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revision 412 by ph10, Sat Apr 11 10:34:37 2009 UTC revision 471 by ph10, Fri Dec 11 15:11:55 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    
13    Version 8.00 19-Oct-09
14    ----------------------
15    
16    1.  The table for translating pcre_compile() error codes into POSIX error codes
17        was out-of-date, and there was no check on the pcre_compile() error code
18        being within the table. This could lead to an OK return being given in
19        error.
20    
21    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
22        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
23        in a Windows environment.
24    
25    3.  The pcregrep --count option prints the count for each file even when it is
26        zero, as does GNU grep. However, pcregrep was also printing all files when
27        --files-with-matches was added. Now, when both options are given, it prints
28        counts only for those files that have at least one match. (GNU grep just
29        prints the file name in this circumstance, but including the count seems
30        more useful - otherwise, why use --count?) Also ensured that the
31        combination -clh just lists non-zero counts, with no names.
32    
33    4.  The long form of the pcregrep -F option was incorrectly implemented as
34        --fixed_strings instead of --fixed-strings. This is an incompatible change,
35        but it seems right to fix it, and I didn't think it was worth preserving
36        the old behaviour.
37    
38    5.  The command line items --regex=pattern and --regexp=pattern were not
39        recognized by pcregrep, which required --regex pattern or --regexp pattern
40        (with a space rather than an '='). The man page documented the '=' forms,
41        which are compatible with GNU grep; these now work.
42    
43    6.  No libpcreposix.pc file was created for pkg-config; there was just
44        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
45    
46    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
47        when UCP support is not needed, by modifying the Python script that
48        generates it from Unicode data files. This should not matter if the module
49        is correctly used as a library, but I received one complaint about 50K of
50        unwanted data. My guess is that the person linked everything into his
51        program rather than using a library. Anyway, it does no harm.
52    
53    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
54        was a minimum greater than 1 for a wide character in a possessive
55        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
56        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
57        character. Chaos in the form of incorrect output or a compiling loop could
58        result.
59    
60    9.  The restrictions on what a pattern can contain when partial matching is
61        requested for pcre_exec() have been removed. All patterns can now be
62        partially matched by this function. In addition, if there are at least two
63        slots in the offset vector, the offset of the earliest inspected character
64        for the match and the offset of the end of the subject are set in them when
65        PCRE_ERROR_PARTIAL is returned.
66    
67    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
68        synonymous with PCRE_PARTIAL, for backwards compatibility, and
69        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
70        and may be more useful for multi-segment matching.
71    
72    11. Partial matching with pcre_exec() is now more intuitive. A partial match
73        used to be given if ever the end of the subject was reached; now it is
74        given only if matching could not proceed because another character was
75        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
76        string "Z", which now yields "no match" instead of "partial match". In the
77        case of pcre_dfa_exec(), "no match" is given if every matching path for the
78        final character ended with (*FAIL).
79    
80    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
81        if the pattern had a "must contain" character that was already found in the
82        earlier partial match, unless partial matching was again requested. For
83        example, with the pattern /dog.(body)?/, the "must contain" character is
84        "g". If the first part-match was for the string "dog", restarting with
85        "sbody" failed. This bug has been fixed.
86    
87    13. The string returned by pcre_dfa_exec() after a partial match has been
88        changed so that it starts at the first inspected character rather than the
89        first character of the match. This makes a difference only if the pattern
90        starts with a lookbehind assertion or \b or \B (\K is not supported by
91        pcre_dfa_exec()). It's an incompatible change, but it makes the two
92        matching functions compatible, and I think it's the right thing to do.
93    
94    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
95        so that the demonstration program is easily available in environments where
96        PCRE has not been installed from source.
97    
98    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
99        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
100        library.
101    
102    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
103        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
104        is not the first non-POSIX option to be added. Clearly some people find
105        these options useful.
106    
107    17. If a caller to the POSIX matching function regexec() passes a non-zero
108        value for nmatch with a NULL value for pmatch, the value of
109        nmatch is forced to zero.
110    
111    18. RunGrepTest did not have a test for the availability of the -u option of
112        the diff command, as RunTest does. It now checks in the same way as
113        RunTest, and also checks for the -b option.
114    
115    19. If an odd number of negated classes containing just a single character
116        interposed, within parentheses, between a forward reference to a named
117        subpattern and the definition of the subpattern, compilation crashed with
118        an internal error, complaining that it could not find the referenced
119        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
120        [The bug was that it was starting one character too far in when skipping
121        over the character class, thus treating the ] as data rather than
122        terminating the class. This meant it could skip too much.]
123    
124    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
125        /g option in pcretest when the pattern contains \K, which makes it possible
126        to have an empty string match not at the start, even when the pattern is
127        anchored. Updated pcretest and pcredemo to use this option.
128    
129    21. If the maximum number of capturing subpatterns in a recursion was greater
130        than the maximum at the outer level, the higher number was returned, but
131        with unset values at the outer level. The correct (outer level) value is
132        now given.
133    
134    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
135        PCRE did not set those parentheses (unlike Perl). I have now found a way to
136        make it do so. The string so far is captured, making this feature
137        compatible with Perl.
138    
139    23. The tests have been re-organized, adding tests 11 and 12, to make it
140        possible to check the Perl 5.10 features against Perl 5.10.
141    
142    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
143        pattern matches a fixed length string. PCRE did not allow this; now it
144        does. Neither allows recursion.
145    
146    25. I finally figured out how to implement a request to provide the minimum
147        length of subject string that was needed in order to match a given pattern.
148        (It was back references and recursion that I had previously got hung up
149        on.) This code has now been added to pcre_study(); it finds a lower bound
150        to the length of subject needed. It is not necessarily the greatest lower
151        bound, but using it to avoid searching strings that are too short does give
152        some useful speed-ups. The value is available to calling programs via
153        pcre_fullinfo().
154    
155    26. While implementing 25, I discovered to my embarrassment that pcretest had
156        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
157        study optimizations had never been tested with that matching function.
158        Oops. What is worse, even when it was passed study data, there was a bug in
159        pcre_dfa_exec() that meant it never actually used it. Double oops. There
160        were also very few tests of studied patterns with pcre_dfa_exec().
161    
162    27. If (?| is used to create subpatterns with duplicate numbers, they are now
163        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
164        on the other side of the coin, they are no longer allowed to have different
165        names, because these cannot be distinguished in PCRE, and this has caused
166        confusion. (This is a difference from Perl.)
167    
168    28. When duplicate subpattern names are present (necessarily with different
169        numbers, as required by 27 above), and a test is made by name in a
170        conditional pattern, either for a subpattern having been matched, or for
171        recursion in such a pattern, all the associated numbered subpatterns are
172        tested, and the overall condition is true if the condition is true for any
173        one of them. This is the way Perl works, and is also more like the way
174        testing by number works.
175    
176    
177  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
178  ---------------------  ---------------------
179    
# Line 112  Version 7.9 11-Apr-09 Line 285  Version 7.9 11-Apr-09
285    
286  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
287      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).
288    
289  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
290      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
291      pre-defined.      pre-defined.
292    
293  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
294    
295    29. Arrange for flags added by the "release type" setting in CMake to be shown
296        in the configuration summary.
297    
298    
299  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08
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