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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.0 02 Jul-08  Version 8.01 11-Dec-09
5    ----------------------
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).
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.)
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.
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
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.
34    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
35        removed. (These were left over from very, very early versions of PCRE.)
37    7.  Some cosmetic changes to the code to make life easier when compiling it
38        as part of something else:
40        (a) Change DEBUG to PCRE_DEBUG.
42        (b) In pcre_compile(), rename the member of the "branch_chain" structure
43            called "current" as "current_branch", to prevent a collision with the
44            Linux macro when compiled as a kernel module.
46        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
47            prevent a collision with the Linux macro when compiled as a kernel
48            module.
50    8.  In pcre_compile() there are some checks for integer overflows that used to
51        cast potentially large values to (double). This has been changed to that
52        when building, a check for int64_t is made, and if it is found, it is used
53        instead, thus avoiding the use of floating point arithmetic. (There is no
54        other use of FP in PCRE.) If int64_t is not found, the fallback is to
55        double.
57    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
58        2005 (difference between two addresses compared to an unsigned value).
62    Version 8.00 19-Oct-09
63    ----------------------
65    1.  The table for translating pcre_compile() error codes into POSIX error codes
66        was out-of-date, and there was no check on the pcre_compile() error code
67        being within the table. This could lead to an OK return being given in
68        error.
70    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
71        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
72        in a Windows environment.
74    3.  The pcregrep --count option prints the count for each file even when it is
75        zero, as does GNU grep. However, pcregrep was also printing all files when
76        --files-with-matches was added. Now, when both options are given, it prints
77        counts only for those files that have at least one match. (GNU grep just
78        prints the file name in this circumstance, but including the count seems
79        more useful - otherwise, why use --count?) Also ensured that the
80        combination -clh just lists non-zero counts, with no names.
82    4.  The long form of the pcregrep -F option was incorrectly implemented as
83        --fixed_strings instead of --fixed-strings. This is an incompatible change,
84        but it seems right to fix it, and I didn't think it was worth preserving
85        the old behaviour.
87    5.  The command line items --regex=pattern and --regexp=pattern were not
88        recognized by pcregrep, which required --regex pattern or --regexp pattern
89        (with a space rather than an '='). The man page documented the '=' forms,
90        which are compatible with GNU grep; these now work.
92    6.  No libpcreposix.pc file was created for pkg-config; there was just
93        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
95    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
96        when UCP support is not needed, by modifying the Python script that
97        generates it from Unicode data files. This should not matter if the module
98        is correctly used as a library, but I received one complaint about 50K of
99        unwanted data. My guess is that the person linked everything into his
100        program rather than using a library. Anyway, it does no harm.
102    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
103        was a minimum greater than 1 for a wide character in a possessive
104        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
105        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
106        character. Chaos in the form of incorrect output or a compiling loop could
107        result.
109    9.  The restrictions on what a pattern can contain when partial matching is
110        requested for pcre_exec() have been removed. All patterns can now be
111        partially matched by this function. In addition, if there are at least two
112        slots in the offset vector, the offset of the earliest inspected character
113        for the match and the offset of the end of the subject are set in them when
114        PCRE_ERROR_PARTIAL is returned.
116    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
117        synonymous with PCRE_PARTIAL, for backwards compatibility, and
118        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
119        and may be more useful for multi-segment matching.
121    11. Partial matching with pcre_exec() is now more intuitive. A partial match
122        used to be given if ever the end of the subject was reached; now it is
123        given only if matching could not proceed because another character was
124        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
125        string "Z", which now yields "no match" instead of "partial match". In the
126        case of pcre_dfa_exec(), "no match" is given if every matching path for the
127        final character ended with (*FAIL).
129    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
130        if the pattern had a "must contain" character that was already found in the
131        earlier partial match, unless partial matching was again requested. For
132        example, with the pattern /dog.(body)?/, the "must contain" character is
133        "g". If the first part-match was for the string "dog", restarting with
134        "sbody" failed. This bug has been fixed.
136    13. The string returned by pcre_dfa_exec() after a partial match has been
137        changed so that it starts at the first inspected character rather than the
138        first character of the match. This makes a difference only if the pattern
139        starts with a lookbehind assertion or \b or \B (\K is not supported by
140        pcre_dfa_exec()). It's an incompatible change, but it makes the two
141        matching functions compatible, and I think it's the right thing to do.
143    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
144        so that the demonstration program is easily available in environments where
145        PCRE has not been installed from source.
147    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
148        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
149        library.
151    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
152        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
153        is not the first non-POSIX option to be added. Clearly some people find
154        these options useful.
