. After further experiments with Perl, which convinced me that
1333        Perl has bugs and confusions, a closing square bracket is no longer allowed
1334        in a POSIX name. This bug also affected patterns with classes that started
1335        with full stops.
1336    
1337    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1338        captured substring, but while checking the failing first alternative,
1339        substring 1 is temporarily captured. If the output vector supplied to
1340        pcre_exec() was not big enough for this capture, the yield of the function
1341        was still zero ("insufficient space for captured substrings"). This cannot
1342        be totally fixed without adding another stack variable, which seems a lot
1343        of expense for a edge case. However, I have improved the situation in cases
1344        such as /(a)(b)x|abc/ matched against "abc", where the return code
1345        indicates that fewer than the maximum number of slots in the ovector have
1346        been set.
1347    
1348    3.  Related to (2) above: when there are more back references in a pattern than
1349        slots in the output vector, pcre_exec() uses temporary memory during
1350        matching, and copies in the captures as far as possible afterwards. It was
1351        using the entire output vector, but this conflicts with the specification
1352        that only 2/3 is used for passing back captured substrings. Now it uses
1353        only the first 2/3, for compatibility. This is, of course, another edge
1354        case.
1355    
1356    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1357        main code base, and can be used by building with --enable-jit. When this is
1358        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1359        runtime --no-jit option is given.
1360    
1361    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1362        ovector, the return from the function was zero, implying that there were
1363        other matches that did not fit. The correct "exactly full" value is now
1364        returned.
1365    
1366    6.  If a subpattern that was called recursively or as a subroutine contained
1367        (*PRUNE) or any other control that caused it to give a non-standard return,
1368        invalid errors such as "Error -26 (nested recursion at the same subject
1369        position)" or even infinite loops could occur.
1370    
1371    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1372        computing the minimum length on reaching *ACCEPT, and so ended up with the
1373        wrong value of 1 rather than 0. Further investigation indicates that
1374        computing a minimum subject length in the presence of *ACCEPT is difficult
1375        (think back references, subroutine calls), and so I have changed the code
1376        so that no minimum is registered for a pattern that contains *ACCEPT.
1377    
1378    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1379        it was not handled as intended. [But see 16 below.]
1380    
1381    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1382        Sheri Pierce.
1383    
1384    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1385        the first byte in a match must be "a".
1386    
1387    11. Change 17 for 8.13 increased the recursion depth for patterns like
1388        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1389        pattern contains any instances of (*THEN). If it does not, the old
1390        optimizations are restored. It would be nice to do this on a per-group
1391        basis, but at the moment that is not feasible.
1392    
1393    12. In some environments, the output of pcretest -C is CRLF terminated. This
1394        broke RunTest's code that checks for the link size. A single white space
1395        character after the value is now allowed for.
1396    
1397    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1398        For "fr", it uses the Windows-specific input and output files.
1399    
1400    14. If (*THEN) appeared in a group that was called recursively or as a
1401        subroutine, it did not work as intended. [But see next item.]
1402    
1403    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1404        pattern fragments (but not containing any | characters). If A and B are
1405        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1406        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1407        D. In other words, Perl considers parentheses that do not contain any |
1408        characters to be part of a surrounding alternative, whereas PCRE was
1409        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1410        differently. PCRE now behaves in the same way as Perl, except in the case
1411        of subroutine/recursion calls such as (?1) which have in any case always
1412        been different (but PCRE had them first :-).
1413    
1414    16. Related to 15 above: Perl does not treat the | in a conditional group as
1415        creating alternatives. Such a group is treated in the same way as an
1416        ordinary group without any | characters when processing (*THEN). PCRE has
1417        been changed to match Perl's behaviour.
1418    
1419    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1420        RunGrepTest script failed.
1421    
1422    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1423        inevitable for groups that contain captures, but it can lead to a lot of
1424        stack use in large patterns. The old behaviour has been restored for atomic
1425        groups that do not contain any capturing parentheses.
1426    
1427    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1428        suppress the check for a minimum subject length at run time. (If it was
1429        given to pcre_exec() or pcre_dfa_exec() it did work.)
1430    
1431    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1432        fail to work when decoding hex characters in data strings in EBCDIC
1433        environments.
