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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 02-Aug-2011  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    18. A pattern with an unmatched closing parenthesis that contained a backward
75        assertion which itself contained a forward reference caused buffer
76        overflow. And example pattern is: /(?=di(?<=(?1))|(?=(.))))/.
77    
78    19. JIT should return with error when the compiled pattern requires more stack
79        space than the maximum.
80    
81    20. A possessively repeated conditional group that could match an empty string,
82        for example, /(?(R))*+/, was incorrectly compiled.
83    
84    21. Fix infinite recursion in the JIT compiler when certain patterns such as
85        /(?:|a|){100}x/ are analysed.
86    
87    22. Some patterns with character classes involving [: and \\ were incorrectly
88        compiled and could cause reading from uninitialized memory or an incorrect
89        error diagnosis.
90    
91    23. Pathological patterns containing many nested occurrences of [: caused
92        pcre_compile() to run for a very long time.
93    
94    24. A conditional group with only one branch has an implicit empty alternative
95        branch and must therefore be treated as potentially matching an empty
96        string.
97    
98    25. If (?R was followed by - or + incorrect behaviour happened instead of a
99        diagnostic.
100    
101    26. Arrange to give up on finding the minimum matching length for overly
102        complex patterns.
103    
104    27. Similar to (4) above: in a pattern with duplicated named groups and an
105        occurrence of (?| it is possible for an apparently non-recursive back
106        reference to become recursive if a later named group with the relevant
107        number is encountered. This could lead to a buffer overflow. Wen Guanxing
108        from Venustech ADLAB discovered this bug.
109    
110    
111    Version 8.37 28-April-2015
112    --------------------------
113    
114    1.  When an (*ACCEPT) is triggered inside capturing parentheses, it arranges
115        for those parentheses to be closed with whatever has been captured so far.
116        However, it was failing to mark any other groups between the hightest
117        capture so far and the currrent group as "unset". Thus, the ovector for
118        those groups contained whatever was previously there. An example is the
119        pattern /(x)|((*ACCEPT))/ when matched against "abcd".
120    
121    2.  If an assertion condition was quantified with a minimum of zero (an odd
122        thing to do, but it happened), SIGSEGV or other misbehaviour could occur.
123    
124    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
125        unrecognized modifier, a crash could occur.
126    
127    4.  An attempt to do global matching in pcretest with a zero-length ovector
128        caused a crash.
129    
130    5.  Fixed a memory leak during matching that could occur for a subpattern
131        subroutine call (recursive or otherwise) if the number of captured groups
132        that had to be saved was greater than ten.
133    
134    6.  Catch a bad opcode during auto-possessification after compiling a bad UTF
135        string with NO_UTF_CHECK. This is a tidyup, not a bug fix, as passing bad
136        UTF with NO_UTF_CHECK is documented as having an undefined outcome.
137    
138    7.  A UTF pattern containing a "not" match of a non-ASCII character and a
139        subroutine reference could loop at compile time. Example: /[^\xff]((?1))/.
140    
141    8. When a pattern is compiled, it remembers the highest back reference so that
142       when matching, if the ovector is too small, extra memory can be obtained to
143       use instead. A conditional subpattern whose condition is a check on a
144       capture having happened, such as, for example in the pattern
145       /^(?:(a)|b)(?(1)A|B)/, is another kind of back reference, but it was not
146       setting the highest backreference number. This mattered only if pcre_exec()
147       was called with an ovector that was too small to hold the capture, and there
148       was no other kind of back reference (a situation which is probably quite
149       rare). The effect of the bug was that the condition was always treated as
150       FALSE when the capture could not be consulted, leading to a incorrect
151       behaviour by pcre_exec(). This bug has been fixed.
152    
153    9. A reference to a duplicated named group (either a back reference or a test
154       for being set in a conditional) that occurred in a part of the pattern where
155       PCRE_DUPNAMES was not set caused the amount of memory needed for the pattern
156       to be incorrectly calculated, leading to overwriting.
157    
158    10. A mutually recursive set of back references such as (\2)(\1) caused a
159        segfault at study time (while trying to find the minimum matching length).
160        The infinite loop is now broken (with the minimum length unset, that is,
161        zero).
162    
163    11. If an assertion that was used as a condition was quantified with a minimum
164        of zero, matching went wrong. In particular, if the whole group had
165        unlimited repetition and could match an empty string, a segfault was
166        likely. The pattern (?(?=0)?)+ is an example that caused this. Perl allows
167        assertions to be quantified, but not if they are being used as conditions,
168        so the above pattern is faulted by Perl. PCRE has now been changed so that
169        it also rejects such patterns.
170    
171    12. A possessive capturing group such as (a)*+ with a minimum repeat of zero
172        failed to allow the zero-repeat case if pcre2_exec() was called with an
173        ovector too small to capture the group.
174    
175    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
176        Red Hat Product Security:
177    
178        (a) A crash if /K and /F were both set with the option to save the compiled
179        pattern.
180    
181        (b) Another crash if the option to print captured substrings in a callout
182        was combined with setting a null ovector, for example \O\C+ as a subject
183        string.
184    
185    14. A pattern such as "((?2){0,1999}())?", which has a group containing a
186        forward reference repeated a large (but limited) number of times within a
187        repeated outer group that has a zero minimum quantifier, caused incorrect
188        code to be compiled, leading to the error "internal error:
189        previously-checked referenced subpattern not found" when an incorrect
190        memory address was read. This bug was reported as "heap overflow",
191        discovered by Kai Lu of Fortinet's FortiGuard Labs and given the CVE number
192        CVE-2015-2325.
193    
194    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
195        call within a group that also contained a recursive back reference caused
196        incorrect code to be compiled. This bug was reported as "heap overflow",
197        discovered by Kai Lu of Fortinet's FortiGuard Labs, and given the CVE
198        number CVE-2015-2326.
199    
200    24. Computing the size of the JIT read-only data in advance has been a source
201        of various issues, and new ones are still appear unfortunately. To fix
202        existing and future issues, size computation is eliminated from the code,
203        and replaced by on-demand memory allocation.
204    
205    25. A pattern such as /(?i)[A-`]/, where characters in the other case are
206        adjacent to the end of the range, and the range contained characters with
207        more than one other case, caused incorrect behaviour when compiled in UTF
208        mode. In that example, the range a-j was left out of the class.
209    
210    26. Fix JIT compilation of conditional blocks, which assertion
211        is converted to (*FAIL). E.g: /(?(?!))/.
212    
213    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
214        discovered by the LLVM fuzzer.
215    
216    28. The assertion (?!) is optimized to (*FAIL). This was not handled correctly
217        when this assertion was used as a condition, for example (?(?!)a|b). In
218        pcre2_match() it worked by luck; in pcre2_dfa_match() it gave an incorrect
219        error about an unsupported item.
