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Revision 172 - (show annotations) (download)
Tue Jun 5 10:40:13 2007 UTC (7 years, 3 months ago) by ph10
File size: 129235 byte(s)
Drastically reduce workspace used for alternatives in groups; also some 
trailing space removals for a test release.

1 ChangeLog for PCRE
2 ------------------
3
4 Version 7.2 05-June-07
5 ---------------------
6
7 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
8 which is apparently normally available under Windows.
9
10 2. Re-jig the pcregrep tests with different newline settings in an attempt
11 to make them independent of the local environment's newline setting.
12
13 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
14
15 4. Some of the "internals" tests were previously cut out when the link size
16 was not 2, because the output contained actual offsets. The recent new
17 "Z" feature of pcretest means that these can be cut out, making the tests
18 usable with all link sizes.
19
20 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
21 stack recursion. This gives a massive performance boost under BSD, but just
22 a small improvement under Linux. However, it saves one field in the frame
23 in all cases.
24
25 6. Added more features from the forthcoming Perl 5.10:
26
27 (a) (?-n) (where n is a string of digits) is a relative subroutine or
28 recursion call. It refers to the nth most recently opened parentheses.
29
30 (b) (?+n) is also a relative subroutine call; it refers to the nth next
31 to be opened parentheses.
32
33 (c) Conditions that refer to capturing parentheses can be specified
34 relatively, for example, (?(-2)... or (?(+3)...
35
36 (d) \K resets the start of the current match so that everything before
37 is not part of it.
38
39 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
40
41 (f) \g{name} is another synonym - part of Perl 5.10's unification of
42 reference syntax.
43
44 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
45 PCRE_INFO_JCHANGED.
46
47 8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
48 terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
49 for detecting groups that can match an empty string.
50
51 9. A pattern with a very large number of alternatives (more than several
52 hundred) was running out of internal workspace during the pre-compile
53 phase, where pcre_compile() figures out how much memory will be needed. A
54 bit of new cunning has reduced the workspace needed for groups with
55 alternatives. The 1000-alternative test pattern now uses 12 bytes of
56 workspace instead of running out of the 4096 that are available.
57
58
59 Version 7.1 24-Apr-07
60 ---------------------
61
62 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
63 that is more "standard", making use of automake and other Autotools. There
64 is some re-arrangement of the files and adjustment of comments consequent
65 on this.
66
67 2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
68 for recursive directory scanning broke on some systems because the files
69 are not scanned in any specific order and on different systems the order
70 was different. A call to "sort" has been inserted into RunGrepTest for the
71 approprate test as a short-term fix. In the longer term there may be an
72 alternative.
73
74 3. I had an email from Eric Raymond about problems translating some of PCRE's
75 man pages to HTML (despite the fact that I distribute HTML pages, some
76 people do their own conversions for various reasons). The problems
77 concerned the use of low-level troff macros .br and .in. I have therefore
78 removed all such uses from the man pages (some were redundant, some could
79 be replaced by .nf/.fi pairs). The 132html script that I use to generate
80 HTML has been updated to handle .nf/.fi and to complain if it encounters
81 .br or .in.
82
83 4. Updated comments in configure.ac that get placed in config.h.in and also
84 arranged for config.h to be included in the distribution, with the name
85 config.h.generic, for the benefit of those who have to compile without
86 Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
87
88 5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
89 Weber: (1) pcre_internal.h was missing some function renames; (2) updated
90 makevp.bat for the current PCRE, using the additional files
91 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
92
93 6. A Windows user reported a minor discrepancy with test 2, which turned out
94 to be caused by a trailing space on an input line that had got lost in his
95 copy. The trailing space was an accident, so I've just removed it.
96
97 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
98 that is needed.
99
100 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
101 as "const" (a) because they are and (b) because it helps the PHP
102 maintainers who have recently made a script to detect big data structures
103 in the php code that should be moved to the .rodata section. I remembered
104 to update Builducptable as well, so it won't revert if ucptable.h is ever
105 re-created.
106
107 9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
108 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
109 order to be able to cut out the UTF-8 tables in the latter when UTF-8
110 support is not required. This saves 1.5-2K of code, which is important in
111 some applications.
112
113 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
114 so as not to refer to the tables, even though these functions will never be
115 called when UTF-8 support is disabled. Otherwise there are problems with a
116 shared library.
117
118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
119
120 (a) It was defining its arguments as char * instead of void *.
121
122 (b) It was assuming that all moves were upwards in memory; this was true
123 a long time ago when I wrote it, but is no longer the case.
124
125 The emulated memove() is provided for those environments that have neither
126 memmove() nor bcopy(). I didn't think anyone used it these days, but that
127 is clearly not the case, as these two bugs were recently reported.
128
129 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
130 and Detrail to create the HTML documentation, the .txt form of the man
131 pages, and it removes trailing spaces from listed files. It also creates
132 pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
133 case, it wraps all the #defines with #ifndefs. This script should be run
134 before "make dist".
135
136 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
137 with Unicode property support.
138
139 (a) For a maximizing quantifier, if the two different cases of the
140 character were of different lengths in their UTF-8 codings (there are
141 some cases like this - I found 11), and the matching function had to
142 back up over a mixture of the two cases, it incorrectly assumed they
143 were both the same length.
144
145 (b) When PCRE was configured to use the heap rather than the stack for
146 recursion during matching, it was not correctly preserving the data for
147 the other case of a UTF-8 character when checking ahead for a match
148 while processing a minimizing repeat. If the check also involved
149 matching a wide character, but failed, corruption could cause an
150 erroneous result when trying to check for a repeat of the original
151 character.
152
153 13. Some tidying changes to the testing mechanism:
154
155 (a) The RunTest script now detects the internal link size and whether there
156 is UTF-8 and UCP support by running ./pcretest -C instead of relying on
157 values substituted by "configure". (The RunGrepTest script already did
158 this for UTF-8.) The configure.ac script no longer substitutes the
159 relevant variables.
160
161 (b) The debugging options /B and /D in pcretest show the compiled bytecode
162 with length and offset values. This means that the output is different
163 for different internal link sizes. Test 2 is skipped for link sizes
164 other than 2 because of this, bypassing the problem. Unfortunately,
165 there was also a test in test 3 (the locale tests) that used /B and
166 failed for link sizes other than 2. Rather than cut the whole test out,
167 I have added a new /Z option to pcretest that replaces the length and
168 offset values with spaces. This is now used to make test 3 independent
169 of link size. (Test 2 will be tidied up later.)
170
171 14. If erroroffset was passed as NULL to pcre_compile, it provoked a
172 segmentation fault instead of returning the appropriate error message.
173
174 15. In multiline mode when the newline sequence was set to "any", the pattern
175 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
176 This doesn't seem right; it now treats the CRLF combination as the line
177 ending, and so does not match in that case. It's only a pattern such as ^$
178 that would hit this one: something like ^ABC$ would have failed after \r
179 and then tried again after \r\n.
180
181 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
182 in an attempt to make files that differ only in their line terminators
183 compare equal. This works on Linux.
184
185 17. Under certain error circumstances pcregrep might try to free random memory
186 as it exited. This is now fixed, thanks to valgrind.
187
188 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
189 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
190 was because its rules for how to advance for /g after matching an empty
191 string at the end of a line did not allow for this case. They now check for
192 it specially.
193
194 20. pcretest is supposed to handle patterns and data of any length, by
195 extending its buffers when necessary. It was getting this wrong when the
196 buffer for a data line had to be extended.
197
198 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
199 CRLF as a newline sequence.
200
201 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
202 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
203 I have nevertheless tidied it up.
204
205 23. Added some casts to kill warnings from HP-UX ia64 compiler.
206
207 24. Added a man page for pcre-config.
208
209
210 Version 7.0 19-Dec-06
211 ---------------------
212
213 1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
214 moving to gcc 4.1.1.
215
216 2. The -S option for pcretest uses setrlimit(); I had omitted to #include
217 sys/time.h, which is documented as needed for this function. It doesn't
218 seem to matter on Linux, but it showed up on some releases of OS X.
219
220 3. It seems that there are systems where bytes whose values are greater than
221 127 match isprint() in the "C" locale. The "C" locale should be the
222 default when a C program starts up. In most systems, only ASCII printing
223 characters match isprint(). This difference caused the output from pcretest
224 to vary, making some of the tests fail. I have changed pcretest so that:
225
226 (a) When it is outputting text in the compiled version of a pattern, bytes
227 other than 32-126 are always shown as hex escapes.
228
229 (b) When it is outputting text that is a matched part of a subject string,
230 it does the same, unless a different locale has been set for the match
231 (using the /L modifier). In this case, it uses isprint() to decide.
232
233 4. Fixed a major bug that caused incorrect computation of the amount of memory
234 required for a compiled pattern when options that changed within the
235 pattern affected the logic of the preliminary scan that determines the
236 length. The relevant options are -x, and -i in UTF-8 mode. The result was
237 that the computed length was too small. The symptoms of this bug were
238 either the PCRE error "internal error: code overflow" from pcre_compile(),
239 or a glibc crash with a message such as "pcretest: free(): invalid next
240 size (fast)". Examples of patterns that provoked this bug (shown in
241 pcretest format) are:
242
243 /(?-x: )/x
244 /(?x)(?-x: \s*#\s*)/
245 /((?i)[\x{c0}])/8
246 /(?i:[\x{c0}])/8
247
248 HOWEVER: Change 17 below makes this fix obsolete as the memory computation
249 is now done differently.
250
251 5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
252 wrapper classes; (b) implement a new function in the C++ scanner that is
253 more efficient than the old way of doing things because it avoids levels of
254 recursion in the regex matching; (c) add a paragraph to the documentation
255 for the FullMatch() function.
256
257 6. The escape sequence \n was being treated as whatever was defined as
258 "newline". Not only was this contrary to the documentation, which states
259 that \n is character 10 (hex 0A), but it also went horribly wrong when
260 "newline" was defined as CRLF. This has been fixed.
261
262 7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
263 was being set to -1 for the "end of line" case (supposedly a value that no
264 character can have). Though this value is never used (the check for end of
265 line is "zero bytes in current character"), it caused compiler complaints.
266 I've changed it to 0xffffffff.
267
268 8. In pcre_version.c, the version string was being built by a sequence of
269 C macros that, in the event of PCRE_PRERELEASE being defined as an empty
270 string (as it is for production releases) called a macro with an empty
271 argument. The C standard says the result of this is undefined. The gcc
272 compiler treats it as an empty string (which was what was wanted) but it is
273 reported that Visual C gives an error. The source has been hacked around to
274 avoid this problem.
275
276 9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
277 builds of pcretest, and changed the call to _setmode() to use _O_BINARY
278 instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
279 of them did).
280
281 10. Originally, pcretest opened its input and output without "b"; then I was
282 told that "b" was needed in some environments, so it was added for release
283 5.0 to both the input and output. (It makes no difference on Unix-like
284 systems.) Later I was told that it is wrong for the input on Windows. I've
285 now abstracted the modes into two macros, to make it easier to fiddle with
286 them, and removed "b" from the input mode under Windows.
287
288 11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
289
290 12. Added -help and --help to pcretest as an official way of being reminded
291 of the options.
292
293 13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
294 and pcrecpp.cc because they annoy compilers at high warning levels.
295
296 14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
297
298 15. Fixed an occurrence of == in configure.ac that should have been = (shell
299 scripts are not C programs :-) and which was not noticed because it works
300 on Linux.
301
302 16. pcretest is supposed to handle any length of pattern and data line (as one
303 line or as a continued sequence of lines) by extending its input buffer if
304 necessary. This feature was broken for very long pattern lines, leading to
305 a string of junk being passed to pcre_compile() if the pattern was longer
306 than about 50K.
307
308 17. I have done a major re-factoring of the way pcre_compile() computes the
309 amount of memory needed for a compiled pattern. Previously, there was code
310 that made a preliminary scan of the pattern in order to do this. That was
311 OK when PCRE was new, but as the facilities have expanded, it has become
312 harder and harder to keep it in step with the real compile phase, and there
313 have been a number of bugs (see for example, 4 above). I have now found a
314 cunning way of running the real compile function in a "fake" mode that
315 enables it to compute how much memory it would need, while actually only
316 ever using a few hundred bytes of working memory and without too many
317 tests of the mode. This should make future maintenance and development
318 easier. A side effect of this work is that the limit of 200 on the nesting
319 depth of parentheses has been removed (though this was never a serious
320 limitation, I suspect). However, there is a downside: pcre_compile() now
321 runs more slowly than before (30% or more, depending on the pattern). I
322 hope this isn't a big issue. There is no effect on runtime performance.