1434    
1435    21. It appears that in at least one Mac OS environment, the isxdigit() function
1436        is implemented as a macro that evaluates to its argument more than once,
1437        contravening the C 90 Standard (I haven't checked a later standard). There
1438        was an instance in pcretest which caused it to go wrong when processing
1439        \x{...} escapes in subject strings. The has been rewritten to avoid using
1440        things like p++ in the argument of isxdigit().
1441    
1442    
1443    Version 8.13 16-Aug-2011
1444    ------------------------
1445    
1446    1.  The Unicode data tables have been updated to Unicode 6.0.0.
1447    
1448    2.  Two minor typos in pcre_internal.h have been fixed.
1449    
1450    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
1451        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
1452        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
1453    
1454    4.  There were a number of related bugs in the code for matching backrefences
1455        caselessly in UTF-8 mode when codes for the characters concerned were
1456        different numbers of bytes. For example, U+023A and U+2C65 are an upper
1457        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
1458        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
1459        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1460        2-byte code at the end of the subject (it thought there wasn't enough data
1461        left).
1462    
1463    5.  Comprehensive information about what went wrong is now returned by
1464        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1465        as the output vector has at least 2 elements. The offset of the start of
1466        the failing character and a reason code are placed in the vector.
1467    
1468    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1469        now returned is for the first byte of the failing character, instead of the
1470        last byte inspected. This is an incompatible change, but I hope it is small
1471        enough not to be a problem. It makes the returned offset consistent with
1472        pcre_exec() and pcre_dfa_exec().
1473    
1474    7.  pcretest now gives a text phrase as well as the error number when
1475        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1476        failure, the offset and reason code are output.
1477    
1478    8.  When \R was used with a maximizing quantifier it failed to skip backwards
1479        over a \r\n pair if the subsequent match failed. Instead, it just skipped
1480        back over a single character (\n). This seems wrong (because it treated the
1481        two characters as a single entity when going forwards), conflicts with the
1482        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1483        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1484        has been changed.
1485    
1486    9.  Some internal refactoring has changed the processing so that the handling
1487        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1488        time (the PCRE_DOTALL option was changed this way some time ago: version
1489        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1490        which was always a bit of a fudge. It also means that there is one less
1491        argument for the match() function, which reduces its stack requirements
1492        slightly. This change also fixes an incompatibility with Perl: the pattern
1493        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1494    
1495    10. More internal refactoring has drastically reduced the number of recursive
1496        calls to match() for possessively repeated groups such as (abc)++ when
1497        using pcre_exec().
1498    
1499    11. While implementing 10, a number of bugs in the handling of groups were
1500        discovered and fixed:
1501    
1502        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1503        (a|)*(?1) gave a compile-time internal error.
1504        ((a|)+)+  did not notice that the outer group could match an empty string.
1505        (^a|^)+   was not marked as anchored.
1506        (.*a|.*)+ was not marked as matching at start or after a newline.
1507    
1508    12. Yet more internal refactoring has removed another argument from the match()
1509        function. Special calls to this function are now indicated by setting a
1510        value in a variable in the "match data" data block.
1511    
1512    13. Be more explicit in pcre_study() instead of relying on "default" for
1513        opcodes that mean there is no starting character; this means that when new
1514        ones are added and accidentally left out of pcre_study(), testing should
1515        pick them up.
1516    
1517    14. The -s option of pcretest has been documented for ages as being an old
1518        synonym of -m (show memory usage). I have changed it to mean "force study
1519        for every regex", that is, assume /S for every regex. This is similar to -i
1520        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1521        using it. It makes it easier to run collections of tests with and without
1522        study enabled, and thereby test pcre_study() more easily. All the standard
1523        tests are now run with and without -s (but some patterns can be marked as
1524        "never study" - see 20 below).
1525    
1526    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1527        restoration of the capturing data to the outer values was not happening
1528        correctly.
1529    
1530    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1531        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1532        pattern had matched an empty string, and so incorrectly returned a no
1533        match.
1534    
1535    17. There was optimizing code for the last branch of non-capturing parentheses,
1536        and also for the obeyed branch of a conditional subexpression, which used
1537        tail recursion to cut down on stack usage. Unfortunately, now that there is
1538        the possibility of (*THEN) occurring in these branches, tail recursion is
1539        no longer possible because the return has to be checked for (*THEN). These
1540        two optimizations have therefore been removed. [But see 8.20/11 above.]