220    
221    29. For some types of pattern, for example /Z*(|d*){216}/, the auto-
222        possessification code could take exponential time to complete. A recursion
223        depth limit of 1000 has been imposed to limit the resources used by this
224        optimization.
225    
226    30. A pattern such as /(*UTF)[\S\V\H]/, which contains a negated special class
227        such as \S in non-UCP mode, explicit wide characters (> 255) can be ignored
228        because \S ensures they are all in the class. The code for doing this was
229        interacting badly with the code for computing the amount of space needed to
230        compile the pattern, leading to a buffer overflow. This bug was discovered
231        by the LLVM fuzzer.
232    
233    31. A pattern such as /((?2)+)((?1))/ which has mutual recursion nested inside
234        other kinds of group caused stack overflow at compile time. This bug was
235        discovered by the LLVM fuzzer.
236    
237    32. A pattern such as /(?1)(?#?'){8}(a)/ which had a parenthesized comment
238        between a subroutine call and its quantifier was incorrectly compiled,
239        leading to buffer overflow or other errors. This bug was discovered by the
240        LLVM fuzzer.
241    
242    33. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an
243        assertion after (?(. The code was failing to check the character after
244        (?(?< for the ! or = that would indicate a lookbehind assertion. This bug
245        was discovered by the LLVM fuzzer.
246    
247    34. A pattern such as /X((?2)()*+){2}+/ which has a possessive quantifier with
248        a fixed maximum following a group that contains a subroutine reference was
249        incorrectly compiled and could trigger buffer overflow. This bug was
250        discovered by the LLVM fuzzer.
251    
252    35. A mutual recursion within a lookbehind assertion such as (?<=((?2))((?1)))
253        caused a stack overflow instead of the diagnosis of a non-fixed length
254        lookbehind assertion. This bug was discovered by the LLVM fuzzer.
255    
256    36. The use of \K in a positive lookbehind assertion in a non-anchored pattern
257        (e.g. /(?<=\Ka)/) could make pcregrep loop.
258    
259    37. There was a similar problem to 36 in pcretest for global matches.
260    
261    38. If a greedy quantified \X was preceded by \C in UTF mode (e.g. \C\X*),
262        and a subsequent item in the pattern caused a non-match, backtracking over
263        the repeated \X did not stop, but carried on past the start of the subject,
264        causing reference to random memory and/or a segfault. There were also some
265        other cases where backtracking after \C could crash. This set of bugs was
266        discovered by the LLVM fuzzer.
267    
268    39. The function for finding the minimum length of a matching string could take
269        a very long time if mutual recursion was present many times in a pattern,
270        for example, /((?2){73}(?2))((?1))/. A better mutual recursion detection
271        method has been implemented. This infelicity was discovered by the LLVM
272        fuzzer.
273    
274    40. Static linking against the PCRE library using the pkg-config module was
275        failing on missing pthread symbols.
276    
277    
278    Version 8.36 26-September-2014
279    ------------------------------
280    
281    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
282        -Wmissing-field-initializers and -Wunused-parameter.
283    
284    2.  The tests for quantifiers being too big (greater than 65535) were being
285        applied after reading the number, and stupidly assuming that integer
286        overflow would give a negative number. The tests are now applied as the
287        numbers are read.
288    
289    3.  Tidy code in pcre_exec.c where two branches that used to be different are
290        now the same.
291    
292    4.  The JIT compiler did not generate match limit checks for certain
293        bracketed expressions with quantifiers. This may lead to exponential
294        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
295        issue should be resolved now.
296    
297    5.  Fixed an issue, which occures when nested alternatives are optimized
298        with table jumps.
299    
300    6.  Inserted two casts and changed some ints to size_t in the light of some
301        reported 64-bit compiler warnings (Bugzilla 1477).
302    
303    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
304        an empty string, which sometimes were behaving incorrectly in the
305        interpreter (though correctly in the JIT matcher). This pcretest input is
306        an example:
307    
308          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
309          NON QUOTED "QUOT""ED" AFTER "NOT MATCHED
310    
311        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
312        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
313        for an empty string was breaking the inner loop and carrying on at a lower
314        level, when possessive repeated groups should always return to a higher
315        level as they have no backtrack points in them. The empty string test now
316        occurs at the outer level.
317    
318    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
319        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
320    
321    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
322        doesn't).
323    
324    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
325        to hold a pattern to be incorrectly computed (too small) when there were
326        named back references to duplicated names. This could cause "internal
327        error: code overflow" or "double free or corruption" or other memory
328        handling errors.
329    
330    11. When named subpatterns had the same prefixes, back references could be
331        confused. For example, in this pattern:
332    
333          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
334    
335        the reference to 'Name' was incorrectly treated as a reference to a
336        duplicate name.
337    
338    12. A pattern such as /^s?c/mi8 where the optional character has more than
339        one "other case" was incorrectly compiled such that it would only try to
340        match starting at "c".
341    
342    13. When a pattern starting with \s was studied, VT was not included in the
343        list of possible starting characters; this should have been part of the
344        8.34/18 patch.
345    
346    14. If a character class started [\Qx]... where x is any character, the class
347        was incorrectly terminated at the ].
348    
349    15. If a pattern that started with a caseless match for a character with more
350        than one "other case" was studied, PCRE did not set up the starting code
351        unit bit map for the list of possible characters. Now it does. This is an
352        optimization improvement, not a bug fix.
353    
354    16. The Unicode data tables have been updated to Unicode 7.0.0.
355    
356    17. Fixed a number of memory leaks in pcregrep.
357    
358    18. Avoid a compiler warning (from some compilers) for a function call with
359        a cast that removes "const" from an lvalue by using an intermediate
360        variable (to which the compiler does not object).
361    
362    19. Incorrect code was compiled if a group that contained an internal recursive
363        back reference was optional (had quantifier with a minimum of zero). This
364        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
365        caused segmentation faults because of stack overflows at compile time.
366    
367    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
368        group that is quantified with an indefinite repeat, caused a compile-time
369        loop which used up all the system stack and provoked a segmentation fault.
370        This was not the same bug as 19 above.
371    
372    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
373        Patch by Mike Frysinger.
374    
375    
376    Version 8.35 04-April-2014
377    --------------------------
378    
379    1.  A new flag is set, when property checks are present in an XCLASS.
380        When this flag is not set, PCRE can perform certain optimizations
381        such as studying these XCLASS-es.
382    
383    2.  The auto-possessification of character sets were improved: a normal
384        and an extended character set can be compared now. Furthermore
385        the JIT compiler optimizes more character set checks.
386    
387    3.  Got rid of some compiler warnings for potentially uninitialized variables
388        that show up only when compiled with -O2.
389    
390    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
391        of a match later then the end of the match. The pcretest program was not
392        handling the case sensibly - it was outputting from the start to the next
393        binary zero. It now reports this situation in a message, and outputs the
394        text from the end to the start.
