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revision 742 by zherczeg, Sun Nov 6 08:05:33 2011 UTC revision 1359 by ph10, Tue Sep 3 10:10:59 2013 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.21  Version 8.34 xx-xxxx-201x
5  ------------  --------------------------
6    
7    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
8        executable memory. Patch inspired by Carsten Klein.
9    
10    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
11        this macro is never tested and has no effect, because the work to support
12        coverage involves only compiling and linking options and special targets in
13        the Makefile. The comment in config.h implied that defining the macro would
14        enable coverage support, which is totally false. There was also support for
15        setting this macro in the CMake files (my fault, I just copied it from
16        configure). SUPPORT_GCOV has now been removed.
17    
18    3.  Make a small performance improvement in strlen16() and strlen32() in
19        pcretest.
20    
21    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
22        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
23        these cases). There was also one in pcretest.c.
24    
25    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
26    
27    6.  In UTF mode, the code for checking whether a group could match an empty
28        string (which is used for indefinitely repeated groups to allow for
29        breaking an infinite loop) was broken when the group contained a repeated
30        negated single-character class with a character that occupied more than one
31        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
32        UTF-8 mode). The effect was undefined: the group might or might not be
33        deemed as matching an empty string, or the program might have crashed.
34    
35    7.  The code for checking whether a group could match an empty string was not
36        recognizing that \h, \H, \v, \V, and \R must match a character.
37    
38    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
39        an empty string. If it can, pcretest shows this in its information output.
40    
41    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
42        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
43        matched by pcre_exec() without using JIT:
44    
45        (a) If the rest of the pattern did not match after a maximal run of
46            grapheme clusters, the code for backing up to try with fewer of them
47            did not always back up over a full grapheme when characters that do not
48            have the modifier quality were involved, e.g. Hangul syllables.
49    
50        (b) If the match point in a subject started with modifier character, and
51            there was no match, the code could incorrectly back up beyond the match
52            point, and potentially beyond the first character in the subject,
53            leading to a segfault or an incorrect match result.
54    
55    10. A conditional group with an assertion condition could lead to PCRE
56        recording an incorrect first data item for a match if no other first data
57        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
58        first data item, and therefore matched "ca" after "c" instead of at the
59        start.
60    
61    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
62        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
63    
64    12. The source of pcregrep now includes z/OS-specific code so that it can be
65        compiled for z/OS as part of the special z/OS distribution.
66    
67    13. Added the -T and -TM options to pcretest.
68    
69    14. The code in pcre_compile.c for creating the table of named capturing groups
70        has been refactored. Instead of creating the table dynamically during the
71        actual compiling pass, the information is remembered during the pre-compile
72        pass (on the stack unless there are more than 20 named groups, in which
73        case malloc() is used) and the whole table is created before the actual
74        compile happens. This has simplified the code (it is now nearly 150 lines
75        shorter) and prepared the way for better handling of references to groups
76        with duplicate names.
77    
78    
79    Version 8.33 28-May-2013
80    ------------------------
81    
82    1.  Added 'U' to some constants that are compared to unsigned integers, to
83        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
84        variables that are added to signed variables, to ensure the result is
85        signed and can be negated.
86    
87    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
88        CMake config files.
89    
90    3.  Revise the creation of config.h.generic so that all boolean macros are
91        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
92        overriding via -D on the command line possible.
93    
94    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
95        to unsigned int is reported to make a quite noticeable speed difference in
96        a specific Windows environment. Testing on Linux did also appear to show
97        some benefit (and it is clearly not harmful). Also fixed the definition of
98        Xop which should be unsigned.
99    
100    5.  Related to (4), changing the definition of the intermediate variable cc
101        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
102        improvements.
103    
104    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
105        unnecessary spaces.
106    
107    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
108        and later.
109    
110    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
111    
112    9.  Optimizing fast_forward_start_bits in JIT.
113    
114    10. Adding support for callouts in JIT, and fixing some issues revealed
115        during this work. Namely:
116    
117        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
118    
119        (b) Minimum length was not checked before the matching is started.
120    
121    11. The value of capture_last that is passed to callouts was incorrect in some
122        cases when there was a capture on one path that was subsequently abandoned
123        after a backtrack. Also, the capture_last value is now reset after a
124        recursion, since all captures are also reset in this case.