1541    
1542    18. If a pattern containing \R was studied, it was assumed that \R always
1543        matched two bytes, thus causing the minimum subject length to be
1544        incorrectly computed because \R can also match just one byte.
1545    
1546    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1547        was incorrectly computed.
1548    
1549    20. If /S is present twice on a test pattern in pcretest input, it now
1550        *disables* studying, thereby overriding the use of -s on the command line
1551        (see 14 above). This is necessary for one or two tests to keep the output
1552        identical in both cases.
1553    
1554    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1555        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1556    
1557    22. When an atomic group that contained a capturing parenthesis was
1558        successfully matched, but the branch in which it appeared failed, the
1559        capturing was not being forgotten if a higher numbered group was later
1560        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1561        group 1 to "a", when in fact it should be unset. This applied to multi-
1562        branched capturing and non-capturing groups, repeated or not, and also to
1563        positive assertions (capturing in negative assertions does not happen
1564        in PCRE) and also to nested atomic groups.
1565    
1566    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1567        subject after a captured substring, to make it easier to tell which of a
1568        number of identical substrings has been captured.
1569    
1570    24. The way atomic groups are processed by pcre_exec() has been changed so that
1571        if they are repeated, backtracking one repetition now resets captured
1572        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1573        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1574        "aaa". Previously, it would have been "a". As part of this code
1575        refactoring, the way recursive calls are handled has also been changed.
1576    
1577    25. If an assertion condition captured any substrings, they were not passed
1578        back unless some other capturing happened later. For example, if
1579        (?(?=(a))a) was matched against "a", no capturing was returned.
1580    
1581    26. When studying a pattern that contained subroutine calls or assertions,
1582        the code for finding the minimum length of a possible match was handling
1583        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1584        group 1 called group 2 while simultaneously a separate group 2 called group
1585        1). A stack overflow occurred in this case. I have fixed this by limiting
1586        the recursion depth to 10.
1587    
1588    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1589        Fortmann. This supports explicit test numbers on the command line, and has
1590        argument validation and error reporting.
1591    
1592    28. An instance of \X with an unlimited repeat could fail if at any point the
1593        first character it looked at was a mark character.
1594    
1595    29. Some minor code refactoring concerning Unicode properties and scripts
1596        should reduce the stack requirement of match() slightly.
1597    
1598    30. Added the '=' option to pcretest to check the setting of unused capturing
1599        slots at the end of the pattern, which are documented as being -1, but are
1600        not included in the return count.
1601    
1602    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1603        compiled something random. Now it gives a compile-time error (as does
1604        Perl).
1605    
1606    32. A *MARK encountered during the processing of a positive assertion is now
1607        recorded and passed back (compatible with Perl).
1608    
1609    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1610        had alternative anchored branches, the search for a second match in a line
1611        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1612        matched the line "0102" twice. The same bug affected patterns that started
1613        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1614        twice.
1615    
1616    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1617        does, and because of capturing effects, quantifying parenthesized
1618        assertions may at times be useful. Quantifiers are now allowed for
1619        parenthesized assertions.
1620    
1621    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1622    
1623    36. \g was being checked for fancy things in a character class, when it should
1624        just be a literal "g".
1625    
1626    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1627        appearance of a nested POSIX class supersedes an apparent external class.
1628        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1629        unescaped square brackets may also appear as part of class names. For
1630        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1631        more like Perl. (But see 8.20/1 above.)
1632    
1633    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1634        was because it thought it was \N{name}, which is not supported).
1635    
1636    39. Add minix to OS list not supporting the -S option in pcretest.
1637    
1638    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1639        cannot analyze patterns in sufficient detail to catch mutual recursions
1640        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1641        subgroup is called recursively as a subpattern for a second time at the
1642        same position in the subject string. In previous releases this might have
1643        been caught by the recursion limit, or it might have run out of stack.
1644    
1645    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1646        happen only once. PCRE was, however incorrectly giving a compile time error
1647        "recursive call could loop indefinitely" because it cannot analyze the
1648        pattern in sufficient detail. The compile time test no longer happens when
1649        PCRE is compiling a conditional subpattern, but actual runaway loops are
1650        now caught at runtime (see 40 above).
1651    
1652    42. It seems that Perl allows any characters other than a closing parenthesis
1653        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1654        has been changed to be the same.
