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revision 659 by ph10, Tue Aug 16 09:48:29 2011 UTC revision 881 by ph10, Sun Jan 15 18:07:05 2012 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.30
5    ------------
7    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
8        name is defined in ctype.h.
10    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
11        only in quite long subpatterns.
13    3.  Removed the function pcre_info(), which has been obsolete and deprecated
14        since it was replaced by pcre_fullinfo() in February 2000.
16    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
17        match a (*MARK), and the match failed at the start of the subject, a
18        reference to memory before the start of the subject could occur. This bug
19        was introduced by fix 17 of release 8.21.
21    5.  A reference to an unset group with zero minimum repetition was giving
22        totally wrong answers (in non-JavaScript-compatibility mode). For example,
23        /(another)?(\1?)test/ matched against "hello world test". This bug was
24        introduced in release 8.13.
26    6.  Add support for 16-bit character strings (a large amount of work involving
27        many changes and refactorings).
29    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
30        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
31        from a file.
33    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
34        rounding is not applied in this particular case).
36    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
37        if they appear, or are escaped, in patterns.
39    10. Get rid of a number of -Wunused-but-set-variable warnings.
42    Version 8.21 12-Dec-2011
43    ------------------------
45    1.  Updating the JIT compiler.
47    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
48        are added as well.
50    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
51        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
52        calling _pcre_jit_exec. Some extra comments are added.
54    4.  (*MARK) settings inside atomic groups that do not contain any capturing
55        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
56        was introduced by change 18 for 8.20.
58    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
59        ECMA-262 standard.
61    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
62        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
63        This bug was probably introduced by change 9 of 8.13.
65    7.  While fixing 6 above, I noticed that a number of other items were being
66        incorrectly rejected as "not fixed length". This arose partly because newer
67        opcodes had not been added to the fixed-length checking code. I have (a)
68        corrected the bug and added tests for these items, and (b) arranged for an
69        error to occur if an unknown opcode is encountered while checking for fixed
70        length instead of just assuming "not fixed length". The items that were
71        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
72        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
73        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
75    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
76        being incorrectly compiled and would have given unpredicatble results.
78    9.  A possessively repeated subpattern with minimum repeat count greater than
79        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
80        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
81        the first (A) could occur when it should not.
83    10. Add a cast and remove a redundant test from the code.
85    11. JIT should use pcre_malloc/pcre_free for allocation.
87    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
88        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
89        is anything other than /usr, -L is still shown).
91    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
93    14. Perl does not support \N without a following name in a [] class; PCRE now
94        also gives an error.
96    15. If a forward reference was repeated with an upper limit of around 2000,
97        it caused the error "internal error: overran compiling workspace". The
98        maximum number of forward references (including repeats) was limited by the
99        internal workspace, and dependent on the LINK_SIZE. The code has been
100        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
101        the default depends on LINK_SIZE. There is a new upper limit (for safety)
102        of around 200,000 forward references. While doing this, I also speeded up
103        the filling in of repeated forward references.
105    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
106        incorrectly expecting the subject to contain another "a" after the start.
108    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
109        in the match, the SKIP should be ignored. This was not happening; instead
110        the SKIP was being treated as NOMATCH. For patterns such as
111        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
112        tested.
114    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
115        now much more compatible with Perl, in particular in cases where the result
116        is a non-match for a non-anchored pattern. For example, if
117        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
118        "m", where previously it did not return a name. A side effect of this
119        change is that for partial matches, the last encountered mark name is
120        returned, as for non matches. A number of tests that were previously not
121        Perl-compatible have been moved into the Perl-compatible test files. The
122        refactoring has had the pleasing side effect of removing one argument from
123        the match() function, thus reducing its stack requirements.
125    19. If the /S+ option was used in pcretest to study a pattern using JIT,
126        subsequent uses of /S (without +) incorrectly behaved like /S+.
128    21. Retrieve executable code size support for the JIT compiler and fixing
129        some warnings.
131    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
132        not work when the shorter character appeared right at the end of the
133        subject string.
135    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
136        systems.
138    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
139        output it when the /M option is used in pcretest.
141    25. The CheckMan script was not being included in the distribution. Also, added
142        an explicit "perl" to run Perl scripts from the PrepareRelease script
143        because this is reportedly needed in Windows.
145    26. If study data was being save in a file and studying had not found a set of
146        "starts with" bytes for the pattern, the data written to the file (though
147        never used) was taken from uninitialized memory and so caused valgrind to
148        complain.
150    27. Updated RunTest.bat as provided by Sheri Pierce.
152    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
154    29. Computation of memory usage for the table of capturing group names was
155        giving an unnecessarily large value.
158    Version 8.20 21-Oct-2011
159    ------------------------
161    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
162        a POSIX class. After further experiments with Perl, which convinced me that
163        Perl has bugs and confusions, a closing square bracket is no longer allowed
164        in a POSIX name. This bug also affected patterns with classes that started
165        with full stops.
