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revision 699 by ph10, Tue Sep 20 10:46:54 2011 UTC revision 742 by zherczeg, Sun Nov 6 08:05:33 2011 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.20 12-Sep-2011  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    
17    Version 8.20 21-Oct-2011
18  ------------------------  ------------------------
19    
20  1. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had  1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
21     a POSIX class. After further experiments with Perl, which convinced me that      a POSIX class. After further experiments with Perl, which convinced me that
22     Perl has bugs and confusions, a closing square bracket is no longer allowed      Perl has bugs and confusions, a closing square bracket is no longer allowed
23     in a POSIX name. This bug also affected patterns with classes that started      in a POSIX name. This bug also affected patterns with classes that started
24     with full stops.      with full stops.
25    
26  2. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured  2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
27     substring, but while checking the failing first alternative, substring 1 is      captured substring, but while checking the failing first alternative,
28     temporarily captured. If the output vector supplied to pcre_exec() was not      substring 1 is temporarily captured. If the output vector supplied to
29     big enough for this capture, the yield of the function was still zero      pcre_exec() was not big enough for this capture, the yield of the function
30     ("insufficient space for captured substrings"). This cannot be totally fixed      was still zero ("insufficient space for captured substrings"). This cannot
31     without adding another stack variable, which seems a lot of expense for a      be totally fixed without adding another stack variable, which seems a lot
32     edge case. However, I have improved the situation in cases such as      of expense for a edge case. However, I have improved the situation in cases
33     /(a)(b)x|abc/ matched against "abc", where the return code indicates that      such as /(a)(b)x|abc/ matched against "abc", where the return code
34     fewer than the maximum number of slots in the ovector have been set.      indicates that fewer than the maximum number of slots in the ovector have
35        been set.
36  3. Related to (2) above: when there are more back references in a pattern than  
37     slots in the output vector, pcre_exec() uses temporary memory during  3.  Related to (2) above: when there are more back references in a pattern than
38     matching, and copies in the captures as far as possible afterwards. It was      slots in the output vector, pcre_exec() uses temporary memory during
39     using the entire output vector, but this conflicts with the specification      matching, and copies in the captures as far as possible afterwards. It was
40     that only 2/3 is used for passing back captured substrings. Now it uses only      using the entire output vector, but this conflicts with the specification
41     the first 2/3, for compatibility. This is, of course, another edge case.      that only 2/3 is used for passing back captured substrings. Now it uses
42        only the first 2/3, for compatibility. This is, of course, another edge
43  4. Zoltan Herczeg's just-in-time compiler support has been integrated into the      case.
44     main code base, and can be used by building with --enable-jit. When this is  
45     done, pcregrep automatically uses it unless --disable-pcregrep-jit or the  4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
46     runtime --no-jit option is given.      main code base, and can be used by building with --enable-jit. When this is
47        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
48  5. When the number of matches in a pcre_dfa_exec() run exactly filled the      runtime --no-jit option is given.
49     ovector, the return from the function was zero, implying that there were  
50     other matches that did not fit. The correct "exactly full" value is now  5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
51     returned.      ovector, the return from the function was zero, implying that there were
52        other matches that did not fit. The correct "exactly full" value is now
53  6. If a subpattern that was called recursively or as a subroutine contained      returned.
54     (*PRUNE) or any other control that caused it to give a non-standard return,  
55     invalid errors such as "Error -26 (nested recursion at the same subject  6.  If a subpattern that was called recursively or as a subroutine contained
56     position)" or even infinite loops could occur.      (*PRUNE) or any other control that caused it to give a non-standard return,
57        invalid errors such as "Error -26 (nested recursion at the same subject
58  7. If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped      position)" or even infinite loops could occur.
59     computing the minimum length on reaching *ACCEPT, and so ended up with the  
60     wrong value of 1 rather than 0. Further investigation indicates that  7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
61     computing a minimum subject length in the presence of *ACCEPT is difficult      computing the minimum length on reaching *ACCEPT, and so ended up with the
62     (think back references, subroutine calls), and so I have changed the code so      wrong value of 1 rather than 0. Further investigation indicates that
63     that no minimum is registered for a pattern that contains *ACCEPT.      computing a minimum subject length in the presence of *ACCEPT is difficult
64        (think back references, subroutine calls), and so I have changed the code
65  8. If (*THEN) was present in the first (true) branch of a conditional group,      so that no minimum is registered for a pattern that contains *ACCEPT.
66     it was not handled as intended.  
67    8.  If (*THEN) was present in the first (true) branch of a conditional group,
68        it was not handled as intended. [But see 16 below.]
69    
70    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
71        Sheri Pierce.
72    
73    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
74        the first byte in a match must be "a".
75    
76    11. Change 17 for 8.13 increased the recursion depth for patterns like
77        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
78        pattern contains any instances of (*THEN). If it does not, the old
79        optimizations are restored. It would be nice to do this on a per-group
80        basis, but at the moment that is not feasible.
81    
82    12. In some environments, the output of pcretest -C is CRLF terminated. This
83        broke RunTest's code that checks for the link size. A single white space
84        character after the value is now allowed for.
85    
86    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
87        For "fr", it uses the Windows-specific input and output files.
88    
89    14. If (*THEN) appeared in a group that was called recursively or as a
90        subroutine, it did not work as intended. [But see next item.]
91    
92    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
93        pattern fragments (but not containing any | characters). If A and B are
94        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
95        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
96        D. In other words, Perl considers parentheses that do not contain any |
97        characters to be part of a surrounding alternative, whereas PCRE was
98        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
99        differently. PCRE now behaves in the same way as Perl, except in the case
100        of subroutine/recursion calls such as (?1) which have in any case always
101        been different (but PCRE had them first :-).
102    
103    16. Related to 15 above: Perl does not treat the | in a conditional group as
104        creating alternatives. Such a group is treated in the same way as an
105        ordinary group without any | characters when processing (*THEN). PCRE has
106        been changed to match Perl's behaviour.
107    
108    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
109        RunGrepTest script failed.
110    
111    18. Change 22 for version 13 caused atomic groups to use more stack. This is
112        inevitable for groups that contain captures, but it can lead to a lot of
113        stack use in large patterns. The old behaviour has been restored for atomic
114        groups that do not contain any capturing parentheses.
115    
116    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
117        suppress the check for a minimum subject length at run time. (If it was
118        given to pcre_exec() or pcre_dfa_exec() it did work.)
119    
120    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
121        fail to work when decoding hex characters in data strings in EBCDIC
122        environments.
123    
124    21. It appears that in at least one Mac OS environment, the isxdigit() function
125        is implemented as a macro that evaluates to its argument more than once,
126        contravening the C 90 Standard (I haven't checked a later standard). There
127        was an instance in pcretest which caused it to go wrong when processing
128        \x{...} escapes in subject strings. The has been rewritten to avoid using
129        things like p++ in the argument of isxdigit().
130    
131    
132  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
# Line 150  Version 8.13 16-Aug-2011 Line 226  Version 8.13 16-Aug-2011
226      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
227      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
228      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
229      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
230    
231  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
232      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be

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