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revision 659 by ph10, Tue Aug 16 09:48:29 2011 UTC revision 751 by ph10, Fri Nov 18 11:13:30 2011 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.21
5    ------------
6    
7    1.  Updating the JIT compiler.
8    
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
11    
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
15    
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
19    
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
22    
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
26    
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
36    
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
39    
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
44    
45    10. Add a cast and remove a redundant test from the code.
46    
47    
48    Version 8.20 21-Oct-2011
49    ------------------------
50    
51    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
52        a POSIX class. After further experiments with Perl, which convinced me that
53        Perl has bugs and confusions, a closing square bracket is no longer allowed
54        in a POSIX name. This bug also affected patterns with classes that started
55        with full stops.
56    
57    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
58        captured substring, but while checking the failing first alternative,
59        substring 1 is temporarily captured. If the output vector supplied to
60        pcre_exec() was not big enough for this capture, the yield of the function
61        was still zero ("insufficient space for captured substrings"). This cannot
62        be totally fixed without adding another stack variable, which seems a lot
63        of expense for a edge case. However, I have improved the situation in cases
64        such as /(a)(b)x|abc/ matched against "abc", where the return code
65        indicates that fewer than the maximum number of slots in the ovector have
66        been set.
67    
68    3.  Related to (2) above: when there are more back references in a pattern than
69        slots in the output vector, pcre_exec() uses temporary memory during
70        matching, and copies in the captures as far as possible afterwards. It was
71        using the entire output vector, but this conflicts with the specification
72        that only 2/3 is used for passing back captured substrings. Now it uses
73        only the first 2/3, for compatibility. This is, of course, another edge
74        case.
75    
76    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
77        main code base, and can be used by building with --enable-jit. When this is
78        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
79        runtime --no-jit option is given.
80    
81    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
82        ovector, the return from the function was zero, implying that there were
83        other matches that did not fit. The correct "exactly full" value is now
84        returned.
85    
86    6.  If a subpattern that was called recursively or as a subroutine contained
87        (*PRUNE) or any other control that caused it to give a non-standard return,
88        invalid errors such as "Error -26 (nested recursion at the same subject
89        position)" or even infinite loops could occur.
90    
91    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
92        computing the minimum length on reaching *ACCEPT, and so ended up with the
93        wrong value of 1 rather than 0. Further investigation indicates that
94        computing a minimum subject length in the presence of *ACCEPT is difficult
95        (think back references, subroutine calls), and so I have changed the code
96        so that no minimum is registered for a pattern that contains *ACCEPT.
97    
98    8.  If (*THEN) was present in the first (true) branch of a conditional group,
99        it was not handled as intended. [But see 16 below.]
100    
101    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
102        Sheri Pierce.
103    
104    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
105        the first byte in a match must be "a".
106    
107    11. Change 17 for 8.13 increased the recursion depth for patterns like
108        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
109        pattern contains any instances of (*THEN). If it does not, the old
110        optimizations are restored. It would be nice to do this on a per-group
111        basis, but at the moment that is not feasible.
112    
113    12. In some environments, the output of pcretest -C is CRLF terminated. This
114        broke RunTest's code that checks for the link size. A single white space
115        character after the value is now allowed for.
116    
117    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
118        For "fr", it uses the Windows-specific input and output files.
119    
120    14. If (*THEN) appeared in a group that was called recursively or as a
121        subroutine, it did not work as intended. [But see next item.]
122    
123    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
124        pattern fragments (but not containing any | characters). If A and B are
125        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
126        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
127        D. In other words, Perl considers parentheses that do not contain any |
128        characters to be part of a surrounding alternative, whereas PCRE was
129        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
130        differently. PCRE now behaves in the same way as Perl, except in the case
131        of subroutine/recursion calls such as (?1) which have in any case always
132        been different (but PCRE had them first :-).
133    
134    16. Related to 15 above: Perl does not treat the | in a conditional group as
135        creating alternatives. Such a group is treated in the same way as an
136        ordinary group without any | characters when processing (*THEN). PCRE has
137        been changed to match Perl's behaviour.
138    
139    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
140        RunGrepTest script failed.
141    
142    18. Change 22 for version 13 caused atomic groups to use more stack. This is
143        inevitable for groups that contain captures, but it can lead to a lot of
144        stack use in large patterns. The old behaviour has been restored for atomic
145        groups that do not contain any capturing parentheses.
146    
147    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
148        suppress the check for a minimum subject length at run time. (If it was
149        given to pcre_exec() or pcre_dfa_exec() it did work.)
150    
151    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
152        fail to work when decoding hex characters in data strings in EBCDIC
153        environments.
154    
155    21. It appears that in at least one Mac OS environment, the isxdigit() function
156        is implemented as a macro that evaluates to its argument more than once,
157        contravening the C 90 Standard (I haven't checked a later standard). There
158        was an instance in pcretest which caused it to go wrong when processing
159        \x{...} escapes in subject strings. The has been rewritten to avoid using
160        things like p++ in the argument of isxdigit().
161    
162    
163  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
164  ------------------------  ------------------------
165    
# Line 98  Version 8.13 16-Aug-2011 Line 257  Version 8.13 16-Aug-2011
257      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
258      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
259      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
260      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
261    
262  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
263      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 16-Aug-2011 Line 348  Version 8.13 16-Aug-2011
348      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
349      unescaped square brackets may also appear as part of class names. For      unescaped square brackets may also appear as part of class names. For
350      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
351      more like Perl.      more like Perl. (But see 8.20/1 above.)
352    
353  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
354      was because it thought it was \N{name}, which is not supported).      was because it thought it was \N{name}, which is not supported).

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