1655    
1656    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1657        as not to get warnings when autogen.sh is called. Also changed
1658        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1659    
1660    44. To help people who use pcregrep to scan files containing exceedingly long
1661        lines, the following changes have been made:
1662    
1663        (a) The default value of the buffer size parameter has been increased from
1664            8K to 20K. (The actual buffer used is three times this size.)
1665    
1666        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1667            PCRE is built.
1668    
1669        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1670            to be set at run time.
1671    
1672        (d) Numerical values in pcregrep options can be followed by K or M, for
1673            example --buffer-size=50K.
1674    
1675        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1676            given and the return code is set to 2.
1677    
1678    45. Add a pointer to the latest mark to the callout data block.
1679    
1680    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1681        partial match of an empty string instead of no match. This was specific to
1682        the use of ".".
1683    
1684    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1685        complete match instead of a partial match. This bug was dependent on both
1686        the PCRE_UTF8 and PCRE_DOTALL options being set.
1687    
1688    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1689        starting byte set, because \b was not being ignored.
1690    
1691    
1692    Version 8.12 15-Jan-2011
1693    ------------------------
1694    
1695    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1696        checks for such things as part of the documentation building process.
1697    
1698    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1699        --match-limit and --recursion-limit options (added for 8.11). In
1700        particular, this made one of the standard tests fail. (The integer value
1701        went into the wrong half of a long int.)
1702    
1703    3.  If the --colour option was given to pcregrep with -v (invert match), it
1704        did strange things, either producing crazy output, or crashing. It should,
1705        of course, ignore a request for colour when reporting lines that do not
1706        match.
1707    
1708    4.  Another pcregrep bug caused similar problems if --colour was specified with
1709        -M (multiline) and the pattern match finished with a line ending.
1710    
1711    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1712        matched in multiline mode, the following line was shown as part of the
1713        match. This seems wrong, so I have changed it.
1714    
1715    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1716        the check for further matches in the same line (so they could be coloured)
1717        to overrun the end of the current line. If another match was found, it was
1718        incorrectly shown (and then shown again when found in the next line).
1719    
1720    7.  If pcregrep was compiled under Windows, there was a reference to the
1721        function pcregrep_exit() before it was defined. I am assuming this was
1722        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1723        reported by a user. I've moved the definition above the reference.
1724    
1725    
1726    Version 8.11 10-Dec-2010
1727    ------------------------
1728    
1729    1.  (*THEN) was not working properly if there were untried alternatives prior
1730        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1731        backtracked to try for "b" instead of moving to the next alternative branch
1732        at the same level (in this case, to look for "c"). The Perl documentation
1733        is clear that when (*THEN) is backtracked onto, it goes to the "next
1734        alternative in the innermost enclosing group".
1735    
1736    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1737        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1738        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1739        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1740        (*THEN).
1741    
1742    3.  If \s appeared in a character class, it removed the VT character from
1743        the class, even if it had been included by some previous item, for example
1744        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1745        of \s, but is part of the POSIX "space" class.)
1746    
1747    4.  A partial match never returns an empty string (because you can always
1748        match an empty string at the end of the subject); however the checking for
1749        an empty string was starting at the "start of match" point. This has been
1750        changed to the "earliest inspected character" point, because the returned
1751        data for a partial match starts at this character. This means that, for
1752        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1753        (previously it gave "no match").
1754    
1755    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1756        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1757        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1758        has an implication that the given string is incomplete (because a partial
1759        match is preferred over a full match). For this reason, these items now
1760        give a partial match in this situation. [Aside: previously, the one case
1761        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1762        match rather than a full match, which was wrong by the old rules, but is
1763        now correct.]
1764    
1765    6.  There was a bug in the handling of #-introduced comments, recognized when
1766        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1767        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1768        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1769        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1770        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1771        places in pcre_compile().
1772    
1773    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1774        comments when looking ahead for named forward references to subpatterns,
1775        the only newline sequence it recognized was NL. It now handles newlines
1776        according to the set newline convention.
1777    
1778    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1779        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1780        cater for a lack of strerror(). These oversights have been fixed.
1781    
1782    9.  Added --match-limit and --recursion-limit to pcregrep.
1783    
1784    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1785    
1786    11. When the -o option was used, pcregrep was setting a return code of 1, even
1787        when matches were found, and --line-buffered was not being honoured.
1788    
1789    12. Added an optional parentheses number to the -o and --only-matching options
1790        of pcregrep.