323
324 18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
325 newline (only possible for the last line of a file) and it was a
326 pattern that set a locale (followed by /Lsomething), pcretest crashed.
327
328 19. Added additional timing features to pcretest. (1) The -tm option now times
329 matching only, not compiling. (2) Both -t and -tm can be followed, as a
330 separate command line item, by a number that specifies the number of
331 repeats to use when timing. The default is 50000; this gives better
332 precision, but takes uncomfortably long for very large patterns.
333
334 20. Extended pcre_study() to be more clever in cases where a branch of a
335 subpattern has no definite first character. For example, (a*|b*)[cd] would
336 previously give no result from pcre_study(). Now it recognizes that the
337 first character must be a, b, c, or d.
338
339 21. There was an incorrect error "recursive call could loop indefinitely" if
340 a subpattern (or the entire pattern) that was being tested for matching an
341 empty string contained only one non-empty item after a nested subpattern.
342 For example, the pattern (?>\x{100}*)\d(?R) provoked this error
343 incorrectly, because the \d was being skipped in the check.
344
345 22. The pcretest program now has a new pattern option /B and a command line
346 option -b, which is equivalent to adding /B to every pattern. This causes
347 it to show the compiled bytecode, without the additional information that
348 -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
349 is the same as /B/I).
350
351 23. A new optimization is now able automatically to treat some sequences such
352 as a*b as a*+b. More specifically, if something simple (such as a character
353 or a simple class like \d) has an unlimited quantifier, and is followed by
354 something that cannot possibly match the quantified thing, the quantifier
355 is automatically "possessified".
356
357 24. A recursive reference to a subpattern whose number was greater than 39
358 went wrong under certain circumstances in UTF-8 mode. This bug could also
359 have affected the operation of pcre_study().
360
361 25. Realized that a little bit of performance could be had by replacing
362 (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
363
364 26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
365
366 27. Possessive quantifiers such as a++ were previously implemented by turning
367 them into atomic groups such as ($>a+). Now they have their own opcodes,
368 which improves performance. This includes the automatically created ones
369 from 23 above.
370
371 28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
372 lookahead was broken if it was not anchored. PCRE was mistakenly expecting
373 the first matched character to be a colon. This applied both to named and
374 numbered groups.
375
376 29. The ucpinternal.h header file was missing its idempotency #ifdef.
377
378 30. I was sent a "project" file called libpcre.a.dev which I understand makes
379 building PCRE on Windows easier, so I have included it in the distribution.
380
381 31. There is now a check in pcretest against a ridiculously large number being
382 returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
383 loop, the loop is abandoned.
384
385 32. Forward references to subpatterns in conditions such as (?(2)...) where
386 subpattern 2 is defined later cause pcre_compile() to search forwards in
387 the pattern for the relevant set of parentheses. This search went wrong
388 when there were unescaped parentheses in a character class, parentheses
389 escaped with \Q...\E, or parentheses in a #-comment in /x mode.
390
391 33. "Subroutine" calls and backreferences were previously restricted to
392 referencing subpatterns earlier in the regex. This restriction has now
393 been removed.
394
395 34. Added a number of extra features that are going to be in Perl 5.10. On the
396 whole, these are just syntactic alternatives for features that PCRE had
397 previously implemented using the Python syntax or my own invention. The
398 other formats are all retained for compatibility.
399
400 (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
401 as (?P<name>...). The new forms, as well as being in Perl 5.10, are
402 also .NET compatible.
403
404 (b) A recursion or subroutine call to a named group can now be defined as
405 (?&name) as well as (?P>name).
406
407 (c) A backreference to a named group can now be defined as \k<name> or
408 \k'name' as well as (?P=name). The new forms, as well as being in Perl
409 5.10, are also .NET compatible.
410
411 (d) A conditional reference to a named group can now use the syntax
412 (?(<name>) or (?('name') as well as (?(name).
413
414 (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
415 groups (named and numbered) that are never evaluated inline, but can be
416 called as "subroutines" from elsewhere. In effect, the DEFINE condition
417 is always false. There may be only one alternative in such a group.
418
419 (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
420 as the simple (?(R). The condition is true only if the most recent
421 recursion is that of the given number or name. It does not search out
422 through the entire recursion stack.
423
424 (g) The escape \gN or \g{N} has been added, where N is a positive or
425 negative number, specifying an absolute or relative reference.
426
427 35. Tidied to get rid of some further signed/unsigned compiler warnings and
428 some "unreachable code" warnings.
429
430 36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
431 things, this adds five new scripts.
432
433 37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
434 There were also incompatibilities regarding the handling of \Q..\E inside
435 character classes, for example with patterns like [\Qa\E-\Qz\E] where the
436 hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
437
438 38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
439 matches an empty string, and forcibly breaks the loop. There were bugs in
440 this code in non-simple cases. For a pattern such as ^(a()*)* matched
441 against aaaa the result was just "a" rather than "aaaa", for example. Two
442 separate and independent bugs (that affected different cases) have been
443 fixed.
444
445 39. Refactored the code to abolish the use of different opcodes for small
446 capturing bracket numbers. This is a tidy that I avoided doing when I
447 removed the limit on the number of capturing brackets for 3.5 back in 2001.
448 The new approach is not only tidier, it makes it possible to reduce the
449 memory needed to fix the previous bug (38).
450
451 40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
452 sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
453 processing dot, circumflex, or dollar metacharacters, or #-comments in /x
454 mode.
455
456 41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
457 report.
458
459 42. Applied patch, originally from Ari Pollak, modified by Google, to allow
460 copy construction and assignment in the C++ wrapper.
461
462 43. Updated pcregrep to support "--newline=any". In the process, I fixed a
463 couple of bugs that could have given wrong results in the "--newline=crlf"
464 case.
465
466 44. Added a number of casts and did some reorganization of signed/unsigned int
467 variables following suggestions from Dair Grant. Also renamed the variable
468 "this" as "item" because it is a C++ keyword.
469
470 45. Arranged for dftables to add
471
472 #include "pcre_internal.h"
473
474 to pcre_chartables.c because without it, gcc 4.x may remove the array
475 definition from the final binary if PCRE is built into a static library and
476 dead code stripping is activated.
477
478 46. For an unanchored pattern, if a match attempt fails at the start of a
479 newline sequence, and the newline setting is CRLF or ANY, and the next two
480 characters are CRLF, advance by two characters instead of one.
481
482
483 Version 6.7 04-Jul-06
484 ---------------------
485
486 1. In order to handle tests when input lines are enormously long, pcretest has
487 been re-factored so that it automatically extends its buffers when
488 necessary. The code is crude, but this _is_ just a test program. The
489 default size has been increased from 32K to 50K.
490
491 2. The code in pcre_study() was using the value of the re argument before
492 testing it for NULL. (Of course, in any sensible call of the function, it
493 won't be NULL.)
494
495 3. The memmove() emulation function in pcre_internal.h, which is used on
496 systems that lack both memmove() and bcopy() - that is, hardly ever -
497 was missing a "static" storage class specifier.
498
499 4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
500 containing an extended class (one that cannot be represented by a bitmap
501 because it contains high-valued characters or Unicode property items, e.g.
502 [\pZ]). Almost always one would set UTF-8 mode when processing such a
503 pattern, but PCRE should not loop if you do not (it no longer does).
504 [Detail: two cases were found: (a) a repeated subpattern containing an
505 extended class; (b) a recursive reference to a subpattern that followed a
506 previous extended class. It wasn't skipping over the extended class
507 correctly when UTF-8 mode was not set.]
508
509 5. A negated single-character class was not being recognized as fixed-length
510 in lookbehind assertions such as (?<=[^f]), leading to an incorrect
511 compile error "lookbehind assertion is not fixed length".
512
513 6. The RunPerlTest auxiliary script was showing an unexpected difference
514 between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
515 write a Perl script that can interpret lines of an input file either as
516 byte characters or as UTF-8, which is what "perltest" was being required to
517 do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
518 can't do is switch easily at run time between having the "use utf8;" pragma
519 or not. In the end, I fudged it by using the RunPerlTest script to insert
520 "use utf8;" explicitly for the UTF-8 tests.
521
522 7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
523 the end of the subject string, contrary to the documentation and to what
524 Perl does. This was true of both matching functions. Now it matches only at
525 the start of the subject and immediately after *internal* newlines.
526
527 8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
528 a pointer to an int instead of a pointer to an unsigned long int. This
529 caused problems on 64-bit systems.
530
531 9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
532 instance of the 'standard' template library not being so standard".
533
534 10. There was no check on the number of named subpatterns nor the maximum
535 length of a subpattern name. The product of these values is used to compute
536 the size of the memory block for a compiled pattern. By supplying a very
537 long subpattern name and a large number of named subpatterns, the size
538 computation could be caused to overflow. This is now prevented by limiting
539 the length of names to 32 characters, and the number of named subpatterns
540 to 10,000.
541
542 11. Subpatterns that are repeated with specific counts have to be replicated in
543 the compiled pattern. The size of memory for this was computed from the
544 length of the subpattern and the repeat count. The latter is limited to
545 65535, but there was no limit on the former, meaning that integer overflow
546 could in principle occur. The compiled length of a repeated subpattern is
547 now limited to 30,000 bytes in order to prevent this.
548
549 12. Added the optional facility to have named substrings with the same name.
550
551 13. Added the ability to use a named substring as a condition, using the
552 Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
553 are numbers (not recommended). Forward references are permitted.
554
555 14. Added forward references in named backreferences (if you see what I mean).
556
557 15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
558 pattern could run off the end of the subject. For example, the pattern
559 "(?s)(.{1,5})"8 did this with the subject "ab".
560
561 16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
562 PCRE_CASELESS was set when matching characters that were quantified with ?
563 or *.
564
565 17. A character class other than a single negated character that had a minimum
566 but no maximum quantifier - for example [ab]{6,} - was not handled
567 correctly by pce_dfa_exec(). It would match only one character.
568
569 18. A valid (though odd) pattern that looked like a POSIX character
570 class but used an invalid character after [ (for example [[,abc,]]) caused
571 pcre_compile() to give the error "Failed: internal error: code overflow" or
572 in some cases to crash with a glibc free() error. This could even happen if
573 the pattern terminated after [[ but there just happened to be a sequence of
574 letters, a binary zero, and a closing ] in the memory that followed.
575
576 19. Perl's treatment of octal escapes in the range \400 to \777 has changed
577 over the years. Originally (before any Unicode support), just the bottom 8
578 bits were taken. Thus, for example, \500 really meant \100. Nowadays the
579 output from "man perlunicode" includes this:
580
581 The regular expression compiler produces polymorphic opcodes. That
582 is, the pattern adapts to the data and automatically switches to
583 the Unicode character scheme when presented with Unicode data--or
584 instead uses a traditional byte scheme when presented with byte
585 data.
586
587 Sadly, a wide octal escape does not cause a switch, and in a string with
588 no other multibyte characters, these octal escapes are treated as before.
589 Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
590 /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
591 Unicode string.
592
593 I have not perpetrated such confusion in PCRE. Up till now, it took just
594 the bottom 8 bits, as in old Perl. I have now made octal escapes with
595 values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
596 translate to the appropriate multibyte character.
597
598 29. Applied some refactoring to reduce the number of warnings from Microsoft
599 and Borland compilers. This has included removing the fudge introduced
600 seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
601 a warning about an unused variable.
602
603 21. PCRE has not included VT (character 0x0b) in the set of whitespace
604 characters since release 4.0, because Perl (from release 5.004) does not.
605 [Or at least, is documented not to: some releases seem to be in conflict
606 with the documentation.] However, when a pattern was studied with
607 pcre_study() and all its branches started with \s, PCRE still included VT
608 as a possible starting character. Of course, this did no harm; it just
609 caused an unnecessary match attempt.
610
611 22. Removed a now-redundant internal flag bit that recorded the fact that case
612 dependency changed within the pattern. This was once needed for "required
613 byte" processing, but is no longer used. This recovers a now-scarce options
614 bit. Also moved the least significant internal flag bit to the most-
615 significant bit of the word, which was not previously used (hangover from
616 the days when it was an int rather than a uint) to free up another bit for
617 the future.
618
619 23. Added support for CRLF line endings as well as CR and LF. As well as the
620 default being selectable at build time, it can now be changed at runtime
621 via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
622 specify that it is scanning data with non-default line endings.
623
624 24. Changed the definition of CXXLINK to make it agree with the definition of
625 LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
626
627 25. Applied Ian Taylor's patches to avoid using another stack frame for tail
628 recursions. This makes a big different to stack usage for some patterns.
