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revision 412 by ph10, Sat Apr 11 10:34:37 2009 UTC revision 484 by ph10, Mon Jan 4 17:11:54 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.01 11-Dec-09
5    ----------------------
6    
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).
11    
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.)
18    
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.
24    
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
28        PCRE_ERROR_DFA_UITEM.
29    
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.
33    
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.)
36    
37    7.  Some cosmetic changes to the code to make life easier when compiling it
38        as part of something else:
39    
40        (a) Change DEBUG to PCRE_DEBUG.
41    
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.
45    
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.
49    
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.
56    
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).
59    
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:
62    
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.
70    
71    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
72        messages were output:
73    
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.
77    
78        I have done both of these things.
79    
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.
84    
85    13. Now that we have gone to the x.xx style of version numbers, the minor
86        version may start with zero. Using 08 or 09 is a bad idea because users
87        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
88        interpreted as invalid octal numbers. I've updated the previous comment in
89        configure.ac, and also added a check that gives an error if 08 or 09 are
90        used.
91    
92    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
93        causing partial matching to fail when the end of the subject matched \W
94        in a UTF-8 pattern where \W was quantified with a minimum of 3.
95    
96    15. There were some discrepancies between the declarations in pcre_internal.h
97        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
98        their definitions. The declarations used "const uschar *" and the
99        definitions used USPTR. Even though USPTR is normally defined as "const
100        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
101        reported that: "This difference in casting confuses some C++ compilers, for
102        example, SunCC recognizes above declarations as different functions and
103        generates broken code for hbpcre." I have changed the declarations to use
104        USPTR.
105    
106    16. GNU libtool is named differently on some systems. The autogen.sh script now
107        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
108        (FreeBSD).
109    
110    
111    
112    Version 8.00 19-Oct-09
113    ----------------------
114    
115    1.  The table for translating pcre_compile() error codes into POSIX error codes
116        was out-of-date, and there was no check on the pcre_compile() error code
117        being within the table. This could lead to an OK return being given in
118        error.
119    
120    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
121        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
122        in a Windows environment.
123    
124    3.  The pcregrep --count option prints the count for each file even when it is
125        zero, as does GNU grep. However, pcregrep was also printing all files when
126        --files-with-matches was added. Now, when both options are given, it prints
127        counts only for those files that have at least one match. (GNU grep just
128        prints the file name in this circumstance, but including the count seems
129        more useful - otherwise, why use --count?) Also ensured that the
130        combination -clh just lists non-zero counts, with no names.
131    
132    4.  The long form of the pcregrep -F option was incorrectly implemented as
133        --fixed_strings instead of --fixed-strings. This is an incompatible change,
134        but it seems right to fix it, and I didn't think it was worth preserving
135        the old behaviour.
136    
137    5.  The command line items --regex=pattern and --regexp=pattern were not
138        recognized by pcregrep, which required --regex pattern or --regexp pattern
139        (with a space rather than an '='). The man page documented the '=' forms,
140        which are compatible with GNU grep; these now work.
141    
142    6.  No libpcreposix.pc file was created for pkg-config; there was just
143        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
144    
145    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
146        when UCP support is not needed, by modifying the Python script that
147        generates it from Unicode data files. This should not matter if the module
148        is correctly used as a library, but I received one complaint about 50K of
149        unwanted data. My guess is that the person linked everything into his
150        program rather than using a library. Anyway, it does no harm.
151    
152    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
153        was a minimum greater than 1 for a wide character in a possessive
154        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
155        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
156        character. Chaos in the form of incorrect output or a compiling loop could
157        result.
158    
159    9.  The restrictions on what a pattern can contain when partial matching is
160        requested for pcre_exec() have been removed. All patterns can now be
161        partially matched by this function. In addition, if there are at least two
162        slots in the offset vector, the offset of the earliest inspected character
163        for the match and the offset of the end of the subject are set in them when
164        PCRE_ERROR_PARTIAL is returned.
165    
166    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
167        synonymous with PCRE_PARTIAL, for backwards compatibility, and
168        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
169        and may be more useful for multi-segment matching.
170    
171    11. Partial matching with pcre_exec() is now more intuitive. A partial match
172        used to be given if ever the end of the subject was reached; now it is
173        given only if matching could not proceed because another character was
174        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
175        string "Z", which now yields "no match" instead of "partial match". In the
176        case of pcre_dfa_exec(), "no match" is given if every matching path for the
177        final character ended with (*FAIL).
