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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.31 02-June-2012  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 firse 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    
68    Version 8.33 28-May-2013
69    ------------------------
70    
71    1.  Added 'U' to some constants that are compared to unsigned integers, to
72        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
73        variables that are added to signed variables, to ensure the result is
74        signed and can be negated.
75    
76    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
77        CMake config files.
78    
79    3.  Revise the creation of config.h.generic so that all boolean macros are
80        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
81        overriding via -D on the command line possible.
82    
83    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
84        to unsigned int is reported to make a quite noticeable speed difference in
85        a specific Windows environment. Testing on Linux did also appear to show
86        some benefit (and it is clearly not harmful). Also fixed the definition of
87        Xop which should be unsigned.
88    
89    5.  Related to (4), changing the definition of the intermediate variable cc
90        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
91        improvements.
92    
93    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
94        unnecessary spaces.
95    
96    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
97        and later.
98    
99    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
100    
101    9.  Optimizing fast_forward_start_bits in JIT.
102    
103    10. Adding support for callouts in JIT, and fixing some issues revealed
104        during this work. Namely:
105    
106        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
107    
108        (b) Minimum length was not checked before the matching is started.
109    
110    11. The value of capture_last that is passed to callouts was incorrect in some
111        cases when there was a capture on one path that was subsequently abandoned
112        after a backtrack. Also, the capture_last value is now reset after a
113        recursion, since all captures are also reset in this case.
114    
115    12. The interpreter no longer returns the "too many substrings" error in the
116        case when an overflowing capture is in a branch that is subsequently
117        abandoned after a backtrack.
118    
119    13. In the pathological case when an offset vector of size 2 is used, pcretest
120        now prints out the matched string after a yield of 0 or 1.
121    
122    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
123        Only supported by the JIT compiler at the moment.
124    
125    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
126    
127    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
128        offset of the starting point of the matching process, provided the offsets
129        vector is large enough.
130    
131    17. The \A escape now records a lookbehind value of 1, though its execution
132        does not actually inspect the previous character. This is to ensure that,
133        in partial multi-segment matching, at least one character from the old
134        segment is retained when a new segment is processed. Otherwise, if there
135        are no lookbehinds in the pattern, \A might match incorrectly at the start
136        of a new segment.
137    
138    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
139    
140    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
141        gives some modest performance improvement in 8-bit mode.
142    
143    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
144        be expressed in certain programming languages using Universal Character
145        Names.
146    
147    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
148        which points out that "non characters" are not "characters that may not
149        appear in Unicode strings" but rather "characters that are reserved for
150        internal use and have only local meaning".
151    
152    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
153        there was a conditional group that depended on an assertion, if the
154        assertion was false, the callout that immediately followed the alternation
155        in the condition was skipped when pcre_exec() was used for matching.
156    
157    23. Allow an explicit callout to be inserted before an assertion that is the
158        condition for a conditional group, for compatibility with automatic
159        callouts, which always insert a callout at this point.
160    
161    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
162        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
163    
164    25. (*PRUNE) is now supported by the JIT compiler.
165    
166    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
167    
168    27. Fix the case where there are two or more SKIPs with arguments that may be
169        ignored.
170    
171    28. (*SKIP) is now supported by the JIT compiler.
172    
173    29. (*THEN) is now supported by the JIT compiler.
174    
175    30. Update RunTest with additional test selector options.
176    
177    31. The way PCRE handles backtracking verbs has been changed in two ways.
178    
179        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
180        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
181        backtracking. In some cases this makes it more Perl-compatible, but Perl's
182        rather obscure rules do not always do the same thing.
183    
184        (2) Previously, backtracking verbs were confined within assertions. This is
185        no longer the case for positive assertions, except for (*ACCEPT). Again,
186        this sometimes improves Perl compatibility, and sometimes does not.
187    
188    32. A number of tests that were in test 2 because Perl did things differently
189        have been moved to test 1, because either Perl or PCRE has changed, and
190        these tests are now compatible.
191    
192    32. Backtracking control verbs are now handled in the same way in JIT and
193        interpreter.
194    
195    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
196        contained a forward subroutine reference caused a compile error.
197    
198    34. Auto-detect and optimize limited repetitions in JIT.
199    
200    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
201        blocking (*UTF) etc.
