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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    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
31    Version 8.00 19-Oct-09
32    ----------------------
34    1.  The table for translating pcre_compile() error codes into POSIX error codes
35        was out-of-date, and there was no check on the pcre_compile() error code
36        being within the table. This could lead to an OK return being given in
37        error.
39    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
40        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
41        in a Windows environment.
43    3.  The pcregrep --count option prints the count for each file even when it is
44        zero, as does GNU grep. However, pcregrep was also printing all files when
45        --files-with-matches was added. Now, when both options are given, it prints
46        counts only for those files that have at least one match. (GNU grep just
47        prints the file name in this circumstance, but including the count seems
48        more useful - otherwise, why use --count?) Also ensured that the
49        combination -clh just lists non-zero counts, with no names.
51    4.  The long form of the pcregrep -F option was incorrectly implemented as
52        --fixed_strings instead of --fixed-strings. This is an incompatible change,
53        but it seems right to fix it, and I didn't think it was worth preserving
54        the old behaviour.
56    5.  The command line items --regex=pattern and --regexp=pattern were not
57        recognized by pcregrep, which required --regex pattern or --regexp pattern
58        (with a space rather than an '='). The man page documented the '=' forms,
59        which are compatible with GNU grep; these now work.
61    6.  No libpcreposix.pc file was created for pkg-config; there was just
62        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
64    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
65        when UCP support is not needed, by modifying the Python script that
66        generates it from Unicode data files. This should not matter if the module
67        is correctly used as a library, but I received one complaint about 50K of
68        unwanted data. My guess is that the person linked everything into his
69        program rather than using a library. Anyway, it does no harm.
71    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
72        was a minimum greater than 1 for a wide character in a possessive
73        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
74        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
75        character. Chaos in the form of incorrect output or a compiling loop could
76        result.
78    9.  The restrictions on what a pattern can contain when partial matching is
79        requested for pcre_exec() have been removed. All patterns can now be
80        partially matched by this function. In addition, if there are at least two
81        slots in the offset vector, the offset of the earliest inspected character
82        for the match and the offset of the end of the subject are set in them when
83        PCRE_ERROR_PARTIAL is returned.
85    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
86        synonymous with PCRE_PARTIAL, for backwards compatibility, and
87        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
88        and may be more useful for multi-segment matching.
90    11. Partial matching with pcre_exec() is now more intuitive. A partial match
91        used to be given if ever the end of the subject was reached; now it is
92        given only if matching could not proceed because another character was
93        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
94        string "Z", which now yields "no match" instead of "partial match". In the
95        case of pcre_dfa_exec(), "no match" is given if every matching path for the
96        final character ended with (*FAIL).
98    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
99        if the pattern had a "must contain" character that was already found in the
100        earlier partial match, unless partial matching was again requested. For
101        example, with the pattern /dog.(body)?/, the "must contain" character is
102        "g". If the first part-match was for the string "dog", restarting with
103        "sbody" failed. This bug has been fixed.
105    13. The string returned by pcre_dfa_exec() after a partial match has been
106        changed so that it starts at the first inspected character rather than the
107        first character of the match. This makes a difference only if the pattern
108        starts with a lookbehind assertion or \b or \B (\K is not supported by
109        pcre_dfa_exec()). It's an incompatible change, but it makes the two
110        matching functions compatible, and I think it's the right thing to do.
112    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
113        so that the demonstration program is easily available in environments where
114        PCRE has not been installed from source.
116    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
117        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
118        library.
120    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
121        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
122        is not the first non-POSIX option to be added. Clearly some people find
123        these options useful.
125    17. If a caller to the POSIX matching function regexec() passes a non-zero
126        value for nmatch with a NULL value for pmatch, the value of
127        nmatch is forced to zero.
129    18. RunGrepTest did not have a test for the availability of the -u option of
130        the diff command, as RunTest does. It now checks in the same way as
131        RunTest, and also checks for the -b option.
133    19. If an odd number of negated classes containing just a single character
134        interposed, within parentheses, between a forward reference to a named
135        subpattern and the definition of the subpattern, compilation crashed with
136        an internal error, complaining that it could not find the referenced
137        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
138        [The bug was that it was starting one character too far in when skipping
139        over the character class, thus treating the ] as data rather than
140        terminating the class. This meant it could skip too much.]