178    
179    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
180        if the pattern had a "must contain" character that was already found in the
181        earlier partial match, unless partial matching was again requested. For
182        example, with the pattern /dog.(body)?/, the "must contain" character is
183        "g". If the first part-match was for the string "dog", restarting with
184        "sbody" failed. This bug has been fixed.
185    
186    13. The string returned by pcre_dfa_exec() after a partial match has been
187        changed so that it starts at the first inspected character rather than the
188        first character of the match. This makes a difference only if the pattern
189        starts with a lookbehind assertion or \b or \B (\K is not supported by
190        pcre_dfa_exec()). It's an incompatible change, but it makes the two
191        matching functions compatible, and I think it's the right thing to do.
192    
193    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
194        so that the demonstration program is easily available in environments where
195        PCRE has not been installed from source.
196    
197    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
198        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
199        library.
200    
201    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
202        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
203        is not the first non-POSIX option to be added. Clearly some people find
204        these options useful.
205    
206    17. If a caller to the POSIX matching function regexec() passes a non-zero
207        value for nmatch with a NULL value for pmatch, the value of
208        nmatch is forced to zero.
209    
210    18. RunGrepTest did not have a test for the availability of the -u option of
211        the diff command, as RunTest does. It now checks in the same way as
212        RunTest, and also checks for the -b option.
213    
214    19. If an odd number of negated classes containing just a single character
215        interposed, within parentheses, between a forward reference to a named
216        subpattern and the definition of the subpattern, compilation crashed with
217        an internal error, complaining that it could not find the referenced
218        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
219        [The bug was that it was starting one character too far in when skipping
220        over the character class, thus treating the ] as data rather than
221        terminating the class. This meant it could skip too much.]
222    
223    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
224        /g option in pcretest when the pattern contains \K, which makes it possible
225        to have an empty string match not at the start, even when the pattern is
226        anchored. Updated pcretest and pcredemo to use this option.
227    
228    21. If the maximum number of capturing subpatterns in a recursion was greater
229        than the maximum at the outer level, the higher number was returned, but
230        with unset values at the outer level. The correct (outer level) value is
231        now given.
232    
233    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
234        PCRE did not set those parentheses (unlike Perl). I have now found a way to
235        make it do so. The string so far is captured, making this feature
236        compatible with Perl.
237    
238    23. The tests have been re-organized, adding tests 11 and 12, to make it
239        possible to check the Perl 5.10 features against Perl 5.10.
240    
241    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
242        pattern matches a fixed length string. PCRE did not allow this; now it
243        does. Neither allows recursion.
244    
245    25. I finally figured out how to implement a request to provide the minimum
246        length of subject string that was needed in order to match a given pattern.
247        (It was back references and recursion that I had previously got hung up
248        on.) This code has now been added to pcre_study(); it finds a lower bound
249        to the length of subject needed. It is not necessarily the greatest lower
250        bound, but using it to avoid searching strings that are too short does give
251        some useful speed-ups. The value is available to calling programs via
252        pcre_fullinfo().
253    
254    26. While implementing 25, I discovered to my embarrassment that pcretest had
255        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
256        study optimizations had never been tested with that matching function.
257        Oops. What is worse, even when it was passed study data, there was a bug in
258        pcre_dfa_exec() that meant it never actually used it. Double oops. There
259        were also very few tests of studied patterns with pcre_dfa_exec().
260    
261    27. If (?| is used to create subpatterns with duplicate numbers, they are now
262        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
263        on the other side of the coin, they are no longer allowed to have different
264        names, because these cannot be distinguished in PCRE, and this has caused
265        confusion. (This is a difference from Perl.)
266    
267    28. When duplicate subpattern names are present (necessarily with different
268        numbers, as required by 27 above), and a test is made by name in a
269        conditional pattern, either for a subpattern having been matched, or for
270        recursion in such a pattern, all the associated numbered subpatterns are
271        tested, and the overall condition is true if the condition is true for any
272        one of them. This is the way Perl works, and is also more like the way
273        testing by number works.
274    
275    
276  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
277  ---------------------  ---------------------
278    
# Line 112  Version 7.9 11-Apr-09 Line 384  Version 7.9 11-Apr-09
384    
385  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
386      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).
387    
388  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
389      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
390      pre-defined.      pre-defined.
391    
392  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
393    
394    29. Arrange for flags added by the "release type" setting in CMake to be shown
395        in the configuration summary.
396    
397    
398  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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