125    
126    12. The interpreter no longer returns the "too many substrings" error in the
127        case when an overflowing capture is in a branch that is subsequently
128        abandoned after a backtrack.
129    
130    13. In the pathological case when an offset vector of size 2 is used, pcretest
131        now prints out the matched string after a yield of 0 or 1.
132    
133    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
134        Only supported by the JIT compiler at the moment.
135    
136    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
137    
138    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
139        offset of the starting point of the matching process, provided the offsets
140        vector is large enough.
141    
142    17. The \A escape now records a lookbehind value of 1, though its execution
143        does not actually inspect the previous character. This is to ensure that,
144        in partial multi-segment matching, at least one character from the old
145        segment is retained when a new segment is processed. Otherwise, if there
146        are no lookbehinds in the pattern, \A might match incorrectly at the start
147        of a new segment.
148    
149    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
150    
151    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
152        gives some modest performance improvement in 8-bit mode.
153    
154    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
155        be expressed in certain programming languages using Universal Character
156        Names.
157    
158    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
159        which points out that "non characters" are not "characters that may not
160        appear in Unicode strings" but rather "characters that are reserved for
161        internal use and have only local meaning".
162    
163    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
164        there was a conditional group that depended on an assertion, if the
165        assertion was false, the callout that immediately followed the alternation
166        in the condition was skipped when pcre_exec() was used for matching.
167    
168    23. Allow an explicit callout to be inserted before an assertion that is the
169        condition for a conditional group, for compatibility with automatic
170        callouts, which always insert a callout at this point.
171    
172    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
173        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
174    
175    25. (*PRUNE) is now supported by the JIT compiler.
176    
177    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
178    
179    27. Fix the case where there are two or more SKIPs with arguments that may be
180        ignored.
181    
182    28. (*SKIP) is now supported by the JIT compiler.
183    
184    29. (*THEN) is now supported by the JIT compiler.
185    
186    30. Update RunTest with additional test selector options.
187    
188    31. The way PCRE handles backtracking verbs has been changed in two ways.
189    
190        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
191        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
192        backtracking. In some cases this makes it more Perl-compatible, but Perl's
193        rather obscure rules do not always do the same thing.
194    
195        (2) Previously, backtracking verbs were confined within assertions. This is
196        no longer the case for positive assertions, except for (*ACCEPT). Again,
197        this sometimes improves Perl compatibility, and sometimes does not.
198    
199    32. A number of tests that were in test 2 because Perl did things differently
200        have been moved to test 1, because either Perl or PCRE has changed, and
201        these tests are now compatible.
202    
203    32. Backtracking control verbs are now handled in the same way in JIT and
204        interpreter.
205    
206    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
207        contained a forward subroutine reference caused a compile error.
208    
209    34. Auto-detect and optimize limited repetitions in JIT.
210    
211    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
212        blocking (*UTF) etc.
213    
214    36. In the interpreter, maximizing pattern repetitions for characters and
215        character types now use tail recursion, which reduces stack usage.
216    
217    37. The value of the max lookbehind was not correctly preserved if a compiled
218        and saved regex was reloaded on a host of different endianness.
219    
220    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
221        of the compiled pattern block, expand the flags field from 16 to 32 bits
222        because it was almost full.
223    
224    39. Try madvise first before posix_madvise.
225    
226    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
227        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
228        original change locked out all matches of empty strings. This has been
229        changed so that one match of an empty string per line is recognized.
230        Subsequent searches on the same line (for colouring or for --only-matching,
231        for example) do not recognize empty strings.
232    
233    41. Applied a user patch to fix a number of spelling mistakes in comments.
234    
235    42. Data lines longer than 65536 caused pcretest to crash.
236    
237    43. Clarified the data type for length and startoffset arguments for pcre_exec
238        and pcre_dfa_exec in the function-specific man pages, where they were
239        explicitly stated to be in bytes, never having been updated. I also added
240        some clarification to the pcreapi man page.
241    
242    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
243        a segmentation fault.
244    
245    
246    Version 8.32 30-November-2012
247    -----------------------------
248    
249    1.  Improved JIT compiler optimizations for first character search and single
250        character iterators.
