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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
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).
60    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
61        custom one, because of the following reported problem in Windows:
63          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
64            under Win32.
65          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
66            therefore missing the function definition.
67          - The compiler thus generates a "C" signature for the test function.
68          - The linker fails to find the "C" function.
69          - PCRE fails to configure if asked to do so against libbz2.
71    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
72        messages were output:
74          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
75          rerunning libtoolize, to keep the correct libtool macros in-tree.
76          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
78        I have done both of these things.
80    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
81        most of the time, it *can* run out if it is given a pattern that contains a
82        runaway infinite recursion. I updated the discussion in the pcrestack man
83        page.
87    Version 8.00 19-Oct-09
88    ----------------------
90    1.  The table for translating pcre_compile() error codes into POSIX error codes
91        was out-of-date, and there was no check on the pcre_compile() error code
92        being within the table. This could lead to an OK return being given in
93        error.
95    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
96        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
97        in a Windows environment.
99    3.  The pcregrep --count option prints the count for each file even when it is
100        zero, as does GNU grep. However, pcregrep was also printing all files when
101        --files-with-matches was added. Now, when both options are given, it prints
102        counts only for those files that have at least one match. (GNU grep just
103        prints the file name in this circumstance, but including the count seems
104        more useful - otherwise, why use --count?) Also ensured that the
105        combination -clh just lists non-zero counts, with no names.
107    4.  The long form of the pcregrep -F option was incorrectly implemented as
108        --fixed_strings instead of --fixed-strings. This is an incompatible change,
109        but it seems right to fix it, and I didn't think it was worth preserving
110        the old behaviour.
112    5.  The command line items --regex=pattern and --regexp=pattern were not
113        recognized by pcregrep, which required --regex pattern or --regexp pattern
114        (with a space rather than an '='). The man page documented the '=' forms,
115        which are compatible with GNU grep; these now work.
117    6.  No libpcreposix.pc file was created for pkg-config; there was just
118        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
120    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
121        when UCP support is not needed, by modifying the Python script that
122        generates it from Unicode data files. This should not matter if the module
123        is correctly used as a library, but I received one complaint about 50K of
124        unwanted data. My guess is that the person linked everything into his
125        program rather than using a library. Anyway, it does no harm.
127    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
128        was a minimum greater than 1 for a wide character in a possessive
129        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
130        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
131        character. Chaos in the form of incorrect output or a compiling loop could
132        result.
134    9.  The restrictions on what a pattern can contain when partial matching is
135        requested for pcre_exec() have been removed. All patterns can now be
136        partially matched by this function. In addition, if there are at least two
137        slots in the offset vector, the offset of the earliest inspected character
138        for the match and the offset of the end of the subject are set in them when
139        PCRE_ERROR_PARTIAL is returned.
141    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
142        synonymous with PCRE_PARTIAL, for backwards compatibility, and
143        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
144        and may be more useful for multi-segment matching.
146    11. Partial matching with pcre_exec() is now more intuitive. A partial match
147        used to be given if ever the end of the subject was reached; now it is
148        given only if matching could not proceed because another character was
149        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
150        string "Z", which now yields "no match" instead of "partial match". In the
151        case of pcre_dfa_exec(), "no match" is given if every matching path for the
152        final character ended with (*FAIL).
154    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
155        if the pattern had a "must contain" character that was already found in the
156        earlier partial match, unless partial matching was again requested. For
157        example, with the pattern /dog.(body)?/, the "must contain" character is
158        "g". If the first part-match was for the string "dog", restarting with
159        "sbody" failed. This bug has been fixed.
161    13. The string returned by pcre_dfa_exec() after a partial match has been
162        changed so that it starts at the first inspected character rather than the
163        first character of the match. This makes a difference only if the pattern
164        starts with a lookbehind assertion or \b or \B (\K is not supported by
165        pcre_dfa_exec()). It's an incompatible change, but it makes the two
166        matching functions compatible, and I think it's the right thing to do.
168    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
169        so that the demonstration program is easily available in environments where
170        PCRE has not been installed from source.
172    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
173        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
174        library.
176    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
177        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
178        is not the first non-POSIX option to be added. Clearly some people find
179        these options useful.
181    17. If a caller to the POSIX matching function regexec() passes a non-zero
182        value for nmatch with a NULL value for pmatch, the value of
183        nmatch is forced to zero.
185    18. RunGrepTest did not have a test for the availability of the -u option of
186        the diff command, as RunTest does. It now checks in the same way as
187        RunTest, and also checks for the -b option.
189    19. If an odd number of negated classes containing just a single character
190        interposed, within parentheses, between a forward reference to a named
191        subpattern and the definition of the subpattern, compilation crashed with
192        an internal error, complaining that it could not find the referenced
193        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
194        [The bug was that it was starting one character too far in when skipping
195        over the character class, thus treating the ] as data rather than
196        terminating the class. This meant it could skip too much.]
198    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
199        /g option in pcretest when the pattern contains \K, which makes it possible
200        to have an empty string match not at the start, even when the pattern is
201        anchored. Updated pcretest and pcredemo to use this option.
203    21. If the maximum number of capturing subpatterns in a recursion was greater
204        than the maximum at the outer level, the higher number was returned, but
205        with unset values at the outer level. The correct (outer level) value is
206        now given.
