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revision 659 by ph10, Tue Aug 16 09:48:29 2011 UTC revision 923 by ph10, Tue Feb 21 13:25:05 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.
46    Version 8.30 04-February-2012
47    -----------------------------
49    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
50        name is defined in ctype.h.
52    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
53        only in quite long subpatterns.
55    3.  Removed the function pcre_info(), which has been obsolete and deprecated
56        since it was replaced by pcre_fullinfo() in February 2000.
58    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
59        match a (*MARK), and the match failed at the start of the subject, a
60        reference to memory before the start of the subject could occur. This bug
61        was introduced by fix 17 of release 8.21.
63    5.  A reference to an unset group with zero minimum repetition was giving
64        totally wrong answers (in non-JavaScript-compatibility mode). For example,
65        /(another)?(\1?)test/ matched against "hello world test". This bug was
66        introduced in release 8.13.
68    6.  Add support for 16-bit character strings (a large amount of work involving
69        many changes and refactorings).
71    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
72        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
73        from a file.
75    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
76        rounding is not applied in this particular case).
78    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
79        if they appear, or are escaped, in patterns.
81    10. Get rid of a number of -Wunused-but-set-variable warnings.
83    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
84        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
85        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
86        also returns the mark "x". This bug applied to capturing parentheses,
87        non-capturing parentheses, and atomic parentheses. It also applied to some
88        assertions.
90    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
91        information out of configure.ac instead of relying on pcre.h.generic, which
92        is not stored in the repository.
94    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
95        -lreadline.
97    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
99    15. Applied Graycode's patch to put the top-level frame on the stack rather
100        than the heap when not using the stack for recursion. This gives a
101        performance improvement in many cases when recursion is not deep.
103    16. Experimental code added to "pcretest -C" to output the stack frame size.
106    Version 8.21 12-Dec-2011
107    ------------------------
109    1.  Updating the JIT compiler.
111    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
112        are added as well.
114    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
115        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
116        calling _pcre_jit_exec. Some extra comments are added.
118    4.  (*MARK) settings inside atomic groups that do not contain any capturing
119        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
120        was introduced by change 18 for 8.20.
122    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
123        ECMA-262 standard.
125    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
126        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
127        This bug was probably introduced by change 9 of 8.13.
129    7.  While fixing 6 above, I noticed that a number of other items were being
130        incorrectly rejected as "not fixed length". This arose partly because newer
131        opcodes had not been added to the fixed-length checking code. I have (a)
132        corrected the bug and added tests for these items, and (b) arranged for an
133        error to occur if an unknown opcode is encountered while checking for fixed
134        length instead of just assuming "not fixed length". The items that were
135        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
136        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
137        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
139    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
140        being incorrectly compiled and would have given unpredicatble results.
142    9.  A possessively repeated subpattern with minimum repeat count greater than
143        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
144        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
145        the first (A) could occur when it should not.
147    10. Add a cast and remove a redundant test from the code.
149    11. JIT should use pcre_malloc/pcre_free for allocation.
151    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
152        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
153        is anything other than /usr, -L is still shown).
155    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
157    14. Perl does not support \N without a following name in a [] class; PCRE now
158        also gives an error.
160    15. If a forward reference was repeated with an upper limit of around 2000,
161        it caused the error "internal error: overran compiling workspace". The
162        maximum number of forward references (including repeats) was limited by the
163        internal workspace, and dependent on the LINK_SIZE. The code has been
164        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
165        the default depends on LINK_SIZE. There is a new upper limit (for safety)
166        of around 200,000 forward references. While doing this, I also speeded up
167        the filling in of repeated forward references.
169    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
170        incorrectly expecting the subject to contain another "a" after the start.
172    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
173        in the match, the SKIP should be ignored. This was not happening; instead
174        the SKIP was being treated as NOMATCH. For patterns such as
175        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
176        tested.
178    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
179        now much more compatible with Perl, in particular in cases where the result
180        is a non-match for a non-anchored pattern. For example, if
181        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
182        "m", where previously it did not return a name. A side effect of this
183        change is that for partial matches, the last encountered mark name is
184        returned, as for non matches. A number of tests that were previously not
185        Perl-compatible have been moved into the Perl-compatible test files. The
186        refactoring has had the pleasing side effect of removing one argument from
187        the match() function, thus reducing its stack requirements.
189    19. If the /S+ option was used in pcretest to study a pattern using JIT,
190        subsequent uses of /S (without +) incorrectly behaved like /S+.
192    21. Retrieve executable code size support for the JIT compiler and fixing
193        some warnings.
195    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
196        not work when the shorter character appeared right at the end of the
197        subject string.
199    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
200        systems.
202    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
203        output it when the /M option is used in pcretest.
205    25. The CheckMan script was not being included in the distribution. Also, added
206        an explicit "perl" to run Perl scripts from the PrepareRelease script
207        because this is reportedly needed in Windows.
209    26. If study data was being save in a file and studying had not found a set of
210        "starts with" bytes for the pattern, the data written to the file (though
211        never used) was taken from uninitialized memory and so caused valgrind to
212        complain.