251    
252    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
253        Patch by Daniel Richard G.
254    
255    3.  Single character iterator optimizations in the JIT compiler.
256    
257    4.  Improved JIT compiler optimizations for character ranges.
258    
259    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
260        Reported by Giuseppe D'Angelo.
261    
262    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
263        of a line, was being set incorrectly in cases where .* appeared inside
264        atomic brackets at the start of a pattern, or where there was a subsequent
265        *PRUNE or *SKIP.
266    
267    7.  Improved instruction cache flush for POWER/PowerPC.
268        Patch by Daniel Richard G.
269    
270    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
271        grep:
272    
273        (a) There is now no limit to the number of patterns to be matched.
274    
275        (b) An error is given if a pattern is too long.
276    
277        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
278            are now supported.
279    
280        (d) --exclude-from and --include-from (multiple use) have been added.
281    
282        (e) Exclusions and inclusions now apply to all files and directories, not
283            just to those obtained from scanning a directory recursively.
284    
285        (f) Multiple uses of -f and --file-list are now supported.
286    
287        (g) In a Windows environment, the default for -d has been changed from
288            "read" (the GNU grep default) to "skip", because otherwise the presence
289            of a directory in the file list provokes an error.
290    
291        (h) The documentation has been revised and clarified in places.
292    
293    9.  Improve the matching speed of capturing brackets.
294    
295    10. Changed the meaning of \X so that it now matches a Unicode extended
296        grapheme cluster.
297    
298    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
299        out POSIX threads when JIT support is configured.
300    
301    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
302    
303    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
304        structure could go wrong in environments where size_t is not the same size
305        as int.
306    
307    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
308        set.
309    
310    15. The EBCDIC support had decayed; later updates to the code had included
311        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
312        general tidy up of EBCDIC-related issues, and the documentation was also
313        not quite right. There is now a test that can be run on ASCII systems to
314        check some of the EBCDIC-related things (but is it not a full test).
315    
316    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
317        in a small tidy to the code.
318    
319    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
320    
321    18. If the --only-matching (-o) option in pcregrep is specified multiple
322        times, each one causes appropriate output. For example, -o1 -o2 outputs the
323        substrings matched by the 1st and 2nd capturing parentheses. A separating
324        string can be specified by --om-separator (default empty).
325    
326    19. Improving the first n character searches.
327    
328    20. Turn case lists for horizontal and vertical white space into macros so that
329        they are defined only once.
330    
331    21. This set of changes together give more compatible Unicode case-folding
332        behaviour for characters that have more than one other case when UCP
333        support is available.
334    
335        (a) The Unicode property table now has offsets into a new table of sets of
336            three or more characters that are case-equivalent. The MultiStage2.py
337            script that generates these tables (the pcre_ucd.c file) now scans
338            CaseFolding.txt instead of UnicodeData.txt for character case
339            information.
340    
341        (b) The code for adding characters or ranges of characters to a character
342            class has been abstracted into a generalized function that also handles
343            case-independence. In UTF-mode with UCP support, this uses the new data
344            to handle characters with more than one other case.
345    
346        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
347            whose other case is greater than 256 are now correctly matched
348            caselessly. Previously, the high codepoint matched the low one, but not
349            vice versa.
350    
351        (d) The processing of \h, \H, \v, and \ in character classes now makes use
352            of the new class addition function, using character lists defined as
353            macros alongside the case definitions of 20 above.
354    
355        (e) Caseless back references now work with characters that have more than
356            one other case.
357    
358        (f) General caseless matching of characters with more than one other case
359            is supported.
360    
361    22. Unicode character properties were updated from Unicode 6.2.0
362    
363    23. Improved CMake support under Windows. Patch by Daniel Richard G.
364    
365    24. Add support for 32-bit character strings, and UTF-32
366    
367    25. Major JIT compiler update (code refactoring and bugfixing).
368        Experimental Sparc 32 support is added.
369    
370    26. Applied a modified version of Daniel Richard G's patch to create
371        pcre.h.generic and config.h.generic by "make" instead of in the
372        PrepareRelease script.
373    
374    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
375        pcre_compile.c when checking for a zero character.
