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Revision 182 - (show annotations) (download)
Wed Jun 13 15:09:54 2007 UTC (7 years, 3 months ago) by ph10
File size: 129796 byte(s)
More document tidies, pre-release.

1 ChangeLog for PCRE
2 ------------------
3
4 Version 7.2 13-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 (g) (?| introduces a group in which the numbering of parentheses in each
45 alternative starts with the same number.
46
47 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
48
49 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
50 PCRE_INFO_JCHANGED.
51
52 8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
53 terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
54 for detecting groups that can match an empty string.
55
56 9. A pattern with a very large number of alternatives (more than several
57 hundred) was running out of internal workspace during the pre-compile
58 phase, where pcre_compile() figures out how much memory will be needed. A
59 bit of new cunning has reduced the workspace needed for groups with
60 alternatives. The 1000-alternative test pattern now uses 12 bytes of
61 workspace instead of running out of the 4096 that are available.
62
63 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
64
65 11. Applied patch from Google to remove an optimization that didn't quite work.
66 The report of the bug said:
67
68 pcrecpp::RE("a*").FullMatch("aaa") matches, while
69 pcrecpp::RE("a*?").FullMatch("aaa") does not, and
70 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
71
72
73 Version 7.1 24-Apr-07
74 ---------------------
75
76 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
77 that is more "standard", making use of automake and other Autotools. There
78 is some re-arrangement of the files and adjustment of comments consequent
79 on this.
80
81 2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
82 for recursive directory scanning broke on some systems because the files
83 are not scanned in any specific order and on different systems the order
84 was different. A call to "sort" has been inserted into RunGrepTest for the
85 approprate test as a short-term fix. In the longer term there may be an
86 alternative.
87
88 3. I had an email from Eric Raymond about problems translating some of PCRE's
89 man pages to HTML (despite the fact that I distribute HTML pages, some
90 people do their own conversions for various reasons). The problems
91 concerned the use of low-level troff macros .br and .in. I have therefore
92 removed all such uses from the man pages (some were redundant, some could
93 be replaced by .nf/.fi pairs). The 132html script that I use to generate
94 HTML has been updated to handle .nf/.fi and to complain if it encounters
95 .br or .in.
96
97 4. Updated comments in configure.ac that get placed in config.h.in and also
98 arranged for config.h to be included in the distribution, with the name
99 config.h.generic, for the benefit of those who have to compile without
100 Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
101
102 5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
103 Weber: (1) pcre_internal.h was missing some function renames; (2) updated
104 makevp.bat for the current PCRE, using the additional files
105 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
106
107 6. A Windows user reported a minor discrepancy with test 2, which turned out
108 to be caused by a trailing space on an input line that had got lost in his
109 copy. The trailing space was an accident, so I've just removed it.
110
111 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
112 that is needed.
113
114 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
115 as "const" (a) because they are and (b) because it helps the PHP
116 maintainers who have recently made a script to detect big data structures
117 in the php code that should be moved to the .rodata section. I remembered
118 to update Builducptable as well, so it won't revert if ucptable.h is ever
119 re-created.
120
121 9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
122 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
123 order to be able to cut out the UTF-8 tables in the latter when UTF-8
124 support is not required. This saves 1.5-2K of code, which is important in
125 some applications.
126
127 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
128 so as not to refer to the tables, even though these functions will never be
129 called when UTF-8 support is disabled. Otherwise there are problems with a
130 shared library.
131
132 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
133
134 (a) It was defining its arguments as char * instead of void *.
135
136 (b) It was assuming that all moves were upwards in memory; this was true
137 a long time ago when I wrote it, but is no longer the case.
138
139 The emulated memove() is provided for those environments that have neither
140 memmove() nor bcopy(). I didn't think anyone used it these days, but that
141 is clearly not the case, as these two bugs were recently reported.
142
143 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
144 and Detrail to create the HTML documentation, the .txt form of the man
145 pages, and it removes trailing spaces from listed files. It also creates
146 pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
147 case, it wraps all the #defines with #ifndefs. This script should be run
148 before "make dist".
149
150 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
151 with Unicode property support.
152
153 (a) For a maximizing quantifier, if the two different cases of the
154 character were of different lengths in their UTF-8 codings (there are
155 some cases like this - I found 11), and the matching function had to
156 back up over a mixture of the two cases, it incorrectly assumed they
157 were both the same length.
158
159 (b) When PCRE was configured to use the heap rather than the stack for
160 recursion during matching, it was not correctly preserving the data for
161 the other case of a UTF-8 character when checking ahead for a match
162 while processing a minimizing repeat. If the check also involved
163 matching a wide character, but failed, corruption could cause an
164 erroneous result when trying to check for a repeat of the original
165 character.
