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revision 989 by zherczeg, Sat Jul 7 11:11:02 2012 UTC revision 1362 by chpe, Tue Oct 1 11:27:04 2013 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.32  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    15. A back reference to a named subpattern when there is more than one of the
79        same name now checks them in the order in which they appear in the pattern.
80        The first one that is set is used for the reference. Previously only the
81        first one was inspected. This change makes PCRE more compatible with Perl.
82    
83    16. Unicode character properties were updated from Unicode 6.3.0.
84    
85    Version 8.33 28-May-2013
86    ------------------------
87    
88    1.  Added 'U' to some constants that are compared to unsigned integers, to
89        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
90        variables that are added to signed variables, to ensure the result is
91        signed and can be negated.
92    
93    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
94        CMake config files.
95    
96    3.  Revise the creation of config.h.generic so that all boolean macros are
97        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
98        overriding via -D on the command line possible.
99    
100    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
101        to unsigned int is reported to make a quite noticeable speed difference in
102        a specific Windows environment. Testing on Linux did also appear to show
103        some benefit (and it is clearly not harmful). Also fixed the definition of
104        Xop which should be unsigned.
105    
106    5.  Related to (4), changing the definition of the intermediate variable cc
107        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
108        improvements.
109    
110    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
111        unnecessary spaces.
112    
113    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
114        and later.
115    
116    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
117    
118    9.  Optimizing fast_forward_start_bits in JIT.
119    
120    10. Adding support for callouts in JIT, and fixing some issues revealed
121        during this work. Namely:
122    
123        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
124    
125        (b) Minimum length was not checked before the matching is started.
126    
127    11. The value of capture_last that is passed to callouts was incorrect in some
128        cases when there was a capture on one path that was subsequently abandoned
129        after a backtrack. Also, the capture_last value is now reset after a
130        recursion, since all captures are also reset in this case.
131    
132    12. The interpreter no longer returns the "too many substrings" error in the
133        case when an overflowing capture is in a branch that is subsequently
134        abandoned after a backtrack.
135    
136    13. In the pathological case when an offset vector of size 2 is used, pcretest
137        now prints out the matched string after a yield of 0 or 1.
138    
139    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
140        Only supported by the JIT compiler at the moment.
141    
142    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
143    
144    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
145        offset of the starting point of the matching process, provided the offsets
146        vector is large enough.
147    
148    17. The \A escape now records a lookbehind value of 1, though its execution
149        does not actually inspect the previous character. This is to ensure that,
150        in partial multi-segment matching, at least one character from the old
151        segment is retained when a new segment is processed. Otherwise, if there
152        are no lookbehinds in the pattern, \A might match incorrectly at the start
153        of a new segment.
154    
155    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
156    
157    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
158        gives some modest performance improvement in 8-bit mode.
159    
160    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
161        be expressed in certain programming languages using Universal Character
162        Names.
163    
164    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
165        which points out that "non characters" are not "characters that may not
166        appear in Unicode strings" but rather "characters that are reserved for
167        internal use and have only local meaning".
168    
169    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
170        there was a conditional group that depended on an assertion, if the
171        assertion was false, the callout that immediately followed the alternation
172        in the condition was skipped when pcre_exec() was used for matching.
173    
174    23. Allow an explicit callout to be inserted before an assertion that is the
175        condition for a conditional group, for compatibility with automatic
176        callouts, which always insert a callout at this point.
177    
178    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
179        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
180    
181    25. (*PRUNE) is now supported by the JIT compiler.
182    
183    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
184    
185    27. Fix the case where there are two or more SKIPs with arguments that may be
186        ignored.
187    
188    28. (*SKIP) is now supported by the JIT compiler.
189    
190    29. (*THEN) is now supported by the JIT compiler.
191    
192    30. Update RunTest with additional test selector options.
193    
194    31. The way PCRE handles backtracking verbs has been changed in two ways.
195    
196        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
197        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
198        backtracking. In some cases this makes it more Perl-compatible, but Perl's
199        rather obscure rules do not always do the same thing.