202    
203    36. In the interpreter, maximizing pattern repetitions for characters and
204        character types now use tail recursion, which reduces stack usage.
205    
206    37. The value of the max lookbehind was not correctly preserved if a compiled
207        and saved regex was reloaded on a host of different endianness.
208    
209    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
210        of the compiled pattern block, expand the flags field from 16 to 32 bits
211        because it was almost full.
212    
213    39. Try madvise first before posix_madvise.
214    
215    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
216        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
217        original change locked out all matches of empty strings. This has been
218        changed so that one match of an empty string per line is recognized.
219        Subsequent searches on the same line (for colouring or for --only-matching,
220        for example) do not recognize empty strings.
221    
222    41. Applied a user patch to fix a number of spelling mistakes in comments.
223    
224    42. Data lines longer than 65536 caused pcretest to crash.
225    
226    43. Clarified the data type for length and startoffset arguments for pcre_exec
227        and pcre_dfa_exec in the function-specific man pages, where they were
228        explicitly stated to be in bytes, never having been updated. I also added
229        some clarification to the pcreapi man page.
230    
231    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
232        a segmentation fault.
233    
234    
235    Version 8.32 30-November-2012
236    -----------------------------
237    
238    1.  Improved JIT compiler optimizations for first character search and single
239        character iterators.
240    
241    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
242        Patch by Daniel Richard G.
243    
244    3.  Single character iterator optimizations in the JIT compiler.
245    
246    4.  Improved JIT compiler optimizations for character ranges.
247    
248    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
249        Reported by Giuseppe D'Angelo.
250    
251    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
252        of a line, was being set incorrectly in cases where .* appeared inside
253        atomic brackets at the start of a pattern, or where there was a subsequent
254        *PRUNE or *SKIP.
255    
256    7.  Improved instruction cache flush for POWER/PowerPC.
257        Patch by Daniel Richard G.
258    
259    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
260        grep:
261    
262        (a) There is now no limit to the number of patterns to be matched.
263    
264        (b) An error is given if a pattern is too long.
265    
266        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
267            are now supported.
268    
269        (d) --exclude-from and --include-from (multiple use) have been added.
270    
271        (e) Exclusions and inclusions now apply to all files and directories, not
272            just to those obtained from scanning a directory recursively.
273    
274        (f) Multiple uses of -f and --file-list are now supported.
275    
276        (g) In a Windows environment, the default for -d has been changed from
277            "read" (the GNU grep default) to "skip", because otherwise the presence
278            of a directory in the file list provokes an error.
279    
280        (h) The documentation has been revised and clarified in places.
281    
282    9.  Improve the matching speed of capturing brackets.
283    
284    10. Changed the meaning of \X so that it now matches a Unicode extended
285        grapheme cluster.
286    
287    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
288        out POSIX threads when JIT support is configured.
289    
290    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
291    
292    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
293        structure could go wrong in environments where size_t is not the same size
294        as int.
295    
296    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
297        set.
298    
299    15. The EBCDIC support had decayed; later updates to the code had included
300        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
301        general tidy up of EBCDIC-related issues, and the documentation was also
302        not quite right. There is now a test that can be run on ASCII systems to
303        check some of the EBCDIC-related things (but is it not a full test).
304    
305    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
306        in a small tidy to the code.
307    
308    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
309    
310    18. If the --only-matching (-o) option in pcregrep is specified multiple
311        times, each one causes appropriate output. For example, -o1 -o2 outputs the
312        substrings matched by the 1st and 2nd capturing parentheses. A separating
313        string can be specified by --om-separator (default empty).
314    
315    19. Improving the first n character searches.
316    
317    20. Turn case lists for horizontal and vertical white space into macros so that
318        they are defined only once.
319    
320    21. This set of changes together give more compatible Unicode case-folding
321        behaviour for characters that have more than one other case when UCP
322        support is available.
323    
324        (a) The Unicode property table now has offsets into a new table of sets of
325            three or more characters that are case-equivalent. The MultiStage2.py
326            script that generates these tables (the pcre_ucd.c file) now scans
327            CaseFolding.txt instead of UnicodeData.txt for character case
328            information.