395    
396    5.  Fast forward search is improved in JIT. Instead of the first three
397        characters, any three characters with fixed position can be searched.
398        Search order: first, last, middle.
399    
400    6.  Improve character range checks in JIT. Characters are read by an inprecise
401        function now, which returns with an unknown value if the character code is
402        above a certain threshold (e.g: 256). The only limitation is that the value
403        must be bigger than the threshold as well. This function is useful when
404        the characters above the threshold are handled in the same way.
405    
406    7.  The macros whose names start with RAWUCHAR are placeholders for a future
407        mode in which only the bottom 21 bits of 32-bit data items are used. To
408        make this more memorable for those maintaining the code, the names have
409        been changed to start with UCHAR21, and an extensive comment has been added
410        to their definition.
411    
412    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
413        to the export list in Makefile.am (they were accidentally omitted from the
414        8.34 tarball).
415    
416    9.  The informational output from pcretest used the phrase "starting byte set"
417        which is inappropriate for the 16-bit and 32-bit libraries. As the output
418        for "first char" and "need char" really means "non-UTF-char", I've changed
419        "byte" to "char", and slightly reworded the output. The documentation about
420        these values has also been (I hope) clarified.
421    
422    10. Another JIT related optimization: use table jumps for selecting the correct
423        backtracking path, when more than four alternatives are present inside a
424        bracket.
425    
426    11. Empty match is not possible, when the minimum length is greater than zero,
427        and there is no \K in the pattern. JIT should avoid empty match checks in
428        such cases.
429    
430    12. In a caseless character class with UCP support, when a character with more
431        than one alternative case was not the first character of a range, not all
432        the alternative cases were added to the class. For example, s and \x{17f}
433        are both alternative cases for S: the class [RST] was handled correctly,
434        but [R-T] was not.
435    
436    13. The configure.ac file always checked for pthread support when JIT was
437        enabled. This is not used in Windows, so I have put this test inside a
438        check for the presence of windows.h (which was already tested for).
439    
440    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
441        The algorithm provides a way to skip certain starting offsets, and usually
442        faster than linear prefix searches.
443    
444    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
445        as for 'fr_FR' and 'french'. For some reason, however, it then used the
446        Windows-specific input and output files, which have 'french' screwed in.
447        So this could never have worked. One of the problems with locales is that
448        they aren't always the same. I have now updated RunTest so that it checks
449        the output of the locale test (test 3) against three different output
450        files, and it allows the test to pass if any one of them matches. With luck
451        this should make the test pass on some versions of Solaris where it was
452        failing. Because of the uncertainty, the script did not used to stop if
453        test 3 failed; it now does. If further versions of a French locale ever
454        come to light, they can now easily be added.
455    
456    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
457        there was a message during ./configure, but it did not stop. This now
458        provokes an error. The invalid example in README has been corrected.
459        If a value less than the minimum is given, the minimum value has always
460        been used, but now a warning is given.
461    
462    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
463        was a bug in the test system, which is now fixed. Also, the list of various
464        configurations that are tested for each release did not have one with both
465        16/32 bits and --enable-bar-anycrlf. It now does.
466    
467    18. pcretest was missing "-C bsr" for displaying the \R default setting.
468    
469    19. Little endian PowerPC systems are supported now by the JIT compiler.
470    
471    20. The fast forward newline mechanism could enter to an infinite loop on
472        certain invalid UTF-8 input. Although we don't support these cases
473        this issue can be fixed by a performance optimization.
474    
475    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
476        not take account if existing stack usage. There is now a new global
477        variable called pcre_stack_guard that can be set to point to an external
478        function to check stack availability. It is called at the start of
479        processing every parenthesized group.
480    
481    22. A typo in the code meant that in ungreedy mode the max/min qualifier
482        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
483        not match "ab".
484    
485    23. When UTF was disabled, the JIT program reported some incorrect compile
486        errors. These messages are silenced now.
487    
488    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
489        compiler.
490    
491    25. Change all the temporary files used in RunGrepTest to be different to those
492        used by RunTest so that the tests can be run simultaneously, for example by
493        "make -j check".
494    
495    
496    Version 8.34 15-December-2013
497    -----------------------------
498    
499    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
500        executable memory. Patch inspired by Carsten Klein.
501    
502    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
503        this macro is never tested and has no effect, because the work to support
504        coverage involves only compiling and linking options and special targets in
505        the Makefile. The comment in config.h implied that defining the macro would
506        enable coverage support, which is totally false. There was also support for
507        setting this macro in the CMake files (my fault, I just copied it from
508        configure). SUPPORT_GCOV has now been removed.
509    
510    3.  Make a small performance improvement in strlen16() and strlen32() in
511        pcretest.
512    
513    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
514        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
515        these cases). There was also one in pcretest.c.
516    
517    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
518    
519    6.  In UTF mode, the code for checking whether a group could match an empty
520        string (which is used for indefinitely repeated groups to allow for
521        breaking an infinite loop) was broken when the group contained a repeated
522        negated single-character class with a character that occupied more than one
523        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
524        UTF-8 mode). The effect was undefined: the group might or might not be
525        deemed as matching an empty string, or the program might have crashed.
526    
527    7.  The code for checking whether a group could match an empty string was not
528        recognizing that \h, \H, \v, \V, and \R must match a character.
529    
530    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
531        an empty string. If it can, pcretest shows this in its information output.
532    
533    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
534        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
535        matched by pcre_exec() without using JIT:
536    
537        (a) If the rest of the pattern did not match after a maximal run of
538            grapheme clusters, the code for backing up to try with fewer of them
539            did not always back up over a full grapheme when characters that do not
540            have the modifier quality were involved, e.g. Hangul syllables.
541    
542        (b) If the match point in a subject started with modifier character, and
543            there was no match, the code could incorrectly back up beyond the match
544            point, and potentially beyond the first character in the subject,
545            leading to a segfault or an incorrect match result.
546    
547    10. A conditional group with an assertion condition could lead to PCRE
548        recording an incorrect first data item for a match if no other first data
549        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
550        first data item, and therefore matched "ca" after "c" instead of at the
551        start.
552    
553    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
554        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
555    
556    12. The source of pcregrep now includes z/OS-specific code so that it can be
557        compiled for z/OS as part of the special z/OS distribution.
558    
559    13. Added the -T and -TM options to pcretest.
560    
561    14. The code in pcre_compile.c for creating the table of named capturing groups
562        has been refactored. Instead of creating the table dynamically during the
563        actual compiling pass, the information is remembered during the pre-compile
564        pass (on the stack unless there are more than 20 named groups, in which
565        case malloc() is used) and the whole table is created before the actual
566        compile happens. This has simplified the code (it is now nearly 150 lines
567        shorter) and prepared the way for better handling of references to groups
568        with duplicate names.
569    
570    15. A back reference to a named subpattern when there is more than one of the
571        same name now checks them in the order in which they appear in the pattern.
