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revision 426 by ph10, Wed Aug 26 15:38:32 2009 UTC revision 481 by ph10, Sun Jan 3 17:45:53 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.01 11-Dec-09
5  ----------------------  ----------------------
6    
7  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  If a pattern contained a conditional subpattern with only one branch (in
8      was out-of-date, and there was no check on the pcre_compile() error code      particular, this includes all (DEFINE) patterns), a call to pcre_study()
9      being within the table. This could lead to an OK return being given in      computed the wrong minimum data length (which is of course zero for such
10      error.      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  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
81      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      most of the time, it *can* run out if it is given a pattern that contains a
82      in a Windows environment.      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    
93    
94    Version 8.00 19-Oct-09
95    ----------------------
96    
97    1.  The table for translating pcre_compile() error codes into POSIX error codes
98        was out-of-date, and there was no check on the pcre_compile() error code
99        being within the table. This could lead to an OK return being given in
100        error.
101    
102    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
103        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
104        in a Windows environment.
105    
106  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
107      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
108      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
109      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
110      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
111      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
112      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
113    
114  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
115      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
116      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
117      the old behaviour.      the old behaviour.
118    
119  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
120      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
121      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
122      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
123    
124  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
125      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
126    
127  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
128      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
129      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
130      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
131      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
132      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
133    
134  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
135      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
136      repetition. Chaos could result.      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
137        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
138        character. Chaos in the form of incorrect output or a compiling loop could
139        result.
140    
141  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
142      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
143      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
144      slots in the offset vector, the offsets of the first-encountered partial      slots in the offset vector, the offset of the earliest inspected character
145      match are set in them when PCRE_ERROR_PARTIAL is returned.      for the match and the offset of the end of the subject are set in them when
146        PCRE_ERROR_PARTIAL is returned.
147    
148    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
149        synonymous with PCRE_PARTIAL, for backwards compatibility, and
150        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
151        and may be more useful for multi-segment matching.
152    
153    11. Partial matching with pcre_exec() is now more intuitive. A partial match
154        used to be given if ever the end of the subject was reached; now it is
155        given only if matching could not proceed because another character was
156        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
157        string "Z", which now yields "no match" instead of "partial match". In the
158        case of pcre_dfa_exec(), "no match" is given if every matching path for the
159        final character ended with (*FAIL).
160    
161    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
162        if the pattern had a "must contain" character that was already found in the
163        earlier partial match, unless partial matching was again requested. For
164        example, with the pattern /dog.(body)?/, the "must contain" character is
165        "g". If the first part-match was for the string "dog", restarting with
166        "sbody" failed. This bug has been fixed.
167    
168    13. The string returned by pcre_dfa_exec() after a partial match has been
169        changed so that it starts at the first inspected character rather than the
170        first character of the match. This makes a difference only if the pattern
171        starts with a lookbehind assertion or \b or \B (\K is not supported by
172        pcre_dfa_exec()). It's an incompatible change, but it makes the two
173        matching functions compatible, and I think it's the right thing to do.
174    
175    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
176        so that the demonstration program is easily available in environments where
177        PCRE has not been installed from source.
178    
179    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
180        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
181        library.
182    
183    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
184        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
185        is not the first non-POSIX option to be added. Clearly some people find
186        these options useful.
187    
188    17. If a caller to the POSIX matching function regexec() passes a non-zero
189        value for nmatch with a NULL value for pmatch, the value of
190        nmatch is forced to zero.
191    
192    18. RunGrepTest did not have a test for the availability of the -u option of
193        the diff command, as RunTest does. It now checks in the same way as
194        RunTest, and also checks for the -b option.
195    
196    19. If an odd number of negated classes containing just a single character
197        interposed, within parentheses, between a forward reference to a named
198        subpattern and the definition of the subpattern, compilation crashed with
199        an internal error, complaining that it could not find the referenced
200        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
201        [The bug was that it was starting one character too far in when skipping
202        over the character class, thus treating the ] as data rather than
203        terminating the class. This meant it could skip too much.]
204    
205    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
206        /g option in pcretest when the pattern contains \K, which makes it possible
207        to have an empty string match not at the start, even when the pattern is
208        anchored. Updated pcretest and pcredemo to use this option.
209    
210    21. If the maximum number of capturing subpatterns in a recursion was greater
211        than the maximum at the outer level, the higher number was returned, but
212        with unset values at the outer level. The correct (outer level) value is
213        now given.
214    
215    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
216        PCRE did not set those parentheses (unlike Perl). I have now found a way to
217        make it do so. The string so far is captured, making this feature
218        compatible with Perl.
219    
220    23. The tests have been re-organized, adding tests 11 and 12, to make it
221        possible to check the Perl 5.10 features against Perl 5.10.
222    
223    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
224        pattern matches a fixed length string. PCRE did not allow this; now it
225        does. Neither allows recursion.
226    
227    25. I finally figured out how to implement a request to provide the minimum
228        length of subject string that was needed in order to match a given pattern.
229        (It was back references and recursion that I had previously got hung up
230        on.) This code has now been added to pcre_study(); it finds a lower bound
231        to the length of subject needed. It is not necessarily the greatest lower
232        bound, but using it to avoid searching strings that are too short does give
233        some useful speed-ups. The value is available to calling programs via
234        pcre_fullinfo().
235    
236    26. While implementing 25, I discovered to my embarrassment that pcretest had
237        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
238        study optimizations had never been tested with that matching function.
239        Oops. What is worse, even when it was passed study data, there was a bug in
240        pcre_dfa_exec() that meant it never actually used it. Double oops. There
241        were also very few tests of studied patterns with pcre_dfa_exec().
242    
243    27. If (?| is used to create subpatterns with duplicate numbers, they are now
244        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
245        on the other side of the coin, they are no longer allowed to have different
246        names, because these cannot be distinguished in PCRE, and this has caused
247        confusion. (This is a difference from Perl.)
248    
249    28. When duplicate subpattern names are present (necessarily with different
250        numbers, as required by 27 above), and a test is made by name in a
251        conditional pattern, either for a subpattern having been matched, or for
252        recursion in such a pattern, all the associated numbered subpatterns are
253        tested, and the overall condition is true if the condition is true for any
254        one of them. This is the way Perl works, and is also more like the way
255        testing by number works.
256    
257    
258  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
259  ---------------------  ---------------------

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