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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.02 01-Mar-2010
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 5.2.0.
9    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
10        configured.
12    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
13        original author of that file, following a query about its status.
16    Version 8.01 19-Jan-2010
17    ------------------------
19    1.  If a pattern contained a conditional subpattern with only one branch (in
20        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
21        computed the wrong minimum data length (which is of course zero for such
22        subpatterns). This could cause incorrect "no match" results.
24    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
25        the pattern is reset in the first branch, pcre_compile() failed with
26        "internal error: code overflow at offset...". This happened only when
27        the reset was to the original external option setting. (An optimization
28        abstracts leading options settings into an external setting, which was the
29        cause of this.)
31    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
32        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
33        assertion pattern did not match (meaning that the assertion was true), it
34        was incorrectly treated as false if the SKIP had been reached during the
35        matching. This also applied to assertions used as conditions.
37    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
38        assertion subpattern, including such a pattern used as a condition,
39        unpredictable results occurred, instead of the error return
42    5.  The C++ GlobalReplace function was not working like Perl for the special
43        situation when an empty string is matched. It now does the fancy magic
44        stuff that is necessary.
46    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
47        removed. (These were left over from very, very early versions of PCRE.)
49    7.  Some cosmetic changes to the code to make life easier when compiling it
50        as part of something else:
52        (a) Change DEBUG to PCRE_DEBUG.
54        (b) In pcre_compile(), rename the member of the "branch_chain" structure
55            called "current" as "current_branch", to prevent a collision with the
56            Linux macro when compiled as a kernel module.
58        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
59            prevent a collision with the Linux macro when compiled as a kernel
60            module.
62    8.  In pcre_compile() there are some checks for integer overflows that used to
63        cast potentially large values to (double). This has been changed to that
64        when building, a check for int64_t is made, and if it is found, it is used
65        instead, thus avoiding the use of floating point arithmetic. (There is no
66        other use of FP in PCRE.) If int64_t is not found, the fallback is to
67        double.
69    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
70        2005 (difference between two addresses compared to an unsigned value).
72    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
73        custom one, because of the following reported problem in Windows:
75          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
76              under Win32.
77          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
78              therefore missing the function definition.
79          - The compiler thus generates a "C" signature for the test function.
80          - The linker fails to find the "C" function.
81          - PCRE fails to configure if asked to do so against libbz2.
83    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
84        messages were output:
86          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
87          rerunning libtoolize, to keep the correct libtool macros in-tree.
88          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
90        I have done both of these things.
92    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
93        most of the time, it *can* run out if it is given a pattern that contains a
94        runaway infinite recursion. I updated the discussion in the pcrestack man
95        page.
97    13. Now that we have gone to the x.xx style of version numbers, the minor
98        version may start with zero. Using 08 or 09 is a bad idea because users
99        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
100        interpreted as invalid octal numbers. I've updated the previous comment in
101        configure.ac, and also added a check that gives an error if 08 or 09 are
102        used.
104    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
105        causing partial matching to fail when the end of the subject matched \W
106        in a UTF-8 pattern where \W was quantified with a minimum of 3.
108    15. There were some discrepancies between the declarations in pcre_internal.h
109        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
110        their definitions. The declarations used "const uschar *" and the
111        definitions used USPTR. Even though USPTR is normally defined as "const
112        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
113        reported that: "This difference in casting confuses some C++ compilers, for
114        example, SunCC recognizes above declarations as different functions and
115        generates broken code for hbpcre." I have changed the declarations to use
116        USPTR.
118    16. GNU libtool is named differently on some systems. The autogen.sh script now
119        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
120        (FreeBSD).
122    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
123        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
124        comment: "Figure out how to create a longlong from a string: strtoll and
125        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
126        instance, but it only takes 2 args instead of 3!"