572        The first one that is set is used for the reference. Previously only the
573        first one was inspected. This change makes PCRE more compatible with Perl.
574    
575    16. Unicode character properties were updated from Unicode 6.3.0.
576    
577    17. The compile-time code for auto-possessification has been refactored, based
578        on a patch by Zoltan Herczeg. It now happens after instead of during
579        compilation. The code is cleaner, and more cases are handled. The option
580        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
581        options in pcretest are provided to set it. It can also be set by
582        (*NO_AUTO_POSSESS) at the start of a pattern.
583    
584    18. The character VT has been added to the default ("C" locale) set of
585        characters that match \s and are generally treated as white space,
586        following this same change in Perl 5.18. There is now no difference between
587        "Perl space" and "POSIX space". Whether VT is treated as white space in
588        other locales depends on the locale.
589    
590    19. The code for checking named groups as conditions, either for being set or
591        for being recursed, has been refactored (this is related to 14 and 15
592        above). Processing unduplicated named groups should now be as fast at
593        numerical groups, and processing duplicated groups should be faster than
594        before.
595    
596    20. Two patches to the CMake build system, by Alexander Barkov:
597    
598          (1) Replace the "source" command by "." in CMakeLists.txt because
599              "source" is a bash-ism.
600    
601          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
602              without these the CMake build does not work on Solaris.
603    
604    21. Perl has changed its handling of \8 and \9. If there is no previously
605        encountered capturing group of those numbers, they are treated as the
606        literal characters 8 and 9 instead of a binary zero followed by the
607        literals. PCRE now does the same.
608    
609    22. Following Perl, added \o{} to specify codepoints in octal, making it
610        possible to specify values greater than 0777 and also making them
611        unambiguous.
612    
613    23. Perl now gives an error for missing closing braces after \x{... instead of
614        treating the string as literal. PCRE now does the same.
615    
616    24. RunTest used to grumble if an inappropriate test was selected explicitly,
617        but just skip it when running all tests. This make it awkward to run ranges
618        of tests when one of them was inappropriate. Now it just skips any
619        inappropriate tests, as it always did when running all tests.
620    
621    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
622        character types such as \d or \w, too many callouts were inserted, and the
623        data that they returned was rubbish.
624    
625    26. In UCP mode, \s was not matching two of the characters that Perl matches,
626        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
627        were matched by \h. The code has now been refactored so that the lists of
628        the horizontal and vertical whitespace characters used for \h and \v (which
629        are defined only in one place) are now also used for \s.
630    
631    27. Add JIT support for the 64 bit TileGX architecture.
632        Patch by Jiong Wang (Tilera Corporation).
633    
634    28. Possessive quantifiers for classes (both explicit and automatically
635        generated) now use special opcodes instead of wrapping in ONCE brackets.
636    
637    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
638        (because it's meaningless), this was not happening when PCRE_CASELESS was
639        set. Not wrong, but inefficient.
640    
641    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
642        properties for \w, \d, etc) is present in a test regex. Otherwise if the
643        test contains no characters greater than 255, Perl doesn't realise it
644        should be using Unicode semantics.
645    
646    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
647        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
648        does in Unicode mode.
649    
650    32. Added the "forbid" facility to pcretest so that putting tests into the
651        wrong test files can sometimes be quickly detected.
652    
653    33. There is now a limit (default 250) on the depth of nesting of parentheses.
654        This limit is imposed to control the amount of system stack used at compile
655        time. It can be changed at build time by --with-parens-nest-limit=xxx or
656        the equivalent in CMake.
657    
658    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
659        errors. Perl warns for these when in warning mode, but PCRE has no facility
660        for giving warnings.
661    
662    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
663        However, this was not working for (?!) because it is optimized to (*FAIL),
664        for which PCRE does not allow quantifiers. The optimization is now disabled
665        when a quantifier follows (?!). I can't see any use for this, but it makes
666        things uniform.
667    
668    36. Perl no longer allows group names to start with digits, so I have made this
669        change also in PCRE. It simplifies the code a bit.
670    
671    37. In extended mode, Perl ignores spaces before a + that indicates a
672        possessive quantifier. PCRE allowed a space before the quantifier, but not
673        before the possessive +. It now does.
674    
675    38. The use of \K (reset reported match start) within a repeated possessive
676        group such as (a\Kb)*+ was not working.
677    
678    40. Document that the same character tables must be used at compile time and
679        run time, and that the facility to pass tables to pcre_exec() and
680        pcre_dfa_exec() is for use only with saved/restored patterns.
681    
682    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
683        features for Builds with MSVC:
684    
685        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
686           builds). The .rc files can be used to set FileDescription and many other
687           attributes.
688    
689        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
690           This allows higher-level build scripts which want .pdb files to avoid
691           hard-coding the exact files needed."
692    
693    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
694        mean "start of word" and "end of word", respectively, as a transition aid.
695    
696    43. A minimizing repeat of a class containing codepoints greater than 255 in
697        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
698        compiled to use the heap for recursion.
699    
700    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
701        is configured.
702    
703    
704    Version 8.33 28-May-2013
705    ------------------------
706    
707    1.  Added 'U' to some constants that are compared to unsigned integers, to
708        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
709        variables that are added to signed variables, to ensure the result is
710        signed and can be negated.
711    
712    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
713        CMake config files.
714    
715    3.  Revise the creation of config.h.generic so that all boolean macros are
716        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
717        overriding via -D on the command line possible.
718    
719    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
720        to unsigned int is reported to make a quite noticeable speed difference in
721        a specific Windows environment. Testing on Linux did also appear to show
722        some benefit (and it is clearly not harmful). Also fixed the definition of
723        Xop which should be unsigned.
724    
725    5.  Related to (4), changing the definition of the intermediate variable cc
726        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
727        improvements.
728    
729    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
730        unnecessary spaces.
731    
732    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
733        and later.
734    
735    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
736    
737    9.  Optimizing fast_forward_start_bits in JIT.
738    
739    10. Adding support for callouts in JIT, and fixing some issues revealed
740        during this work. Namely:
741    
742        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
743    
744        (b) Minimum length was not checked before the matching is started.
745    
746    11. The value of capture_last that is passed to callouts was incorrect in some
747        cases when there was a capture on one path that was subsequently abandoned
748        after a backtrack. Also, the capture_last value is now reset after a
749        recursion, since all captures are also reset in this case.
750    
751    12. The interpreter no longer returns the "too many substrings" error in the
752        case when an overflowing capture is in a branch that is subsequently
753        abandoned after a backtrack.
754    
755    13. In the pathological case when an offset vector of size 2 is used, pcretest
756        now prints out the matched string after a yield of 0 or 1.
757    
758    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
759        Only supported by the JIT compiler at the moment.
760    
761    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
762    
763    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
764        offset of the starting point of the matching process, provided the offsets
765        vector is large enough.
