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revision 691 by ph10, Sun Sep 11 14:31:21 2011 UTC revision 740 by zherczeg, Mon Oct 31 06:10:14 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    
10    Version 8.20 21-Oct-2011
11  ------------------------  ------------------------
12    
13  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
14     a POSIX class. After further experiments with Perl, which convinced me that      a POSIX class. After further experiments with Perl, which convinced me that
15     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
16     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
17     with full stops.      with full stops.
18    
19  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
20     substring, but while checking the failing first alternative, substring 1 is      captured substring, but while checking the failing first alternative,
21     temporarily captured. If the output vector supplied to pcre_exec() was not      substring 1 is temporarily captured. If the output vector supplied to
22     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
23     ("insufficient space for captured substrings"). This cannot be totally fixed      was still zero ("insufficient space for captured substrings"). This cannot
24     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
25     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
26     /(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
27     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
28        been set.
29  3. Related to (2) above: when there are more back references in a pattern than  
30     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
31     matching, and copies in the captures as far as possible afterwards. It was      slots in the output vector, pcre_exec() uses temporary memory during
32     using the entire output vector, but this conflicts with the specification      matching, and copies in the captures as far as possible afterwards. It was
33     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
34     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
35        only the first 2/3, for compatibility. This is, of course, another edge
36  4. Zoltan Herczeg's just-in-time compiler support has been integrated into the      case.
37     main code base, and can be used by building with --enable-jit. When this is  
38     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
39     runtime --no-jit option is given.      main code base, and can be used by building with --enable-jit. When this is
40        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
41  5. When the number of matches in a pcre_dfa_exec() run exactly filled the      runtime --no-jit option is given.
42     ovector, the return from the function was zero, implying that there were  
43     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
44     returned.      ovector, the return from the function was zero, implying that there were
45        other matches that did not fit. The correct "exactly full" value is now
46  6. If a subpattern that was called recursively or as a subroutine contained      returned.
47     (*PRUNE) or any other control that caused it to give a non-standard return,  
48     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
49     position)" or even infinite loops could occur.      (*PRUNE) or any other control that caused it to give a non-standard return,
50        invalid errors such as "Error -26 (nested recursion at the same subject
51        position)" or even infinite loops could occur.
52    
53    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
54        computing the minimum length on reaching *ACCEPT, and so ended up with the
55        wrong value of 1 rather than 0. Further investigation indicates that
56        computing a minimum subject length in the presence of *ACCEPT is difficult
57        (think back references, subroutine calls), and so I have changed the code
58        so that no minimum is registered for a pattern that contains *ACCEPT.
59    
60    8.  If (*THEN) was present in the first (true) branch of a conditional group,
61        it was not handled as intended. [But see 16 below.]
62    
63    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
64        Sheri Pierce.
65    
66    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
67        the first byte in a match must be "a".
68    
69    11. Change 17 for 8.13 increased the recursion depth for patterns like
70        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
71        pattern contains any instances of (*THEN). If it does not, the old
72        optimizations are restored. It would be nice to do this on a per-group
73        basis, but at the moment that is not feasible.
74    
75    12. In some environments, the output of pcretest -C is CRLF terminated. This
76        broke RunTest's code that checks for the link size. A single white space
77        character after the value is now allowed for.
78    
79    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
80        For "fr", it uses the Windows-specific input and output files.
81    
82    14. If (*THEN) appeared in a group that was called recursively or as a
83        subroutine, it did not work as intended. [But see next item.]
84    
85    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
86        pattern fragments (but not containing any | characters). If A and B are
87        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
88        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
89        D. In other words, Perl considers parentheses that do not contain any |
90        characters to be part of a surrounding alternative, whereas PCRE was
91        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
92        differently. PCRE now behaves in the same way as Perl, except in the case
93        of subroutine/recursion calls such as (?1) which have in any case always
94        been different (but PCRE had them first :-).
95    
96    16. Related to 15 above: Perl does not treat the | in a conditional group as
97        creating alternatives. Such a group is treated in the same way as an
98        ordinary group without any | characters when processing (*THEN). PCRE has
99        been changed to match Perl's behaviour.
100    
101    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
102        RunGrepTest script failed.
103    
104    18. Change 22 for version 13 caused atomic groups to use more stack. This is
105        inevitable for groups that contain captures, but it can lead to a lot of
106        stack use in large patterns. The old behaviour has been restored for atomic
107        groups that do not contain any capturing parentheses.
108    
109    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
110        suppress the check for a minimum subject length at run time. (If it was
111        given to pcre_exec() or pcre_dfa_exec() it did work.)
112    
113    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
114        fail to work when decoding hex characters in data strings in EBCDIC
115        environments.
116    
117    21. It appears that in at least one Mac OS environment, the isxdigit() function
118        is implemented as a macro that evaluates to its argument more than once,
119        contravening the C 90 Standard (I haven't checked a later standard). There
120        was an instance in pcretest which caused it to go wrong when processing
121        \x{...} escapes in subject strings. The has been rewritten to avoid using
122        things like p++ in the argument of isxdigit().
123    
124    
125  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
# Line 140  Version 8.13 16-Aug-2011 Line 219  Version 8.13 16-Aug-2011
219      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
220      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
221      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
222      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
223    
224  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
225      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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