142    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
143        /g option in pcretest when the pattern contains \K, which makes it possible
144        to have an empty string match not at the start, even when the pattern is
145        anchored. Updated pcretest and pcredemo to use this option.
147    21. If the maximum number of capturing subpatterns in a recursion was greater
148        than the maximum at the outer level, the higher number was returned, but
149        with unset values at the outer level. The correct (outer level) value is
150        now given.
152    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
153        PCRE did not set those parentheses (unlike Perl). I have now found a way to
154        make it do so. The string so far is captured, making this feature
155        compatible with Perl.
157    23. The tests have been re-organized, adding tests 11 and 12, to make it
158        possible to check the Perl 5.10 features against Perl 5.10.
160    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
161        pattern matches a fixed length string. PCRE did not allow this; now it
162        does. Neither allows recursion.
164    25. I finally figured out how to implement a request to provide the minimum
165        length of subject string that was needed in order to match a given pattern.
166        (It was back references and recursion that I had previously got hung up
167        on.) This code has now been added to pcre_study(); it finds a lower bound
168        to the length of subject needed. It is not necessarily the greatest lower
169        bound, but using it to avoid searching strings that are too short does give
170        some useful speed-ups. The value is available to calling programs via
171        pcre_fullinfo().
173    26. While implementing 25, I discovered to my embarrassment that pcretest had
174        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
175        study optimizations had never been tested with that matching function.
176        Oops. What is worse, even when it was passed study data, there was a bug in
177        pcre_dfa_exec() that meant it never actually used it. Double oops. There
178        were also very few tests of studied patterns with pcre_dfa_exec().
180    27. If (?| is used to create subpatterns with duplicate numbers, they are now
181        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
182        on the other side of the coin, they are no longer allowed to have different
183        names, because these cannot be distinguished in PCRE, and this has caused
184        confusion. (This is a difference from Perl.)
186    28. When duplicate subpattern names are present (necessarily with different
187        numbers, as required by 27 above), and a test is made by name in a
188        conditional pattern, either for a subpattern having been matched, or for
189        recursion in such a pattern, all the associated numbered subpatterns are
190        tested, and the overall condition is true if the condition is true for any
191        one of them. This is the way Perl works, and is also more like the way
192        testing by number works.
195    Version 7.9 11-Apr-09
196    ---------------------
198    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
199        (pcretest), all targets were linked against these libraries. This included
200        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
201        libraries. This caused unwanted dependencies to be created. This problem
202        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
203        pcretest is linked with readline.
205    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
206        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
207        moved outside it again, because FALSE and TRUE are already defined in AIX,
208        but BOOL is not.
210    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
211        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
213    4.  The pcregrep documentation said spaces were inserted as well as colons (or
214        hyphens) following file names and line numbers when outputting matching
215        lines. This is not true; no spaces are inserted. I have also clarified the
216        wording for the --colour (or --color) option.
218    5.  In pcregrep, when --colour was used with -o, the list of matching strings
219        was not coloured; this is different to GNU grep, so I have changed it to be
220        the same.
222    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
223        each matching line was coloured. Now it goes on to look for further matches
224        of any of the test patterns, which is the same behaviour as GNU grep.
226    7.  A pattern that could match an empty string could cause pcregrep to loop; it
227        doesn't make sense to accept an empty string match in pcregrep, so I have
228        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
229        seems to be how GNU grep behaves.
231    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
232        start or after a newline", because the conditional assertion was not being
233        correctly handled. The rule now is that both the assertion and what follows
234        in the first alternative must satisfy the test.
236    9.  If auto-callout was enabled in a pattern with a conditional group whose
237        condition was an assertion, PCRE could crash during matching, both with
238        pcre_exec() and pcre_dfa_exec().
240    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
241        used for matching.