376    
377    28. Introducing a native interface for JIT. Through this interface, the compiled
378        machine code can be directly executed. The purpose of this interface is to
379        provide fast pattern matching, so several sanity checks are not performed.
380        However, feature tests are still performed. The new interface provides
381        1.4x speedup compared to the old one.
382    
383    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
384        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
385        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
386    
387    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
388        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
389        the "old" RFC 2279). Instead, it ended up passing a negative length to
390        pcre_exec().
391    
392    31. Add support for GCC's visibility feature to hide internal functions.
393    
394    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
395        "unknown -C option" after outputting 0 or 1.
396    
397    33. There is now support for generating a code coverage report for the test
398        suite in environments where gcc is the compiler and lcov is installed. This
399        is mainly for the benefit of the developers.
400    
401    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
402        unaddressable using valgrind annotations, allowing valgrind to detect
403        invalid memory accesses. This is mainly for the benefit of the developers.
404    
405    25. (*UTF) can now be used to start a pattern in any of the three libraries.
406    
407    26. Give configure error if --enable-cpp but no C++ compiler found.
408    
409    
410    Version 8.31 06-July-2012
411    -------------------------
412    
413    1.  Fixing a wrong JIT test case and some compiler warnings.
414    
415    2.  Removed a bashism from the RunTest script.
416    
417    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
418        to unsigned type, result still unsigned" that was given by an MS compiler
419        on encountering the code "-sizeof(xxx)".
420    
421    4.  Partial matching support is added to the JIT compiler.
422    
423    5.  Fixed several bugs concerned with partial matching of items that consist
424        of more than one character:
425    
426        (a) /^(..)\1/ did not partially match "aba" because checking references was
427            done on an "all or nothing" basis. This also applied to repeated
428            references.
429    
430        (b) \R did not give a hard partial match if \r was found at the end of the
431            subject.
432    
433        (c) \X did not give a hard partial match after matching one or more
434            characters at the end of the subject.
435    
436        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
437            a partial match for the string "\r".
438    
439        (e) When newline was set to CRLF, the metacharacter "." did not recognize
440            a partial match for a CR character at the end of the subject string.
441    
442    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
443        running pcretest, the text "(JIT)" added to the output whenever JIT is
444        actually used to run the match.
445    
446    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
447        or /S+[+] with a digit between 1 and 7.
448    
449    8.  OP_NOT now supports any UTF character not just single-byte ones.
450    
451    9.  (*MARK) control verb is now supported by the JIT compiler.
452    
453    10. The command "./RunTest list" lists the available tests without actually
454        running any of them. (Because I keep forgetting what they all are.)
455    
456    11. Add PCRE_INFO_MAXLOOKBEHIND.
457    
458    12. Applied a (slightly modified) user-supplied patch that improves performance
459        when the heap is used for recursion (compiled with --disable-stack-for-
460        recursion). Instead of malloc and free for each heap frame each time a
461        logical recursion happens, frames are retained on a chain and re-used where
462        possible. This sometimes gives as much as 30% improvement.
463    
464    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
465        call.
466    
467    14. As documented, (*COMMIT) is now confined to within a positive assertion.
468    
469    15. It is now possible to link pcretest with libedit as an alternative to
470        libreadline.
471    
472    16. (*COMMIT) control verb is now supported by the JIT compiler.
473    
474    17. The Unicode data tables have been updated to Unicode 6.1.0.
475    
476    18. Added --file-list option to pcregrep.
477    
478    19. Added binary file support to pcregrep, including the -a, --binary-files,
479        -I, and --text options.
480    
481    20. The madvise function is renamed for posix_madvise for QNX compatibility
482        reasons. Fixed by Giuseppe D'Angelo.
483    
484    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
485    
486    22. Changed the option for creating symbolic links for 16-bit man pages from
487        -s to -sf so that re-installing does not cause issues.
488    
489    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
490    
491    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
492        matches in certain environments (the workspace was not being correctly
493        retained). Also added to pcre_dfa_exec() a simple plausibility check on
494        some of the workspace data at the beginning of a restart.
495    
496    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
497        was not doing so when it should - probably a typo introduced by SVN 528
498        (change 8.10/14).
499    
500    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
501        \w+ when the character tables indicated that \x{c4} was a word character.