766    
767    17. The \A escape now records a lookbehind value of 1, though its execution
768        does not actually inspect the previous character. This is to ensure that,
769        in partial multi-segment matching, at least one character from the old
770        segment is retained when a new segment is processed. Otherwise, if there
771        are no lookbehinds in the pattern, \A might match incorrectly at the start
772        of a new segment.
773    
774    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
775    
776    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
777        gives some modest performance improvement in 8-bit mode.
778    
779    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
780        be expressed in certain programming languages using Universal Character
781        Names.
782    
783    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
784        which points out that "non characters" are not "characters that may not
785        appear in Unicode strings" but rather "characters that are reserved for
786        internal use and have only local meaning".
787    
788    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
789        there was a conditional group that depended on an assertion, if the
790        assertion was false, the callout that immediately followed the alternation
791        in the condition was skipped when pcre_exec() was used for matching.
792    
793    23. Allow an explicit callout to be inserted before an assertion that is the
794        condition for a conditional group, for compatibility with automatic
795        callouts, which always insert a callout at this point.
796    
797    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
798        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
799    
800    25. (*PRUNE) is now supported by the JIT compiler.
801    
802    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
803    
804    27. Fix the case where there are two or more SKIPs with arguments that may be
805        ignored.
806    
807    28. (*SKIP) is now supported by the JIT compiler.
808    
809    29. (*THEN) is now supported by the JIT compiler.
810    
811    30. Update RunTest with additional test selector options.
812    
813    31. The way PCRE handles backtracking verbs has been changed in two ways.
814    
815        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
816        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
817        backtracking. In some cases this makes it more Perl-compatible, but Perl's
818        rather obscure rules do not always do the same thing.
819    
820        (2) Previously, backtracking verbs were confined within assertions. This is
821        no longer the case for positive assertions, except for (*ACCEPT). Again,
822        this sometimes improves Perl compatibility, and sometimes does not.
823    
824    32. A number of tests that were in test 2 because Perl did things differently
825        have been moved to test 1, because either Perl or PCRE has changed, and
826        these tests are now compatible.
827    
828    32. Backtracking control verbs are now handled in the same way in JIT and
829        interpreter.
830    
831    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
832        contained a forward subroutine reference caused a compile error.
833    
834    34. Auto-detect and optimize limited repetitions in JIT.
835    
836    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
837        blocking (*UTF) etc.
838    
839    36. In the interpreter, maximizing pattern repetitions for characters and
840        character types now use tail recursion, which reduces stack usage.
841    
842    37. The value of the max lookbehind was not correctly preserved if a compiled
843        and saved regex was reloaded on a host of different endianness.
844    
845    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
846        of the compiled pattern block, expand the flags field from 16 to 32 bits
847        because it was almost full.
848    
849    39. Try madvise first before posix_madvise.
850    
851    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
852        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
853        original change locked out all matches of empty strings. This has been
854        changed so that one match of an empty string per line is recognized.
855        Subsequent searches on the same line (for colouring or for --only-matching,
856        for example) do not recognize empty strings.
857    
858    41. Applied a user patch to fix a number of spelling mistakes in comments.
859    
860    42. Data lines longer than 65536 caused pcretest to crash.
861    
862    43. Clarified the data type for length and startoffset arguments for pcre_exec
863        and pcre_dfa_exec in the function-specific man pages, where they were
864        explicitly stated to be in bytes, never having been updated. I also added
865        some clarification to the pcreapi man page.
866    
867    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
868        a segmentation fault.
869    
870    
871    Version 8.32 30-November-2012
872    -----------------------------
873    
874    1.  Improved JIT compiler optimizations for first character search and single
875        character iterators.
876    
877    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
878        Patch by Daniel Richard G.
879    
880    3.  Single character iterator optimizations in the JIT compiler.
881    
882    4.  Improved JIT compiler optimizations for character ranges.
883    
884    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
885        Reported by Giuseppe D'Angelo.
886    
887    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
888        of a line, was being set incorrectly in cases where .* appeared inside
889        atomic brackets at the start of a pattern, or where there was a subsequent
890        *PRUNE or *SKIP.
891    
892    7.  Improved instruction cache flush for POWER/PowerPC.
893        Patch by Daniel Richard G.
894    
895    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
896        grep:
897    
898        (a) There is now no limit to the number of patterns to be matched.
899    
900        (b) An error is given if a pattern is too long.
901    
902        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
903            are now supported.
904    
905        (d) --exclude-from and --include-from (multiple use) have been added.
906    
907        (e) Exclusions and inclusions now apply to all files and directories, not
908            just to those obtained from scanning a directory recursively.
909    
910        (f) Multiple uses of -f and --file-list are now supported.
911    
912        (g) In a Windows environment, the default for -d has been changed from
913            "read" (the GNU grep default) to "skip", because otherwise the presence
914            of a directory in the file list provokes an error.
915    
916        (h) The documentation has been revised and clarified in places.
917    
918    9.  Improve the matching speed of capturing brackets.
919    
920    10. Changed the meaning of \X so that it now matches a Unicode extended
921        grapheme cluster.
922    
923    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
924        out POSIX threads when JIT support is configured.
925    
926    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
927    
928    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
929        structure could go wrong in environments where size_t is not the same size
930        as int.
931    
932    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
933        set.
934    
935    15. The EBCDIC support had decayed; later updates to the code had included
936        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
937        general tidy up of EBCDIC-related issues, and the documentation was also
938        not quite right. There is now a test that can be run on ASCII systems to
939        check some of the EBCDIC-related things (but is it not a full test).
940    
941    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
942        in a small tidy to the code.
943    
944    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
945    
946    18. If the --only-matching (-o) option in pcregrep is specified multiple
947        times, each one causes appropriate output. For example, -o1 -o2 outputs the
948        substrings matched by the 1st and 2nd capturing parentheses. A separating
949        string can be specified by --om-separator (default empty).
950    
951    19. Improving the first n character searches.
952    
953    20. Turn case lists for horizontal and vertical white space into macros so that
954        they are defined only once.
955    
956    21. This set of changes together give more compatible Unicode case-folding
957        behaviour for characters that have more than one other case when UCP
958        support is available.
959    
960        (a) The Unicode property table now has offsets into a new table of sets of
961            three or more characters that are case-equivalent. The MultiStage2.py
962            script that generates these tables (the pcre_ucd.c file) now scans
963            CaseFolding.txt instead of UnicodeData.txt for character case
964            information.
965    
966        (b) The code for adding characters or ranges of characters to a character
967            class has been abstracted into a generalized function that also handles
968            case-independence. In UTF-mode with UCP support, this uses the new data
969            to handle characters with more than one other case.
970    
971        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
972            whose other case is greater than 256 are now correctly matched
973            caselessly. Previously, the high codepoint matched the low one, but not
974            vice versa.