166
167 13. Some tidying changes to the testing mechanism:
168
169 (a) The RunTest script now detects the internal link size and whether there
170 is UTF-8 and UCP support by running ./pcretest -C instead of relying on
171 values substituted by "configure". (The RunGrepTest script already did
172 this for UTF-8.) The configure.ac script no longer substitutes the
173 relevant variables.
174
175 (b) The debugging options /B and /D in pcretest show the compiled bytecode
176 with length and offset values. This means that the output is different
177 for different internal link sizes. Test 2 is skipped for link sizes
178 other than 2 because of this, bypassing the problem. Unfortunately,
179 there was also a test in test 3 (the locale tests) that used /B and
180 failed for link sizes other than 2. Rather than cut the whole test out,
181 I have added a new /Z option to pcretest that replaces the length and
182 offset values with spaces. This is now used to make test 3 independent
183 of link size. (Test 2 will be tidied up later.)
184
185 14. If erroroffset was passed as NULL to pcre_compile, it provoked a
186 segmentation fault instead of returning the appropriate error message.
187
188 15. In multiline mode when the newline sequence was set to "any", the pattern
189 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
190 This doesn't seem right; it now treats the CRLF combination as the line
191 ending, and so does not match in that case. It's only a pattern such as ^$
192 that would hit this one: something like ^ABC$ would have failed after \r
193 and then tried again after \r\n.
194
195 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
196 in an attempt to make files that differ only in their line terminators
197 compare equal. This works on Linux.
198
199 17. Under certain error circumstances pcregrep might try to free random memory
200 as it exited. This is now fixed, thanks to valgrind.
201
202 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
203 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
204 was because its rules for how to advance for /g after matching an empty
205 string at the end of a line did not allow for this case. They now check for
206 it specially.
207
208 20. pcretest is supposed to handle patterns and data of any length, by
209 extending its buffers when necessary. It was getting this wrong when the
210 buffer for a data line had to be extended.
211
212 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
213 CRLF as a newline sequence.
214
215 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
216 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
217 I have nevertheless tidied it up.
218
219 23. Added some casts to kill warnings from HP-UX ia64 compiler.
220
221 24. Added a man page for pcre-config.
222
223
224 Version 7.0 19-Dec-06
225 ---------------------
226
227 1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
228 moving to gcc 4.1.1.
229
230 2. The -S option for pcretest uses setrlimit(); I had omitted to #include
231 sys/time.h, which is documented as needed for this function. It doesn't
232 seem to matter on Linux, but it showed up on some releases of OS X.
233
234 3. It seems that there are systems where bytes whose values are greater than
235 127 match isprint() in the "C" locale. The "C" locale should be the
236 default when a C program starts up. In most systems, only ASCII printing
237 characters match isprint(). This difference caused the output from pcretest
238 to vary, making some of the tests fail. I have changed pcretest so that:
239
240 (a) When it is outputting text in the compiled version of a pattern, bytes
241 other than 32-126 are always shown as hex escapes.
242
243 (b) When it is outputting text that is a matched part of a subject string,
244 it does the same, unless a different locale has been set for the match
245 (using the /L modifier). In this case, it uses isprint() to decide.
246
247 4. Fixed a major bug that caused incorrect computation of the amount of memory
248 required for a compiled pattern when options that changed within the
249 pattern affected the logic of the preliminary scan that determines the
250 length. The relevant options are -x, and -i in UTF-8 mode. The result was
251 that the computed length was too small. The symptoms of this bug were
252 either the PCRE error "internal error: code overflow" from pcre_compile(),
253 or a glibc crash with a message such as "pcretest: free(): invalid next
254 size (fast)". Examples of patterns that provoked this bug (shown in
255 pcretest format) are:
256
257 /(?-x: )/x
258 /(?x)(?-x: \s*#\s*)/
259 /((?i)[\x{c0}])/8
260 /(?i:[\x{c0}])/8
261
262 HOWEVER: Change 17 below makes this fix obsolete as the memory computation
263 is now done differently.
264
265 5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
266 wrapper classes; (b) implement a new function in the C++ scanner that is
267 more efficient than the old way of doing things because it avoids levels of
268 recursion in the regex matching; (c) add a paragraph to the documentation
269 for the FullMatch() function.
270
271 6. The escape sequence \n was being treated as whatever was defined as
272 "newline". Not only was this contrary to the documentation, which states
273 that \n is character 10 (hex 0A), but it also went horribly wrong when
274 "newline" was defined as CRLF. This has been fixed.
275
276 7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
277 was being set to -1 for the "end of line" case (supposedly a value that no
278 character can have). Though this value is never used (the check for end of
279 line is "zero bytes in current character"), it caused compiler complaints.