156    17. If a caller to the POSIX matching function regexec() passes a non-zero
157        value for nmatch with a NULL value for pmatch, the value of
158        nmatch is forced to zero.
160    18. RunGrepTest did not have a test for the availability of the -u option of
161        the diff command, as RunTest does. It now checks in the same way as
162        RunTest, and also checks for the -b option.
164    19. If an odd number of negated classes containing just a single character
165        interposed, within parentheses, between a forward reference to a named
166        subpattern and the definition of the subpattern, compilation crashed with
167        an internal error, complaining that it could not find the referenced
168        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
169        [The bug was that it was starting one character too far in when skipping
170        over the character class, thus treating the ] as data rather than
171        terminating the class. This meant it could skip too much.]
173    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
174        /g option in pcretest when the pattern contains \K, which makes it possible
175        to have an empty string match not at the start, even when the pattern is
176        anchored. Updated pcretest and pcredemo to use this option.
178    21. If the maximum number of capturing subpatterns in a recursion was greater
179        than the maximum at the outer level, the higher number was returned, but
180        with unset values at the outer level. The correct (outer level) value is
181        now given.
183    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
184        PCRE did not set those parentheses (unlike Perl). I have now found a way to
185        make it do so. The string so far is captured, making this feature
186        compatible with Perl.
188    23. The tests have been re-organized, adding tests 11 and 12, to make it
189        possible to check the Perl 5.10 features against Perl 5.10.
191    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
192        pattern matches a fixed length string. PCRE did not allow this; now it
193        does. Neither allows recursion.
195    25. I finally figured out how to implement a request to provide the minimum
196        length of subject string that was needed in order to match a given pattern.
197        (It was back references and recursion that I had previously got hung up
198        on.) This code has now been added to pcre_study(); it finds a lower bound
199        to the length of subject needed. It is not necessarily the greatest lower
200        bound, but using it to avoid searching strings that are too short does give
201        some useful speed-ups. The value is available to calling programs via
202        pcre_fullinfo().
204    26. While implementing 25, I discovered to my embarrassment that pcretest had
205        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
206        study optimizations had never been tested with that matching function.
207        Oops. What is worse, even when it was passed study data, there was a bug in
208        pcre_dfa_exec() that meant it never actually used it. Double oops. There
209        were also very few tests of studied patterns with pcre_dfa_exec().
211    27. If (?| is used to create subpatterns with duplicate numbers, they are now
212        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
213        on the other side of the coin, they are no longer allowed to have different
214        names, because these cannot be distinguished in PCRE, and this has caused
215        confusion. (This is a difference from Perl.)
217    28. When duplicate subpattern names are present (necessarily with different
218        numbers, as required by 27 above), and a test is made by name in a
219        conditional pattern, either for a subpattern having been matched, or for
220        recursion in such a pattern, all the associated numbered subpatterns are
221        tested, and the overall condition is true if the condition is true for any
222        one of them. This is the way Perl works, and is also more like the way
223        testing by number works.
226    Version 7.9 11-Apr-09
227    ---------------------
229    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
230        (pcretest), all targets were linked against these libraries. This included
231        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
232        libraries. This caused unwanted dependencies to be created. This problem
233        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
234        pcretest is linked with readline.
236    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
237        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
238        moved outside it again, because FALSE and TRUE are already defined in AIX,
239        but BOOL is not.
241    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
242        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
244    4.  The pcregrep documentation said spaces were inserted as well as colons (or
245        hyphens) following file names and line numbers when outputting matching
246        lines. This is not true; no spaces are inserted. I have also clarified the
247        wording for the --colour (or --color) option.
249    5.  In pcregrep, when --colour was used with -o, the list of matching strings
250        was not coloured; this is different to GNU grep, so I have changed it to be
251        the same.
253    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
254        each matching line was coloured. Now it goes on to look for further matches
255        of any of the test patterns, which is the same behaviour as GNU grep.
257    7.  A pattern that could match an empty string could cause pcregrep to loop; it
258        doesn't make sense to accept an empty string match in pcregrep, so I have
259        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
260        seems to be how GNU grep behaves.
262    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
263        start or after a newline", because the conditional assertion was not being
264        correctly handled. The rule now is that both the assertion and what follows
265        in the first alternative must satisfy the test.
267    9.  If auto-callout was enabled in a pattern with a conditional group whose
268        condition was an assertion, PCRE could crash during matching, both with
269        pcre_exec() and pcre_dfa_exec().
271    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
272        used for matching.
274    11. Unicode property support in character classes was not working for
275        characters (bytes) greater than 127 when not in UTF-8 mode.
277    12. Added the -M command line option to pcretest.