975    
976        (d) The processing of \h, \H, \v, and \ in character classes now makes use
977            of the new class addition function, using character lists defined as
978            macros alongside the case definitions of 20 above.
979    
980        (e) Caseless back references now work with characters that have more than
981            one other case.
982    
983        (f) General caseless matching of characters with more than one other case
984            is supported.
985    
986    22. Unicode character properties were updated from Unicode 6.2.0
987    
988    23. Improved CMake support under Windows. Patch by Daniel Richard G.
989    
990    24. Add support for 32-bit character strings, and UTF-32
991    
992    25. Major JIT compiler update (code refactoring and bugfixing).
993        Experimental Sparc 32 support is added.
994    
995    26. Applied a modified version of Daniel Richard G's patch to create
996        pcre.h.generic and config.h.generic by "make" instead of in the
997        PrepareRelease script.
998    
999    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
1000        pcre_compile.c when checking for a zero character.
1001    
1002    28. Introducing a native interface for JIT. Through this interface, the compiled
1003        machine code can be directly executed. The purpose of this interface is to
1004        provide fast pattern matching, so several sanity checks are not performed.
1005        However, feature tests are still performed. The new interface provides
1006        1.4x speedup compared to the old one.
1007    
1008    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
1009        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
1010        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
1011    
1012    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
1013        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
1014        the "old" RFC 2279). Instead, it ended up passing a negative length to
1015        pcre_exec().
1016    
1017    31. Add support for GCC's visibility feature to hide internal functions.
1018    
1019    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
1020        "unknown -C option" after outputting 0 or 1.
1021    
1022    33. There is now support for generating a code coverage report for the test
1023        suite in environments where gcc is the compiler and lcov is installed. This
1024        is mainly for the benefit of the developers.
1025    
1026    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
1027        unaddressable using valgrind annotations, allowing valgrind to detect
1028        invalid memory accesses. This is mainly for the benefit of the developers.
1029    
1030    25. (*UTF) can now be used to start a pattern in any of the three libraries.
1031    
1032    26. Give configure error if --enable-cpp but no C++ compiler found.
1033    
1034    
1035    Version 8.31 06-July-2012
1036    -------------------------
1037    
1038    1.  Fixing a wrong JIT test case and some compiler warnings.
1039    
1040    2.  Removed a bashism from the RunTest script.
1041    
1042    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
1043        to unsigned type, result still unsigned" that was given by an MS compiler
1044        on encountering the code "-sizeof(xxx)".
1045    
1046    4.  Partial matching support is added to the JIT compiler.
1047    
1048    5.  Fixed several bugs concerned with partial matching of items that consist
1049        of more than one character:
1050    
1051        (a) /^(..)\1/ did not partially match "aba" because checking references was
1052            done on an "all or nothing" basis. This also applied to repeated
1053            references.
1054    
1055        (b) \R did not give a hard partial match if \r was found at the end of the
1056            subject.
1057    
1058        (c) \X did not give a hard partial match after matching one or more
1059            characters at the end of the subject.
1060    
1061        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
1062            a partial match for the string "\r".
1063    
1064        (e) When newline was set to CRLF, the metacharacter "." did not recognize
1065            a partial match for a CR character at the end of the subject string.
1066    
1067    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
1068        running pcretest, the text "(JIT)" added to the output whenever JIT is
1069        actually used to run the match.
1070    
1071    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
1072        or /S+[+] with a digit between 1 and 7.
1073    
1074    8.  OP_NOT now supports any UTF character not just single-byte ones.
1075    
1076    9.  (*MARK) control verb is now supported by the JIT compiler.
1077    
1078    10. The command "./RunTest list" lists the available tests without actually
1079        running any of them. (Because I keep forgetting what they all are.)
1080    
1081    11. Add PCRE_INFO_MAXLOOKBEHIND.
1082    
1083    12. Applied a (slightly modified) user-supplied patch that improves performance
1084        when the heap is used for recursion (compiled with --disable-stack-for-
1085        recursion). Instead of malloc and free for each heap frame each time a
1086        logical recursion happens, frames are retained on a chain and re-used where
1087        possible. This sometimes gives as much as 30% improvement.
1088    
1089    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
1090        call.
1091    
1092    14. As documented, (*COMMIT) is now confined to within a positive assertion.
1093    
1094    15. It is now possible to link pcretest with libedit as an alternative to
1095        libreadline.
1096    
1097    16. (*COMMIT) control verb is now supported by the JIT compiler.
1098    
1099    17. The Unicode data tables have been updated to Unicode 6.1.0.
1100    
1101    18. Added --file-list option to pcregrep.
1102    
1103    19. Added binary file support to pcregrep, including the -a, --binary-files,
1104        -I, and --text options.
1105    
1106    20. The madvise function is renamed for posix_madvise for QNX compatibility
1107        reasons. Fixed by Giuseppe D'Angelo.
1108    
1109    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
1110    
1111    22. Changed the option for creating symbolic links for 16-bit man pages from
1112        -s to -sf so that re-installing does not cause issues.
1113    
1114    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
1115    
1116    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
1117        matches in certain environments (the workspace was not being correctly
1118        retained). Also added to pcre_dfa_exec() a simple plausibility check on
1119        some of the workspace data at the beginning of a restart.
1120    
1121    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
1122        was not doing so when it should - probably a typo introduced by SVN 528
1123        (change 8.10/14).
1124    
1125    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
1126        \w+ when the character tables indicated that \x{c4} was a word character.
1127        There were several related cases, all because the tests for doing a table
1128        lookup were testing for characters less than 127 instead of 255.
1129    
1130    27. If a pattern contains capturing parentheses that are not used in a match,
1131        their slots in the ovector are set to -1. For those that are higher than
1132        any matched groups, this happens at the end of processing. In the case when
1133        there were back references that the ovector was too small to contain
1134        (causing temporary malloc'd memory to be used during matching), and the
1135        highest capturing number was not used, memory off the end of the ovector
1136        was incorrectly being set to -1. (It was using the size of the temporary
1137        memory instead of the true size.)
1138    
1139    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
1140        ovector size, it uses memory at the end of the block that it has got.
1141    
1142    29. Check for an overlong MARK name and give an error at compile time. The
1143        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
1144    
1145    30. JIT compiler update.
1146    
1147    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
1148        Rill for the patch.
1149    
1150    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
1151    
1152    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
1153    
1154    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
1155        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
1156        was enabled.
1157    
1158    35. Improve JIT code generation for greedy plus quantifier.
1159    
1160    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
1161        1 to "aa" instead of to an empty string. The bug affected repeated groups
1162        that could potentially match an empty string.
1163    
1164    37. Optimizing single character iterators in JIT.
1165    
1166    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
1167        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
1168        codepoints that are too big for the mode are faulted, and in a UTF mode,
1169        disallowed codepoints are also faulted.