502        There were several related cases, all because the tests for doing a table
503        lookup were testing for characters less than 127 instead of 255.
504    
505    27. If a pattern contains capturing parentheses that are not used in a match,
506        their slots in the ovector are set to -1. For those that are higher than
507        any matched groups, this happens at the end of processing. In the case when
508        there were back references that the ovector was too small to contain
509        (causing temporary malloc'd memory to be used during matching), and the
510        highest capturing number was not used, memory off the end of the ovector
511        was incorrectly being set to -1. (It was using the size of the temporary
512        memory instead of the true size.)
513    
514    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
515        ovector size, it uses memory at the end of the block that it has got.
516    
517    29. Check for an overlong MARK name and give an error at compile time. The
518        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
519    
520    30. JIT compiler update.
521    
522    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
523        Rill for the patch.
524    
525    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
526    
527    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
528    
529    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
530        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
531        was enabled.
532    
533    35. Improve JIT code generation for greedy plus quantifier.
534    
535    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
536        1 to "aa" instead of to an empty string. The bug affected repeated groups
537        that could potentially match an empty string.
538    
539    37. Optimizing single character iterators in JIT.
540    
541    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
542        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
543        codepoints that are too big for the mode are faulted, and in a UTF mode,
544        disallowed codepoints are also faulted.
545    
546    39. If PCRE was compiled with UTF support, in three places in the DFA
547        matcher there was code that should only have been obeyed in UTF mode, but
548        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
549        processing when bytes with values greater than 127 were present. In 16-bit
550        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
551        both cases the values are those that cannot be the first data item in a UTF
552        character. The three items that might have provoked this were recursions,
553        possessively repeated groups, and atomic groups.
554    
555    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
556        and pcregrep, because some OS require shared objects to be explicitly
557        passed to ld, causing the link step to fail if they are not.
558    
559    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
560        mode, patterns that started with \h* or \R* might be incorrectly matched.
561    
562    
563    Version 8.30 04-February-2012
564    -----------------------------
565    
566    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
567        name is defined in ctype.h.
568    
569    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
570        only in quite long subpatterns.
571    
572    3.  Removed the function pcre_info(), which has been obsolete and deprecated
573        since it was replaced by pcre_fullinfo() in February 2000.
574    
575    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
576        match a (*MARK), and the match failed at the start of the subject, a
577        reference to memory before the start of the subject could occur. This bug
578        was introduced by fix 17 of release 8.21.
579    
580    5.  A reference to an unset group with zero minimum repetition was giving
581        totally wrong answers (in non-JavaScript-compatibility mode). For example,
582        /(another)?(\1?)test/ matched against "hello world test". This bug was
583        introduced in release 8.13.
584    
585    6.  Add support for 16-bit character strings (a large amount of work involving
586        many changes and refactorings).
587    
588    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
589        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
590        from a file.
591    
592    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
593        rounding is not applied in this particular case).
594    
595    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
596        if they appear, or are escaped, in patterns.
597    
598    10. Get rid of a number of -Wunused-but-set-variable warnings.
599    
600    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
601        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
602        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
603        also returns the mark "x". This bug applied to capturing parentheses,
604        non-capturing parentheses, and atomic parentheses. It also applied to some
605        assertions.
606    
607    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
608        information out of configure.ac instead of relying on pcre.h.generic, which
609        is not stored in the repository.
610    
611    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
612        -lreadline.
613    
614    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
615    
616    15. Applied Graycode's patch to put the top-level frame on the stack rather
617        than the heap when not using the stack for recursion. This gives a
618        performance improvement in many cases when recursion is not deep.
619    
620    16. Experimental code added to "pcretest -C" to output the stack frame size.
621    
622    
623    Version 8.21 12-Dec-2011
624    ------------------------
625    
626  1.  Updating the JIT compiler.  1.  Updating the JIT compiler.
627    
# Line 13  Version 8.21 Line 632  Version 8.21
632      PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before      PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
633      calling _pcre_jit_exec. Some extra comments are added.      calling _pcre_jit_exec. Some extra comments are added.
634    
635    4.  (*MARK) settings inside atomic groups that do not contain any capturing
636        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
637        was introduced by change 18 for 8.20.
