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revision 408 by ph10, Fri Mar 27 17:52:03 2009 UTC revision 491 by ph10, Mon Mar 1 17:45:08 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.9 xx-xxx-09  Version 8.02 01-Mar-2010
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 5.2.0.
10    Version 8.01 19-Jan-2010
11    ------------------------
13    1.  If a pattern contained a conditional subpattern with only one branch (in
14        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
15        computed the wrong minimum data length (which is of course zero for such
16        subpatterns). This could cause incorrect "no match" results.
18    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
19        the pattern is reset in the first branch, pcre_compile() failed with
20        "internal error: code overflow at offset...". This happened only when
21        the reset was to the original external option setting. (An optimization
22        abstracts leading options settings into an external setting, which was the
23        cause of this.)
25    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
26        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
27        assertion pattern did not match (meaning that the assertion was true), it
28        was incorrectly treated as false if the SKIP had been reached during the
29        matching. This also applied to assertions used as conditions.
31    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
32        assertion subpattern, including such a pattern used as a condition,
33        unpredictable results occurred, instead of the error return
36    5.  The C++ GlobalReplace function was not working like Perl for the special
37        situation when an empty string is matched. It now does the fancy magic
38        stuff that is necessary.
40    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
41        removed. (These were left over from very, very early versions of PCRE.)
43    7.  Some cosmetic changes to the code to make life easier when compiling it
44        as part of something else:
46        (a) Change DEBUG to PCRE_DEBUG.
48        (b) In pcre_compile(), rename the member of the "branch_chain" structure
49            called "current" as "current_branch", to prevent a collision with the
50            Linux macro when compiled as a kernel module.
52        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
53            prevent a collision with the Linux macro when compiled as a kernel
54            module.
56    8.  In pcre_compile() there are some checks for integer overflows that used to
57        cast potentially large values to (double). This has been changed to that
58        when building, a check for int64_t is made, and if it is found, it is used
59        instead, thus avoiding the use of floating point arithmetic. (There is no
60        other use of FP in PCRE.) If int64_t is not found, the fallback is to
61        double.
63    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
64        2005 (difference between two addresses compared to an unsigned value).
66    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
67        custom one, because of the following reported problem in Windows:
69          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
70              under Win32.
71          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
72              therefore missing the function definition.
73          - The compiler thus generates a "C" signature for the test function.
74          - The linker fails to find the "C" function.
75          - PCRE fails to configure if asked to do so against libbz2.
77    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
78        messages were output:
80          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
81          rerunning libtoolize, to keep the correct libtool macros in-tree.
82          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
84        I have done both of these things.
86    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
87        most of the time, it *can* run out if it is given a pattern that contains a
88        runaway infinite recursion. I updated the discussion in the pcrestack man
89        page.
91    13. Now that we have gone to the x.xx style of version numbers, the minor
92        version may start with zero. Using 08 or 09 is a bad idea because users
93        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
94        interpreted as invalid octal numbers. I've updated the previous comment in
95        configure.ac, and also added a check that gives an error if 08 or 09 are
96        used.
98    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
99        causing partial matching to fail when the end of the subject matched \W
100        in a UTF-8 pattern where \W was quantified with a minimum of 3.
102    15. There were some discrepancies between the declarations in pcre_internal.h
103        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
104        their definitions. The declarations used "const uschar *" and the
105        definitions used USPTR. Even though USPTR is normally defined as "const
106        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
107        reported that: "This difference in casting confuses some C++ compilers, for
108        example, SunCC recognizes above declarations as different functions and
109        generates broken code for hbpcre." I have changed the declarations to use
110        USPTR.
112    16. GNU libtool is named differently on some systems. The autogen.sh script now
113        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
114        (FreeBSD).
116    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
117        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
118        comment: "Figure out how to create a longlong from a string: strtoll and
119        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
120        instance, but it only takes 2 args instead of 3!"
122    18. A subtle bug concerned with back references has been fixed by a change of
123        specification, with a corresponding code fix. A pattern such as
124        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
125        refers, was giving matches when it shouldn't. For example, xa=xaaa would
126        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
127        same bug. Such groups have to be quantified to be useful, or contained
128        inside another quantified group. (If there's no repetition, the reference
129        can never match.) The problem arises because, having left the group and
130        moved on to the rest of the pattern, a later failure that backtracks into
131        the group uses the captured value from the final iteration of the group
132        rather than the correct earlier one. I have fixed this in PCRE by forcing
133        any group that contains a reference to itself to be an atomic group; that
134        is, there cannot be any backtracking into it once it has completed. This is
135        similar to recursive and subroutine calls.