280 I've changed it to 0xffffffff.
281
282 8. In pcre_version.c, the version string was being built by a sequence of
283 C macros that, in the event of PCRE_PRERELEASE being defined as an empty
284 string (as it is for production releases) called a macro with an empty
285 argument. The C standard says the result of this is undefined. The gcc
286 compiler treats it as an empty string (which was what was wanted) but it is
287 reported that Visual C gives an error. The source has been hacked around to
288 avoid this problem.
289
290 9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
291 builds of pcretest, and changed the call to _setmode() to use _O_BINARY
292 instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
293 of them did).
294
295 10. Originally, pcretest opened its input and output without "b"; then I was
296 told that "b" was needed in some environments, so it was added for release
297 5.0 to both the input and output. (It makes no difference on Unix-like
298 systems.) Later I was told that it is wrong for the input on Windows. I've
299 now abstracted the modes into two macros, to make it easier to fiddle with
300 them, and removed "b" from the input mode under Windows.
301
302 11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
303
304 12. Added -help and --help to pcretest as an official way of being reminded
305 of the options.
306
307 13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
308 and pcrecpp.cc because they annoy compilers at high warning levels.
309
310 14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
311
312 15. Fixed an occurrence of == in configure.ac that should have been = (shell
313 scripts are not C programs :-) and which was not noticed because it works
314 on Linux.
315
316 16. pcretest is supposed to handle any length of pattern and data line (as one
317 line or as a continued sequence of lines) by extending its input buffer if
318 necessary. This feature was broken for very long pattern lines, leading to
319 a string of junk being passed to pcre_compile() if the pattern was longer
320 than about 50K.
321
322 17. I have done a major re-factoring of the way pcre_compile() computes the
323 amount of memory needed for a compiled pattern. Previously, there was code
324 that made a preliminary scan of the pattern in order to do this. That was
325 OK when PCRE was new, but as the facilities have expanded, it has become
326 harder and harder to keep it in step with the real compile phase, and there
327 have been a number of bugs (see for example, 4 above). I have now found a
328 cunning way of running the real compile function in a "fake" mode that
329 enables it to compute how much memory it would need, while actually only
330 ever using a few hundred bytes of working memory and without too many
331 tests of the mode. This should make future maintenance and development
332 easier. A side effect of this work is that the limit of 200 on the nesting
333 depth of parentheses has been removed (though this was never a serious
334 limitation, I suspect). However, there is a downside: pcre_compile() now
335 runs more slowly than before (30% or more, depending on the pattern). I
336 hope this isn't a big issue. There is no effect on runtime performance.
337
338 18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
339 newline (only possible for the last line of a file) and it was a
340 pattern that set a locale (followed by /Lsomething), pcretest crashed.
341
342 19. Added additional timing features to pcretest. (1) The -tm option now times
343 matching only, not compiling. (2) Both -t and -tm can be followed, as a
344 separate command line item, by a number that specifies the number of
345 repeats to use when timing. The default is 50000; this gives better
346 precision, but takes uncomfortably long for very large patterns.
347
348 20. Extended pcre_study() to be more clever in cases where a branch of a
349 subpattern has no definite first character. For example, (a*|b*)[cd] would
350 previously give no result from pcre_study(). Now it recognizes that the
351 first character must be a, b, c, or d.
352
353 21. There was an incorrect error "recursive call could loop indefinitely" if
354 a subpattern (or the entire pattern) that was being tested for matching an
355 empty string contained only one non-empty item after a nested subpattern.
356 For example, the pattern (?>\x{100}*)\d(?R) provoked this error
357 incorrectly, because the \d was being skipped in the check.
358
359 22. The pcretest program now has a new pattern option /B and a command line
360 option -b, which is equivalent to adding /B to every pattern. This causes
361 it to show the compiled bytecode, without the additional information that
362 -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
363 is the same as /B/I).
364
365 23. A new optimization is now able automatically to treat some sequences such
366 as a*b as a*+b. More specifically, if something simple (such as a character
367 or a simple class like \d) has an unlimited quantifier, and is followed by
368 something that cannot possibly match the quantified thing, the quantifier
369 is automatically "possessified".
370
371 24. A recursive reference to a subpattern whose number was greater than 39
372 went wrong under certain circumstances in UTF-8 mode. This bug could also
373 have affected the operation of pcre_study().
374
375 25. Realized that a little bit of performance could be had by replacing
376 (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
377
378 26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
379
380 27. Possessive quantifiers such as a++ were previously implemented by turning
381 them into atomic groups such as ($>a+). Now they have their own opcodes,
382 which improves performance. This includes the automatically created ones
383 from 23 above.
384
385 28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
386 lookahead was broken if it was not anchored. PCRE was mistakenly expecting
387 the first matched character to be a colon. This applied both to named and
388 numbered groups.
389
390 29. The ucpinternal.h header file was missing its idempotency #ifdef.
