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revision 659 by ph10, Tue Aug 16 09:48:29 2011 UTC revision 924 by zherczeg, Wed Feb 22 10:23:56 2012 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.31
5    -----------------------------
7    1.  Fixing a wrong JIT test case and some compiler warnings.
9    2.  Removed a bashism from the RunTest script.
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
15    4.  Partial matching support is added to the JIT compiler.
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
36    6.  When matching is performed using JIT-compiled code, the flag bit
37        PCRE_EXTRA_USED_JIT is set in the pcre_extra block and can be tested by the
38        caller. This bit is checked by pcretest if JIT is requested by /S++ or -s++
39        (instead of just /S+ or -s+) and the text "(JIT)" added to the output if
40        the bit is set.
42    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
43        or /S+[+] with a digit between 1 and 7.
45    8.  OP_NOT now supports any UTF character not just single character ones.
48    Version 8.30 04-February-2012
49    -----------------------------
51    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
52        name is defined in ctype.h.
54    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
55        only in quite long subpatterns.
57    3.  Removed the function pcre_info(), which has been obsolete and deprecated
58        since it was replaced by pcre_fullinfo() in February 2000.
60    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
61        match a (*MARK), and the match failed at the start of the subject, a
62        reference to memory before the start of the subject could occur. This bug
63        was introduced by fix 17 of release 8.21.
65    5.  A reference to an unset group with zero minimum repetition was giving
66        totally wrong answers (in non-JavaScript-compatibility mode). For example,
67        /(another)?(\1?)test/ matched against "hello world test". This bug was
68        introduced in release 8.13.
70    6.  Add support for 16-bit character strings (a large amount of work involving
71        many changes and refactorings).
73    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
74        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
75        from a file.
77    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
78        rounding is not applied in this particular case).
80    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
81        if they appear, or are escaped, in patterns.
83    10. Get rid of a number of -Wunused-but-set-variable warnings.
85    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
86        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
87        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
88        also returns the mark "x". This bug applied to capturing parentheses,
89        non-capturing parentheses, and atomic parentheses. It also applied to some
90        assertions.
92    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
93        information out of configure.ac instead of relying on pcre.h.generic, which
94        is not stored in the repository.
96    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
97        -lreadline.
99    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
101    15. Applied Graycode's patch to put the top-level frame on the stack rather
102        than the heap when not using the stack for recursion. This gives a
103        performance improvement in many cases when recursion is not deep.
105    16. Experimental code added to "pcretest -C" to output the stack frame size.
108    Version 8.21 12-Dec-2011
109    ------------------------
111    1.  Updating the JIT compiler.
113    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
114        are added as well.
116    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
117        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
118        calling _pcre_jit_exec. Some extra comments are added.
120    4.  (*MARK) settings inside atomic groups that do not contain any capturing
121        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
122        was introduced by change 18 for 8.20.
124    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
125        ECMA-262 standard.
127    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
128        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
129        This bug was probably introduced by change 9 of 8.13.
131    7.  While fixing 6 above, I noticed that a number of other items were being
132        incorrectly rejected as "not fixed length". This arose partly because newer
133        opcodes had not been added to the fixed-length checking code. I have (a)
134        corrected the bug and added tests for these items, and (b) arranged for an
135        error to occur if an unknown opcode is encountered while checking for fixed
136        length instead of just assuming "not fixed length". The items that were
137        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
138        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
139        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
141    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
142        being incorrectly compiled and would have given unpredicatble results.
144    9.  A possessively repeated subpattern with minimum repeat count greater than
145        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
146        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
147        the first (A) could occur when it should not.
149    10. Add a cast and remove a redundant test from the code.
151    11. JIT should use pcre_malloc/pcre_free for allocation.
153    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
154        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
155        is anything other than /usr, -L is still shown).
157    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
159    14. Perl does not support \N without a following name in a [] class; PCRE now
160        also gives an error.
162    15. If a forward reference was repeated with an upper limit of around 2000,
163        it caused the error "internal error: overran compiling workspace". The
164        maximum number of forward references (including repeats) was limited by the
165        internal workspace, and dependent on the LINK_SIZE. The code has been
166        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
167        the default depends on LINK_SIZE. There is a new upper limit (for safety)
168        of around 200,000 forward references. While doing this, I also speeded up
169        the filling in of repeated forward references.
171    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
172        incorrectly expecting the subject to contain another "a" after the start.
174    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
175        in the match, the SKIP should be ignored. This was not happening; instead
176        the SKIP was being treated as NOMATCH. For patterns such as
177        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
178        tested.
180    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
181        now much more compatible with Perl, in particular in cases where the result
182        is a non-match for a non-anchored pattern. For example, if
183        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
184        "m", where previously it did not return a name. A side effect of this
185        change is that for partial matches, the last encountered mark name is
186        returned, as for non matches. A number of tests that were previously not
187        Perl-compatible have been moved into the Perl-compatible test files. The
188        refactoring has had the pleasing side effect of removing one argument from
189        the match() function, thus reducing its stack requirements.
191    19. If the /S+ option was used in pcretest to study a pattern using JIT,
192        subsequent uses of /S (without +) incorrectly behaved like /S+.
194    21. Retrieve executable code size support for the JIT compiler and fixing
195        some warnings.
197    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
198        not work when the shorter character appeared right at the end of the
199        subject string.
201    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
202        systems.
204    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
205        output it when the /M option is used in pcretest.