329    
330        (b) The code for adding characters or ranges of characters to a character
331            class has been abstracted into a generalized function that also handles
332            case-independence. In UTF-mode with UCP support, this uses the new data
333            to handle characters with more than one other case.
334    
335        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
336            whose other case is greater than 256 are now correctly matched
337            caselessly. Previously, the high codepoint matched the low one, but not
338            vice versa.
339    
340        (d) The processing of \h, \H, \v, and \ in character classes now makes use
341            of the new class addition function, using character lists defined as
342            macros alongside the case definitions of 20 above.
343    
344        (e) Caseless back references now work with characters that have more than
345            one other case.
346    
347        (f) General caseless matching of characters with more than one other case
348            is supported.
349    
350    22. Unicode character properties were updated from Unicode 6.2.0
351    
352    23. Improved CMake support under Windows. Patch by Daniel Richard G.
353    
354    24. Add support for 32-bit character strings, and UTF-32
355    
356    25. Major JIT compiler update (code refactoring and bugfixing).
357        Experimental Sparc 32 support is added.
358    
359    26. Applied a modified version of Daniel Richard G's patch to create
360        pcre.h.generic and config.h.generic by "make" instead of in the
361        PrepareRelease script.
362    
363    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
364        pcre_compile.c when checking for a zero character.
365    
366    28. Introducing a native interface for JIT. Through this interface, the compiled
367        machine code can be directly executed. The purpose of this interface is to
368        provide fast pattern matching, so several sanity checks are not performed.
369        However, feature tests are still performed. The new interface provides
370        1.4x speedup compared to the old one.
371    
372    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
373        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
374        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
375    
376    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
377        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
378        the "old" RFC 2279). Instead, it ended up passing a negative length to
379        pcre_exec().
380    
381    31. Add support for GCC's visibility feature to hide internal functions.
382    
383    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
384        "unknown -C option" after outputting 0 or 1.
385    
386    33. There is now support for generating a code coverage report for the test
387        suite in environments where gcc is the compiler and lcov is installed. This
388        is mainly for the benefit of the developers.
389    
390    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
391        unaddressable using valgrind annotations, allowing valgrind to detect
392        invalid memory accesses. This is mainly for the benefit of the developers.
393    
394    25. (*UTF) can now be used to start a pattern in any of the three libraries.
395    
396    26. Give configure error if --enable-cpp but no C++ compiler found.
397    
398    
399    Version 8.31 06-July-2012
400  -------------------------  -------------------------
401    
402  1.  Fixing a wrong JIT test case and some compiler warnings.  1.  Fixing a wrong JIT test case and some compiler warnings.
# Line 130  Version 8.31 02-June-2012 Line 525  Version 8.31 02-June-2012
525      1 to "aa" instead of to an empty string. The bug affected repeated groups      1 to "aa" instead of to an empty string. The bug affected repeated groups
526      that could potentially match an empty string.      that could potentially match an empty string.
527    
528    37. Optimizing single character iterators in JIT.
529    
530    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
531        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
532        codepoints that are too big for the mode are faulted, and in a UTF mode,
533        disallowed codepoints are also faulted.
534    
535    39. If PCRE was compiled with UTF support, in three places in the DFA
536        matcher there was code that should only have been obeyed in UTF mode, but
537        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
538        processing when bytes with values greater than 127 were present. In 16-bit
539        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
540        both cases the values are those that cannot be the first data item in a UTF
541        character. The three items that might have provoked this were recursions,
542        possessively repeated groups, and atomic groups.
543    
544    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
545        and pcregrep, because some OS require shared objects to be explicitly
546        passed to ld, causing the link step to fail if they are not.
547    
548    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
549        mode, patterns that started with \h* or \R* might be incorrectly matched.
550    
551    
552  Version 8.30 04-February-2012  Version 8.30 04-February-2012
553  -----------------------------  -----------------------------
# Line 1321  Version 7.9 11-Apr-09 Line 1739  Version 7.9 11-Apr-09
1739  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
1740      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
1741      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1742      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1743        8.33.]
1744    
1745  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
1746      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 1564  Version 7.7 07-May-08 Line 1983  Version 7.7 07-May-08
1983      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
1984      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
1985      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
1986      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
1987      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
1988      was subsequently set up correctly.)      was subsequently set up correctly.)
1989    

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