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revision 422 by ph10, Fri Aug 14 16:42:55 2009 UTC revision 469 by ph10, Mon Oct 19 14:38:48 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.00 19-Oct-09
5  ----------------------  ----------------------
6    
7  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
8      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
9      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
10      error.      error.
11    
12  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
13      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
14      in a Windows environment.      in a Windows environment.
15    
16  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
17      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
18      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
19      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
20      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
21      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
22      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
23    
24  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
25      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
26      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
27      the old behaviour.      the old behaviour.
28    
29  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
30      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
31      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
32      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
33    
34    6.  No libpcreposix.pc file was created for pkg-config; there was just
35        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
36    
37    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
38        when UCP support is not needed, by modifying the Python script that
39        generates it from Unicode data files. This should not matter if the module
40        is correctly used as a library, but I received one complaint about 50K of
41        unwanted data. My guess is that the person linked everything into his
42        program rather than using a library. Anyway, it does no harm.
43    
44    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
45        was a minimum greater than 1 for a wide character in a possessive
46        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
47        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
48        character. Chaos in the form of incorrect output or a compiling loop could
49        result.
50    
51    9.  The restrictions on what a pattern can contain when partial matching is
52        requested for pcre_exec() have been removed. All patterns can now be
53        partially matched by this function. In addition, if there are at least two
54        slots in the offset vector, the offset of the earliest inspected character
55        for the match and the offset of the end of the subject are set in them when
56        PCRE_ERROR_PARTIAL is returned.
57    
58    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
59        synonymous with PCRE_PARTIAL, for backwards compatibility, and
60        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
61        and may be more useful for multi-segment matching.
62    
63    11. Partial matching with pcre_exec() is now more intuitive. A partial match
64        used to be given if ever the end of the subject was reached; now it is
65        given only if matching could not proceed because another character was
66        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
67        string "Z", which now yields "no match" instead of "partial match". In the
68        case of pcre_dfa_exec(), "no match" is given if every matching path for the
69        final character ended with (*FAIL).
70    
71    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
72        if the pattern had a "must contain" character that was already found in the
73        earlier partial match, unless partial matching was again requested. For
74        example, with the pattern /dog.(body)?/, the "must contain" character is
75        "g". If the first part-match was for the string "dog", restarting with
76        "sbody" failed. This bug has been fixed.
77    
78    13. The string returned by pcre_dfa_exec() after a partial match has been
79        changed so that it starts at the first inspected character rather than the
80        first character of the match. This makes a difference only if the pattern
81        starts with a lookbehind assertion or \b or \B (\K is not supported by
82        pcre_dfa_exec()). It's an incompatible change, but it makes the two
83        matching functions compatible, and I think it's the right thing to do.
84    
85    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
86        so that the demonstration program is easily available in environments where
87        PCRE has not been installed from source.
88    
89    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
90        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
91        library.
92    
93    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
94        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
95        is not the first non-POSIX option to be added. Clearly some people find
96        these options useful.
97    
98    17. If a caller to the POSIX matching function regexec() passes a non-zero
99        value for nmatch with a NULL value for pmatch, the value of
100        nmatch is forced to zero.
101    
102    18. RunGrepTest did not have a test for the availability of the -u option of
103        the diff command, as RunTest does. It now checks in the same way as
104        RunTest, and also checks for the -b option.
105    
106    19. If an odd number of negated classes containing just a single character
107        interposed, within parentheses, between a forward reference to a named
108        subpattern and the definition of the subpattern, compilation crashed with
109        an internal error, complaining that it could not find the referenced
110        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
111        [The bug was that it was starting one character too far in when skipping
112        over the character class, thus treating the ] as data rather than
113        terminating the class. This meant it could skip too much.]
114    
115    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
116        /g option in pcretest when the pattern contains \K, which makes it possible
117        to have an empty string match not at the start, even when the pattern is
118        anchored. Updated pcretest and pcredemo to use this option.
119    
120    21. If the maximum number of capturing subpatterns in a recursion was greater
121        than the maximum at the outer level, the higher number was returned, but
122        with unset values at the outer level. The correct (outer level) value is
123        now given.
124    
125    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
126        PCRE did not set those parentheses (unlike Perl). I have now found a way to
127        make it do so. The string so far is captured, making this feature
128        compatible with Perl.
129    
130    23. The tests have been re-organized, adding tests 11 and 12, to make it
131        possible to check the Perl 5.10 features against Perl 5.10.
132    
133    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
134        pattern matches a fixed length string. PCRE did not allow this; now it
135        does. Neither allows recursion.
136    
137    25. I finally figured out how to implement a request to provide the minimum
138        length of subject string that was needed in order to match a given pattern.
139        (It was back references and recursion that I had previously got hung up
140        on.) This code has now been added to pcre_study(); it finds a lower bound
141        to the length of subject needed. It is not necessarily the greatest lower
142        bound, but using it to avoid searching strings that are too short does give
143        some useful speed-ups. The value is available to calling programs via
144        pcre_fullinfo().
145    
146    26. While implementing 25, I discovered to my embarrassment that pcretest had
147        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
148        study optimizations had never been tested with that matching function.
149        Oops. What is worse, even when it was passed study data, there was a bug in
150        pcre_dfa_exec() that meant it never actually used it. Double oops. There
151        were also very few tests of studied patterns with pcre_dfa_exec().
152    
153    27. If (?| is used to create subpatterns with duplicate numbers, they are now
154        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
155        on the other side of the coin, they are no longer allowed to have different
156        names, because these cannot be distinguished in PCRE, and this has caused
157        confusion. (This is a difference from Perl.)
158    
159    28. When duplicate subpattern names are present (necessarily with different
160        numbers, as required by 27 above), and a test is made by name in a
161        conditional pattern, either for a subpattern having been matched, or for
162        recursion in such a pattern, all the associated numbered subpatterns are
163        tested, and the overall condition is true if the condition is true for any
164        one of them. This is the way Perl works, and is also more like the way
165        testing by number works.
166    
167    
168  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
169  ---------------------  ---------------------

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