128    18. A subtle bug concerned with back references has been fixed by a change of
129        specification, with a corresponding code fix. A pattern such as
130        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
131        refers, was giving matches when it shouldn't. For example, xa=xaaa would
132        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
133        same bug. Such groups have to be quantified to be useful, or contained
134        inside another quantified group. (If there's no repetition, the reference
135        can never match.) The problem arises because, having left the group and
136        moved on to the rest of the pattern, a later failure that backtracks into
137        the group uses the captured value from the final iteration of the group
138        rather than the correct earlier one. I have fixed this in PCRE by forcing
139        any group that contains a reference to itself to be an atomic group; that
140        is, there cannot be any backtracking into it once it has completed. This is
141        similar to recursive and subroutine calls.
144    Version 8.00 19-Oct-09
145    ----------------------
147    1.  The table for translating pcre_compile() error codes into POSIX error codes
148        was out-of-date, and there was no check on the pcre_compile() error code
149        being within the table. This could lead to an OK return being given in
150        error.
152    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
153        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
154        in a Windows environment.
156    3.  The pcregrep --count option prints the count for each file even when it is
157        zero, as does GNU grep. However, pcregrep was also printing all files when
158        --files-with-matches was added. Now, when both options are given, it prints
159        counts only for those files that have at least one match. (GNU grep just
160        prints the file name in this circumstance, but including the count seems
161        more useful - otherwise, why use --count?) Also ensured that the
162        combination -clh just lists non-zero counts, with no names.
164    4.  The long form of the pcregrep -F option was incorrectly implemented as
165        --fixed_strings instead of --fixed-strings. This is an incompatible change,
166        but it seems right to fix it, and I didn't think it was worth preserving
167        the old behaviour.
169    5.  The command line items --regex=pattern and --regexp=pattern were not
170        recognized by pcregrep, which required --regex pattern or --regexp pattern
171        (with a space rather than an '='). The man page documented the '=' forms,
172        which are compatible with GNU grep; these now work.
174    6.  No libpcreposix.pc file was created for pkg-config; there was just
175        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
177    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
178        when UCP support is not needed, by modifying the Python script that
179        generates it from Unicode data files. This should not matter if the module
180        is correctly used as a library, but I received one complaint about 50K of
181        unwanted data. My guess is that the person linked everything into his
182        program rather than using a library. Anyway, it does no harm.
184    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
185        was a minimum greater than 1 for a wide character in a possessive
186        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
187        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
188        character. Chaos in the form of incorrect output or a compiling loop could
189        result.
191    9.  The restrictions on what a pattern can contain when partial matching is
192        requested for pcre_exec() have been removed. All patterns can now be
193        partially matched by this function. In addition, if there are at least two
194        slots in the offset vector, the offset of the earliest inspected character
195        for the match and the offset of the end of the subject are set in them when
196        PCRE_ERROR_PARTIAL is returned.
198    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
199        synonymous with PCRE_PARTIAL, for backwards compatibility, and
200        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
201        and may be more useful for multi-segment matching.
203    11. Partial matching with pcre_exec() is now more intuitive. A partial match
204        used to be given if ever the end of the subject was reached; now it is
205        given only if matching could not proceed because another character was
206        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
207        string "Z", which now yields "no match" instead of "partial match". In the
208        case of pcre_dfa_exec(), "no match" is given if every matching path for the
209        final character ended with (*FAIL).
211    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
212        if the pattern had a "must contain" character that was already found in the
213        earlier partial match, unless partial matching was again requested. For
214        example, with the pattern /dog.(body)?/, the "must contain" character is
215        "g". If the first part-match was for the string "dog", restarting with
216        "sbody" failed. This bug has been fixed.
218    13. The string returned by pcre_dfa_exec() after a partial match has been
219        changed so that it starts at the first inspected character rather than the
220        first character of the match. This makes a difference only if the pattern
221        starts with a lookbehind assertion or \b or \B (\K is not supported by
222        pcre_dfa_exec()). It's an incompatible change, but it makes the two
223        matching functions compatible, and I think it's the right thing to do.