167    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
168        captured substring, but while checking the failing first alternative,
169        substring 1 is temporarily captured. If the output vector supplied to
170        pcre_exec() was not big enough for this capture, the yield of the function
171        was still zero ("insufficient space for captured substrings"). This cannot
172        be totally fixed without adding another stack variable, which seems a lot
173        of expense for a edge case. However, I have improved the situation in cases
174        such as /(a)(b)x|abc/ matched against "abc", where the return code
175        indicates that fewer than the maximum number of slots in the ovector have
176        been set.
178    3.  Related to (2) above: when there are more back references in a pattern than
179        slots in the output vector, pcre_exec() uses temporary memory during
180        matching, and copies in the captures as far as possible afterwards. It was
181        using the entire output vector, but this conflicts with the specification
182        that only 2/3 is used for passing back captured substrings. Now it uses
183        only the first 2/3, for compatibility. This is, of course, another edge
184        case.
186    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
187        main code base, and can be used by building with --enable-jit. When this is
188        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
189        runtime --no-jit option is given.
191    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
192        ovector, the return from the function was zero, implying that there were
193        other matches that did not fit. The correct "exactly full" value is now
194        returned.
196    6.  If a subpattern that was called recursively or as a subroutine contained
197        (*PRUNE) or any other control that caused it to give a non-standard return,
198        invalid errors such as "Error -26 (nested recursion at the same subject
199        position)" or even infinite loops could occur.
201    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
202        computing the minimum length on reaching *ACCEPT, and so ended up with the
203        wrong value of 1 rather than 0. Further investigation indicates that
204        computing a minimum subject length in the presence of *ACCEPT is difficult
205        (think back references, subroutine calls), and so I have changed the code
206        so that no minimum is registered for a pattern that contains *ACCEPT.
208    8.  If (*THEN) was present in the first (true) branch of a conditional group,
209        it was not handled as intended. [But see 16 below.]
211    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
212        Sheri Pierce.
214    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
215        the first byte in a match must be "a".
217    11. Change 17 for 8.13 increased the recursion depth for patterns like
218        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
219        pattern contains any instances of (*THEN). If it does not, the old
220        optimizations are restored. It would be nice to do this on a per-group
221        basis, but at the moment that is not feasible.
223    12. In some environments, the output of pcretest -C is CRLF terminated. This
224        broke RunTest's code that checks for the link size. A single white space
225        character after the value is now allowed for.
227    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
228        For "fr", it uses the Windows-specific input and output files.
230    14. If (*THEN) appeared in a group that was called recursively or as a
231        subroutine, it did not work as intended. [But see next item.]
233    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
234        pattern fragments (but not containing any | characters). If A and B are
235        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
236        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
237        D. In other words, Perl considers parentheses that do not contain any |
238        characters to be part of a surrounding alternative, whereas PCRE was
239        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
240        differently. PCRE now behaves in the same way as Perl, except in the case
241        of subroutine/recursion calls such as (?1) which have in any case always
242        been different (but PCRE had them first :-).
244    16. Related to 15 above: Perl does not treat the | in a conditional group as
245        creating alternatives. Such a group is treated in the same way as an
246        ordinary group without any | characters when processing (*THEN). PCRE has
247        been changed to match Perl's behaviour.
249    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
250        RunGrepTest script failed.
252    18. Change 22 for version 13 caused atomic groups to use more stack. This is
253        inevitable for groups that contain captures, but it can lead to a lot of
254        stack use in large patterns. The old behaviour has been restored for atomic
255        groups that do not contain any capturing parentheses.
257    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
258        suppress the check for a minimum subject length at run time. (If it was
259        given to pcre_exec() or pcre_dfa_exec() it did work.)
261    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
262        fail to work when decoding hex characters in data strings in EBCDIC
263        environments.
265    21. It appears that in at least one Mac OS environment, the isxdigit() function
266        is implemented as a macro that evaluates to its argument more than once,
267        contravening the C 90 Standard (I haven't checked a later standard). There
268        was an instance in pcretest which caused it to go wrong when processing
269        \x{...} escapes in subject strings. The has been rewritten to avoid using
270        things like p++ in the argument of isxdigit().
273  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
274  ------------------------  ------------------------
# Line 98  Version 8.13 16-Aug-2011 Line 367  Version 8.13 16-Aug-2011
367      tail recursion to cut down on stack usage. Unfortunately, now that there is      tail recursion to cut down on stack usage. Unfortunately, now that there is
368      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
369      no longer possible because the return has to be checked for (*THEN). These      no longer possible because the return has to be checked for (*THEN). These
370      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
372  18. If a pattern containing \R was studied, it was assumed that \R always  18. If a pattern containing \R was studied, it was assumed that \R always
373      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
# Line 189  Version 8.13 16-Aug-2011 Line 458  Version 8.13 16-Aug-2011
458      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
459      unescaped square brackets may also appear as part of class names. For      unescaped square brackets may also appear as part of class names. For
460      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
461      more like Perl.      more like Perl. (But see 8.20/1 above.)
463  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
464      was because it thought it was \N{name}, which is not supported).      was because it thought it was \N{name}, which is not supported).

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