629
630 26. If a subpattern containing a named recursion or subroutine reference such
631 as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
632 the space required for the compiled pattern went wrong and gave too small a
633 value. Depending on the environment, this could lead to "Failed: internal
634 error: code overflow at offset 49" or "glibc detected double free or
635 corruption" errors.
636
637 27. Applied patches from Google (a) to support the new newline modes and (b) to
638 advance over multibyte UTF-8 characters in GlobalReplace.
639
640 28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
641 difference for some implementation of PCRE in some Windows version.
642
643 29. Added some extra testing facilities to pcretest:
644
645 \q<number> in a data line sets the "match limit" value
646 \Q<number> in a data line sets the "match recursion limt" value
647 -S <number> sets the stack size, where <number> is in megabytes
648
649 The -S option isn't available for Windows.
650
651
652 Version 6.6 06-Feb-06
653 ---------------------
654
655 1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
656 in pcreposix.h. I have copied the definition from pcre.h.
657
658 2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
659 because pcre.h is no longer a built file.
660
661 3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
662 not normally included in the compiled code.
663
664
665 Version 6.5 01-Feb-06
666 ---------------------
667
668 1. When using the partial match feature with pcre_dfa_exec(), it was not
669 anchoring the second and subsequent partial matches at the new starting
670 point. This could lead to incorrect results. For example, with the pattern
671 /1234/, partially matching against "123" and then "a4" gave a match.
672
673 2. Changes to pcregrep:
674
675 (a) All non-match returns from pcre_exec() were being treated as failures
676 to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
677 error message is output. Some extra information is given for the
678 PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
679 probably the only errors that are likely to be caused by users (by
680 specifying a regex that has nested indefinite repeats, for instance).
681 If there are more than 20 of these errors, pcregrep is abandoned.
682
683 (b) A binary zero was treated as data while matching, but terminated the
684 output line if it was written out. This has been fixed: binary zeroes
685 are now no different to any other data bytes.
686
687 (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
688 used to set a locale for matching. The --locale=xxxx long option has
689 been added (no short equivalent) to specify a locale explicitly on the
690 pcregrep command, overriding the environment variables.
691
692 (d) When -B was used with -n, some line numbers in the output were one less
693 than they should have been.
694
695 (e) Added the -o (--only-matching) option.
696
697 (f) If -A or -C was used with -c (count only), some lines of context were
698 accidentally printed for the final match.
699
700 (g) Added the -H (--with-filename) option.
701
702 (h) The combination of options -rh failed to suppress file names for files
703 that were found from directory arguments.
704
705 (i) Added the -D (--devices) and -d (--directories) options.
706
707 (j) Added the -F (--fixed-strings) option.
708
709 (k) Allow "-" to be used as a file name for -f as well as for a data file.
710
711 (l) Added the --colo(u)r option.
712
713 (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
714 is not present by default.
715
716 3. A nasty bug was discovered in the handling of recursive patterns, that is,
717 items such as (?R) or (?1), when the recursion could match a number of
718 alternatives. If it matched one of the alternatives, but subsequently,
719 outside the recursion, there was a failure, the code tried to back up into
720 the recursion. However, because of the way PCRE is implemented, this is not
721 possible, and the result was an incorrect result from the match.
722
723 In order to prevent this happening, the specification of recursion has
724 been changed so that all such subpatterns are automatically treated as
725 atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
726
727 4. I had overlooked the fact that, in some locales, there are characters for
728 which isalpha() is true but neither isupper() nor islower() are true. In
729 the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
730 and ordfeminine) are like this. This affected the treatment of \w and \W
731 when they appeared in character classes, but not when they appeared outside
732 a character class. The bit map for "word" characters is now created
733 separately from the results of isalnum() instead of just taking it from the
734 upper, lower, and digit maps. (Plus the underscore character, of course.)
735
736 5. The above bug also affected the handling of POSIX character classes such as
737 [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
738 permanent tables. Instead, the bit maps for such a class were previously
739 created as the appropriate unions of the upper, lower, and digit bitmaps.
740 Now they are created by subtraction from the [[:word:]] class, which has
741 its own bitmap.
742
743 6. The [[:blank:]] character class matches horizontal, but not vertical space.
744 It is created by subtracting the vertical space characters (\x09, \x0a,
745 \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
746 subtraction was done in the overall bitmap for a character class, meaning
747 that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
748 be recognized. This bug has been fixed.
749
750 7. Patches from the folks at Google:
751
752 (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
753 real life, but is still worth protecting against".
754
755 (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
756 regular expressions".
757
758 (c) pcre_scanner.cc: avoid use of std::count() because not all systems
759 have it.
760
761 (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
762 "configure" and the latter not, in order to fix a problem somebody had
763 with compiling the Arg class on HP-UX.
764
765 (e) Improve the error-handling of the C++ wrapper a little bit.
766
767 (f) New tests for checking recursion limiting.
768
769 8. The pcre_memmove() function, which is used only if the environment does not
770 have a standard memmove() function (and is therefore rarely compiled),
771 contained two bugs: (a) use of int instead of size_t, and (b) it was not
772 returning a result (though PCRE never actually uses the result).
773
774 9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
775 large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
776 returned instead of calling malloc() with an overflowing number that would
777 most likely cause subsequent chaos.
778
779 10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
780
781 11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
782 with this option is matched, the nmatch and pmatch options of regexec() are
783 ignored.
784
785 12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
786 provided in case anyone wants to the the POSIX interface with UTF-8
787 strings.
788
789 13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
790 C++ linking (needed for some HP-UX environments).
791
792 14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
793 (unused parameter) and in the pcre_printint() function (omitted "default"
794 switch label when the default is to do nothing).
795
796 15. Added some code to make it possible, when PCRE is compiled as a C++
797 library, to replace subject pointers for pcre_exec() with a smart pointer
798 class, thus making it possible to process discontinuous strings.
799
800 16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
801 much the same function. They were added by different people who were trying
802 to make PCRE easy to compile on non-Unix systems. It has been suggested
803 that PCRE_EXPORT be abolished now that there is more automatic apparatus
804 for compiling on Windows systems. I have therefore replaced it with
805 PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
806 defaults to "extern" for C or "extern C" for C++, which works fine on
807 Unix-like systems. It is now possible to override the value of PCRE_DATA_
808 SCOPE with something explicit in config.h. In addition:
809
810 (a) pcreposix.h still had just "extern" instead of either of these macros;
811 I have replaced it with PCRE_DATA_SCOPE.
812
813 (b) Functions such as _pcre_xclass(), which are internal to the library,
814 but external in the C sense, all had PCRE_EXPORT in their definitions.
815 This is apparently wrong for the Windows case, so I have removed it.
816 (It makes no difference on Unix-like systems.)
817
818 17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
819 of recursive calls to match(). This is different to MATCH_LIMIT because
820 that limits the total number of calls to match(), not all of which increase
821 the depth of recursion. Limiting the recursion depth limits the amount of
822 stack (or heap if NO_RECURSE is set) that is used. The default can be set
823 when PCRE is compiled, and changed at run time. A patch from Google adds
824 this functionality to the C++ interface.
825
826 18. Changes to the handling of Unicode character properties:
827
828 (a) Updated the table to Unicode 4.1.0.
829
830 (b) Recognize characters that are not in the table as "Cn" (undefined).
831
832 (c) I revised the way the table is implemented to a much improved format
833 which includes recognition of ranges. It now supports the ranges that
834 are defined in UnicodeData.txt, and it also amalgamates other
835 characters into ranges. This has reduced the number of entries in the
836 table from around 16,000 to around 3,000, thus reducing its size
837 considerably. I realized I did not need to use a tree structure after
838 all - a binary chop search is just as efficient. Having reduced the
839 number of entries, I extended their size from 6 bytes to 8 bytes to
840 allow for more data.
841
842 (d) Added support for Unicode script names via properties such as \p{Han}.
843
844 19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
845 matching that character.
846
847 20. When matching a repeated Unicode property with a minimum greater than zero,
848 (for example \pL{2,}), PCRE could look past the end of the subject if it
849 reached it while seeking the minimum number of characters. This could
850 happen only if some of the characters were more than one byte long, because
851 there is a check for at least the minimum number of bytes.
852
853 21. Refactored the implementation of \p and \P so as to be more general, to
854 allow for more different types of property in future. This has changed the
855 compiled form incompatibly. Anybody with saved compiled patterns that use
856 \p or \P will have to recompile them.
857
858 22. Added "Any" and "L&" to the supported property types.
859
860 23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
861 but give a compile time error if the value is greater than 0xff.
862
863 24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
864 accidentally not being installed or uninstalled.
865
866 25. The pcre.h file was built from pcre.h.in, but the only changes that were
867 made were to insert the current release number. This seemed silly, because
868 it made things harder for people building PCRE on systems that don't run
869 "configure". I have turned pcre.h into a distributed file, no longer built
870 by "configure", with the version identification directly included. There is
871 no longer a pcre.h.in file.
872
873 However, this change necessitated a change to the pcre-config script as
874 well. It is built from pcre-config.in, and one of the substitutions was the
875 release number. I have updated configure.ac so that ./configure now finds
876 the release number by grepping pcre.h.
877
878 26. Added the ability to run the tests under valgrind.
879
880
881 Version 6.4 05-Sep-05
882 ---------------------
883
884 1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
885 "--" to be printed when multiple files were scanned, even when none of the
886 -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
887 consider it to be a bug, and have restored the previous behaviour.
888
889 2. A couple of code tidies to get rid of compiler warnings.
890
891 3. The pcretest program used to cheat by referring to symbols in the library
892 whose names begin with _pcre_. These are internal symbols that are not
893 really supposed to be visible externally, and in some environments it is
894 possible to suppress them. The cheating is now confined to including
895 certain files from the library's source, which is a bit cleaner.
896
897 4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
898 file's purpose clearer.
899
900 5. Reorganized pcre_ucp_findchar().
901
902
903 Version 6.3 15-Aug-05
904 ---------------------
905
906 1. The file libpcre.pc.in did not have general read permission in the tarball.
907
908 2. There were some problems when building without C++ support:
909
910 (a) If C++ support was not built, "make install" and "make test" still
911 tried to test it.
912
913 (b) There were problems when the value of CXX was explicitly set. Some
914 changes have been made to try to fix these, and ...
915
916 (c) --disable-cpp can now be used to explicitly disable C++ support.
917
918 (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
919 backslash in a target when C++ was disabled. This confuses some
920 versions of "make", apparently. Using an intermediate variable solves
921 this. (Same for CPP_LOBJ.)
922
923 3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
924 (non-Windows) now includes $(CFLAGS) because these flags are sometimes
925 necessary on certain architectures.
926
927 4. Added a setting of -export-symbols-regex to the link command to remove
928 those symbols that are exported in the C sense, but actually are local
929 within the library, and not documented. Their names all begin with
930 "_pcre_". This is not a perfect job, because (a) we have to except some
931 symbols that pcretest ("illegally") uses, and (b) the facility isn't always
932 available (and never for static libraries). I have made a note to try to
933 find a way round (a) in the future.
934
935
936 Version 6.2 01-Aug-05
937 ---------------------
938
939 1. There was no test for integer overflow of quantifier values. A construction
940 such as {1111111111111111} would give undefined results. What is worse, if
941 a minimum quantifier for a parenthesized subpattern overflowed and became
942 negative, the calculation of the memory size went wrong. This could have
943 led to memory overwriting.
944
945 2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
946
947 3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
948 operating environments where this matters.
949
950 4. Applied Giuseppe Maxia's patch to add additional features for controlling
951 PCRE options from within the C++ wrapper.
952
953 5. Named capturing subpatterns were not being correctly counted when a pattern
954 was compiled. This caused two problems: (a) If there were more than 100
955 such subpatterns, the calculation of the memory needed for the whole
956 compiled pattern went wrong, leading to an overflow error. (b) Numerical
957 back references of the form \12, where the number was greater than 9, were
958 not recognized as back references, even though there were sufficient
959 previous subpatterns.
960
961 6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
962 versions of gcc, e.g. 2.95.4.
963
964
965 Version 6.1 21-Jun-05
966 ---------------------
967
968 1. There was one reference to the variable "posix" in pcretest.c that was not
969 surrounded by "#if !defined NOPOSIX".
970
971 2. Make it possible to compile pcretest without DFA support, UTF8 support, or
972 the cross-check on the old pcre_info() function, for the benefit of the
973 cut-down version of PCRE that is currently imported into Exim.
