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revision 413 by ph10, Sat Apr 11 11:41:52 2009 UTC revision 472 by ph10, Fri Dec 11 16:42:50 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.01 11-Dec-09
5    ----------------------
6    
7    1.  If a pattern contained a conditional subpattern with only one branch (in
8        particular, this includes all (DEFINE) patterns), a call to pcre_study()
9        computed the wrong minimum data length (which is of course zero for such
10        subpatterns).
11    
12    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
13        the pattern is reset in the first branch, pcre_compile() failed with
14        "internal error: code overflow at offset...". This happened only when
15        the reset was to the original external option setting. (An optimization
16        abstracts leading options settings into an external setting, which was the
17        cause of this.)
18    
19    
20    Version 8.00 19-Oct-09
21    ----------------------
22    
23    1.  The table for translating pcre_compile() error codes into POSIX error codes
24        was out-of-date, and there was no check on the pcre_compile() error code
25        being within the table. This could lead to an OK return being given in
26        error.
27    
28    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
29        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
30        in a Windows environment.
31    
32    3.  The pcregrep --count option prints the count for each file even when it is
33        zero, as does GNU grep. However, pcregrep was also printing all files when
34        --files-with-matches was added. Now, when both options are given, it prints
35        counts only for those files that have at least one match. (GNU grep just
36        prints the file name in this circumstance, but including the count seems
37        more useful - otherwise, why use --count?) Also ensured that the
38        combination -clh just lists non-zero counts, with no names.
39    
40    4.  The long form of the pcregrep -F option was incorrectly implemented as
41        --fixed_strings instead of --fixed-strings. This is an incompatible change,
42        but it seems right to fix it, and I didn't think it was worth preserving
43        the old behaviour.
44    
45    5.  The command line items --regex=pattern and --regexp=pattern were not
46        recognized by pcregrep, which required --regex pattern or --regexp pattern
47        (with a space rather than an '='). The man page documented the '=' forms,
48        which are compatible with GNU grep; these now work.
49    
50    6.  No libpcreposix.pc file was created for pkg-config; there was just
51        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
52    
53    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
54        when UCP support is not needed, by modifying the Python script that
55        generates it from Unicode data files. This should not matter if the module
56        is correctly used as a library, but I received one complaint about 50K of
57        unwanted data. My guess is that the person linked everything into his
58        program rather than using a library. Anyway, it does no harm.
59    
60    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
61        was a minimum greater than 1 for a wide character in a possessive
62        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
63        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
64        character. Chaos in the form of incorrect output or a compiling loop could
65        result.
66    
67    9.  The restrictions on what a pattern can contain when partial matching is
68        requested for pcre_exec() have been removed. All patterns can now be
69        partially matched by this function. In addition, if there are at least two
70        slots in the offset vector, the offset of the earliest inspected character
71        for the match and the offset of the end of the subject are set in them when
72        PCRE_ERROR_PARTIAL is returned.
73    
74    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
75        synonymous with PCRE_PARTIAL, for backwards compatibility, and
76        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
77        and may be more useful for multi-segment matching.
78    
79    11. Partial matching with pcre_exec() is now more intuitive. A partial match
80        used to be given if ever the end of the subject was reached; now it is
81        given only if matching could not proceed because another character was
82        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
83        string "Z", which now yields "no match" instead of "partial match". In the
84        case of pcre_dfa_exec(), "no match" is given if every matching path for the
85        final character ended with (*FAIL).
86    
87    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
88        if the pattern had a "must contain" character that was already found in the
89        earlier partial match, unless partial matching was again requested. For
90        example, with the pattern /dog.(body)?/, the "must contain" character is
91        "g". If the first part-match was for the string "dog", restarting with
92        "sbody" failed. This bug has been fixed.
93    
94    13. The string returned by pcre_dfa_exec() after a partial match has been
95        changed so that it starts at the first inspected character rather than the
96        first character of the match. This makes a difference only if the pattern
97        starts with a lookbehind assertion or \b or \B (\K is not supported by
98        pcre_dfa_exec()). It's an incompatible change, but it makes the two
99        matching functions compatible, and I think it's the right thing to do.