1791    
1792    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1793        can match an empty string. The code to do it in pcretest and pcredemo
1794        needed fixing:
1795    
1796        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1797            only one byte after an empty string match just before CRLF (this case
1798            just got forgotten; "any" and "anycrlf" were OK).
1799    
1800        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1801            mode when an empty string match preceded an ASCII character followed by
1802            a non-ASCII character. (The code for advancing by one character rather
1803            than one byte was nonsense.)
1804    
1805        (c) The pcredemo.c sample program did not have any code at all to handle
1806            the cases when CRLF is a valid newline sequence.
1807    
1808    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1809        as a starting offset was within the subject string. There is now a new
1810        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1811        negative or greater than the length of the string. In order to test this,
1812        pcretest is extended to allow the setting of negative starting offsets.
1813    
1814    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1815        starting offset points to the beginning of a UTF-8 character was
1816        unnecessarily clumsy. I tidied it up.
1817    
1818    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1819        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1820    
1821    17. Nobody had reported that the --include_dir option, which was added in
1822        release 7.7 should have been called --include-dir (hyphen, not underscore)
1823        for compatibility with GNU grep. I have changed it to --include-dir, but
1824        left --include_dir as an undocumented synonym, and the same for
1825        --exclude-dir, though that is not available in GNU grep, at least as of
1826        release 2.5.4.
1827    
1828    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1829        characters from a string of bytes) have been redefined so as not to use
1830        loops, in order to improve performance in some environments. At the same
1831        time, I abstracted some of the common code into auxiliary macros to save
1832        repetition (this should not affect the compiled code).
1833    
1834    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1835        compile-time error is now given if \c is not followed by an ASCII
1836        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1837        different, and any byte value is allowed.)
1838    
1839    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1840        START_OPTIMIZE option, which is now allowed at compile time - but just
1841        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1842        to pcregrep and other applications that have no direct access to PCRE
1843        options. The new /Y option in pcretest sets this option when calling
1844        pcre_compile().
1845    
1846    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1847        back references. Groups containing recursive back references were forced to
1848        be atomic by that change, but in the case of named groups, the amount of
1849        memory required was incorrectly computed, leading to "Failed: internal
1850        error: code overflow". This has been fixed.
1851    
1852    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1853        pcretest.c, to avoid build problems in some Borland environments.
1854    
1855    
1856    Version 8.10 25-Jun-2010
1857    ------------------------
1858    
1859    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1860        THEN.
1861    
1862    2.  (*ACCEPT) was not working when inside an atomic group.
1863    
1864    3.  Inside a character class, \B is treated as a literal by default, but
1865        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1866        causes the error). The code is unchanged, but I tidied the documentation.
1867    
1868    4.  Inside a character class, PCRE always treated \R and \X as literals,
1869        whereas Perl faults them if its -w option is set. I have changed PCRE so
1870        that it faults them when PCRE_EXTRA is set.
1871    
1872    5.  Added support for \N, which always matches any character other than
1873        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1874    
1875    6.  When compiling pcregrep with newer versions of gcc which may have
1876        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1877        declared with attribute warn_unused_result" were given. Just casting the
1878        result to (void) does not stop the warnings; a more elaborate fudge is
1879        needed. I've used a macro to implement this.
1880    
1881    7.  Minor change to pcretest.c to avoid a compiler warning.
1882    
1883    8.  Added four artifical Unicode properties to help with an option to make
1884        \s etc use properties (see next item). The new properties are: Xan
1885        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1886    
1887    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1888        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1889        this option. Modified pcretest to add /W to test this facility. Added
1890        REG_UCP to make it available via the POSIX interface.
1891    
1892    10. Added --line-buffered to pcregrep.
1893    
1894    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1895        studied, and the match started with a letter with a code point greater than
1896        127 whose first byte was different to the first byte of the other case of
1897        the letter, the other case of this starting letter was not recognized
1898        (#976).
1899    
1900    12. If a pattern that was studied started with a repeated Unicode property
1901        test, for example, \p{Nd}+, there was the theoretical possibility of
1902        setting up an incorrect bitmap of starting bytes, but fortunately it could
1903        not have actually happened in practice until change 8 above was made (it
1904        added property types that matched character-matching opcodes).
1905    
1906    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1907        possible starting bytes for non-anchored patterns.
