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revision 368 by ph10, Sun Aug 24 16:25:20 2008 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 7.8 25-Aug-08  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24        was out-of-date, and there was no check on the pcre_compile() error code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
185    ---------------------
186    
187    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
188        (pcretest), all targets were linked against these libraries. This included
189        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
190        libraries. This caused unwanted dependencies to be created. This problem
191        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
192        pcretest is linked with readline.
193    
194    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
195        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
196        moved outside it again, because FALSE and TRUE are already defined in AIX,
197        but BOOL is not.
198    
199    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
200        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
201    
202    4.  The pcregrep documentation said spaces were inserted as well as colons (or
203        hyphens) following file names and line numbers when outputting matching
204        lines. This is not true; no spaces are inserted. I have also clarified the
205        wording for the --colour (or --color) option.
206    
207    5.  In pcregrep, when --colour was used with -o, the list of matching strings
208        was not coloured; this is different to GNU grep, so I have changed it to be
209        the same.
210    
211    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
212        each matching line was coloured. Now it goes on to look for further matches
213        of any of the test patterns, which is the same behaviour as GNU grep.
214    
215    7.  A pattern that could match an empty string could cause pcregrep to loop; it
216        doesn't make sense to accept an empty string match in pcregrep, so I have
217        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
218        seems to be how GNU grep behaves.
219    
220    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
221        start or after a newline", because the conditional assertion was not being
222        correctly handled. The rule now is that both the assertion and what follows
223        in the first alternative must satisfy the test.
224    
225    9.  If auto-callout was enabled in a pattern with a conditional group whose
226        condition was an assertion, PCRE could crash during matching, both with
227        pcre_exec() and pcre_dfa_exec().
228    
229    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
230        used for matching.
231    
232    11. Unicode property support in character classes was not working for
233        characters (bytes) greater than 127 when not in UTF-8 mode.
234    
235    12. Added the -M command line option to pcretest.
236    
237    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
238    
239    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
240    
241    16. Added comments and documentation about mis-use of no_arg in the C++
242        wrapper.
243    
244    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
245        from Martin Jerabek that uses macro names for all relevant character and
246        string constants.
247    
248    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
249        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
250        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
251        these, but not everybody uses configure.
252    
253    19. A conditional group that had only one branch was not being correctly
254        recognized as an item that could match an empty string. This meant that an
255        enclosing group might also not be so recognized, causing infinite looping
256        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
257        with the subject "ab", where knowledge that the repeated group can match
258        nothing is needed in order to break the loop.
259    
260    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
261        exec(), but without supplying a callout function, matching went wrong.
262    
263    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
264        leak if the size of the offset vector was greater than 30. When the vector
265        is smaller, the saved offsets during recursion go onto a local stack
266        vector, but for larger vectors malloc() is used. It was failing to free
267        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
268        error, in fact).
269    
270    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
271        heapframe that is used only when UTF-8 support is enabled. This caused no
272        problem, but was untidy.
273    
274    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
275        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
276        included within another project.
277    
278    24. Steven Van Ingelgem's patches to add more options to the CMake support,
279        slightly modified by me:
280    
281          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
282              not building pcregrep.
283    
284          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
285              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
286    
287    25. Forward references, both numeric and by name, in patterns that made use of
288        duplicate group numbers, could behave incorrectly or give incorrect errors,
289        because when scanning forward to find the reference group, PCRE was not
290        taking into account the duplicate group numbers. A pattern such as
291        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
292    
293    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).
295    
296    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
298        pre-defined.
299    
300    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
303        in the configuration summary.
304    
305    
306    Version 7.8 05-Sep-08
307  ---------------------  ---------------------
308    
309  1.  Replaced UCP searching code with optimized version as implemented for Ad  1.  Replaced UCP searching code with optimized version as implemented for Ad
# Line 31  Version 7.8 25-Aug-08 Line 333  Version 7.8 25-Aug-08
333    
334  7.  Added two (int) casts to pcregrep when printing the difference of two  7.  Added two (int) casts to pcregrep when printing the difference of two
335      pointers, in case they are 64-bit values.      pointers, in case they are 64-bit values.
336    
337  8.  Added comments about Mac OS X stack usage to the pcrestack man page and to  8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
338      test 2 if it fails.      test 2 if it fails.
339    
340  9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,  9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
341      and a #define of that name to empty if it is not externally set. This is to      and a #define of that name to empty if it is not externally set. This is to
342      allow users of MSVC to set it if necessary.      allow users of MSVC to set it if necessary.
343    
344  10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from  10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
345      the convenience functions in the pcre_get.c source file.      the convenience functions in the pcre_get.c source file.
346    
347  11. An option change at the start of a pattern that had top-level alternatives  11. An option change at the start of a pattern that had top-level alternatives
348      could cause overwriting and/or a crash. This command provoked a crash in      could cause overwriting and/or a crash. This command provoked a crash in
349      some environments:      some environments:
350    
351        printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest        printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
352    
353      This potential security problem was recorded as CVE-2008-2371.      This potential security problem was recorded as CVE-2008-2371.
354    
355  12. For a pattern where the match had to start at the beginning or immediately  12. For a pattern where the match had to start at the beginning or immediately
356      after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and      after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
357      pcre_dfa_exec() could read past the end of the passed subject if there was      pcre_dfa_exec() could read past the end of the passed subject if there was
358      no match. To help with detecting such bugs (e.g. with valgrind), I modified      no match. To help with detecting such bugs (e.g. with valgrind), I modified
359      pcretest so that it places the subject at the end of its malloc-ed buffer.      pcretest so that it places the subject at the end of its malloc-ed buffer.
360    
361  13. The change to pcretest in 12 above threw up a couple more cases when pcre_  13. The change to pcretest in 12 above threw up a couple more cases when pcre_
362      exec() might read past the end of the data buffer in UTF-8 mode.      exec() might read past the end of the data buffer in UTF-8 mode.
363    
364  14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and  14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
365      the data contained the byte 0x85 as part of a UTF-8 character within its      the data contained the byte 0x85 as part of a UTF-8 character within its
366      first line. This applied both to normal and DFA matching.      first line. This applied both to normal and DFA matching.
367    
368  15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,  15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
369      /^[^d]*?$/8 failed to match "abc".      /^[^d]*?$/8 failed to match "abc".
370    
371  16. Added a missing copyright notice to pcrecpp_internal.h.  16. Added a missing copyright notice to pcrecpp_internal.h.
372    
373  17. Make it more clear in the documentation that values returned from  17. Make it more clear in the documentation that values returned from
374      pcre_exec() in ovector are byte offsets, not character counts.      pcre_exec() in ovector are byte offsets, not character counts.
375    
376    18. Tidied a few places to stop certain compilers from issuing warnings.
377    
378    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
379        supplied by Stefan Weber. I made a further small update for 7.8 because
380        there is a change of source arrangements: the pcre_searchfuncs.c module is
381        replaced by pcre_ucd.c.
382    
383    
384  Version 7.7 07-May-08  Version 7.7 07-May-08
385  ---------------------  ---------------------

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