207    25. The CheckMan script was not being included in the distribution. Also, added
208        an explicit "perl" to run Perl scripts from the PrepareRelease script
209        because this is reportedly needed in Windows.
211    26. If study data was being save in a file and studying had not found a set of
212        "starts with" bytes for the pattern, the data written to the file (though
213        never used) was taken from uninitialized memory and so caused valgrind to
214        complain.
216    27. Updated RunTest.bat as provided by Sheri Pierce.
218    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
220    29. Computation of memory usage for the table of capturing group names was
221        giving an unnecessarily large value.
224    Version 8.20 21-Oct-2011
225    ------------------------
227    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
228        a POSIX class. After further experiments with Perl, which convinced me that
229        Perl has bugs and confusions, a closing square bracket is no longer allowed
230        in a POSIX name. This bug also affected patterns with classes that started
231        with full stops.
233    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
234        captured substring, but while checking the failing first alternative,
235        substring 1 is temporarily captured. If the output vector supplied to
236        pcre_exec() was not big enough for this capture, the yield of the function
237        was still zero ("insufficient space for captured substrings"). This cannot
238        be totally fixed without adding another stack variable, which seems a lot
239        of expense for a edge case. However, I have improved the situation in cases
240        such as /(a)(b)x|abc/ matched against "abc", where the return code
241        indicates that fewer than the maximum number of slots in the ovector have
242        been set.
244    3.  Related to (2) above: when there are more back references in a pattern than
245        slots in the output vector, pcre_exec() uses temporary memory during
246        matching, and copies in the captures as far as possible afterwards. It was
247        using the entire output vector, but this conflicts with the specification
248        that only 2/3 is used for passing back captured substrings. Now it uses
249        only the first 2/3, for compatibility. This is, of course, another edge
250        case.
252    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
253        main code base, and can be used by building with --enable-jit. When this is
254        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
255        runtime --no-jit option is given.
257    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
258        ovector, the return from the function was zero, implying that there were
259        other matches that did not fit. The correct "exactly full" value is now
260        returned.
262    6.  If a subpattern that was called recursively or as a subroutine contained
263        (*PRUNE) or any other control that caused it to give a non-standard return,
264        invalid errors such as "Error -26 (nested recursion at the same subject
265        position)" or even infinite loops could occur.
267    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
268        computing the minimum length on reaching *ACCEPT, and so ended up with the
269        wrong value of 1 rather than 0. Further investigation indicates that
270        computing a minimum subject length in the presence of *ACCEPT is difficult
271        (think back references, subroutine calls), and so I have changed the code
272        so that no minimum is registered for a pattern that contains *ACCEPT.
274    8.  If (*THEN) was present in the first (true) branch of a conditional group,
275        it was not handled as intended. [But see 16 below.]
277    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
278        Sheri Pierce.
280    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
281        the first byte in a match must be "a".
283    11. Change 17 for 8.13 increased the recursion depth for patterns like
284        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
285        pattern contains any instances of (*THEN). If it does not, the old
286        optimizations are restored. It would be nice to do this on a per-group
287        basis, but at the moment that is not feasible.
289    12. In some environments, the output of pcretest -C is CRLF terminated. This
290        broke RunTest's code that checks for the link size. A single white space
291        character after the value is now allowed for.
293    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
294        For "fr", it uses the Windows-specific input and output files.
296    14. If (*THEN) appeared in a group that was called recursively or as a
297        subroutine, it did not work as intended. [But see next item.]
299    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
300        pattern fragments (but not containing any | characters). If A and B are
301        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
302        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
303        D. In other words, Perl considers parentheses that do not contain any |
304        characters to be part of a surrounding alternative, whereas PCRE was
305        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
306        differently. PCRE now behaves in the same way as Perl, except in the case
307        of subroutine/recursion calls such as (?1) which have in any case always
308        been different (but PCRE had them first :-).
310    16. Related to 15 above: Perl does not treat the | in a conditional group as
311        creating alternatives. Such a group is treated in the same way as an
312        ordinary group without any | characters when processing (*THEN). PCRE has
313        been changed to match Perl's behaviour.
315    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
316        RunGrepTest script failed.
318    18. Change 22 for version 13 caused atomic groups to use more stack. This is
319        inevitable for groups that contain captures, but it can lead to a lot of
320        stack use in large patterns. The old behaviour has been restored for atomic
321        groups that do not contain any capturing parentheses.
323    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
324        suppress the check for a minimum subject length at run time. (If it was
325        given to pcre_exec() or pcre_dfa_exec() it did work.)
327    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
328        fail to work when decoding hex characters in data strings in EBCDIC
329        environments.
331    21. It appears that in at least one Mac OS environment, the isxdigit() function
332        is implemented as a macro that evaluates to its argument more than once,
333        contravening the C 90 Standard (I haven't checked a later standard). There
334        was an instance in pcretest which caused it to go wrong when processing
335        \x{...} escapes in subject strings. The has been rewritten to avoid using
336        things like p++ in the argument of isxdigit().
339  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
340  ------------------------  ------------------------
# Line 98  Version 8.13 16-Aug-2011 Line 433  Version 8.13 16-Aug-2011
433      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
434      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
435      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
436      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
438  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
439      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 524  Version 8.13 16-Aug-2011
524      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
525      unescaped square brackets may also appear as part of class names. For      unescaped square brackets may also appear as part of class names. For
526      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
527      more like Perl.      more like Perl. (But see 8.20/1 above.)
529  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
530      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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