200    
201        (2) Previously, backtracking verbs were confined within assertions. This is
202        no longer the case for positive assertions, except for (*ACCEPT). Again,
203        this sometimes improves Perl compatibility, and sometimes does not.
204    
205    32. A number of tests that were in test 2 because Perl did things differently
206        have been moved to test 1, because either Perl or PCRE has changed, and
207        these tests are now compatible.
208    
209    32. Backtracking control verbs are now handled in the same way in JIT and
210        interpreter.
211    
212    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
213        contained a forward subroutine reference caused a compile error.
214    
215    34. Auto-detect and optimize limited repetitions in JIT.
216    
217    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
218        blocking (*UTF) etc.
219    
220    36. In the interpreter, maximizing pattern repetitions for characters and
221        character types now use tail recursion, which reduces stack usage.
222    
223    37. The value of the max lookbehind was not correctly preserved if a compiled
224        and saved regex was reloaded on a host of different endianness.
225    
226    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
227        of the compiled pattern block, expand the flags field from 16 to 32 bits
228        because it was almost full.
229    
230    39. Try madvise first before posix_madvise.
231    
232    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
233        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
234        original change locked out all matches of empty strings. This has been
235        changed so that one match of an empty string per line is recognized.
236        Subsequent searches on the same line (for colouring or for --only-matching,
237        for example) do not recognize empty strings.
238    
239    41. Applied a user patch to fix a number of spelling mistakes in comments.
240    
241    42. Data lines longer than 65536 caused pcretest to crash.
242    
243    43. Clarified the data type for length and startoffset arguments for pcre_exec
244        and pcre_dfa_exec in the function-specific man pages, where they were
245        explicitly stated to be in bytes, never having been updated. I also added
246        some clarification to the pcreapi man page.
247    
248    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
249        a segmentation fault.
250    
251    
252    Version 8.32 30-November-2012
253    -----------------------------
254    
255  1.  Improved JIT compiler optimizations for first character search and single  1.  Improved JIT compiler optimizations for first character search and single
256      character iterators.      character iterators.
# Line 12  Version 8.32 Line 260  Version 8.32
260    
261  3.  Single character iterator optimizations in the JIT compiler.  3.  Single character iterator optimizations in the JIT compiler.
262    
263    4.  Improved JIT compiler optimizations for character ranges.
264    
265    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
266        Reported by Giuseppe D'Angelo.
267    
268    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
269        of a line, was being set incorrectly in cases where .* appeared inside
270        atomic brackets at the start of a pattern, or where there was a subsequent
271        *PRUNE or *SKIP.
272    
273    7.  Improved instruction cache flush for POWER/PowerPC.
274        Patch by Daniel Richard G.
275    
276    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
277        grep:
278    
279        (a) There is now no limit to the number of patterns to be matched.
280    
281        (b) An error is given if a pattern is too long.
282    
283        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
284            are now supported.
285    
286        (d) --exclude-from and --include-from (multiple use) have been added.
287    
288        (e) Exclusions and inclusions now apply to all files and directories, not
289            just to those obtained from scanning a directory recursively.
290    
291        (f) Multiple uses of -f and --file-list are now supported.
292    
293        (g) In a Windows environment, the default for -d has been changed from
294            "read" (the GNU grep default) to "skip", because otherwise the presence
295            of a directory in the file list provokes an error.
296    
297        (h) The documentation has been revised and clarified in places.
298    
299    9.  Improve the matching speed of capturing brackets.
300    
301    10. Changed the meaning of \X so that it now matches a Unicode extended
302        grapheme cluster.
303    
304    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
305        out POSIX threads when JIT support is configured.
306    
307    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
308    
309    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
310        structure could go wrong in environments where size_t is not the same size
311        as int.
312    
313    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
314        set.
315    
316    15. The EBCDIC support had decayed; later updates to the code had included
317        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
318        general tidy up of EBCDIC-related issues, and the documentation was also
319        not quite right. There is now a test that can be run on ASCII systems to
320        check some of the EBCDIC-related things (but is it not a full test).