1170    
1171    39. If PCRE was compiled with UTF support, in three places in the DFA
1172        matcher there was code that should only have been obeyed in UTF mode, but
1173        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
1174        processing when bytes with values greater than 127 were present. In 16-bit
1175        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
1176        both cases the values are those that cannot be the first data item in a UTF
1177        character. The three items that might have provoked this were recursions,
1178        possessively repeated groups, and atomic groups.
1179    
1180    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
1181        and pcregrep, because some OS require shared objects to be explicitly
1182        passed to ld, causing the link step to fail if they are not.
1183    
1184    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
1185        mode, patterns that started with \h* or \R* might be incorrectly matched.
1186    
1187    
1188    Version 8.30 04-February-2012
1189    -----------------------------
1190    
1191    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
1192        name is defined in ctype.h.
1193    
1194    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
1195        only in quite long subpatterns.
1196    
1197    3.  Removed the function pcre_info(), which has been obsolete and deprecated
1198        since it was replaced by pcre_fullinfo() in February 2000.
1199    
1200    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
1201        match a (*MARK), and the match failed at the start of the subject, a
1202        reference to memory before the start of the subject could occur. This bug
1203        was introduced by fix 17 of release 8.21.
1204    
1205    5.  A reference to an unset group with zero minimum repetition was giving
1206        totally wrong answers (in non-JavaScript-compatibility mode). For example,
1207        /(another)?(\1?)test/ matched against "hello world test". This bug was
1208        introduced in release 8.13.
1209    
1210    6.  Add support for 16-bit character strings (a large amount of work involving
1211        many changes and refactorings).
1212    
1213    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
1214        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
1215        from a file.
1216    
1217    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
1218        rounding is not applied in this particular case).
1219    
1220    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
1221        if they appear, or are escaped, in patterns.
1222    
1223    10. Get rid of a number of -Wunused-but-set-variable warnings.
1224    
1225    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
1226        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
1227        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
1228        also returns the mark "x". This bug applied to capturing parentheses,
1229        non-capturing parentheses, and atomic parentheses. It also applied to some
1230        assertions.
1231    
1232    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
1233        information out of configure.ac instead of relying on pcre.h.generic, which
1234        is not stored in the repository.
1235    
1236    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
1237        -lreadline.
1238    
1239    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
1240    
1241    15. Applied Graycode's patch to put the top-level frame on the stack rather
1242        than the heap when not using the stack for recursion. This gives a
1243        performance improvement in many cases when recursion is not deep.
1244    
1245    16. Experimental code added to "pcretest -C" to output the stack frame size.
1246    
1247    
1248    Version 8.21 12-Dec-2011
1249    ------------------------
1250    
1251    1.  Updating the JIT compiler.
1252    
1253    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1254        are added as well.
1255    
1256    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1257        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1258        calling _pcre_jit_exec. Some extra comments are added.
1259    
1260    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1261        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1262        was introduced by change 18 for 8.20.
1263    
1264    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1265        ECMA-262 standard.
1266    
1267    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1268        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1269        This bug was probably introduced by change 9 of 8.13.
1270    
1271    7.  While fixing 6 above, I noticed that a number of other items were being
1272        incorrectly rejected as "not fixed length". This arose partly because newer
1273        opcodes had not been added to the fixed-length checking code. I have (a)
1274        corrected the bug and added tests for these items, and (b) arranged for an
1275        error to occur if an unknown opcode is encountered while checking for fixed
1276        length instead of just assuming "not fixed length". The items that were
1277        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1278        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1279        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1280    
1281    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1282        being incorrectly compiled and would have given unpredicatble results.
1283    
1284    9.  A possessively repeated subpattern with minimum repeat count greater than
1285        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1286        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1287        the first (A) could occur when it should not.
1288    
1289    10. Add a cast and remove a redundant test from the code.
1290    
1291    11. JIT should use pcre_malloc/pcre_free for allocation.
1292    
1293    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1294        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1295        is anything other than /usr, -L is still shown).
1296    
1297    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1298    
1299    14. Perl does not support \N without a following name in a [] class; PCRE now
1300        also gives an error.
1301    
1302    15. If a forward reference was repeated with an upper limit of around 2000,
1303        it caused the error "internal error: overran compiling workspace". The
1304        maximum number of forward references (including repeats) was limited by the
1305        internal workspace, and dependent on the LINK_SIZE. The code has been
1306        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1307        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1308        of around 200,000 forward references. While doing this, I also speeded up
1309        the filling in of repeated forward references.
1310    
1311    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1312        incorrectly expecting the subject to contain another "a" after the start.
1313    
1314    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1315        in the match, the SKIP should be ignored. This was not happening; instead
1316        the SKIP was being treated as NOMATCH. For patterns such as
1317        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1318        tested.
1319    
1320    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1321        now much more compatible with Perl, in particular in cases where the result
1322        is a non-match for a non-anchored pattern. For example, if
1323        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1324        "m", where previously it did not return a name. A side effect of this
1325        change is that for partial matches, the last encountered mark name is
1326        returned, as for non matches. A number of tests that were previously not
1327        Perl-compatible have been moved into the Perl-compatible test files. The
1328        refactoring has had the pleasing side effect of removing one argument from
1329        the match() function, thus reducing its stack requirements.
1330    
1331    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1332        subsequent uses of /S (without +) incorrectly behaved like /S+.
1333    
1334    21. Retrieve executable code size support for the JIT compiler and fixing
1335        some warnings.
1336    
1337    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1338        not work when the shorter character appeared right at the end of the
1339        subject string.
1340    
1341    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1342        systems.
1343    
1344    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1345        output it when the /M option is used in pcretest.
1346    
1347    25. The CheckMan script was not being included in the distribution. Also, added
1348        an explicit "perl" to run Perl scripts from the PrepareRelease script
1349        because this is reportedly needed in Windows.
1350    
1351    26. If study data was being save in a file and studying had not found a set of
1352        "starts with" bytes for the pattern, the data written to the file (though
1353        never used) was taken from uninitialized memory and so caused valgrind to
1354        complain.
1355    
1356    27. Updated RunTest.bat as provided by Sheri Pierce.
1357    
1358    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1359    
1360    29. Computation of memory usage for the table of capturing group names was
1361        giving an unnecessarily large value.
1362    
1363    
1364    Version 8.20 21-Oct-2011
1365    ------------------------
1366    
1367    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1368        a POSIX class. After further experiments with Perl, which convinced me that
1369        Perl has bugs and confusions, a closing square bracket is no longer allowed
1370        in a POSIX name. This bug also affected patterns with classes that started
1371        with full stops.
1372    
1373    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1374        captured substring, but while checking the failing first alternative,
1375        substring 1 is temporarily captured. If the output vector supplied to
1376        pcre_exec() was not big enough for this capture, the yield of the function
1377        was still zero ("insufficient space for captured substrings"). This cannot
1378        be totally fixed without adding another stack variable, which seems a lot
1379        of expense for a edge case. However, I have improved the situation in cases
1380        such as /(a)(b)x|abc/ matched against "abc", where the return code
1381        indicates that fewer than the maximum number of slots in the ovector have
1382        been set.