208    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
209        PCRE did not set those parentheses (unlike Perl). I have now found a way to
210        make it do so. The string so far is captured, making this feature
211        compatible with Perl.
213    23. The tests have been re-organized, adding tests 11 and 12, to make it
214        possible to check the Perl 5.10 features against Perl 5.10.
216    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
217        pattern matches a fixed length string. PCRE did not allow this; now it
218        does. Neither allows recursion.
220    25. I finally figured out how to implement a request to provide the minimum
221        length of subject string that was needed in order to match a given pattern.
222        (It was back references and recursion that I had previously got hung up
223        on.) This code has now been added to pcre_study(); it finds a lower bound
224        to the length of subject needed. It is not necessarily the greatest lower
225        bound, but using it to avoid searching strings that are too short does give
226        some useful speed-ups. The value is available to calling programs via
227        pcre_fullinfo().
229    26. While implementing 25, I discovered to my embarrassment that pcretest had
230        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
231        study optimizations had never been tested with that matching function.
232        Oops. What is worse, even when it was passed study data, there was a bug in
233        pcre_dfa_exec() that meant it never actually used it. Double oops. There
234        were also very few tests of studied patterns with pcre_dfa_exec().
236    27. If (?| is used to create subpatterns with duplicate numbers, they are now
237        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
238        on the other side of the coin, they are no longer allowed to have different
239        names, because these cannot be distinguished in PCRE, and this has caused
240        confusion. (This is a difference from Perl.)
242    28. When duplicate subpattern names are present (necessarily with different
243        numbers, as required by 27 above), and a test is made by name in a
244        conditional pattern, either for a subpattern having been matched, or for
245        recursion in such a pattern, all the associated numbered subpatterns are
246        tested, and the overall condition is true if the condition is true for any
247        one of them. This is the way Perl works, and is also more like the way
248        testing by number works.
251    Version 7.9 11-Apr-09
252    ---------------------
254    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
255        (pcretest), all targets were linked against these libraries. This included
256        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
257        libraries. This caused unwanted dependencies to be created. This problem
258        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
259        pcretest is linked with readline.
261    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
262        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
263        moved outside it again, because FALSE and TRUE are already defined in AIX,
264        but BOOL is not.
266    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
267        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
269    4.  The pcregrep documentation said spaces were inserted as well as colons (or
270        hyphens) following file names and line numbers when outputting matching
271        lines. This is not true; no spaces are inserted. I have also clarified the
272        wording for the --colour (or --color) option.
274    5.  In pcregrep, when --colour was used with -o, the list of matching strings
275        was not coloured; this is different to GNU grep, so I have changed it to be
276        the same.
278    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
279        each matching line was coloured. Now it goes on to look for further matches
280        of any of the test patterns, which is the same behaviour as GNU grep.
282    7.  A pattern that could match an empty string could cause pcregrep to loop; it
283        doesn't make sense to accept an empty string match in pcregrep, so I have
284        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
285        seems to be how GNU grep behaves.
287    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
288        start or after a newline", because the conditional assertion was not being
289        correctly handled. The rule now is that both the assertion and what follows
290        in the first alternative must satisfy the test.
292    9.  If auto-callout was enabled in a pattern with a conditional group whose
293        condition was an assertion, PCRE could crash during matching, both with
294        pcre_exec() and pcre_dfa_exec().
296    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
297        used for matching.
299    11. Unicode property support in character classes was not working for
300        characters (bytes) greater than 127 when not in UTF-8 mode.
302    12. Added the -M command line option to pcretest.
304    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
306    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
308    16. Added comments and documentation about mis-use of no_arg in the C++
309        wrapper.
311    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
312        from Martin Jerabek that uses macro names for all relevant character and
313        string constants.
315    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
316        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
317        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
318        these, but not everybody uses configure.
320    19. A conditional group that had only one branch was not being correctly
321        recognized as an item that could match an empty string. This meant that an
322        enclosing group might also not be so recognized, causing infinite looping
323        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
324        with the subject "ab", where knowledge that the repeated group can match
325        nothing is needed in order to break the loop.
327    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
328        exec(), but without supplying a callout function, matching went wrong.
330    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
331        leak if the size of the offset vector was greater than 30. When the vector
332        is smaller, the saved offsets during recursion go onto a local stack
333        vector, but for larger vectors malloc() is used. It was failing to free
334        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
335        error, in fact).
337    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
338        heapframe that is used only when UTF-8 support is enabled. This caused no
339        problem, but was untidy.
341    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
342        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
343        included within another project.
345    24. Steven Van Ingelgem's patches to add more options to the CMake support,
346        slightly modified by me:
348          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
349              not building pcregrep.
351          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
352              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
354    25. Forward references, both numeric and by name, in patterns that made use of
355        duplicate group numbers, could behave incorrectly or give incorrect errors,
356        because when scanning forward to find the reference group, PCRE was not
357        taking into account the duplicate group numbers. A pattern such as
358        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
360    26. Changed a few more instances of "const unsigned char *" to USPTR, making
361        the feature of a custom pointer more persuasive (as requested by a user).
363    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
364        pcretest.c, inside #ifndefs, because it seems they are sometimes already
365        pre-defined.
367    28. Added support for (*UTF8) at the start of a pattern.
369    29. Arrange for flags added by the "release type" setting in CMake to be shown
370        in the configuration summary.
373  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08
374  ---------------------  ---------------------

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