279    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
281    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
283    16. Added comments and documentation about mis-use of no_arg in the C++
284        wrapper.
286    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
287        from Martin Jerabek that uses macro names for all relevant character and
288        string constants.
290    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
291        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
292        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
293        these, but not everybody uses configure.
295    19. A conditional group that had only one branch was not being correctly
296        recognized as an item that could match an empty string. This meant that an
297        enclosing group might also not be so recognized, causing infinite looping
298        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
299        with the subject "ab", where knowledge that the repeated group can match
300        nothing is needed in order to break the loop.
302    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
303        exec(), but without supplying a callout function, matching went wrong.
305    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
306        leak if the size of the offset vector was greater than 30. When the vector
307        is smaller, the saved offsets during recursion go onto a local stack
308        vector, but for larger vectors malloc() is used. It was failing to free
309        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
310        error, in fact).
312    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
313        heapframe that is used only when UTF-8 support is enabled. This caused no
314        problem, but was untidy.
316    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
317        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
318        included within another project.
320    24. Steven Van Ingelgem's patches to add more options to the CMake support,
321        slightly modified by me:
323          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
324              not building pcregrep.
326          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
327              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
329    25. Forward references, both numeric and by name, in patterns that made use of
330        duplicate group numbers, could behave incorrectly or give incorrect errors,
331        because when scanning forward to find the reference group, PCRE was not
332        taking into account the duplicate group numbers. A pattern such as
333        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
335    26. Changed a few more instances of "const unsigned char *" to USPTR, making
336        the feature of a custom pointer more persuasive (as requested by a user).
338    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
339        pcretest.c, inside #ifndefs, because it seems they are sometimes already
340        pre-defined.
342    28. Added support for (*UTF8) at the start of a pattern.
344    29. Arrange for flags added by the "release type" setting in CMake to be shown
345        in the configuration summary.
348    Version 7.8 05-Sep-08
349  ---------------------  ---------------------
351  1.  Replaced UCP searching code with optimized version as implemented for Ad  1.  Replaced UCP searching code with optimized version as implemented for Ad
352      Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-      Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
353      stage table and inline lookup instead of a function, giving speed ups of 2      stage table and inline lookup instead of a function, giving speed ups of 2
354      to 5 times on some simple patterns that I tested. Permission was given to      to 5 times on some simple patterns that I tested. Permission was given to
355      distribute the MultiStage2.py script that generates the tables (it's not in      distribute the MultiStage2.py script that generates the tables (it's not in
356      the tarball, but is in the Subversion repository).      the tarball, but is in the Subversion repository).
358    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
359        scripts.
361    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
362        a group with a zero qualifier. The result of the study could be incorrect,
363        or the function might crash, depending on the pattern.
365    4.  Caseless matching was not working for non-ASCII characters in back
366        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
367        It now works when Unicode Property Support is available.
369    5.  In pcretest, an escape such as \x{de} in the data was always generating
370        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
371        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
372        truncation.
374    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
376    7.  Added two (int) casts to pcregrep when printing the difference of two
377        pointers, in case they are 64-bit values.
379    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
380        test 2 if it fails.
382    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
383        and a #define of that name to empty if it is not externally set. This is to
384        allow users of MSVC to set it if necessary.
386    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
387        the convenience functions in the pcre_get.c source file.
389    11. An option change at the start of a pattern that had top-level alternatives
390        could cause overwriting and/or a crash. This command provoked a crash in
391        some environments:
393          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
395        This potential security problem was recorded as CVE-2008-2371.
397    12. For a pattern where the match had to start at the beginning or immediately
398        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
399        pcre_dfa_exec() could read past the end of the passed subject if there was
400        no match. To help with detecting such bugs (e.g. with valgrind), I modified
401        pcretest so that it places the subject at the end of its malloc-ed buffer.
403    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
404        exec() might read past the end of the data buffer in UTF-8 mode.
406    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
407        the data contained the byte 0x85 as part of a UTF-8 character within its
408        first line. This applied both to normal and DFA matching.
410    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
411        /^[^d]*?$/8 failed to match "abc".
413    16. Added a missing copyright notice to pcrecpp_internal.h.
415    17. Make it more clear in the documentation that values returned from
416        pcre_exec() in ovector are byte offsets, not character counts.
418    18. Tidied a few places to stop certain compilers from issuing warnings.
420    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
421        supplied by Stefan Weber. I made a further small update for 7.8 because
422        there is a change of source arrangements: the pcre_searchfuncs.c module is
423        replaced by pcre_ucd.c.
426  Version 7.7 07-May-08  Version 7.7 07-May-08

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