100    
101    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
102        so that the demonstration program is easily available in environments where
103        PCRE has not been installed from source.
104    
105    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
106        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
107        library.
108    
109    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
110        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
111        is not the first non-POSIX option to be added. Clearly some people find
112        these options useful.
113    
114    17. If a caller to the POSIX matching function regexec() passes a non-zero
115        value for nmatch with a NULL value for pmatch, the value of
116        nmatch is forced to zero.
117    
118    18. RunGrepTest did not have a test for the availability of the -u option of
119        the diff command, as RunTest does. It now checks in the same way as
120        RunTest, and also checks for the -b option.
121    
122    19. If an odd number of negated classes containing just a single character
123        interposed, within parentheses, between a forward reference to a named
124        subpattern and the definition of the subpattern, compilation crashed with
125        an internal error, complaining that it could not find the referenced
126        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
127        [The bug was that it was starting one character too far in when skipping
128        over the character class, thus treating the ] as data rather than
129        terminating the class. This meant it could skip too much.]
130    
131    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
132        /g option in pcretest when the pattern contains \K, which makes it possible
133        to have an empty string match not at the start, even when the pattern is
134        anchored. Updated pcretest and pcredemo to use this option.
135    
136    21. If the maximum number of capturing subpatterns in a recursion was greater
137        than the maximum at the outer level, the higher number was returned, but
138        with unset values at the outer level. The correct (outer level) value is
139        now given.
140    
141    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
142        PCRE did not set those parentheses (unlike Perl). I have now found a way to
143        make it do so. The string so far is captured, making this feature
144        compatible with Perl.
145    
146    23. The tests have been re-organized, adding tests 11 and 12, to make it
147        possible to check the Perl 5.10 features against Perl 5.10.
148    
149    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
150        pattern matches a fixed length string. PCRE did not allow this; now it
151        does. Neither allows recursion.
152    
153    25. I finally figured out how to implement a request to provide the minimum
154        length of subject string that was needed in order to match a given pattern.
155        (It was back references and recursion that I had previously got hung up
156        on.) This code has now been added to pcre_study(); it finds a lower bound
157        to the length of subject needed. It is not necessarily the greatest lower
158        bound, but using it to avoid searching strings that are too short does give
159        some useful speed-ups. The value is available to calling programs via
160        pcre_fullinfo().
161    
162    26. While implementing 25, I discovered to my embarrassment that pcretest had
163        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
164        study optimizations had never been tested with that matching function.
165        Oops. What is worse, even when it was passed study data, there was a bug in
166        pcre_dfa_exec() that meant it never actually used it. Double oops. There
167        were also very few tests of studied patterns with pcre_dfa_exec().
168    
169    27. If (?| is used to create subpatterns with duplicate numbers, they are now
170        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
171        on the other side of the coin, they are no longer allowed to have different
172        names, because these cannot be distinguished in PCRE, and this has caused
173        confusion. (This is a difference from Perl.)
174    
175    28. When duplicate subpattern names are present (necessarily with different
176        numbers, as required by 27 above), and a test is made by name in a
177        conditional pattern, either for a subpattern having been matched, or for
178        recursion in such a pattern, all the associated numbered subpatterns are
179        tested, and the overall condition is true if the condition is true for any
180        one of them. This is the way Perl works, and is also more like the way
181        testing by number works.
182    
183    
184  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
185  ---------------------  ---------------------
186    
# Line 112  Version 7.9 11-Apr-09 Line 292  Version 7.9 11-Apr-09
292    
293  26. Changed a few more instances of "const unsigned char *" to USPTR, making  26. Changed a few more instances of "const unsigned char *" to USPTR, making
294      the feature of a custom pointer more persuasive (as requested by a user).      the feature of a custom pointer more persuasive (as requested by a user).
295    
296  27. Wrapped the definitions of fileno and isatty for Windows, which appear in  27. Wrapped the definitions of fileno and isatty for Windows, which appear in
297      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
298      pre-defined.      pre-defined.
299    
300  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
301    
302  29. Arrange for flags added by the "release type" setting in CMake to be shown  29. Arrange for flags added by the "release type" setting in CMake to be shown
303      in the configuration summary.      in the configuration summary.

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