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revision 412 by ph10, Sat Apr 11 10:34:37 2009 UTC revision 474 by ph10, Sat Jan 2 16:30:46 2010 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    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
20        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
21        assertion pattern did not match (meaning that the assertion was true), it
22        was incorrectly treated as false if the SKIP had been reached during the
23        matching. This also applied to assertions used as conditions.
24    
25    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
26        assertion subpattern, including such a pattern used as a condition,
27        unpredictable results occurred, instead of the error return
28        PCRE_ERROR_DFA_UITEM.
29    
30    5.  The C++ GlobalReplace function was not working like Perl for the special
31        situation when an empty string is matched. It now does the fancy magic
32        stuff that is necessary.
33    
34    
35    Version 8.00 19-Oct-09
36    ----------------------
37    
38    1.  The table for translating pcre_compile() error codes into POSIX error codes
39        was out-of-date, and there was no check on the pcre_compile() error code
40        being within the table. This could lead to an OK return being given in
41        error.
42    
43    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
44        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
45        in a Windows environment.
46    
47    3.  The pcregrep --count option prints the count for each file even when it is
48        zero, as does GNU grep. However, pcregrep was also printing all files when
49        --files-with-matches was added. Now, when both options are given, it prints
50        counts only for those files that have at least one match. (GNU grep just
51        prints the file name in this circumstance, but including the count seems
52        more useful - otherwise, why use --count?) Also ensured that the
53        combination -clh just lists non-zero counts, with no names.
54    
55    4.  The long form of the pcregrep -F option was incorrectly implemented as
56        --fixed_strings instead of --fixed-strings. This is an incompatible change,
57        but it seems right to fix it, and I didn't think it was worth preserving
58        the old behaviour.
59    
60    5.  The command line items --regex=pattern and --regexp=pattern were not
61        recognized by pcregrep, which required --regex pattern or --regexp pattern
62        (with a space rather than an '='). The man page documented the '=' forms,
63        which are compatible with GNU grep; these now work.
64    
65    6.  No libpcreposix.pc file was created for pkg-config; there was just
66        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
67    
68    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
69        when UCP support is not needed, by modifying the Python script that
70        generates it from Unicode data files. This should not matter if the module
71        is correctly used as a library, but I received one complaint about 50K of
72        unwanted data. My guess is that the person linked everything into his
73        program rather than using a library. Anyway, it does no harm.
74    
75    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
76        was a minimum greater than 1 for a wide character in a possessive
77        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
78        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
79        character. Chaos in the form of incorrect output or a compiling loop could
80        result.
81    
82    9.  The restrictions on what a pattern can contain when partial matching is
83        requested for pcre_exec() have been removed. All patterns can now be
84        partially matched by this function. In addition, if there are at least two
85        slots in the offset vector, the offset of the earliest inspected character
86        for the match and the offset of the end of the subject are set in them when
87        PCRE_ERROR_PARTIAL is returned.
88    
89    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
90        synonymous with PCRE_PARTIAL, for backwards compatibility, and
91        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
92        and may be more useful for multi-segment matching.
93    
94    11. Partial matching with pcre_exec() is now more intuitive. A partial match
95        used to be given if ever the end of the subject was reached; now it is
96        given only if matching could not proceed because another character was
97        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
98        string "Z", which now yields "no match" instead of "partial match". In the
99        case of pcre_dfa_exec(), "no match" is given if every matching path for the
100        final character ended with (*FAIL).
101    
102    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
103        if the pattern had a "must contain" character that was already found in the
104        earlier partial match, unless partial matching was again requested. For
105        example, with the pattern /dog.(body)?/, the "must contain" character is
106        "g". If the first part-match was for the string "dog", restarting with
107        "sbody" failed. This bug has been fixed.