1908    
1909    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1910        \R, and also a number of cases that involve Unicode properties, both
1911        explicit and implicit when PCRE_UCP is set.
1912    
1913    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1914        input, it could crash or give wrong results if characters with values
1915        greater than 0xc0 were present in the subject string. (Detail: it assumed
1916        UTF-8 input when processing these items.)
1917    
1918    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1919        size_t is 64-bit (#991).
1920    
1921    17. Added a check for running out of memory when PCRE is compiled with
1922        --disable-stack-for-recursion (#990).
1923    
1924    18. If the last data line in a file for pcretest does not have a newline on
1925        the end, a newline was missing in the output.
1926    
1927    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1928        less than 128) in its various bitmaps. However, there is a facility for
1929        generating tables according to the current locale when PCRE is compiled. It
1930        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1931        characters, are recognized by isspace() and therefore were getting set in
1932        these tables, and indeed these tables seem to approximate to ISO 8859. This
1933        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1934        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1935        which of course cannot start UTF-8 characters. I have changed the code so
1936        that only real ASCII characters (less than 128) and the correct starting
1937        bytes for UTF-8 encodings are set for characters greater than 127 when in
1938        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1939        altogether.)
1940    
1941    20. Added the /T option to pcretest so as to be able to run tests with non-
1942        standard character tables, thus making it possible to include the tests
1943        used for 19 above in the standard set of tests.
1944    
1945    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1946        reference to a subpattern the other side of a comment that contains an
1947        opening parenthesis caused either an internal compiling error, or a
1948        reference to the wrong subpattern.
1949    
1950    
1951    Version 8.02 19-Mar-2010
1952  ------------------------  ------------------------
1953    
1954  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
1955    
1956    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1957        configured.
1958    
1959    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1960        original author of that file, following a query about its status.
1961    
1962    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1963        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1964    
1965    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1966        quantifier applied to a forward-referencing subroutine call, could compile
1967        incorrect code or give the error "internal error: previously-checked
1968        referenced subpattern not found".
1969    
1970    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1971        variables to point to external functions. For these systems, therefore,
1972        pcre_malloc etc. are now initialized to local functions that call the
1973        relevant global functions.
1974    
1975    7.  There were two entries missing in the vectors called coptable and poptable
1976        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1977        I've fixed the data, and added a kludgy way of testing at compile time that
1978        the lengths are correct (equal to the number of opcodes).
1979    
1980    8.  Following on from 7, I added a similar kludge to check the length of the
1981        eint vector in pcreposix.c.
1982    
1983    9.  Error texts for pcre_compile() are held as one long string to avoid too
1984        much relocation at load time. To find a text, the string is searched,
1985        counting zeros. There was no check for running off the end of the string,
1986        which could happen if a new error number was added without updating the
1987        string.
1988    
1989    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1990    
1991    11. \K was not working if it appeared in an atomic group or in a group that
1992        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1993        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1994        the assertion is positive, but not if it is negative.
1995    
1996    12. Change 11 fortuitously reduced the size of the stack frame used in the
1997        "match()" function of pcre_exec.c by one pointer. Forthcoming
1998        implementation of support for (*MARK) will need an extra pointer on the
1999        stack; I have reserved it now, so that the stack frame size does not
2000        decrease.
2001    
2002    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
2003        item in branch that calls a recursion is a subroutine call - as in the
2004        second branch in the above example - was incorrectly given the compile-
2005        time error "recursive call could loop indefinitely" because pcre_compile()
2006        was not correctly checking the subroutine for matching a non-empty string.
2007    
2008    14. The checks for overrunning compiling workspace could trigger after an
2009        overrun had occurred. This is a "should never occur" error, but it can be
2010        triggered by pathological patterns such as hundreds of nested parentheses.
2011        The checks now trigger 100 bytes before the end of the workspace.
2012    
2013    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
2014    
2015    
2016  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
2017  ------------------------  ------------------------
# Line 333  Version 7.9 11-Apr-09 Line 2339  Version 7.9 11-Apr-09
2339  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
2340      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
2341      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2342      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2343        8.33.]
2344    
2345  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
2346      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 576  Version 7.7 07-May-08 Line 2583  Version 7.7 07-May-08
2583      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2584      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2585      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2586      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2587      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2588      was subsequently set up correctly.)      was subsequently set up correctly.)
2589    

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