138    Version 8.00 19-Oct-09
139    ----------------------
141    1.  The table for translating pcre_compile() error codes into POSIX error codes
142        was out-of-date, and there was no check on the pcre_compile() error code
143        being within the table. This could lead to an OK return being given in
144        error.
146    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
147        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
148        in a Windows environment.
150    3.  The pcregrep --count option prints the count for each file even when it is
151        zero, as does GNU grep. However, pcregrep was also printing all files when
152        --files-with-matches was added. Now, when both options are given, it prints
153        counts only for those files that have at least one match. (GNU grep just
154        prints the file name in this circumstance, but including the count seems
155        more useful - otherwise, why use --count?) Also ensured that the
156        combination -clh just lists non-zero counts, with no names.
158    4.  The long form of the pcregrep -F option was incorrectly implemented as
159        --fixed_strings instead of --fixed-strings. This is an incompatible change,
160        but it seems right to fix it, and I didn't think it was worth preserving
161        the old behaviour.
163    5.  The command line items --regex=pattern and --regexp=pattern were not
164        recognized by pcregrep, which required --regex pattern or --regexp pattern
165        (with a space rather than an '='). The man page documented the '=' forms,
166        which are compatible with GNU grep; these now work.
168    6.  No libpcreposix.pc file was created for pkg-config; there was just
169        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
171    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
172        when UCP support is not needed, by modifying the Python script that
173        generates it from Unicode data files. This should not matter if the module
174        is correctly used as a library, but I received one complaint about 50K of
175        unwanted data. My guess is that the person linked everything into his
176        program rather than using a library. Anyway, it does no harm.
178    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
179        was a minimum greater than 1 for a wide character in a possessive
180        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
181        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
182        character. Chaos in the form of incorrect output or a compiling loop could
183        result.
185    9.  The restrictions on what a pattern can contain when partial matching is
186        requested for pcre_exec() have been removed. All patterns can now be
187        partially matched by this function. In addition, if there are at least two
188        slots in the offset vector, the offset of the earliest inspected character
189        for the match and the offset of the end of the subject are set in them when
190        PCRE_ERROR_PARTIAL is returned.
192    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
193        synonymous with PCRE_PARTIAL, for backwards compatibility, and
194        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
195        and may be more useful for multi-segment matching.
197    11. Partial matching with pcre_exec() is now more intuitive. A partial match
198        used to be given if ever the end of the subject was reached; now it is
199        given only if matching could not proceed because another character was
200        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
201        string "Z", which now yields "no match" instead of "partial match". In the
202        case of pcre_dfa_exec(), "no match" is given if every matching path for the
203        final character ended with (*FAIL).
205    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
206        if the pattern had a "must contain" character that was already found in the
207        earlier partial match, unless partial matching was again requested. For
208        example, with the pattern /dog.(body)?/, the "must contain" character is
209        "g". If the first part-match was for the string "dog", restarting with
210        "sbody" failed. This bug has been fixed.
212    13. The string returned by pcre_dfa_exec() after a partial match has been
213        changed so that it starts at the first inspected character rather than the
214        first character of the match. This makes a difference only if the pattern
215        starts with a lookbehind assertion or \b or \B (\K is not supported by
216        pcre_dfa_exec()). It's an incompatible change, but it makes the two
217        matching functions compatible, and I think it's the right thing to do.
219    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
220        so that the demonstration program is easily available in environments where
221        PCRE has not been installed from source.
223    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
224        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
225        library.
227    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
228        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
229        is not the first non-POSIX option to be added. Clearly some people find
230        these options useful.
232    17. If a caller to the POSIX matching function regexec() passes a non-zero
233        value for nmatch with a NULL value for pmatch, the value of
234        nmatch is forced to zero.