638    
639    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
640        ECMA-262 standard.
641    
642    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
643        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
644        This bug was probably introduced by change 9 of 8.13.
645    
646    7.  While fixing 6 above, I noticed that a number of other items were being
647        incorrectly rejected as "not fixed length". This arose partly because newer
648        opcodes had not been added to the fixed-length checking code. I have (a)
649        corrected the bug and added tests for these items, and (b) arranged for an
650        error to occur if an unknown opcode is encountered while checking for fixed
651        length instead of just assuming "not fixed length". The items that were
652        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
653        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
654        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
655    
656    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
657        being incorrectly compiled and would have given unpredicatble results.
658    
659    9.  A possessively repeated subpattern with minimum repeat count greater than
660        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
661        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
662        the first (A) could occur when it should not.
663    
664    10. Add a cast and remove a redundant test from the code.
665    
666    11. JIT should use pcre_malloc/pcre_free for allocation.
667    
668    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
669        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
670        is anything other than /usr, -L is still shown).
671    
672    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
673    
674    14. Perl does not support \N without a following name in a [] class; PCRE now
675        also gives an error.
676    
677    15. If a forward reference was repeated with an upper limit of around 2000,
678        it caused the error "internal error: overran compiling workspace". The
679        maximum number of forward references (including repeats) was limited by the
680        internal workspace, and dependent on the LINK_SIZE. The code has been
681        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
682        the default depends on LINK_SIZE. There is a new upper limit (for safety)
683        of around 200,000 forward references. While doing this, I also speeded up
684        the filling in of repeated forward references.
685    
686    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
687        incorrectly expecting the subject to contain another "a" after the start.
688    
689    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
690        in the match, the SKIP should be ignored. This was not happening; instead
691        the SKIP was being treated as NOMATCH. For patterns such as
692        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
693        tested.
694    
695    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
696        now much more compatible with Perl, in particular in cases where the result
697        is a non-match for a non-anchored pattern. For example, if
698        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
699        "m", where previously it did not return a name. A side effect of this
700        change is that for partial matches, the last encountered mark name is
701        returned, as for non matches. A number of tests that were previously not
702        Perl-compatible have been moved into the Perl-compatible test files. The
703        refactoring has had the pleasing side effect of removing one argument from
704        the match() function, thus reducing its stack requirements.
705    
706    19. If the /S+ option was used in pcretest to study a pattern using JIT,
707        subsequent uses of /S (without +) incorrectly behaved like /S+.
708    
709    21. Retrieve executable code size support for the JIT compiler and fixing
710        some warnings.
711    
712    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
713        not work when the shorter character appeared right at the end of the
714        subject string.
715    
716    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
717        systems.
718    
719    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
720        output it when the /M option is used in pcretest.
721    
722    25. The CheckMan script was not being included in the distribution. Also, added
723        an explicit "perl" to run Perl scripts from the PrepareRelease script
724        because this is reportedly needed in Windows.
725    
726    26. If study data was being save in a file and studying had not found a set of
727        "starts with" bytes for the pattern, the data written to the file (though
728        never used) was taken from uninitialized memory and so caused valgrind to
729        complain.
730    
731    27. Updated RunTest.bat as provided by Sheri Pierce.
732    
733    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
734    
735    29. Computation of memory usage for the table of capturing group names was
736        giving an unnecessarily large value.
737    
738    
739  Version 8.20 21-Oct-2011  Version 8.20 21-Oct-2011
740  ------------------------  ------------------------
# Line 1028  Version 7.9 11-Apr-09 Line 1750  Version 7.9 11-Apr-09
1750  7.  A pattern that could match an empty string could cause pcregrep to loop; it  7.  A pattern that could match an empty string could cause pcregrep to loop; it
1751      doesn't make sense to accept an empty string match in pcregrep, so I have      doesn't make sense to accept an empty string match in pcregrep, so I have
1752      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1753      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1754        8.33.]
1755    
1756  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1757      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 1271  Version 7.7 07-May-08 Line 1994  Version 7.7 07-May-08
1994      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
1995      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
1996      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
1997      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
1998      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
1999      was subsequently set up correctly.)      was subsequently set up correctly.)
2000    

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