108    
109    13. The string returned by pcre_dfa_exec() after a partial match has been
110        changed so that it starts at the first inspected character rather than the
111        first character of the match. This makes a difference only if the pattern
112        starts with a lookbehind assertion or \b or \B (\K is not supported by
113        pcre_dfa_exec()). It's an incompatible change, but it makes the two
114        matching functions compatible, and I think it's the right thing to do.
115    
116    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
117        so that the demonstration program is easily available in environments where
118        PCRE has not been installed from source.
119    
120    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
121        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
122        library.
123    
124    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
125        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
126        is not the first non-POSIX option to be added. Clearly some people find
127        these options useful.
128    
129    17. If a caller to the POSIX matching function regexec() passes a non-zero
130        value for nmatch with a NULL value for pmatch, the value of
131        nmatch is forced to zero.
132    
133    18. RunGrepTest did not have a test for the availability of the -u option of
134        the diff command, as RunTest does. It now checks in the same way as
135        RunTest, and also checks for the -b option.
136    
137    19. If an odd number of negated classes containing just a single character
138        interposed, within parentheses, between a forward reference to a named
139        subpattern and the definition of the subpattern, compilation crashed with
140        an internal error, complaining that it could not find the referenced
141        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
142        [The bug was that it was starting one character too far in when skipping
143        over the character class, thus treating the ] as data rather than
144        terminating the class. This meant it could skip too much.]
145    
146    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
147        /g option in pcretest when the pattern contains \K, which makes it possible
148        to have an empty string match not at the start, even when the pattern is
149        anchored. Updated pcretest and pcredemo to use this option.
150    
151    21. If the maximum number of capturing subpatterns in a recursion was greater
152        than the maximum at the outer level, the higher number was returned, but
153        with unset values at the outer level. The correct (outer level) value is
154        now given.
155    
156    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
157        PCRE did not set those parentheses (unlike Perl). I have now found a way to
158        make it do so. The string so far is captured, making this feature
159        compatible with Perl.
160    
161    23. The tests have been re-organized, adding tests 11 and 12, to make it
162        possible to check the Perl 5.10 features against Perl 5.10.
163    
164    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
165        pattern matches a fixed length string. PCRE did not allow this; now it
166        does. Neither allows recursion.
167    
168    25. I finally figured out how to implement a request to provide the minimum
169        length of subject string that was needed in order to match a given pattern.
170        (It was back references and recursion that I had previously got hung up
171        on.) This code has now been added to pcre_study(); it finds a lower bound
172        to the length of subject needed. It is not necessarily the greatest lower
173        bound, but using it to avoid searching strings that are too short does give
174        some useful speed-ups. The value is available to calling programs via
175        pcre_fullinfo().
176    
177    26. While implementing 25, I discovered to my embarrassment that pcretest had
178        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
179        study optimizations had never been tested with that matching function.
180        Oops. What is worse, even when it was passed study data, there was a bug in
181        pcre_dfa_exec() that meant it never actually used it. Double oops. There
182        were also very few tests of studied patterns with pcre_dfa_exec().
183    
184    27. If (?| is used to create subpatterns with duplicate numbers, they are now
185        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
186        on the other side of the coin, they are no longer allowed to have different
187        names, because these cannot be distinguished in PCRE, and this has caused
188        confusion. (This is a difference from Perl.)
189    
190    28. When duplicate subpattern names are present (necessarily with different
191        numbers, as required by 27 above), and a test is made by name in a
192        conditional pattern, either for a subpattern having been matched, or for
193        recursion in such a pattern, all the associated numbered subpatterns are
194        tested, and the overall condition is true if the condition is true for any
195        one of them. This is the way Perl works, and is also more like the way
196        testing by number works.
197    
198    
199  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
200  ---------------------  ---------------------
201    
# Line 112  Version 7.9 11-Apr-09 Line 307  Version 7.9 11-Apr-09
307    
308  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
309      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).
310    
311  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
312      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
313      pre-defined.      pre-defined.
314    
315  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
316    
317    29. Arrange for flags added by the "release type" setting in CMake to be shown
318        in the configuration summary.
319    
320    
321  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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