236    18. RunGrepTest did not have a test for the availability of the -u option of
237        the diff command, as RunTest does. It now checks in the same way as
238        RunTest, and also checks for the -b option.
240    19. If an odd number of negated classes containing just a single character
241        interposed, within parentheses, between a forward reference to a named
242        subpattern and the definition of the subpattern, compilation crashed with
243        an internal error, complaining that it could not find the referenced
244        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
245        [The bug was that it was starting one character too far in when skipping
246        over the character class, thus treating the ] as data rather than
247        terminating the class. This meant it could skip too much.]
249    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
250        /g option in pcretest when the pattern contains \K, which makes it possible
251        to have an empty string match not at the start, even when the pattern is
252        anchored. Updated pcretest and pcredemo to use this option.
254    21. If the maximum number of capturing subpatterns in a recursion was greater
255        than the maximum at the outer level, the higher number was returned, but
256        with unset values at the outer level. The correct (outer level) value is
257        now given.
259    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
260        PCRE did not set those parentheses (unlike Perl). I have now found a way to
261        make it do so. The string so far is captured, making this feature
262        compatible with Perl.
264    23. The tests have been re-organized, adding tests 11 and 12, to make it
265        possible to check the Perl 5.10 features against Perl 5.10.
267    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
268        pattern matches a fixed length string. PCRE did not allow this; now it
269        does. Neither allows recursion.
271    25. I finally figured out how to implement a request to provide the minimum
272        length of subject string that was needed in order to match a given pattern.
273        (It was back references and recursion that I had previously got hung up
274        on.) This code has now been added to pcre_study(); it finds a lower bound
275        to the length of subject needed. It is not necessarily the greatest lower
276        bound, but using it to avoid searching strings that are too short does give
277        some useful speed-ups. The value is available to calling programs via
278        pcre_fullinfo().
280    26. While implementing 25, I discovered to my embarrassment that pcretest had
281        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
282        study optimizations had never been tested with that matching function.
283        Oops. What is worse, even when it was passed study data, there was a bug in
284        pcre_dfa_exec() that meant it never actually used it. Double oops. There
285        were also very few tests of studied patterns with pcre_dfa_exec().
287    27. If (?| is used to create subpatterns with duplicate numbers, they are now
288        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
289        on the other side of the coin, they are no longer allowed to have different
290        names, because these cannot be distinguished in PCRE, and this has caused
291        confusion. (This is a difference from Perl.)
293    28. When duplicate subpattern names are present (necessarily with different
294        numbers, as required by 27 above), and a test is made by name in a
295        conditional pattern, either for a subpattern having been matched, or for
296        recursion in such a pattern, all the associated numbered subpatterns are
297        tested, and the overall condition is true if the condition is true for any
298        one of them. This is the way Perl works, and is also more like the way
299        testing by number works.
302    Version 7.9 11-Apr-09
303  ---------------------  ---------------------
305  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 315  Version 7.9 xx-xxx-09
315      but BOOL is not.      but BOOL is not.
317  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
318      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
320  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
321      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 94  Version 7.9 xx-xxx-09 Line 392  Version 7.9 xx-xxx-09
392  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
393      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
394      included within another project.      included within another project.
396  24. Steven Van Ingelgem's patches to add more options to the CMake support,  24. Steven Van Ingelgem's patches to add more options to the CMake support,
397      slightly modified by me:      slightly modified by me:
399        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
400            not building pcregrep.            not building pcregrep.
402        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
403            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
405  25. Forward references, both numeric and by name, in patterns that made use of  25. Forward references, both numeric and by name, in patterns that made use of
406      duplicate group numbers, could behave incorrectly or give incorrect errors,      duplicate group numbers, could behave incorrectly or give incorrect errors,
407      because when scanning forward to find the reference group, PCRE was not      because when scanning forward to find the reference group, PCRE was not
408      taking into account the duplicate group numbers. A pattern such as      taking into account the duplicate group numbers. A pattern such as
409      ^X(?3)(a)(?|(b)|(q))(Y) is an example.      ^X(?3)(a)(?|(b)|(q))(Y) is an example.
411    26. Changed a few more instances of "const unsigned char *" to USPTR, making
412        the feature of a custom pointer more persuasive (as requested by a user).
414    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
415        pcretest.c, inside #ifndefs, because it seems they are sometimes already
416        pre-defined.
418    28. Added support for (*UTF8) at the start of a pattern.
420    29. Arrange for flags added by the "release type" setting in CMake to be shown
421        in the configuration summary.
424  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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