214    27. Updated RunTest.bat as provided by Sheri Pierce.
216    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
218    29. Computation of memory usage for the table of capturing group names was
219        giving an unnecessarily large value.
222    Version 8.20 21-Oct-2011
223    ------------------------
225    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
226        a POSIX class. After further experiments with Perl, which convinced me that
227        Perl has bugs and confusions, a closing square bracket is no longer allowed
228        in a POSIX name. This bug also affected patterns with classes that started
229        with full stops.
231    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
232        captured substring, but while checking the failing first alternative,
233        substring 1 is temporarily captured. If the output vector supplied to
234        pcre_exec() was not big enough for this capture, the yield of the function
235        was still zero ("insufficient space for captured substrings"). This cannot
236        be totally fixed without adding another stack variable, which seems a lot
237        of expense for a edge case. However, I have improved the situation in cases
238        such as /(a)(b)x|abc/ matched against "abc", where the return code
239        indicates that fewer than the maximum number of slots in the ovector have
240        been set.
242    3.  Related to (2) above: when there are more back references in a pattern than
243        slots in the output vector, pcre_exec() uses temporary memory during
244        matching, and copies in the captures as far as possible afterwards. It was
245        using the entire output vector, but this conflicts with the specification
246        that only 2/3 is used for passing back captured substrings. Now it uses
247        only the first 2/3, for compatibility. This is, of course, another edge
248        case.
250    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
251        main code base, and can be used by building with --enable-jit. When this is
252        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
253        runtime --no-jit option is given.
255    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
256        ovector, the return from the function was zero, implying that there were
257        other matches that did not fit. The correct "exactly full" value is now
258        returned.
260    6.  If a subpattern that was called recursively or as a subroutine contained
261        (*PRUNE) or any other control that caused it to give a non-standard return,
262        invalid errors such as "Error -26 (nested recursion at the same subject
263        position)" or even infinite loops could occur.
265    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
266        computing the minimum length on reaching *ACCEPT, and so ended up with the
267        wrong value of 1 rather than 0. Further investigation indicates that
268        computing a minimum subject length in the presence of *ACCEPT is difficult
269        (think back references, subroutine calls), and so I have changed the code
270        so that no minimum is registered for a pattern that contains *ACCEPT.
272    8.  If (*THEN) was present in the first (true) branch of a conditional group,
273        it was not handled as intended. [But see 16 below.]
275    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
276        Sheri Pierce.
278    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
279        the first byte in a match must be "a".
281    11. Change 17 for 8.13 increased the recursion depth for patterns like
282        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
283        pattern contains any instances of (*THEN). If it does not, the old
284        optimizations are restored. It would be nice to do this on a per-group
285        basis, but at the moment that is not feasible.
287    12. In some environments, the output of pcretest -C is CRLF terminated. This
288        broke RunTest's code that checks for the link size. A single white space
289        character after the value is now allowed for.
291    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
292        For "fr", it uses the Windows-specific input and output files.
294    14. If (*THEN) appeared in a group that was called recursively or as a
295        subroutine, it did not work as intended. [But see next item.]
297    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
298        pattern fragments (but not containing any | characters). If A and B are
299        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
300        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
301        D. In other words, Perl considers parentheses that do not contain any |
302        characters to be part of a surrounding alternative, whereas PCRE was
303        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
304        differently. PCRE now behaves in the same way as Perl, except in the case
305        of subroutine/recursion calls such as (?1) which have in any case always
306        been different (but PCRE had them first :-).
308    16. Related to 15 above: Perl does not treat the | in a conditional group as
309        creating alternatives. Such a group is treated in the same way as an
310        ordinary group without any | characters when processing (*THEN). PCRE has
311        been changed to match Perl's behaviour.
313    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
314        RunGrepTest script failed.
316    18. Change 22 for version 13 caused atomic groups to use more stack. This is
317        inevitable for groups that contain captures, but it can lead to a lot of
318        stack use in large patterns. The old behaviour has been restored for atomic
319        groups that do not contain any capturing parentheses.
321    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
322        suppress the check for a minimum subject length at run time. (If it was
323        given to pcre_exec() or pcre_dfa_exec() it did work.)
325    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
326        fail to work when decoding hex characters in data strings in EBCDIC
327        environments.
329    21. It appears that in at least one Mac OS environment, the isxdigit() function
330        is implemented as a macro that evaluates to its argument more than once,
331        contravening the C 90 Standard (I haven't checked a later standard). There
332        was an instance in pcretest which caused it to go wrong when processing
333        \x{...} escapes in subject strings. The has been rewritten to avoid using
334        things like p++ in the argument of isxdigit().
337  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
338  ------------------------  ------------------------
# Line 98  Version 8.13 16-Aug-2011 Line 431  Version 8.13 16-Aug-2011
431      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
432      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
433      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
434      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
436  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
437      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 522  Version 8.13 16-Aug-2011
522      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
523      unescaped square brackets may also appear as part of class names. For      unescaped square brackets may also appear as part of class names. For
524      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
525      more like Perl.      more like Perl. (But see 8.20/1 above.)
527  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
528      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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