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revision 691 by ph10, Sun Sep 11 14:31:21 2011 UTC revision 753 by ph10, Sat Nov 19 17:03:35 2011 UTC
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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    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    11. JIT should use pcre_malloc/pcre_free for allocation.
48    
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
52    
53    
54    Version 8.20 21-Oct-2011
55  ------------------------  ------------------------
56    
57  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
58     a POSIX class. After further experiments with Perl, which convinced me that      a POSIX class. After further experiments with Perl, which convinced me that
59     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
60     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
61     with full stops.      with full stops.
62    
63  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
64     substring, but while checking the failing first alternative, substring 1 is      captured substring, but while checking the failing first alternative,
65     temporarily captured. If the output vector supplied to pcre_exec() was not      substring 1 is temporarily captured. If the output vector supplied to
66     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
67     ("insufficient space for captured substrings"). This cannot be totally fixed      was still zero ("insufficient space for captured substrings"). This cannot
68     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
69     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
70     /(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
71     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
72        been set.
73  3. Related to (2) above: when there are more back references in a pattern than  
74     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
75     matching, and copies in the captures as far as possible afterwards. It was      slots in the output vector, pcre_exec() uses temporary memory during
76     using the entire output vector, but this conflicts with the specification      matching, and copies in the captures as far as possible afterwards. It was
77     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
78     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
79        only the first 2/3, for compatibility. This is, of course, another edge
80  4. Zoltan Herczeg's just-in-time compiler support has been integrated into the      case.
81     main code base, and can be used by building with --enable-jit. When this is  
82     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
83     runtime --no-jit option is given.      main code base, and can be used by building with --enable-jit. When this is
84        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
85  5. When the number of matches in a pcre_dfa_exec() run exactly filled the      runtime --no-jit option is given.
86     ovector, the return from the function was zero, implying that there were  
87     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
88     returned.      ovector, the return from the function was zero, implying that there were
89        other matches that did not fit. The correct "exactly full" value is now
90  6. If a subpattern that was called recursively or as a subroutine contained      returned.
91     (*PRUNE) or any other control that caused it to give a non-standard return,  
92     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
93     position)" or even infinite loops could occur.      (*PRUNE) or any other control that caused it to give a non-standard return,
94        invalid errors such as "Error -26 (nested recursion at the same subject
95        position)" or even infinite loops could occur.
96    
97    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
98        computing the minimum length on reaching *ACCEPT, and so ended up with the
99        wrong value of 1 rather than 0. Further investigation indicates that
100        computing a minimum subject length in the presence of *ACCEPT is difficult
101        (think back references, subroutine calls), and so I have changed the code
102        so that no minimum is registered for a pattern that contains *ACCEPT.
103    
104    8.  If (*THEN) was present in the first (true) branch of a conditional group,
105        it was not handled as intended. [But see 16 below.]
106    
107    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
108        Sheri Pierce.
109    
110    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
111        the first byte in a match must be "a".
112    
113    11. Change 17 for 8.13 increased the recursion depth for patterns like
114        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
115        pattern contains any instances of (*THEN). If it does not, the old
116        optimizations are restored. It would be nice to do this on a per-group
117        basis, but at the moment that is not feasible.
118    
119    12. In some environments, the output of pcretest -C is CRLF terminated. This
120        broke RunTest's code that checks for the link size. A single white space
121        character after the value is now allowed for.
122    
123    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
124        For "fr", it uses the Windows-specific input and output files.
125    
126    14. If (*THEN) appeared in a group that was called recursively or as a
127        subroutine, it did not work as intended. [But see next item.]
128    
129    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
130        pattern fragments (but not containing any | characters). If A and B are
131        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
132        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
133        D. In other words, Perl considers parentheses that do not contain any |
134        characters to be part of a surrounding alternative, whereas PCRE was
135        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
136        differently. PCRE now behaves in the same way as Perl, except in the case
137        of subroutine/recursion calls such as (?1) which have in any case always
138        been different (but PCRE had them first :-).
139    
140    16. Related to 15 above: Perl does not treat the | in a conditional group as
141        creating alternatives. Such a group is treated in the same way as an
142        ordinary group without any | characters when processing (*THEN). PCRE has
143        been changed to match Perl's behaviour.
144    
145    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
146        RunGrepTest script failed.
147    
148    18. Change 22 for version 13 caused atomic groups to use more stack. This is
149        inevitable for groups that contain captures, but it can lead to a lot of
150        stack use in large patterns. The old behaviour has been restored for atomic
151        groups that do not contain any capturing parentheses.
152    
153    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
154        suppress the check for a minimum subject length at run time. (If it was
155        given to pcre_exec() or pcre_dfa_exec() it did work.)
156    
157    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
158        fail to work when decoding hex characters in data strings in EBCDIC
159        environments.
160    
161    21. It appears that in at least one Mac OS environment, the isxdigit() function
162        is implemented as a macro that evaluates to its argument more than once,
163        contravening the C 90 Standard (I haven't checked a later standard). There
164        was an instance in pcretest which caused it to go wrong when processing
165        \x{...} escapes in subject strings. The has been rewritten to avoid using
166        things like p++ in the argument of isxdigit().
167    
168    
169  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
# Line 140  Version 8.13 16-Aug-2011 Line 263  Version 8.13 16-Aug-2011
263      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
264      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
265      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
266      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
267    
268  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
269      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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