974
975 3. A (silly) pattern starting with (?i)(?-i) caused an internal space
976 allocation error. I've done the easy fix, which wastes 2 bytes for sensible
977 patterns that start (?i) but I don't think that matters. The use of (?i) is
978 just an example; this all applies to the other options as well.
979
980 4. Since libtool seems to echo the compile commands it is issuing, the output
981 from "make" can be reduced a bit by putting "@" in front of each libtool
982 compile command.
983
984 5. Patch from the folks at Google for configure.in to be a bit more thorough
985 in checking for a suitable C++ installation before trying to compile the
986 C++ stuff. This should fix a reported problem when a compiler was present,
987 but no suitable headers.
988
989 6. The man pages all had just "PCRE" as their title. I have changed them to
990 be the relevant file name. I have also arranged that these names are
991 retained in the file doc/pcre.txt, which is a concatenation in text format
992 of all the man pages except the little individual ones for each function.
993
994 7. The NON-UNIX-USE file had not been updated for the different set of source
995 files that come with release 6. I also added a few comments about the C++
996 wrapper.
997
998
999 Version 6.0 07-Jun-05
1000 ---------------------
1001
1002 1. Some minor internal re-organization to help with my DFA experiments.
1003
1004 2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1005 didn't matter for the library itself when fully configured, but did matter
1006 when compiling without UCP support, or within Exim, where the ucp files are
1007 not imported.
1008
1009 3. Refactoring of the library code to split up the various functions into
1010 different source modules. The addition of the new DFA matching code (see
1011 below) to a single monolithic source would have made it really too
1012 unwieldy, quite apart from causing all the code to be include in a
1013 statically linked application, when only some functions are used. This is
1014 relevant even without the DFA addition now that patterns can be compiled in
1015 one application and matched in another.
1016
1017 The downside of splitting up is that there have to be some external
1018 functions and data tables that are used internally in different modules of
1019 the library but which are not part of the API. These have all had their
1020 names changed to start with "_pcre_" so that they are unlikely to clash
1021 with other external names.
1022
1023 4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1024 a different (DFA) algorithm. Although it is slower than the original
1025 function, it does have some advantages for certain types of matching
1026 problem.
1027
1028 5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1029 including restarting after a partial match.
1030
1031 6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1032 defined when compiling for Windows was sent to me. I have put it into the
1033 code, though I have no means of testing or verifying it.
1034
1035 7. Added the pcre_refcount() auxiliary function.
1036
1037 8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1038 match before or at the first newline in the subject string. In pcretest,
1039 the /f option on a pattern can be used to set this.
1040
1041 9. A repeated \w when used in UTF-8 mode with characters greater than 256
1042 would behave wrongly. This has been present in PCRE since release 4.0.
1043
1044 10. A number of changes to the pcregrep command:
1045
1046 (a) Refactored how -x works; insert ^(...)$ instead of setting
1047 PCRE_ANCHORED and checking the length, in preparation for adding
1048 something similar for -w.
1049
1050 (b) Added the -w (match as a word) option.
1051
1052 (c) Refactored the way lines are read and buffered so as to have more
1053 than one at a time available.
1054
1055 (d) Implemented a pcregrep test script.
1056
1057 (e) Added the -M (multiline match) option. This allows patterns to match
1058 over several lines of the subject. The buffering ensures that at least
1059 8K, or the rest of the document (whichever is the shorter) is available
1060 for matching (and similarly the previous 8K for lookbehind assertions).
1061
1062 (f) Changed the --help output so that it now says
1063
1064 -w, --word-regex(p)
1065
1066 instead of two lines, one with "regex" and the other with "regexp"
1067 because that confused at least one person since the short forms are the
1068 same. (This required a bit of code, as the output is generated
1069 automatically from a table. It wasn't just a text change.)
1070
1071 (g) -- can be used to terminate pcregrep options if the next thing isn't an
1072 option but starts with a hyphen. Could be a pattern or a path name
1073 starting with a hyphen, for instance.
1074
1075 (h) "-" can be given as a file name to represent stdin.
1076
1077 (i) When file names are being printed, "(standard input)" is used for
1078 the standard input, for compatibility with GNU grep. Previously
1079 "<stdin>" was used.
1080
1081 (j) The option --label=xxx can be used to supply a name to be used for
1082 stdin when file names are being printed. There is no short form.
1083
1084 (k) Re-factored the options decoding logic because we are going to add
1085 two more options that take data. Such options can now be given in four
1086 different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1087
1088 (l) Added the -A, -B, and -C options for requesting that lines of context
1089 around matches be printed.
1090
1091 (m) Added the -L option to print the names of files that do not contain
1092 any matching lines, that is, the complement of -l.
1093
1094 (n) The return code is 2 if any file cannot be opened, but pcregrep does
1095 continue to scan other files.
1096
1097 (o) The -s option was incorrectly implemented. For compatibility with other
1098 greps, it now suppresses the error message for a non-existent or non-
1099 accessible file (but not the return code). There is a new option called
1100 -q that suppresses the output of matching lines, which was what -s was
1101 previously doing.
1102
1103 (p) Added --include and --exclude options to specify files for inclusion
1104 and exclusion when recursing.
1105
1106 11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1107 Hopefully, it now does.
1108
1109 12. Missing cast in pcre_study().
1110
1111 13. Added an "uninstall" target to the makefile.
1112
1113 14. Replaced "extern" in the function prototypes in Makefile.in with
1114 "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1115 world, but is set differently for Windows.
1116
1117 15. Added a second compiling function called pcre_compile2(). The only
1118 difference is that it has an extra argument, which is a pointer to an
1119 integer error code. When there is a compile-time failure, this is set
1120 non-zero, in addition to the error test pointer being set to point to an
1121 error message. The new argument may be NULL if no error number is required
1122 (but then you may as well call pcre_compile(), which is now just a
1123 wrapper). This facility is provided because some applications need a
1124 numeric error indication, but it has also enabled me to tidy up the way
1125 compile-time errors are handled in the POSIX wrapper.
1126
1127 16. Added VPATH=.libs to the makefile; this should help when building with one
1128 prefix path and installing with another. (Or so I'm told by someone who
1129 knows more about this stuff than I do.)
1130
1131 17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1132 passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1133 match everything, including newlines. This is not POSIX-compatible, but
1134 somebody wanted the feature. From pcretest it can be activated by using
1135 both the P and the s flags.
1136
1137 18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1138
1139 19. libpcre.pc was being incorrectly installed as executable.
1140
1141 20. A couple of places in pcretest check for end-of-line by looking for '\n';
1142 it now also looks for '\r' so that it will work unmodified on Windows.
1143
1144 21. Added Google's contributed C++ wrapper to the distribution.
1145
1146 22. Added some untidy missing memory free() calls in pcretest, to keep
1147 Electric Fence happy when testing.
1148
1149
1150
1151 Version 5.0 13-Sep-04
1152 ---------------------
1153
1154 1. Internal change: literal characters are no longer packed up into items
1155 containing multiple characters in a single byte-string. Each character
1156 is now matched using a separate opcode. However, there may be more than one
1157 byte in the character in UTF-8 mode.
1158
1159 2. The pcre_callout_block structure has two new fields: pattern_position and
1160 next_item_length. These contain the offset in the pattern to the next match
1161 item, and its length, respectively.
1162
1163 3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1164 insertion of callouts before each pattern item. Added the /C option to
1165 pcretest to make use of this.
1166
1167 4. On the advice of a Windows user, the lines
1168
1169 #if defined(_WIN32) || defined(WIN32)
1170 _setmode( _fileno( stdout ), 0x8000 );
1171 #endif /* defined(_WIN32) || defined(WIN32) */
1172
1173 have been added to the source of pcretest. This apparently does useful
1174 magic in relation to line terminators.
1175
1176 5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1177 for the benefit of those environments where the "b" makes a difference.
1178
1179 6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1180 to know about it. I have put a hack into configure.in that adds in code
1181 to set GCC=yes if CC=icc. This seems to end up at a point in the
1182 generated configure script that is early enough to affect the setting of
1183 compiler options, which is what is needed, but I have no means of testing
1184 whether it really works. (The user who reported this had patched the
1185 generated configure script, which of course I cannot do.)
1186
1187 LATER: After change 22 below (new libtool files), the configure script
1188 seems to know about icc (and also ecc). Therefore, I have commented out
1189 this hack in configure.in.
1190
1191 7. Added support for pkg-config (2 patches were sent in).
1192
1193 8. Negated POSIX character classes that used a combination of internal tables
1194 were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1195 [[:^ascii]]. Typically, they would match almost any characters. The other
1196 POSIX classes were not broken in this way.
1197
1198 9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1199 to find the match, as PCRE was deluded into thinking that the match had to
1200 start at the start point or following a newline. The same bug applied to
1201 patterns with negative forward assertions or any backward assertions
1202 preceding ".*" at the start, unless the pattern required a fixed first
1203 character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1204
1205 10. In UTF-8 mode, when moving forwards in the subject after a failed match
1206 starting at the last subject character, bytes beyond the end of the subject
1207 string were read.
1208
1209 11. Renamed the variable "class" as "classbits" to make life easier for C++
1210 users. (Previously there was a macro definition, but it apparently wasn't
1211 enough.)
1212
1213 12. Added the new field "tables" to the extra data so that tables can be passed
1214 in at exec time, or the internal tables can be re-selected. This allows
1215 a compiled regex to be saved and re-used at a later time by a different
1216 program that might have everything at different addresses.
1217
1218 13. Modified the pcre-config script so that, when run on Solaris, it shows a
1219 -R library as well as a -L library.
1220
1221 14. The debugging options of pcretest (-d on the command line or D on a
1222 pattern) showed incorrect output for anything following an extended class
1223 that contained multibyte characters and which was followed by a quantifier.
1224
1225 15. Added optional support for general category Unicode character properties
1226 via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1227 support. It adds about 90K to the size of the library. The meanings of the
1228 inbuilt class escapes such as \d and \s have NOT been changed.
1229
1230 16. Updated pcredemo.c to include calls to free() to release the memory for the
1231 compiled pattern.
1232
1233 17. The generated file chartables.c was being created in the source directory
1234 instead of in the building directory. This caused the build to fail if the
1235 source directory was different from the building directory, and was
1236 read-only.
1237
1238 18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1239 file. No doubt somebody will tell me if they don't make sense... Also added
1240 Dan Mooney's comments about building on OpenVMS.
1241
1242 19. Added support for partial matching via the PCRE_PARTIAL option for
1243 pcre_exec() and the \P data escape in pcretest.
1244
1245 20. Extended pcretest with 3 new pattern features:
1246
1247 (i) A pattern option of the form ">rest-of-line" causes pcretest to
1248 write the compiled pattern to the file whose name is "rest-of-line".
1249 This is a straight binary dump of the data, with the saved pointer to
1250 the character tables forced to be NULL. The study data, if any, is
1251 written too. After writing, pcretest reads a new pattern.
1252
1253 (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1254 compiled pattern from the given file. There must not be any
1255 occurrences of "<" in the file name (pretty unlikely); if there are,
1256 pcretest will instead treat the initial "<" as a pattern delimiter.
1257 After reading in the pattern, pcretest goes on to read data lines as
1258 usual.
1259
1260 (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1261 and 16-bit fields in a compiled pattern, to simulate a pattern that
1262 was compiled on a host of opposite endianness.
1263
1264 21. The pcre-exec() function can now cope with patterns that were compiled on
1265 hosts of opposite endianness, with this restriction:
1266
1267 As for any compiled expression that is saved and used later, the tables
1268 pointer field cannot be preserved; the extra_data field in the arguments
1269 to pcre_exec() should be used to pass in a tables address if a value
1270 other than the default internal tables were used at compile time.
1271
1272 22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1273 now diagnosed as an error. Previously, most of the time, a negative number
1274 would have been treated as zero, but if in addition "ovector" was passed as
1275 NULL, a crash could occur.
1276
1277 23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1278 new versions from the libtool 1.5 distribution (the last one is a copy of
1279 a file called libtool.m4). This seems to have fixed the need to patch
1280 "configure" to support Darwin 1.3 (which I used to do). However, I still
1281 had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1282 workstation).
1283
1284 24. Changed the PCRE licence to be the more standard "BSD" licence.
1285
1286
1287 Version 4.5 01-Dec-03
1288 ---------------------
1289
1290 1. There has been some re-arrangement of the code for the match() function so
1291 that it can be compiled in a version that does not call itself recursively.
1292 Instead, it keeps those local variables that need separate instances for
1293 each "recursion" in a frame on the heap, and gets/frees frames whenever it
1294 needs to "recurse". Keeping track of where control must go is done by means
1295 of setjmp/longjmp. The whole thing is implemented by a set of macros that
1296 hide most of the details from the main code, and operates only if
1297 NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1298 "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1299 operating.
