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revision 700 by ph10, Tue Sep 20 10:51:26 2011 UTC revision 741 by zherczeg, Mon Oct 31 09:31:46 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    
13    Version 8.20 21-Oct-2011
14  ------------------------  ------------------------
15    
16  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
17     a POSIX class. After further experiments with Perl, which convinced me that      a POSIX class. After further experiments with Perl, which convinced me that
18     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
19     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
20     with full stops.      with full stops.
21    
22  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
23     substring, but while checking the failing first alternative, substring 1 is      captured substring, but while checking the failing first alternative,
24     temporarily captured. If the output vector supplied to pcre_exec() was not      substring 1 is temporarily captured. If the output vector supplied to
25     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
26     ("insufficient space for captured substrings"). This cannot be totally fixed      was still zero ("insufficient space for captured substrings"). This cannot
27     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
28     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
29     /(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
30     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
31        been set.
32  3. Related to (2) above: when there are more back references in a pattern than  
33     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
34     matching, and copies in the captures as far as possible afterwards. It was      slots in the output vector, pcre_exec() uses temporary memory during
35     using the entire output vector, but this conflicts with the specification      matching, and copies in the captures as far as possible afterwards. It was
36     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
37     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
38        only the first 2/3, for compatibility. This is, of course, another edge
39  4. Zoltan Herczeg's just-in-time compiler support has been integrated into the      case.
40     main code base, and can be used by building with --enable-jit. When this is  
41     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
42     runtime --no-jit option is given.      main code base, and can be used by building with --enable-jit. When this is
43        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
44  5. When the number of matches in a pcre_dfa_exec() run exactly filled the      runtime --no-jit option is given.
45     ovector, the return from the function was zero, implying that there were  
46     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
47     returned.      ovector, the return from the function was zero, implying that there were
48        other matches that did not fit. The correct "exactly full" value is now
49  6. If a subpattern that was called recursively or as a subroutine contained      returned.
50     (*PRUNE) or any other control that caused it to give a non-standard return,  
51     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
52     position)" or even infinite loops could occur.      (*PRUNE) or any other control that caused it to give a non-standard return,
53        invalid errors such as "Error -26 (nested recursion at the same subject
54  7. If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped      position)" or even infinite loops could occur.
55     computing the minimum length on reaching *ACCEPT, and so ended up with the  
56     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
57     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
58     (think back references, subroutine calls), and so I have changed the code so      wrong value of 1 rather than 0. Further investigation indicates that
59     that no minimum is registered for a pattern that contains *ACCEPT.      computing a minimum subject length in the presence of *ACCEPT is difficult
60        (think back references, subroutine calls), and so I have changed the code
61  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.
62     it was not handled as intended.  
63    8.  If (*THEN) was present in the first (true) branch of a conditional group,
64  9. Replaced RunTest.bat with the much improved version provided by Sheri      it was not handled as intended. [But see 16 below.]
65     Pierce.  
66    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
67        Sheri Pierce.
68    
69    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
70        the first byte in a match must be "a".
71    
72    11. Change 17 for 8.13 increased the recursion depth for patterns like
73        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
74        pattern contains any instances of (*THEN). If it does not, the old
75        optimizations are restored. It would be nice to do this on a per-group
76        basis, but at the moment that is not feasible.
77    
78    12. In some environments, the output of pcretest -C is CRLF terminated. This
79        broke RunTest's code that checks for the link size. A single white space
80        character after the value is now allowed for.
81    
82    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
83        For "fr", it uses the Windows-specific input and output files.
84    
85    14. If (*THEN) appeared in a group that was called recursively or as a
86        subroutine, it did not work as intended. [But see next item.]
87    
88    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
89        pattern fragments (but not containing any | characters). If A and B are
90        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
91        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
92        D. In other words, Perl considers parentheses that do not contain any |
93        characters to be part of a surrounding alternative, whereas PCRE was
94        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
95        differently. PCRE now behaves in the same way as Perl, except in the case
96        of subroutine/recursion calls such as (?1) which have in any case always
97        been different (but PCRE had them first :-).
98    
99    16. Related to 15 above: Perl does not treat the | in a conditional group as
100        creating alternatives. Such a group is treated in the same way as an
101        ordinary group without any | characters when processing (*THEN). PCRE has
102        been changed to match Perl's behaviour.
103    
104    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
105        RunGrepTest script failed.
106    
107    18. Change 22 for version 13 caused atomic groups to use more stack. This is
108        inevitable for groups that contain captures, but it can lead to a lot of
109        stack use in large patterns. The old behaviour has been restored for atomic
110        groups that do not contain any capturing parentheses.
111    
112    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
113        suppress the check for a minimum subject length at run time. (If it was
114        given to pcre_exec() or pcre_dfa_exec() it did work.)
115    
116    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
117        fail to work when decoding hex characters in data strings in EBCDIC
118        environments.
119    
120    21. It appears that in at least one Mac OS environment, the isxdigit() function
121        is implemented as a macro that evaluates to its argument more than once,
122        contravening the C 90 Standard (I haven't checked a later standard). There
123        was an instance in pcretest which caused it to go wrong when processing
124        \x{...} escapes in subject strings. The has been rewritten to avoid using
125        things like p++ in the argument of isxdigit().
126    
127    
128  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
# Line 153  Version 8.13 16-Aug-2011 Line 222  Version 8.13 16-Aug-2011
222      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
223      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
224      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
225      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
226    
227  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
228      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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