321    
322    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
323        in a small tidy to the code.
324    
325    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
326    
327    18. If the --only-matching (-o) option in pcregrep is specified multiple
328        times, each one causes appropriate output. For example, -o1 -o2 outputs the
329        substrings matched by the 1st and 2nd capturing parentheses. A separating
330        string can be specified by --om-separator (default empty).
331    
332    19. Improving the first n character searches.
333    
334    20. Turn case lists for horizontal and vertical white space into macros so that
335        they are defined only once.
336    
337    21. This set of changes together give more compatible Unicode case-folding
338        behaviour for characters that have more than one other case when UCP
339        support is available.
340    
341        (a) The Unicode property table now has offsets into a new table of sets of
342            three or more characters that are case-equivalent. The MultiStage2.py
343            script that generates these tables (the pcre_ucd.c file) now scans
344            CaseFolding.txt instead of UnicodeData.txt for character case
345            information.
346    
347        (b) The code for adding characters or ranges of characters to a character
348            class has been abstracted into a generalized function that also handles
349            case-independence. In UTF-mode with UCP support, this uses the new data
350            to handle characters with more than one other case.
351    
352        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
353            whose other case is greater than 256 are now correctly matched
354            caselessly. Previously, the high codepoint matched the low one, but not
355            vice versa.
356    
357        (d) The processing of \h, \H, \v, and \ in character classes now makes use
358            of the new class addition function, using character lists defined as
359            macros alongside the case definitions of 20 above.
360    
361        (e) Caseless back references now work with characters that have more than
362            one other case.
363    
364        (f) General caseless matching of characters with more than one other case
365            is supported.
366    
367    22. Unicode character properties were updated from Unicode 6.2.0
368    
369    23. Improved CMake support under Windows. Patch by Daniel Richard G.
370    
371    24. Add support for 32-bit character strings, and UTF-32
372    
373    25. Major JIT compiler update (code refactoring and bugfixing).
374        Experimental Sparc 32 support is added.
375    
376    26. Applied a modified version of Daniel Richard G's patch to create
377        pcre.h.generic and config.h.generic by "make" instead of in the
378        PrepareRelease script.
379    
380    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
381        pcre_compile.c when checking for a zero character.
382    
383    28. Introducing a native interface for JIT. Through this interface, the compiled
384        machine code can be directly executed. The purpose of this interface is to
385        provide fast pattern matching, so several sanity checks are not performed.
386        However, feature tests are still performed. The new interface provides
387        1.4x speedup compared to the old one.
388    
389    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
390        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
391        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
392    
393    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
394        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
395        the "old" RFC 2279). Instead, it ended up passing a negative length to
396        pcre_exec().
397    
398    31. Add support for GCC's visibility feature to hide internal functions.
399    
400    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
401        "unknown -C option" after outputting 0 or 1.
402    
403    33. There is now support for generating a code coverage report for the test
404        suite in environments where gcc is the compiler and lcov is installed. This
405        is mainly for the benefit of the developers.
406    
407    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
408        unaddressable using valgrind annotations, allowing valgrind to detect
409        invalid memory accesses. This is mainly for the benefit of the developers.
410    
411    25. (*UTF) can now be used to start a pattern in any of the three libraries.
412    
413    26. Give configure error if --enable-cpp but no C++ compiler found.
414    
415    
416  Version 8.31 06-July-2012  Version 8.31 06-July-2012
417  -------------------------  -------------------------
# Line 1356  Version 7.9 11-Apr-09 Line 1756  Version 7.9 11-Apr-09
1756  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
1757      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
1758      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1759      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1760        8.33.]
1761    
1762  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
1763      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 1599  Version 7.7 07-May-08 Line 2000  Version 7.7 07-May-08
2000      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2001      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2002      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2003      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2004      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2005      was subsequently set up correctly.)      was subsequently set up correctly.)
2006    

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