1300
1301 To make it easier for callers to provide specially tailored get/free
1302 functions for this usage, two new functions, pcre_stack_malloc, and
1303 pcre_stack_free, are used. They are always called in strict stacking order,
1304 and the size of block requested is always the same.
1305
1306 The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1307 PCRE has been compiled to use the stack or the heap for recursion. The
1308 -C option of pcretest uses this to show which version is compiled.
1309
1310 A new data escape \S, is added to pcretest; it causes the amounts of store
1311 obtained and freed by both kinds of malloc/free at match time to be added
1312 to the output.
1313
1314 2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1315 what's available on my current Linux desktop machine.
1316
1317 3. When matching a UTF-8 string, the test for a valid string at the start has
1318 been extended. If start_offset is not zero, PCRE now checks that it points
1319 to a byte that is the start of a UTF-8 character. If not, it returns
1320 PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1321 this is necessary because there may be backward assertions in the pattern.
1322 When matching the same subject several times, it may save resources to use
1323 PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1324
1325 4. The code for checking the validity of UTF-8 strings has been tightened so
1326 that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1327 containing "overlong sequences".
1328
1329 5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1330 I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1331 should have been "&", but it just so happened that all the cases this let
1332 through by mistake were picked up later in the function.
1333
1334 6. I had used a variable called "isblank" - this is a C99 function, causing
1335 some compilers to warn. To avoid this, I renamed it (as "blankclass").
1336
1337 7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1338 prompting; (b) run "./pcretest /dev/null" at the start of the test script
1339 so the version is shown; (c) stop "make test" echoing "./RunTest".
1340
1341 8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1342
1343 9. The prototype for memmove() for systems that don't have it was using
1344 size_t, but the inclusion of the header that defines size_t was later. I've
1345 moved the #includes for the C headers earlier to avoid this.
1346
1347 10. Added some adjustments to the code to make it easier to compiler on certain
1348 special systems:
1349
1350 (a) Some "const" qualifiers were missing.
1351 (b) Added the macro EXPORT before all exported functions; by default this
1352 is defined to be empty.
1353 (c) Changed the dftables auxiliary program (that builds chartables.c) so
1354 that it reads its output file name as an argument instead of writing
1355 to the standard output and assuming this can be redirected.
1356
1357 11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1358 class containing characters with values greater than 255, PCRE compilation
1359 went into a loop.
1360
1361 12. A recursive reference to a subpattern that was within another subpattern
1362 that had a minimum quantifier of zero caused PCRE to crash. For example,
1363 (x(y(?2))z)? provoked this bug with a subject that got as far as the
1364 recursion. If the recursively-called subpattern itself had a zero repeat,
1365 that was OK.
1366
1367 13. In pcretest, the buffer for reading a data line was set at 30K, but the
1368 buffer into which it was copied (for escape processing) was still set at
1369 1024, so long lines caused crashes.
1370
1371 14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1372 "internal error: code overflow...". This applied to any character class
1373 that was followed by a possessive quantifier.
1374
1375 15. Modified the Makefile to add libpcre.la as a prerequisite for
1376 libpcreposix.la because I was told this is needed for a parallel build to
1377 work.
1378
1379 16. If a pattern that contained .* following optional items at the start was
1380 studied, the wrong optimizing data was generated, leading to matching
1381 errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1382 matching string must start with a or b or c. The correct conclusion for
1383 this pattern is that a match can start with any character.
1384
1385
1386 Version 4.4 13-Aug-03
1387 ---------------------
1388
1389 1. In UTF-8 mode, a character class containing characters with values between
1390 127 and 255 was not handled correctly if the compiled pattern was studied.
1391 In fixing this, I have also improved the studying algorithm for such
1392 classes (slightly).
1393
1394 2. Three internal functions had redundant arguments passed to them. Removal
1395 might give a very teeny performance improvement.
1396
1397 3. Documentation bug: the value of the capture_top field in a callout is *one
1398 more than* the number of the hightest numbered captured substring.
1399
1400 4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1401 in incorrectly linking with a previously installed version. They now link
1402 explicitly with libpcre.la.
1403
1404 5. configure.in no longer needs to recognize Cygwin specially.
1405
1406 6. A problem in pcre.in for Windows platforms is fixed.
1407
1408 7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1409 pcretest, it used to include the size of the study block as part of its
1410 output. Unfortunately, the structure contains a field that has a different
1411 size on different hardware architectures. This meant that the tests that
1412 showed this size failed. As the block is currently always of a fixed size,
1413 this information isn't actually particularly useful in pcretest output, so
1414 I have just removed it.
1415
1416 8. Three pre-processor statements accidentally did not start in column 1.
1417 Sadly, there are *still* compilers around that complain, even though
1418 standard C has not required this for well over a decade. Sigh.
1419
1420 9. In pcretest, the code for checking callouts passed small integers in the
1421 callout_data field, which is a void * field. However, some picky compilers
1422 complained about the casts involved for this on 64-bit systems. Now
1423 pcretest passes the address of the small integer instead, which should get
1424 rid of the warnings.
1425
1426 10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1427 both compile and run time, and gives an error if an invalid UTF-8 sequence
1428 is found. There is a option for disabling this check in cases where the
1429 string is known to be correct and/or the maximum performance is wanted.
1430
1431 11. In response to a bug report, I changed one line in Makefile.in from
1432
1433 -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1434 to
1435 -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1436
1437 to look similar to other lines, but I have no way of telling whether this
1438 is the right thing to do, as I do not use Windows. No doubt I'll get told
1439 if it's wrong...
1440
1441
1442 Version 4.3 21-May-03
1443 ---------------------
1444
1445 1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1446 Makefile.
1447
1448 2. Some refactoring to improve the quality of the code:
1449
1450 (i) The utf8_table... variables are now declared "const".
1451
1452 (ii) The code for \cx, which used the "case flipping" table to upper case
1453 lower case letters, now just substracts 32. This is ASCII-specific,
1454 but the whole concept of \cx is ASCII-specific, so it seems
1455 reasonable.
1456
1457 (iii) PCRE was using its character types table to recognize decimal and
1458 hexadecimal digits in the pattern. This is silly, because it handles
1459 only 0-9, a-f, and A-F, but the character types table is locale-
1460 specific, which means strange things might happen. A private
1461 table is now used for this - though it costs 256 bytes, a table is
1462 much faster than multiple explicit tests. Of course, the standard
1463 character types table is still used for matching digits in subject
1464 strings against \d.
1465
1466 (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1467 ending in _t are). So I've renamed it as ESC_tee.
1468
1469 3. The first argument for regexec() in the POSIX wrapper should have been
1470 defined as "const".
1471
1472 4. Changed pcretest to use malloc() for its buffers so that they can be
1473 Electric Fenced for debugging.
1474
1475 5. There were several places in the code where, in UTF-8 mode, PCRE would try
1476 to read one or more bytes before the start of the subject string. Often this
1477 had no effect on PCRE's behaviour, but in some circumstances it could
1478 provoke a segmentation fault.
1479
1480 6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1481 to try to read one or more bytes before the start of the subject string.
1482
1483 7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1484 UTF-8 support could misbehave in various ways if the subject string
1485 contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1486 area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1487 back over UTF-8 characters.)
1488
1489
1490 Version 4.2 14-Apr-03
1491 ---------------------
1492
1493 1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1494
1495 2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1496 [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1497 [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1498 [WIN_PREFIX]: new variable, "cyg" for Cygwin
1499 * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1500 and BUILD_EXEEXT
1501 Note: automatic setting of the BUILD variables is not yet working
1502 set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1503 compile-time but not at link-time
1504 [LINK]: use for linking executables only
1505 make different versions for Windows and non-Windows
1506 [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1507 libraries
1508 [LINK_FOR_BUILD]: new variable
1509 [OBJEXT]: use throughout
1510 [EXEEXT]: use throughout
1511 <winshared>: new target
1512 <wininstall>: new target
1513 <dftables.o>: use native compiler
1514 <dftables>: use native linker
1515 <install>: handle Windows platform correctly
1516 <clean>: ditto
1517 <check>: ditto
1518 copy DLL to top builddir before testing
1519
1520 As part of these changes, -no-undefined was removed again. This was reported
1521 to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1522 in any case.
1523
1524 3. Some tidies to get rid of compiler warnings:
1525
1526 . In the match_data structure, match_limit was an unsigned long int, whereas
1527 match_call_count was an int. I've made them both unsigned long ints.
1528
1529 . In pcretest the fact that a const uschar * doesn't automatically cast to
1530 a void * provoked a warning.
1531
1532 . Turning on some more compiler warnings threw up some "shadow" variables
1533 and a few more missing casts.
1534
1535 4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1536 option, a class that contained a single character with a value between 128
1537 and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1538
1539 5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1540 option, a class that contained several characters, but with at least one
1541 whose value was between 128 and 255 caused PCRE to crash.
1542
1543
1544 Version 4.1 12-Mar-03
1545 ---------------------
1546
1547 1. Compiling with gcc -pedantic found a couple of places where casts were
1548 needed, and a string in dftables.c that was longer than standard compilers are
1549 required to support.
1550
1551 2. Compiling with Sun's compiler found a few more places where the code could
1552 be tidied up in order to avoid warnings.
1553
1554 3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1555 first of these names is deprecated in the latest Autoconf in favour of the name
1556 CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1557 compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1558 analogy I have changed it to CFLAGS_FOR_BUILD.
1559
1560 4. Added -no-undefined to the linking command in the Makefile, because this is
1561 apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1562 linking step for the pcreposix library.
1563
1564 5. PCRE was failing to diagnose the case of two named groups with the same
1565 name.
1566
1567 6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1568 literal character that is needed in the subject for a match, and scans along to
1569 ensure that it is present before embarking on the full matching process. This
1570 saves time in cases of nested unlimited repeats that are never going to match.
1571 Problem: the scan can take a lot of time if the subject is very long (e.g.
1572 megabytes), thus penalizing straightforward matches. It is now done only if the
1573 amount of subject to be scanned is less than 1000 bytes.
1574
1575 7. A lesser problem with the same optimization is that it was recording the
1576 first character of an anchored pattern as "needed", thus provoking a search
1577 right along the subject, even when the first match of the pattern was going to
1578 fail. The "needed" character is now not set for anchored patterns, unless it
1579 follows something in the pattern that is of non-fixed length. Thus, it still
1580 fulfils its original purpose of finding quick non-matches in cases of nested
1581 unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1582
1583
1584 Version 4.0 17-Feb-03
1585 ---------------------
1586
1587 1. If a comment in an extended regex that started immediately after a meta-item
1588 extended to the end of string, PCRE compiled incorrect data. This could lead to
1589 all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1590
1591 2. Moved to autoconf 2.53 and libtool 1.4.2.
1592
1593 3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1594 the special perltest8 script is no longer needed - all the tests can be run
1595 from a single perltest script.
1596
1597 4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1598 by \s. It has now been removed in PCRE. This means it isn't recognized as
1599 whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1600 class [:space:] *does* include VT, thereby creating a mess.
1601
1602 5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1603 space and tab.
1604
1605 6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1606 its new features into the main test script, reducing the number of scripts.
1607
1608 7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1609 were backward compatible, and made the (?i) apply to the whole pattern, as if
1610 /i were given. Now it behaves more logically, and applies the option setting
1611 only to what follows. PCRE has been changed to follow suit. However, if it
1612 finds options settings right at the start of the pattern, it extracts them into
1613 the global options, as before. Thus, they show up in the info data.
1614
1615 8. Added support for the \Q...\E escape sequence. Characters in between are
1616 treated as literals. This is slightly different from Perl in that $ and @ are
1617 also handled as literals inside the quotes. In Perl, they will cause variable
1618 interpolation. Note the following examples:
1619
1620 Pattern PCRE matches Perl matches
1621
1622 \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1623 \Qabc\$xyz\E abc\$xyz abc\$xyz
1624 \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1625
1626 For compatibility with Perl, \Q...\E sequences are recognized inside character
1627 classes as well as outside them.
1628
1629 9. Re-organized 3 code statements in pcretest to avoid "overflow in
1630 floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1631 (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1632 signed/unsigned warnings.
1633
1634 10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1635 option for pcretest, so I've replaced it by a simple function that does just
1636 that job.
1637
1638 11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1639 "pcregrep -".
1640
1641 12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1642 Java package. This provides some syntactic sugar for simple cases of what my
1643 documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1644 as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1645 item, you can use this simplified notation. Note that only makes sense with
1646 greedy quantifiers. Consequently, the use of the possessive quantifier forces
1647 greediness, whatever the setting of the PCRE_UNGREEDY option.