225    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
226        so that the demonstration program is easily available in environments where
227        PCRE has not been installed from source.
229    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
230        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
231        library.
233    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
234        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
235        is not the first non-POSIX option to be added. Clearly some people find
236        these options useful.
238    17. If a caller to the POSIX matching function regexec() passes a non-zero
239        value for nmatch with a NULL value for pmatch, the value of
240        nmatch is forced to zero.
242    18. RunGrepTest did not have a test for the availability of the -u option of
243        the diff command, as RunTest does. It now checks in the same way as
244        RunTest, and also checks for the -b option.
246    19. If an odd number of negated classes containing just a single character
247        interposed, within parentheses, between a forward reference to a named
248        subpattern and the definition of the subpattern, compilation crashed with
249        an internal error, complaining that it could not find the referenced
250        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
251        [The bug was that it was starting one character too far in when skipping
252        over the character class, thus treating the ] as data rather than
253        terminating the class. This meant it could skip too much.]
255    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
256        /g option in pcretest when the pattern contains \K, which makes it possible
257        to have an empty string match not at the start, even when the pattern is
258        anchored. Updated pcretest and pcredemo to use this option.
260    21. If the maximum number of capturing subpatterns in a recursion was greater
261        than the maximum at the outer level, the higher number was returned, but
262        with unset values at the outer level. The correct (outer level) value is
263        now given.
265    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
266        PCRE did not set those parentheses (unlike Perl). I have now found a way to
267        make it do so. The string so far is captured, making this feature
268        compatible with Perl.
270    23. The tests have been re-organized, adding tests 11 and 12, to make it
271        possible to check the Perl 5.10 features against Perl 5.10.
273    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
274        pattern matches a fixed length string. PCRE did not allow this; now it
275        does. Neither allows recursion.
277    25. I finally figured out how to implement a request to provide the minimum
278        length of subject string that was needed in order to match a given pattern.
279        (It was back references and recursion that I had previously got hung up
280        on.) This code has now been added to pcre_study(); it finds a lower bound
281        to the length of subject needed. It is not necessarily the greatest lower
282        bound, but using it to avoid searching strings that are too short does give
283        some useful speed-ups. The value is available to calling programs via
284        pcre_fullinfo().
286    26. While implementing 25, I discovered to my embarrassment that pcretest had
287        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
288        study optimizations had never been tested with that matching function.
289        Oops. What is worse, even when it was passed study data, there was a bug in
290        pcre_dfa_exec() that meant it never actually used it. Double oops. There
291        were also very few tests of studied patterns with pcre_dfa_exec().
293    27. If (?| is used to create subpatterns with duplicate numbers, they are now
294        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
295        on the other side of the coin, they are no longer allowed to have different
296        names, because these cannot be distinguished in PCRE, and this has caused
297        confusion. (This is a difference from Perl.)
299    28. When duplicate subpattern names are present (necessarily with different
300        numbers, as required by 27 above), and a test is made by name in a
301        conditional pattern, either for a subpattern having been matched, or for
302        recursion in such a pattern, all the associated numbered subpatterns are
303        tested, and the overall condition is true if the condition is true for any
304        one of them. This is the way Perl works, and is also more like the way
305        testing by number works.
308  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
309  ---------------------  ---------------------
# Line 112  Version 7.9 11-Apr-09 Line 416  Version 7.9 11-Apr-09
417  26. Changed a few more instances of "const unsigned char *" to USPTR, making  26. Changed a few more instances of "const unsigned char *" to USPTR, making
418      the feature of a custom pointer more persuasive (as requested by a user).      the feature of a custom pointer more persuasive (as requested by a user).
420  27. Wrapped the definitions of fileno and isatty for Windows, which appear in  27. Wrapped the definitions of fileno and isatty for Windows, which appear in
421      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
422      pre-defined.      pre-defined.
424  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
426    29. Arrange for flags added by the "release type" setting in CMake to be shown
427        in the configuration summary.
430  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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