243    11. Unicode property support in character classes was not working for
244        characters (bytes) greater than 127 when not in UTF-8 mode.
246    12. Added the -M command line option to pcretest.
248    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
250    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
252    16. Added comments and documentation about mis-use of no_arg in the C++
253        wrapper.
255    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
256        from Martin Jerabek that uses macro names for all relevant character and
257        string constants.
259    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
260        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
261        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
262        these, but not everybody uses configure.
264    19. A conditional group that had only one branch was not being correctly
265        recognized as an item that could match an empty string. This meant that an
266        enclosing group might also not be so recognized, causing infinite looping
267        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
268        with the subject "ab", where knowledge that the repeated group can match
269        nothing is needed in order to break the loop.
271    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
272        exec(), but without supplying a callout function, matching went wrong.
274    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
275        leak if the size of the offset vector was greater than 30. When the vector
276        is smaller, the saved offsets during recursion go onto a local stack
277        vector, but for larger vectors malloc() is used. It was failing to free
278        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
279        error, in fact).
281    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
282        heapframe that is used only when UTF-8 support is enabled. This caused no
283        problem, but was untidy.
285    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
286        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
287        included within another project.
289    24. Steven Van Ingelgem's patches to add more options to the CMake support,
290        slightly modified by me:
292          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
293              not building pcregrep.
295          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
296              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
298    25. Forward references, both numeric and by name, in patterns that made use of
299        duplicate group numbers, could behave incorrectly or give incorrect errors,
300        because when scanning forward to find the reference group, PCRE was not
301        taking into account the duplicate group numbers. A pattern such as
302        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
304    26. Changed a few more instances of "const unsigned char *" to USPTR, making
305        the feature of a custom pointer more persuasive (as requested by a user).
307    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
308        pcretest.c, inside #ifndefs, because it seems they are sometimes already
309        pre-defined.
311    28. Added support for (*UTF8) at the start of a pattern.
313    29. Arrange for flags added by the "release type" setting in CMake to be shown
314        in the configuration summary.
317    Version 7.8 05-Sep-08
318    ---------------------
320    1.  Replaced UCP searching code with optimized version as implemented for Ad
321        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
322        stage table and inline lookup instead of a function, giving speed ups of 2
323        to 5 times on some simple patterns that I tested. Permission was given to
324        distribute the MultiStage2.py script that generates the tables (it's not in
325        the tarball, but is in the Subversion repository).
327    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
328        scripts.
330    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
331        a group with a zero qualifier. The result of the study could be incorrect,
332        or the function might crash, depending on the pattern.
334    4.  Caseless matching was not working for non-ASCII characters in back
335        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
336        It now works when Unicode Property Support is available.
338    5.  In pcretest, an escape such as \x{de} in the data was always generating
339        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
340        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
341        truncation.
343    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
345    7.  Added two (int) casts to pcregrep when printing the difference of two
346        pointers, in case they are 64-bit values.
348    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
349        test 2 if it fails.
351    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
352        and a #define of that name to empty if it is not externally set. This is to
353        allow users of MSVC to set it if necessary.
355    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
356        the convenience functions in the pcre_get.c source file.
358    11. An option change at the start of a pattern that had top-level alternatives
359        could cause overwriting and/or a crash. This command provoked a crash in
360        some environments:
362          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
364        This potential security problem was recorded as CVE-2008-2371.
366    12. For a pattern where the match had to start at the beginning or immediately
367        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
368        pcre_dfa_exec() could read past the end of the passed subject if there was
369        no match. To help with detecting such bugs (e.g. with valgrind), I modified
370        pcretest so that it places the subject at the end of its malloc-ed buffer.
372    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
373        exec() might read past the end of the data buffer in UTF-8 mode.
375    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
376        the data contained the byte 0x85 as part of a UTF-8 character within its
377        first line. This applied both to normal and DFA matching.
379    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
380        /^[^d]*?$/8 failed to match "abc".
382    16. Added a missing copyright notice to pcrecpp_internal.h.
384    17. Make it more clear in the documentation that values returned from
385        pcre_exec() in ovector are byte offsets, not character counts.