1648
1649 13. A change of greediness default within a pattern was not taking effect at
1650 the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1651 subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1652 was abstracted outside.
1653
1654 14. PCRE now supports the \G assertion. It is true when the current matching
1655 position is at the start point of the match. This differs from \A when the
1656 starting offset is non-zero. Used with the /g option of pcretest (or similar
1657 code), it works in the same way as it does for Perl's /g option. If all
1658 alternatives of a regex begin with \G, the expression is anchored to the start
1659 match position, and the "anchored" flag is set in the compiled expression.
1660
1661 15. Some bugs concerning the handling of certain option changes within patterns
1662 have been fixed. These applied to options other than (?ims). For example,
1663 "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1664 been the other way round. Some of this was related to change 7 above.
1665
1666 16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1667 features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1668 and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1669 POSIX classes only within a class (e.g. /[[:alpha:]]/).
1670
1671 17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1672 mode. Unlike ".", it always matches newline, whatever the setting of
1673 PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1674 assertions. Perl allows it, but it doesn't (in general) work because it can't
1675 calculate the length of the lookbehind. At least, that's the case for Perl
1676 5.8.0 - I've been told they are going to document that it doesn't work in
1677 future.
1678
1679 18. Added an error diagnosis for escapes that PCRE does not support: these are
1680 \L, \l, \N, \P, \p, \U, \u, and \X.
1681
1682 19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1683 reading past the end of the pattern in cases such as /[abcd/.
1684
1685 20. PCRE was getting more memory than necessary for patterns with classes that
1686 contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1687
1688 21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1689 compiling PCRE for use with Virtual Pascal.
1690
1691 22. Small fix to the Makefile to make it work properly if the build is done
1692 outside the source tree.
1693
1694 23. Added a new extension: a condition to go with recursion. If a conditional
1695 subpattern starts with (?(R) the "true" branch is used if recursion has
1696 happened, whereas the "false" branch is used only at the top level.
1697
1698 24. When there was a very long string of literal characters (over 255 bytes
1699 without UTF support, over 250 bytes with UTF support), the computation of how
1700 much memory was required could be incorrect, leading to segfaults or other
1701 strange effects.
1702
1703 25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1704 start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1705 there was a subsequent back reference to those brackets. This meant that, for
1706 example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1707 possible to check for precisely this case. All we can do is abandon the
1708 optimization if .* occurs inside capturing brackets when there are any back
1709 references whatsoever. (See below for a better fix that came later.)
1710
1711 26. The handling of the optimization for finding the first character of a
1712 non-anchored pattern, and for finding a character that is required later in the
1713 match were failing in some cases. This didn't break the matching; it just
1714 failed to optimize when it could. The way this is done has been re-implemented.
1715
1716 27. Fixed typo in error message for invalid (?R item (it said "(?p").
1717
1718 28. Added a new feature that provides some of the functionality that Perl
1719 provides with (?{...}). The facility is termed a "callout". The way it is done
1720 in PCRE is for the caller to provide an optional function, by setting
1721 pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1722 global variable. By default it is unset, which disables all calling out. To get
1723 the function called, the regex must include (?C) at appropriate points. This
1724 is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1725 This provides a means of identifying different callout points. When PCRE
1726 reaches such a point in the regex, if pcre_callout has been set, the external
1727 function is called. It is provided with data in a structure called
1728 pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1729 matching continues; if it returns a non-zero value, the match at the current
1730 point fails. However, backtracking will occur if possible. [This was changed
1731 later and other features added - see item 49 below.]
1732
1733 29. pcretest is upgraded to test the callout functionality. It provides a
1734 callout function that displays information. By default, it shows the start of
1735 the match and the current position in the text. There are some new data escapes
1736 to vary what happens:
1737
1738 \C+ in addition, show current contents of captured substrings
1739 \C- do not supply a callout function
1740 \C!n return 1 when callout number n is reached
1741 \C!n!m return 1 when callout number n is reached for the mth time
1742
1743 30. If pcregrep was called with the -l option and just a single file name, it
1744 output "<stdin>" if a match was found, instead of the file name.
1745
1746 31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1747 slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1748 pcre_exec(). This saves a malloc/free per call. The default value of
1749 POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1750 when configuring.
1751
1752 32. The default maximum size of a compiled pattern is 64K. There have been a
1753 few cases of people hitting this limit. The code now uses macros to handle the
1754 storing of links as offsets within the compiled pattern. It defaults to 2-byte
1755 links, but this can be changed to 3 or 4 bytes by --with-link-size when
1756 configuring. Tests 2 and 5 work only with 2-byte links because they output
1757 debugging information about compiled patterns.
1758
1759 33. Internal code re-arrangements:
1760
1761 (a) Moved the debugging function for printing out a compiled regex into
1762 its own source file (printint.c) and used #include to pull it into
1763 pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1764 separate copies.
1765
1766 (b) Defined the list of op-code names for debugging as a macro in
1767 internal.h so that it is next to the definition of the opcodes.
1768
1769 (c) Defined a table of op-code lengths for simpler skipping along compiled
1770 code. This is again a macro in internal.h so that it is next to the
1771 definition of the opcodes.
1772
1773 34. Added support for recursive calls to individual subpatterns, along the
1774 lines of Robin Houston's patch (but implemented somewhat differently).
1775
1776 35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1777 allow it to read and process whole directories in Win32. This code was
1778 contributed by Lionel Fourquaux; it has not been tested by me.
1779
1780 36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1781 used to name a group. Names consist of alphanumerics and underscores, and must
1782 be unique. Back references use the syntax (?P=name) and recursive calls use
1783 (?P>name) which is a PCRE extension to the Python extension. Groups still have
1784 numbers. The function pcre_fullinfo() can be used after compilation to extract
1785 a name/number map. There are three relevant calls:
1786
1787 PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1788 PCRE_INFO_NAMECOUNT yields the number of entries
1789 PCRE_INFO_NAMETABLE yields a pointer to the map.
1790
1791 The map is a vector of fixed-size entries. The size of each entry depends on
1792 the length of the longest name used. The first two bytes of each entry are the
1793 group number, most significant byte first. There follows the corresponding
1794 name, zero terminated. The names are in alphabetical order.
1795
1796 37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1797 case instead of 255. Making it the same both with and without UTF-8 support
1798 means that the same test output works with both.
1799
1800 38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1801 calling malloc() with a zero argument.
1802
1803 39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1804 optimization. I've improved things by keeping a bitmap of backreferences with
1805 numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1806 fact referenced, the optimization can be applied. It is unlikely that a
1807 relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1808 the match to follow \n) will appear inside brackets with a number greater than
1809 31, but if it does, any back reference > 31 suppresses the optimization.
1810
1811 40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1812 of disabling numbered capturing parentheses. Any opening parenthesis that is
1813 not followed by ? behaves as if it were followed by ?: but named parentheses
1814 can still be used for capturing (and they will acquire numbers in the usual
1815 way).
1816
1817 41. Redesigned the return codes from the match() function into yes/no/error so
1818 that errors can be passed back from deep inside the nested calls. A malloc
1819 failure while inside a recursive subpattern call now causes the
1820 PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1821
1822 42. It is now possible to set a limit on the number of times the match()
1823 function is called in a call to pcre_exec(). This facility makes it possible to
1824 limit the amount of recursion and backtracking, though not in a directly
1825 obvious way, because the match() function is used in a number of different
1826 circumstances. The count starts from zero for each position in the subject
1827 string (for non-anchored patterns). The default limit is, for compatibility, a
1828 large number, namely 10 000 000. You can change this in two ways:
1829
1830 (a) When configuring PCRE before making, you can use --with-match-limit=n
1831 to set a default value for the compiled library.
1832
1833 (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1834 a different value is set. See 45 below.
1835
1836 If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1837
1838 43. Added a new function pcre_config(int, void *) to enable run-time extraction
1839 of things that can be changed at compile time. The first argument specifies
1840 what is wanted and the second points to where the information is to be placed.
1841 The current list of available information is:
1842
1843 PCRE_CONFIG_UTF8
1844
1845 The output is an integer that is set to one if UTF-8 support is available;
1846 otherwise it is set to zero.
1847
1848 PCRE_CONFIG_NEWLINE
1849
1850 The output is an integer that it set to the value of the code that is used for
1851 newline. It is either LF (10) or CR (13).
1852
1853 PCRE_CONFIG_LINK_SIZE
1854
1855 The output is an integer that contains the number of bytes used for internal
1856 linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1857
1858 PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1859
1860 The output is an integer that contains the threshold above which the POSIX
1861 interface uses malloc() for output vectors. See item 31 above.
1862
1863 PCRE_CONFIG_MATCH_LIMIT
1864
1865 The output is an unsigned integer that contains the default limit of the number
1866 of match() calls in a pcre_exec() execution. See 42 above.
1867
1868 44. pcretest has been upgraded by the addition of the -C option. This causes it
1869 to extract all the available output from the new pcre_config() function, and to
1870 output it. The program then exits immediately.
1871
1872 45. A need has arisen to pass over additional data with calls to pcre_exec() in
1873 order to support additional features. One way would have been to define
1874 pcre_exec2() (for example) with extra arguments, but this would not have been
1875 extensible, and would also have required all calls to the original function to
1876 be mapped to the new one. Instead, I have chosen to extend the mechanism that
1877 is used for passing in "extra" data from pcre_study().
1878
1879 The pcre_extra structure is now exposed and defined in pcre.h. It currently
1880 contains the following fields:
1881
1882 flags a bitmap indicating which of the following fields are set
1883 study_data opaque data from pcre_study()
1884 match_limit a way of specifying a limit on match() calls for a specific
1885 call to pcre_exec()
1886 callout_data data for callouts (see 49 below)
1887
1888 The flag bits are also defined in pcre.h, and are
1889
1890 PCRE_EXTRA_STUDY_DATA
1891 PCRE_EXTRA_MATCH_LIMIT
1892 PCRE_EXTRA_CALLOUT_DATA
1893
1894 The pcre_study() function now returns one of these new pcre_extra blocks, with
1895 the actual study data pointed to by the study_data field, and the
1896 PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1897 before. That is, this change is entirely upwards-compatible and requires no
1898 change to existing code.
1899
1900 If you want to pass in additional data to pcre_exec(), you can either place it
1901 in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1902 block.
1903
1904 46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1905 data string contains the escape sequence \M, pcretest calls pcre_exec() several
1906 times with different match limits, until it finds the minimum value needed for
1907 pcre_exec() to complete. The value is then output. This can be instructive; for
1908 most simple matches the number is quite small, but for pathological cases it
1909 gets very large very quickly.
1910
1911 47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1912 returns the size of the data block pointed to by the study_data field in a
1913 pcre_extra block, that is, the value that was passed as the argument to
1914 pcre_malloc() when PCRE was getting memory in which to place the information
1915 created by pcre_study(). The fourth argument should point to a size_t variable.
1916 pcretest has been extended so that this information is shown after a successful
1917 pcre_study() call when information about the compiled regex is being displayed.
1918
1919 48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1920 because what follows is always an absolute path. (Later: it turns out that this
1921 is more than cosmetic for MinGW, because it doesn't like empty path
1922 components.)
1923
1924 49. Some changes have been made to the callout feature (see 28 above):
1925
1926 (i) A callout function now has three choices for what it returns:
1927
1928 0 => success, carry on matching
1929 > 0 => failure at this point, but backtrack if possible
1930 < 0 => serious error, return this value from pcre_exec()
1931
1932 Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1933 values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1934 "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1935 use by callout functions. It will never be used by PCRE itself.
1936
1937 (ii) The pcre_extra structure (see 45 above) has a void * field called
1938 callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1939 pcre_callout_block structure has a field of the same name. The contents of
1940 the field passed in the pcre_extra structure are passed to the callout
1941 function in the corresponding field in the callout block. This makes it
1942 easier to use the same callout-containing regex from multiple threads. For
1943 testing, the pcretest program has a new data escape
1944
1945 \C*n pass the number n (may be negative) as callout_data
1946
1947 If the callout function in pcretest receives a non-zero value as
1948 callout_data, it returns that value.
1949
1950 50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1951 there were some redundant $(CFLAGS) in commands that are now specified as
1952 $(LINK), which already includes $(CFLAGS).
1953
1954 51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1955 has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1956 with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1957 one-byte characters throughout. Note that case-insensitive matching applies
1958 only to characters whose values are less than 256. PCRE doesn't support the
1959 notion of cases for higher-valued characters.