1383    
1384    3.  Related to (2) above: when there are more back references in a pattern than
1385        slots in the output vector, pcre_exec() uses temporary memory during
1386        matching, and copies in the captures as far as possible afterwards. It was
1387        using the entire output vector, but this conflicts with the specification
1388        that only 2/3 is used for passing back captured substrings. Now it uses
1389        only the first 2/3, for compatibility. This is, of course, another edge
1390        case.
1391    
1392    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1393        main code base, and can be used by building with --enable-jit. When this is
1394        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1395        runtime --no-jit option is given.
1396    
1397    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1398        ovector, the return from the function was zero, implying that there were
1399        other matches that did not fit. The correct "exactly full" value is now
1400        returned.
1401    
1402    6.  If a subpattern that was called recursively or as a subroutine contained
1403        (*PRUNE) or any other control that caused it to give a non-standard return,
1404        invalid errors such as "Error -26 (nested recursion at the same subject
1405        position)" or even infinite loops could occur.
1406    
1407    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1408        computing the minimum length on reaching *ACCEPT, and so ended up with the
1409        wrong value of 1 rather than 0. Further investigation indicates that
1410        computing a minimum subject length in the presence of *ACCEPT is difficult
1411        (think back references, subroutine calls), and so I have changed the code
1412        so that no minimum is registered for a pattern that contains *ACCEPT.
1413    
1414    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1415        it was not handled as intended. [But see 16 below.]
1416    
1417    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1418        Sheri Pierce.
1419    
1420    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1421        the first byte in a match must be "a".
1422    
1423    11. Change 17 for 8.13 increased the recursion depth for patterns like
1424        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1425        pattern contains any instances of (*THEN). If it does not, the old
1426        optimizations are restored. It would be nice to do this on a per-group
1427        basis, but at the moment that is not feasible.
1428    
1429    12. In some environments, the output of pcretest -C is CRLF terminated. This
1430        broke RunTest's code that checks for the link size. A single white space
1431        character after the value is now allowed for.
1432    
1433    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1434        For "fr", it uses the Windows-specific input and output files.
1435    
1436    14. If (*THEN) appeared in a group that was called recursively or as a
1437        subroutine, it did not work as intended. [But see next item.]
1438    
1439    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1440        pattern fragments (but not containing any | characters). If A and B are
1441        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1442        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1443        D. In other words, Perl considers parentheses that do not contain any |
1444        characters to be part of a surrounding alternative, whereas PCRE was
1445        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1446        differently. PCRE now behaves in the same way as Perl, except in the case
1447        of subroutine/recursion calls such as (?1) which have in any case always
1448        been different (but PCRE had them first :-).
1449    
1450    16. Related to 15 above: Perl does not treat the | in a conditional group as
1451        creating alternatives. Such a group is treated in the same way as an
1452        ordinary group without any | characters when processing (*THEN). PCRE has
1453        been changed to match Perl's behaviour.
1454    
1455    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1456        RunGrepTest script failed.
1457    
1458    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1459        inevitable for groups that contain captures, but it can lead to a lot of
1460        stack use in large patterns. The old behaviour has been restored for atomic
1461        groups that do not contain any capturing parentheses.
1462    
1463    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1464        suppress the check for a minimum subject length at run time. (If it was
1465        given to pcre_exec() or pcre_dfa_exec() it did work.)
1466    
1467    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1468        fail to work when decoding hex characters in data strings in EBCDIC
1469        environments.
1470    
1471    21. It appears that in at least one Mac OS environment, the isxdigit() function
1472        is implemented as a macro that evaluates to its argument more than once,
1473        contravening the C 90 Standard (I haven't checked a later standard). There
1474        was an instance in pcretest which caused it to go wrong when processing
1475        \x{...} escapes in subject strings. The has been rewritten to avoid using
1476        things like p++ in the argument of isxdigit().
1477    
1478    
1479    Version 8.13 16-Aug-2011
1480  ------------------------  ------------------------
1481    
1482  1.  The Unicode data tables have been updated to Unicode 6.0.0.  1.  The Unicode data tables have been updated to Unicode 6.0.0.
# Line 98  Version 8.13 02-Aug-2011 Line 1573  Version 8.13 02-Aug-2011
1573      tail recursion to cut down on stack usage. Unfortunately, now that there is      tail recursion to cut down on stack usage. Unfortunately, now that there is
1574      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
1575      no longer possible because the return has to be checked for (*THEN). These      no longer possible because the return has to be checked for (*THEN). These
1576      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
1577    
1578  18. If a pattern containing \R was studied, it was assumed that \R always  18. If a pattern containing \R was studied, it was assumed that \R always
1579      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
# Line 189  Version 8.13 02-Aug-2011 Line 1664  Version 8.13 02-Aug-2011
1664      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1665      unescaped square brackets may also appear as part of class names. For      unescaped square brackets may also appear as part of class names. For
1666      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1667      more like Perl.      more like Perl. (But see 8.20/1 above.)
1668    
1669  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1670      was because it thought it was \N{name}, which is not supported).      was because it thought it was \N{name}, which is not supported).
# Line 224  Version 8.13 02-Aug-2011 Line 1699  Version 8.13 02-Aug-2011
1699      (a) The default value of the buffer size parameter has been increased from      (a) The default value of the buffer size parameter has been increased from
1700          8K to 20K. (The actual buffer used is three times this size.)          8K to 20K. (The actual buffer used is three times this size.)
1701    
1702      (b) The default can be changed by ./configure --with-pcregrep-bufsiz when      (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1703          PCRE is built.          PCRE is built.
1704    
1705      (c) A --buffer-size=n option has been added to pcregrep, to allow the size      (c) A --buffer-size=n option has been added to pcregrep, to allow the size
# Line 245  Version 8.13 02-Aug-2011 Line 1720  Version 8.13 02-Aug-2011
1720  47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a  47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1721      complete match instead of a partial match. This bug was dependent on both      complete match instead of a partial match. This bug was dependent on both
1722      the PCRE_UTF8 and PCRE_DOTALL options being set.      the PCRE_UTF8 and PCRE_DOTALL options being set.
1723    
1724  48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the  48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1725      starting byte set, because \b was not being ignored.      starting byte set, because \b was not being ignored.
1726    
1727    
1728  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
# Line 900  Version 7.9 11-Apr-09 Line 2375  Version 7.9 11-Apr-09
2375  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
2376      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
2377      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2378      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2379        8.33.]
2380    
2381  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
2382      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 1143  Version 7.7 07-May-08 Line 2619  Version 7.7 07-May-08
2619      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2620      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2621      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2622      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2623      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2624      was subsequently set up correctly.)      was subsequently set up correctly.)
2625    

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