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revision 413 by ph10, Sat Apr 11 11:41:52 2009 UTC revision 486 by ph10, Tue Jan 5 17:44:57 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.01 06-Jan-10
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    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
111        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
112        comment: "Figure out how to create a longlong from a string: strtoll and
113        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
114        instance, but it only takes 2 args instead of 3!"
115    
116    
117    Version 8.00 19-Oct-09
118    ----------------------
119    
120    1.  The table for translating pcre_compile() error codes into POSIX error codes
121        was out-of-date, and there was no check on the pcre_compile() error code
122        being within the table. This could lead to an OK return being given in
123        error.
124    
125    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
126        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
127        in a Windows environment.
128    
129    3.  The pcregrep --count option prints the count for each file even when it is
130        zero, as does GNU grep. However, pcregrep was also printing all files when
131        --files-with-matches was added. Now, when both options are given, it prints
132        counts only for those files that have at least one match. (GNU grep just
133        prints the file name in this circumstance, but including the count seems
134        more useful - otherwise, why use --count?) Also ensured that the
135        combination -clh just lists non-zero counts, with no names.
136    
137    4.  The long form of the pcregrep -F option was incorrectly implemented as
138        --fixed_strings instead of --fixed-strings. This is an incompatible change,
139        but it seems right to fix it, and I didn't think it was worth preserving
140        the old behaviour.
141    
142    5.  The command line items --regex=pattern and --regexp=pattern were not
143        recognized by pcregrep, which required --regex pattern or --regexp pattern
144        (with a space rather than an '='). The man page documented the '=' forms,
145        which are compatible with GNU grep; these now work.
146    
147    6.  No libpcreposix.pc file was created for pkg-config; there was just
148        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
149    
150    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
151        when UCP support is not needed, by modifying the Python script that
152        generates it from Unicode data files. This should not matter if the module
153        is correctly used as a library, but I received one complaint about 50K of
154        unwanted data. My guess is that the person linked everything into his
155        program rather than using a library. Anyway, it does no harm.
156    
157    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
158        was a minimum greater than 1 for a wide character in a possessive
159        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
160        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
161        character. Chaos in the form of incorrect output or a compiling loop could
162        result.
163    
164    9.  The restrictions on what a pattern can contain when partial matching is
165        requested for pcre_exec() have been removed. All patterns can now be
166        partially matched by this function. In addition, if there are at least two
167        slots in the offset vector, the offset of the earliest inspected character
168        for the match and the offset of the end of the subject are set in them when
169        PCRE_ERROR_PARTIAL is returned.
170    
171    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
172        synonymous with PCRE_PARTIAL, for backwards compatibility, and
173        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
174        and may be more useful for multi-segment matching.
175    
176    11. Partial matching with pcre_exec() is now more intuitive. A partial match
177        used to be given if ever the end of the subject was reached; now it is
178        given only if matching could not proceed because another character was
179        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
180        string "Z", which now yields "no match" instead of "partial match". In the
181        case of pcre_dfa_exec(), "no match" is given if every matching path for the
182        final character ended with (*FAIL).
183    
184    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
185        if the pattern had a "must contain" character that was already found in the
186        earlier partial match, unless partial matching was again requested. For
187        example, with the pattern /dog.(body)?/, the "must contain" character is
188        "g". If the first part-match was for the string "dog", restarting with
189        "sbody" failed. This bug has been fixed.
190    
191    13. The string returned by pcre_dfa_exec() after a partial match has been
192        changed so that it starts at the first inspected character rather than the
193        first character of the match. This makes a difference only if the pattern
194        starts with a lookbehind assertion or \b or \B (\K is not supported by
195        pcre_dfa_exec()). It's an incompatible change, but it makes the two
196        matching functions compatible, and I think it's the right thing to do.
197    
198    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
199        so that the demonstration program is easily available in environments where
200        PCRE has not been installed from source.
201    
202    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
203        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
204        library.
205    
206    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
207        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
208        is not the first non-POSIX option to be added. Clearly some people find
209        these options useful.
210    
211    17. If a caller to the POSIX matching function regexec() passes a non-zero
212        value for nmatch with a NULL value for pmatch, the value of
213        nmatch is forced to zero.
214    
215    18. RunGrepTest did not have a test for the availability of the -u option of
216        the diff command, as RunTest does. It now checks in the same way as
217        RunTest, and also checks for the -b option.
218    
219    19. If an odd number of negated classes containing just a single character
220        interposed, within parentheses, between a forward reference to a named
221        subpattern and the definition of the subpattern, compilation crashed with
222        an internal error, complaining that it could not find the referenced
223        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
224        [The bug was that it was starting one character too far in when skipping
225        over the character class, thus treating the ] as data rather than
226        terminating the class. This meant it could skip too much.]
227    
228    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
229        /g option in pcretest when the pattern contains \K, which makes it possible
230        to have an empty string match not at the start, even when the pattern is
231        anchored. Updated pcretest and pcredemo to use this option.
232    
233    21. If the maximum number of capturing subpatterns in a recursion was greater
234        than the maximum at the outer level, the higher number was returned, but
235        with unset values at the outer level. The correct (outer level) value is
236        now given.
237    
238    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
239        PCRE did not set those parentheses (unlike Perl). I have now found a way to
240        make it do so. The string so far is captured, making this feature
241        compatible with Perl.
242    
243    23. The tests have been re-organized, adding tests 11 and 12, to make it
244        possible to check the Perl 5.10 features against Perl 5.10.
245    
246    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
247        pattern matches a fixed length string. PCRE did not allow this; now it
248        does. Neither allows recursion.
249    
250    25. I finally figured out how to implement a request to provide the minimum
251        length of subject string that was needed in order to match a given pattern.
252        (It was back references and recursion that I had previously got hung up
253        on.) This code has now been added to pcre_study(); it finds a lower bound
254        to the length of subject needed. It is not necessarily the greatest lower
255        bound, but using it to avoid searching strings that are too short does give
256        some useful speed-ups. The value is available to calling programs via
257        pcre_fullinfo().
258    
259    26. While implementing 25, I discovered to my embarrassment that pcretest had
260        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
261        study optimizations had never been tested with that matching function.
262        Oops. What is worse, even when it was passed study data, there was a bug in
263        pcre_dfa_exec() that meant it never actually used it. Double oops. There
264        were also very few tests of studied patterns with pcre_dfa_exec().
265    
266    27. If (?| is used to create subpatterns with duplicate numbers, they are now
267        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
268        on the other side of the coin, they are no longer allowed to have different
269        names, because these cannot be distinguished in PCRE, and this has caused
270        confusion. (This is a difference from Perl.)
271    
272    28. When duplicate subpattern names are present (necessarily with different
273        numbers, as required by 27 above), and a test is made by name in a
274        conditional pattern, either for a subpattern having been matched, or for
275        recursion in such a pattern, all the associated numbered subpatterns are
276        tested, and the overall condition is true if the condition is true for any
277        one of them. This is the way Perl works, and is also more like the way
278        testing by number works.
279    
280    
281  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
282  ---------------------  ---------------------
283    
# Line 112  Version 7.9 11-Apr-09 Line 389  Version 7.9 11-Apr-09
389    
390  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
391      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).
392    
393  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
394      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
395      pre-defined.      pre-defined.
396    
397  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
398    
399  29. Arrange for flags added by the "release type" setting in CMake to be shown  29. Arrange for flags added by the "release type" setting in CMake to be shown
400      in the configuration summary.      in the configuration summary.

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