1960
1961 (i) A character class whose characters are all within 0-255 is handled as
1962 a bit map, and the map is inverted for negative classes. Previously, a
1963 character > 255 always failed to match such a class; however it should
1964 match if the class was a negative one (e.g. [^ab]). This has been fixed.
1965
1966 (ii) A negated character class with a single character < 255 is coded as
1967 "not this character" (OP_NOT). This wasn't working properly when the test
1968 character was multibyte, either singly or repeated.
1969
1970 (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1971 mode, for example: \x{100}{2,3}.
1972
1973 (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1974 singly or repeated) now correctly test multibyte characters. However,
1975 PCRE doesn't recognize any characters with values greater than 255 as
1976 digits, spaces, or word characters. Such characters always match \D, \S,
1977 and \W, and never match \d, \s, or \w.
1978
1979 (v) Classes may now contain characters and character ranges with values
1980 greater than 255. For example: [ab\x{100}-\x{400}].
1981
1982 (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1983 PCRE in UTF-8 mode.
1984
1985 52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1986 PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1987 retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1988 value.)
1989
1990 53. The single man page has become too large. I have therefore split it up into
1991 a number of separate man pages. These also give rise to individual HTML pages;
1992 these are now put in a separate directory, and there is an index.html page that
1993 lists them all. Some hyperlinking between the pages has been installed.
1994
1995 54. Added convenience functions for handling named capturing parentheses.
1996
1997 55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1998 aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1999 true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2000 are faulted.
2001
2002 56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2003 calling configure. These values are used when compiling the dftables.c program
2004 which is run to generate the source of the default character tables. They
2005 default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2006 you will need to set these values.
2007
2008 57. Updated the building process for Windows DLL, as provided by Fred Cox.
2009
2010
2011 Version 3.9 02-Jan-02
2012 ---------------------
2013
2014 1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2015
2016 2. If --disable-static was given, the building process failed when trying to
2017 build pcretest and pcregrep. (For some reason it was using libtool to compile
2018 them, which is not right, as they aren't part of the library.)
2019
2020
2021 Version 3.8 18-Dec-01
2022 ---------------------
2023
2024 1. The experimental UTF-8 code was completely screwed up. It was packing the
2025 bytes in the wrong order. How dumb can you get?
2026
2027
2028 Version 3.7 29-Oct-01
2029 ---------------------
2030
2031 1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2032 This caused pcretest, when used on the test data, to segfault. Unfortunately,
2033 this didn't happen under Solaris 8, where I normally test things.
2034
2035 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2036 doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2037 isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2038 this fix an hour or so after the initial 3.7 release.)
2039
2040
2041 Version 3.6 23-Oct-01
2042 ---------------------
2043
2044 1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2045 offsets passed as NULL with zero offset count.
2046
2047 2. The config.guess and config.sub files had not been updated when I moved to
2048 the latest autoconf.
2049
2050
2051 Version 3.5 15-Aug-01
2052 ---------------------
2053
2054 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2055 had been forgotten.
2056
2057 2. By using declared but undefined structures, we can avoid using "void"
2058 definitions in pcre.h while keeping the internal definitions of the structures
2059 private.
2060
2061 3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2062 user point of view, this means that both static and shared libraries are built
2063 by default, but this can be individually controlled. More of the work of
2064 handling this static/shared cases is now inside libtool instead of PCRE's make
2065 file.
2066
2067 4. The pcretest utility is now installed along with pcregrep because it is
2068 useful for users (to test regexs) and by doing this, it automatically gets
2069 relinked by libtool. The documentation has been turned into a man page, so
2070 there are now .1, .txt, and .html versions in /doc.
2071
2072 5. Upgrades to pcregrep:
2073 (i) Added long-form option names like gnu grep.
2074 (ii) Added --help to list all options with an explanatory phrase.
2075 (iii) Added -r, --recursive to recurse into sub-directories.
2076 (iv) Added -f, --file to read patterns from a file.
2077
2078 6. pcre_exec() was referring to its "code" argument before testing that
2079 argument for NULL (and giving an error if it was NULL).
2080
2081 7. Upgraded Makefile.in to allow for compiling in a different directory from
2082 the source directory.
2083
2084 8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2085 options bits, the pointer it was passed was to an int instead of to an unsigned
2086 long int. This mattered only on 64-bit systems.
2087
2088 9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2089 generated) instead of pcre.in, which it its source. Also made the same change
2090 in several of the .c files.
2091
2092 10. A new release of gcc defines printf() as a macro, which broke pcretest
2093 because it had an ifdef in the middle of a string argument for printf(). Fixed
2094 by using separate calls to printf().
2095
2096 11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2097 script, to force use of CR or LF instead of \n in the source. On non-Unix
2098 systems, the value can be set in config.h.
2099
2100 12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2101 absolute limit. Changed the text of the error message to make this clear, and
2102 likewise updated the man page.
2103
2104 13. The limit of 99 on the number of capturing subpatterns has been removed.
2105 The new limit is 65535, which I hope will not be a "real" limit.
2106
2107
2108 Version 3.4 22-Aug-00
2109 ---------------------
2110
2111 1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2112
2113 2. Diagnose condition (?(0) as an error instead of crashing on matching.
2114
2115
2116 Version 3.3 01-Aug-00
2117 ---------------------
2118
2119 1. If an octal character was given, but the value was greater than \377, it
2120 was not getting masked to the least significant bits, as documented. This could
2121 lead to crashes in some systems.
2122
2123 2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2124 the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2125
2126 3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2127 These just pass their arguments on to (pcre_free)(), but they are provided
2128 because some uses of PCRE bind it to non-C systems that can call its functions,
2129 but cannot call free() or pcre_free() directly.
2130
2131 4. Add "make test" as a synonym for "make check". Corrected some comments in
2132 the Makefile.
2133
2134 5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2135 Makefile.
2136
2137 6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2138 command called pgrep for grepping around the active processes.
2139
2140 7. Added the beginnings of support for UTF-8 character strings.
2141
2142 8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2143 RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2144 the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2145 out for the ar command.)
2146
2147
2148 Version 3.2 12-May-00
2149 ---------------------
2150
2151 This is purely a bug fixing release.
2152
2153 1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2154 of ZA. This was just one example of several cases that could provoke this bug,
2155 which was introduced by change 9 of version 2.00. The code for breaking
2156 infinite loops after an iteration that matches an empty string was't working
2157 correctly.
2158
2159 2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2160 when matched against abbab (for example). After matching an empty string, it
2161 wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2162 caused it to match further down the string than it should.
2163
2164 3. The code contained an inclusion of sys/types.h. It isn't clear why this
2165 was there because it doesn't seem to be needed, and it causes trouble on some
2166 systems, as it is not a Standard C header. It has been removed.
2167
2168 4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2169 were reported on the Macintosh. The changes were from
2170
2171 while ((c = *(++ptr)) != 0 && c != '\n');
2172 to
2173 while ((c = *(++ptr)) != 0 && c != '\n') ;
2174
2175 Totally extraordinary, but if that's what it takes...
2176
2177 5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2178 available. Added HAVE_BCOPY and an autoconf test for it; if neither
2179 HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2180 assumes the way PCRE uses memmove() (always moving upwards).
2181
2182 6. PCRE is being used in one environment where strchr() is not available. There
2183 was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2184 faster code anyway.
2185
2186
2187 Version 3.1 09-Feb-00
2188 ---------------------
2189
2190 The only change in this release is the fixing of some bugs in Makefile.in for
2191 the "install" target:
2192
2193 (1) It was failing to install pcreposix.h.
2194
2195 (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2196
2197
2198 Version 3.0 01-Feb-00
2199 ---------------------
2200
2201 1. Add support for the /+ modifier to perltest (to output $` like it does in
2202 pcretest).
2203
2204 2. Add support for the /g modifier to perltest.
2205
2206 3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2207 matches null strings.
2208
2209 4. Fix perltest so that it doesn't do unwanted things when fed an empty
2210 pattern. Perl treats empty patterns specially - it reuses the most recent
2211 pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2212 effect.
2213
2214 5. The POSIX interface was broken in that it was just handing over the POSIX
2215 captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2216 required a bigger vector, with some working space on the end. This means that
2217 the POSIX wrapper now has to get and free some memory, and copy the results.
2218
2219 6. Added some simple autoconf support, placing the test data and the
2220 documentation in separate directories, re-organizing some of the
2221 information files, and making it build pcre-config (a GNU standard). Also added
2222 libtool support for building PCRE as a shared library, which is now the
2223 default.
2224
2225 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2226 09 are not valid octal constants. Single digits will be used for minor values
2227 less than 10.
2228
2229 8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2230 existing programs that set these in the POSIX interface can use PCRE without
2231 modification.
2232
2233 9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2234 return all that pcre_info() returns, plus additional data. The pcre_info()
2235 function is retained for compatibility, but is considered to be obsolete.
2236
2237 10. Added experimental recursion feature (?R) to handle one common case that
2238 Perl 5.6 will be able to do with (?p{...}).
2239
2240 11. Added support for POSIX character classes like [:alpha:], which Perl is
2241 adopting.
2242
2243
2244 Version 2.08 31-Aug-99
2245 ----------------------
2246
2247 1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2248 trying to match at the startoffset position, but instead was moving forward to
2249 the next newline as if a previous match had failed.
2250
2251 2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2252 and could get into a loop if a null string was matched other than at the start
2253 of the subject.
2254
2255 3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2256 be distinguished at compile time, and for completeness also added PCRE_DATE.
2257
2258 5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2259 in GnuWin32 environments.
2260
2261
2262 Version 2.07 29-Jul-99
2263 ----------------------
2264
2265 1. The documentation is now supplied in plain text form and HTML as well as in
2266 the form of man page sources.
2267
2268 2. C++ compilers don't like assigning (void *) values to other pointer types.
2269 In particular this affects malloc(). Although there is no problem in Standard
2270 C, I've put in casts to keep C++ compilers happy.
2271
2272 3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2273 should be (const char *).
2274
2275 4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2276 be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2277 However, I haven't made this a standard facility. The documentation doesn't
2278 mention it, and the Makefile doesn't support it.
2279
2280 5. The Makefile now contains an "install" target, with editable destinations at
2281 the top of the file. The pcretest program is not installed.
2282
2283 6. pgrep -V now gives the PCRE version number and date.
2284
2285 7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2286 causing the entire string to be ignored, instead of just the last character.
2287
2288 8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2289 non-matching string, it can take a very, very long time, even for strings of
2290 quite modest length, because of the nested recursion. PCRE now does better in
2291 some of these cases. It does this by remembering the last required literal
2292 character in the pattern, and pre-searching the subject to ensure it is present
2293 before running the real match. In other words, it applies a heuristic to detect
2294 some types of certain failure quickly, and in the above example, if presented
2295 with a string that has no trailing " it gives "no match" very quickly.
2296
2297 9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2298 other alternatives are tried instead.
2299
2300
2301 Version 2.06 09-Jun-99
2302 ----------------------
2303
2304 1. Change pcretest's output for amount of store used to show just the code
2305 space, because the remainder (the data block) varies in size between 32-bit and
2306 64-bit systems.
2307
2308 2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2309 start matching at. This allows lookbehinds to work when searching for multiple
2310 occurrences in a string.
2311
2312 3. Added additional options to pcretest for testing multiple occurrences:
2313
2314 /+ outputs the rest of the string that follows a match
2315 /g loops for multiple occurrences, using the new startoffset argument
2316 /G loops for multiple occurrences by passing an incremented pointer
2317
2318 4. PCRE wasn't doing the "first character" optimization for patterns starting
2319 with \b or \B, though it was doing it for other lookbehind assertions. That is,
2320 it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2321 the letter 'x'. On long subject strings, this gives a significant speed-up.
2322
2323
2324 Version 2.05 21-Apr-99
2325 ----------------------
2326
2327 1. Changed the type of magic_number from int to long int so that it works
2328 properly on 16-bit systems.
2329
2330 2. Fixed a bug which caused patterns starting with .* not to work correctly
2331 when the subject string contained newline characters. PCRE was assuming
2332 anchoring for such patterns in all cases, which is not correct because .* will
2333 not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2334 DOTALL is set at top level; otherwise it knows that patterns starting with .*
2335 must be retried after every newline in the subject.
2336
2337
2338 Version 2.04 18-Feb-99
2339 ----------------------
2340
2341 1. For parenthesized subpatterns with repeats whose minimum was zero, the
2342 computation of the store needed to hold the pattern was incorrect (too large).
2343 If such patterns were nested a few deep, this could multiply and become a real
2344 problem.