387    18. Tidied a few places to stop certain compilers from issuing warnings.
389    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
390        supplied by Stefan Weber. I made a further small update for 7.8 because
391        there is a change of source arrangements: the pcre_searchfuncs.c module is
392        replaced by pcre_ucd.c.
395    Version 7.7 07-May-08
396    ---------------------
398    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
399        a string to a long long, pretend we don't even have a long long." This is
400        done by checking for the strtoq, strtoll, and _strtoi64 functions.
402    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
403        pre-7.6 versions, which defined a global no_arg variable instead of putting
404        it in the RE class. (See also #8 below.)
406    3.  Remove a line of dead code, identified by coverity and reported by Nuno
407        Lopes.
409    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
411        (1) The include/exclude patterns were being applied to the whole pathnames
412            of files, instead of just to the final components.
414        (2) If there was more than one level of directory, the subdirectories were
415            skipped unless they satisfied the include/exclude conditions. This is
416            inconsistent with GNU grep (and could even be seen as contrary to the
417            pcregrep specification - which I improved to make it absolutely clear).
418            The action now is always to scan all levels of directory, and just
419            apply the include/exclude patterns to regular files.
421    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
422        --exclude_dir in the tests to avoid scanning .svn directories.
424    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
425        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
426        doesn't support NULs in patterns.
428    7.  Added some missing "const"s to declarations of static tables in
429        pcre_compile.c and pcre_dfa_exec.c.
431    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
432        caused by fix #2  above. (Subsequently also a second patch to fix the
433        first patch. And a third patch - this was a messy problem.)
435    9.  Applied Craig's patch to remove the use of push_back().
437    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
438        matching function regexec().
440    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
441        which, however, unlike Perl's \g{...}, are subroutine calls, not back
442        references. PCRE supports relative numbers with this syntax (I don't think
443        Oniguruma does).
445    12. Previously, a group with a zero repeat such as (...){0} was completely
446        omitted from the compiled regex. However, this means that if the group
447        was called as a subroutine from elsewhere in the pattern, things went wrong
448        (an internal error was given). Such groups are now left in the compiled
449        pattern, with a new opcode that causes them to be skipped at execution
450        time.
452    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
453        to the way PCRE behaves:
455        (a) A lone ] character is dis-allowed (Perl treats it as data).
457        (b) A back reference to an unmatched subpattern matches an empty string
458            (Perl fails the current match path).
460        (c) A data ] in a character class must be notated as \] because if the
461            first data character in a class is ], it defines an empty class. (In
462            Perl it is not possible to have an empty class.) The empty class []
463            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
464            The negative empty class [^] matches any one character, independently
465            of the DOTALL setting.
467    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
468        non-existent subpattern following a character class starting with ']' and
469        containing () gave an internal compiling error instead of "reference to
470        non-existent subpattern". Fortunately, when the pattern did exist, the
471        compiled code was correct. (When scanning forwards to check for the
472        existencd of the subpattern, it was treating the data ']' as terminating
473        the class, so got the count wrong. When actually compiling, the reference
474        was subsequently set up correctly.)
476    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
477        it was being rejected as not supported by pcre_dfa_exec(), even though
478        other assertions are supported. I have made pcre_dfa_exec() support
479        (*FAIL).
481    16. The implementation of 13c above involved the invention of a new opcode,
482        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
483        cannot be changed at match time, I realized I could make a small
484        improvement to matching performance by compiling OP_ALLANY instead of
485        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
486        on the OP_ANY path.
488    17. Compiling pcretest on Windows with readline support failed without the
489        following two fixes: (1) Make the unistd.h include conditional on
490        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
492    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
493        ncurses library to be included for pcretest when ReadLine support is
494        requested, but also to allow for it to be overridden. This patch came from
495        Daniel Bergström.
497    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
498        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
499        any errors with the current Unicode tables. Thanks to Peter Kankowski for
500        spotting this.
503  Version 7.6 28-Jan-08  Version 7.6 28-Jan-08
504  ---------------------  ---------------------

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