2345
2346 2. Added /M option to pcretest to show the memory requirement of a specific
2347 pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2348
2349 3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2350 compiled in such a way that the backtracking after subsequent failure was
2351 pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2352 ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2353
2354
2355 Version 2.03 02-Feb-99
2356 ----------------------
2357
2358 1. Fixed typo and small mistake in man page.
2359
2360 2. Added 4th condition (GPL supersedes if conflict) and created separate
2361 LICENCE file containing the conditions.
2362
2363 3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2364 Perl, that is the internal \ allows the delimiter to be included in the
2365 pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2366 the final delimiter, add \ to the end of the pattern (to test the error).
2367
2368 4. Added the convenience functions for extracting substrings after a successful
2369 match. Updated pcretest to make it able to test these functions.
2370
2371
2372 Version 2.02 14-Jan-99
2373 ----------------------
2374
2375 1. Initialized the working variables associated with each extraction so that
2376 their saving and restoring doesn't refer to uninitialized store.
2377
2378 2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2379 compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2380 fix the problem.
2381
2382 3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2383 calls, and wasn't printing the correct value for compiling calls. Increased the
2384 default value of LOOPREPEAT, and the number of significant figures in the
2385 times.
2386
2387 4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2388
2389 5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2390 a building problem on Windows NT with a FAT file system.
2391
2392
2393 Version 2.01 21-Oct-98
2394 ----------------------
2395
2396 1. Changed the API for pcre_compile() to allow for the provision of a pointer
2397 to character tables built by pcre_maketables() in the current locale. If NULL
2398 is passed, the default tables are used.
2399
2400
2401 Version 2.00 24-Sep-98
2402 ----------------------
2403
2404 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2405 it any more.
2406
2407 2. Allow quantification of (?>) groups, and make it work correctly.
2408
2409 3. The first character computation wasn't working for (?>) groups.
2410
2411 4. Correct the implementation of \Z (it is permitted to match on the \n at the
2412 end of the subject) and add 5.005's \z, which really does match only at the
2413 very end of the subject.
2414
2415 5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2416
2417 6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2418 DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2419 localized options. All options to pcre_study() were also removed.
2420
2421 7. Add other new features from 5.005:
2422
2423 $(?<= positive lookbehind
2424 $(?<! negative lookbehind
2425 (?imsx-imsx) added the unsetting capability
2426 such a setting is global if at outer level; local otherwise
2427 (?imsx-imsx:) non-capturing groups with option setting
2428 (?(cond)re|re) conditional pattern matching
2429
2430 A backreference to itself in a repeated group matches the previous
2431 captured string.
2432
2433 8. General tidying up of studying (both automatic and via "study")
2434 consequential on the addition of new assertions.
2435
2436 9. As in 5.005, unlimited repeated groups that could match an empty substring
2437 are no longer faulted at compile time. Instead, the loop is forcibly broken at
2438 runtime if any iteration does actually match an empty substring.
2439
2440 10. Include the RunTest script in the distribution.
2441
2442 11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2443 discrepancies, some of which were old and were also with respect to 5.004. They
2444 have now been fixed.
2445
2446
2447 Version 1.09 28-Apr-98
2448 ----------------------
2449
2450 1. A negated single character class followed by a quantifier with a minimum
2451 value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2452 program crashes, or just wrong answers. This did not apply to negated classes
2453 containing more than one character, or to minima other than one.
2454
2455
2456 Version 1.08 27-Mar-98
2457 ----------------------
2458
2459 1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2460
2461 2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2462 latter must appear before anything that relies on it in the pattern.
2463
2464
2465 Version 1.07 16-Feb-98
2466 ----------------------
2467
2468 1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2469 repeat of a potentially empty string).
2470
2471
2472 Version 1.06 23-Jan-98
2473 ----------------------
2474
2475 1. Added Markus Oberhumer's little patches for C++.
2476
2477 2. Literal strings longer than 255 characters were broken.
2478
2479
2480 Version 1.05 23-Dec-97
2481 ----------------------
2482
2483 1. Negated character classes containing more than one character were failing if
2484 PCRE_CASELESS was set at run time.
2485
2486
2487 Version 1.04 19-Dec-97
2488 ----------------------
2489
2490 1. Corrected the man page, where some "const" qualifiers had been omitted.
2491
2492 2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2493 input syntax.
2494
2495 3. Fixed memory leak which occurred when a regex with back references was
2496 matched with an offsets vector that wasn't big enough. The temporary memory
2497 that is used in this case wasn't being freed if the match failed.
2498
2499 4. Tidied pcretest to ensure it frees memory that it gets.
2500
2501 5. Temporary memory was being obtained in the case where the passed offsets
2502 vector was exactly big enough.
2503
2504 6. Corrected definition of offsetof() from change 5 below.
2505
2506 7. I had screwed up change 6 below and broken the rules for the use of
2507 setjmp(). Now fixed.
2508
2509
2510 Version 1.03 18-Dec-97
2511 ----------------------
2512
2513 1. A erroneous regex with a missing opening parenthesis was correctly
2514 diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2515 on some systems.
2516
2517 2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2518 it was reported that one broken compiler failed on the former because "code" is
2519 also an independent variable.
2520
2521 3. The erroneous regex a[]b caused an array overrun reference.
2522
2523 4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2524 fail on data ending with that character. (It was going on too far, and checking
2525 the next character, typically a binary zero.) This was specific to the
2526 optimized code for single-character negative classes.
2527
2528 5. Added a contributed patch from the TIN world which does the following:
2529
2530 + Add an undef for memmove, in case the the system defines a macro for it.
2531
2532 + Add a definition of offsetof(), in case there isn't one. (I don't know
2533 the reason behind this - offsetof() is part of the ANSI standard - but
2534 it does no harm).
2535
2536 + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2537 most of the places where whitespace preceded '#'. I have given up and
2538 allowed the remaining 2 cases to be at the margin.
2539
2540 + Rename some variables in pcre to eliminate shadowing. This seems very
2541 pedantic, but does no harm, of course.
2542
2543 6. Moved the call to setjmp() into its own function, to get rid of warnings
2544 from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2545
2546 7. Constructs such as \d{8,} were compiling into the equivalent of
2547 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2548 outcome, but in this particular case used more store than had been allocated,
2549 which caused the bug to be discovered because it threw up an internal error.
2550
2551 8. The debugging code in both pcre and pcretest for outputting the compiled
2552 form of a regex was going wrong in the case of back references followed by
2553 curly-bracketed repeats.
2554
2555
2556 Version 1.02 12-Dec-97
2557 ----------------------
2558
2559 1. Typos in pcre.3 and comments in the source fixed.
2560
2561 2. Applied a contributed patch to get rid of places where it used to remove
2562 'const' from variables, and fixed some signed/unsigned and uninitialized
2563 variable warnings.
2564
2565 3. Added the "runtest" target to Makefile.
2566
2567 4. Set default compiler flag to -O2 rather than just -O.
2568
2569
2570 Version 1.01 19-Nov-97
2571 ----------------------
2572
2573 1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2574 like /([ab]*)*/, that is, for classes with more than one character in them.
2575
2576 2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2577 as /((?>a*))*/ (a PCRE_EXTRA facility).
2578
2579
2580 Version 1.00 18-Nov-97
2581 ----------------------
2582
2583 1. Added compile-time macros to support systems such as SunOS4 which don't have
2584 memmove() or strerror() but have other things that can be used instead.
2585
2586 2. Arranged that "make clean" removes the executables.
2587
2588
2589 Version 0.99 27-Oct-97
2590 ----------------------
2591
2592 1. Fixed bug in code for optimizing classes with only one character. It was
2593 initializing a 32-byte map regardless, which could cause it to run off the end
2594 of the memory it had got.
2595
2596 2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2597
2598
2599 Version 0.98 22-Oct-97
2600 ----------------------
2601
2602 1. Fixed bug in code for handling temporary memory usage when there are more
2603 back references than supplied space in the ovector. This could cause segfaults.
2604
2605
2606 Version 0.97 21-Oct-97
2607 ----------------------
2608
2609 1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2610
2611 2. Optimized negated single characters not to use a bit map.
2612
2613 3. Brought error texts together as macro definitions; clarified some of them;
2614 fixed one that was wrong - it said "range out of order" when it meant "invalid
2615 escape sequence".
2616
2617 4. Changed some char * arguments to const char *.
2618
2619 5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2620
2621 6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2622 pcretest.
2623
2624
2625 Version 0.96 16-Oct-97
2626 ----------------------
2627
2628 1. Added a simple "pgrep" utility to the distribution.
2629
2630 2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2631 unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2632 where "ddd" means "one or more decimal digits".
2633
2634 3. Fixed serious bug. If a pattern had a back reference, but the call to
2635 pcre_exec() didn't supply a large enough ovector to record the related
2636 identifying subpattern, the match always failed. PCRE now remembers the number
2637 of the largest back reference, and gets some temporary memory in which to save
2638 the offsets during matching if necessary, in order to ensure that
2639 backreferences always work.
2640
2641 4. Increased the compatibility with Perl in a number of ways:
2642
2643 (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2644 to request this handling. The option can be set at compile or exec time.
2645
2646 (b) $ matches before a terminating newline by default; an option
2647 PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2648 mode). The option can be set at compile or exec time.
2649
2650 (c) The handling of \ followed by a digit other than 0 is now supposed to be
2651 the same as Perl's. If the decimal number it represents is less than 10
2652 or there aren't that many previous left capturing parentheses, an octal
2653 escape is read. Inside a character class, it's always an octal escape,
2654 even if it is a single digit.
2655
2656 (d) An escaped but undefined alphabetic character is taken as a literal,
2657 unless PCRE_EXTRA is set. Currently this just reserves the remaining
2658 escapes.
2659
2660 (e) {0} is now permitted. (The previous item is removed from the compiled
2661 pattern).
2662
2663 5. Changed all the names of code files so that the basic parts are no longer
2664 than 10 characters, and abolished the teeny "globals.c" file.
2665
2666 6. Changed the handling of character classes; they are now done with a 32-byte
2667 bit map always.
2668
2669 7. Added the -d and /D options to pcretest to make it possible to look at the
2670 internals of compilation without having to recompile pcre.
2671
2672
2673 Version 0.95 23-Sep-97
2674 ----------------------
2675
2676 1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2677 \x20 at the start of a run of normal characters. These were being treated as
2678 real characters, instead of the source characters being re-checked.
2679
2680
2681 Version 0.94 18-Sep-97
2682 ----------------------
2683
2684 1. The functions are now thread-safe, with the caveat that the global variables
2685 containing pointers to malloc() and free() or alternative functions are the
2686 same for all threads.
2687
2688 2. Get pcre_study() to generate a bitmap of initial characters for non-
2689 anchored patterns when this is possible, and use it if passed to pcre_exec().
2690
2691
2692 Version 0.93 15-Sep-97
2693 ----------------------
2694
2695 1. /(b)|(:+)/ was computing an incorrect first character.
2696
2697 2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2698 but not actually doing anything yet.
2699
2700 3. Treat "-" characters in classes that cannot be part of ranges as literals,
2701 as Perl does (e.g. [-az] or [az-]).
2702
2703 4. Set the anchored flag if a branch starts with .* or .*? because that tests
2704 all possible positions.
2705
2706 5. Split up into different modules to avoid including unneeded functions in a
2707 compiled binary. However, compile and exec are still in one module. The "study"
2708 function is split off.
2709
2710 6. The character tables are now in a separate module whose source is generated
2711 by an auxiliary program - but can then be edited by hand if required. There are
2712 now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2713 toupper() in the code.
2714
2715 7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2716 make them global. Abolish the function for setting them, as the caller can now
2717 set them directly.
2718
2719
2720 Version 0.92 11-Sep-97
2721 ----------------------
2722
2723 1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2724 (e.g. /a{1,3}/) was broken (I mis-optimized it).
2725
2726 2. Caseless matching was not working in character classes if the characters in
2727 the pattern were in upper case.
2728
2729 3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2730
2731 4. Make PCRE_ANCHORED public and accept as a compile option.
2732
2733 5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2734 PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2735 pass them.
2736
2737 6. Give an error if bad option bits passed at compile or run time.
2738
2739 7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2740 pcretest to cause it to pass that flag.
2741
2742 8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2743 options, and the first character, if set.
2744
2745 9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2746
2747
2748 Version 0.91 10-Sep-97
2749 ----------------------
2750
2751 1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2752 match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2753
2754 2. PCRE was looping on encountering an indefinitely repeated back reference to
2755 a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2756 Perl does - treats the match as successful.
2757
2758 ****

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