391
392 30. I was sent a "project" file called libpcre.a.dev which I understand makes
393 building PCRE on Windows easier, so I have included it in the distribution.
394
395 31. There is now a check in pcretest against a ridiculously large number being
396 returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
397 loop, the loop is abandoned.
398
399 32. Forward references to subpatterns in conditions such as (?(2)...) where
400 subpattern 2 is defined later cause pcre_compile() to search forwards in
401 the pattern for the relevant set of parentheses. This search went wrong
402 when there were unescaped parentheses in a character class, parentheses
403 escaped with \Q...\E, or parentheses in a #-comment in /x mode.
404
405 33. "Subroutine" calls and backreferences were previously restricted to
406 referencing subpatterns earlier in the regex. This restriction has now
407 been removed.
408
409 34. Added a number of extra features that are going to be in Perl 5.10. On the
410 whole, these are just syntactic alternatives for features that PCRE had
411 previously implemented using the Python syntax or my own invention. The
412 other formats are all retained for compatibility.
413
414 (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
415 as (?P<name>...). The new forms, as well as being in Perl 5.10, are
416 also .NET compatible.
417
418 (b) A recursion or subroutine call to a named group can now be defined as
419 (?&name) as well as (?P>name).
420
421 (c) A backreference to a named group can now be defined as \k<name> or
422 \k'name' as well as (?P=name). The new forms, as well as being in Perl
423 5.10, are also .NET compatible.
424
425 (d) A conditional reference to a named group can now use the syntax
426 (?(<name>) or (?('name') as well as (?(name).
427
428 (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
429 groups (named and numbered) that are never evaluated inline, but can be
430 called as "subroutines" from elsewhere. In effect, the DEFINE condition
431 is always false. There may be only one alternative in such a group.
432
433 (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
434 as the simple (?(R). The condition is true only if the most recent
435 recursion is that of the given number or name. It does not search out
436 through the entire recursion stack.
437
438 (g) The escape \gN or \g{N} has been added, where N is a positive or
439 negative number, specifying an absolute or relative reference.
440
441 35. Tidied to get rid of some further signed/unsigned compiler warnings and
442 some "unreachable code" warnings.
443
444 36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
445 things, this adds five new scripts.
446
447 37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
448 There were also incompatibilities regarding the handling of \Q..\E inside
449 character classes, for example with patterns like [\Qa\E-\Qz\E] where the
450 hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
451
452 38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
453 matches an empty string, and forcibly breaks the loop. There were bugs in
454 this code in non-simple cases. For a pattern such as ^(a()*)* matched
455 against aaaa the result was just "a" rather than "aaaa", for example. Two
456 separate and independent bugs (that affected different cases) have been
457 fixed.
458
459 39. Refactored the code to abolish the use of different opcodes for small
460 capturing bracket numbers. This is a tidy that I avoided doing when I
461 removed the limit on the number of capturing brackets for 3.5 back in 2001.
462 The new approach is not only tidier, it makes it possible to reduce the
463 memory needed to fix the previous bug (38).
464
465 40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
466 sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
467 processing dot, circumflex, or dollar metacharacters, or #-comments in /x
468 mode.
469
470 41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
471 report.
472
473 42. Applied patch, originally from Ari Pollak, modified by Google, to allow
474 copy construction and assignment in the C++ wrapper.
475
476 43. Updated pcregrep to support "--newline=any". In the process, I fixed a
477 couple of bugs that could have given wrong results in the "--newline=crlf"
478 case.
479
480 44. Added a number of casts and did some reorganization of signed/unsigned int
481 variables following suggestions from Dair Grant. Also renamed the variable
482 "this" as "item" because it is a C++ keyword.
483
484 45. Arranged for dftables to add
485
486 #include "pcre_internal.h"
487
488 to pcre_chartables.c because without it, gcc 4.x may remove the array
489 definition from the final binary if PCRE is built into a static library and
490 dead code stripping is activated.
491
492 46. For an unanchored pattern, if a match attempt fails at the start of a
493 newline sequence, and the newline setting is CRLF or ANY, and the next two
494 characters are CRLF, advance by two characters instead of one.
495
496
497 Version 6.7 04-Jul-06
498 ---------------------
499
500 1. In order to handle tests when input lines are enormously long, pcretest has
501 been re-factored so that it automatically extends its buffers when
502 necessary. The code is crude, but this _is_ just a test program. The
503 default size has been increased from 32K to 50K.
504
505 2. The code in pcre_study() was using the value of the re argument before
506 testing it for NULL. (Of course, in any sensible call of the function, it
507 won't be NULL.)
508
509 3. The memmove() emulation function in pcre_internal.h, which is used on
510 systems that lack both memmove() and bcopy() - that is, hardly ever -
511 was missing a "static" storage class specifier.
512
513 4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
514 containing an extended class (one that cannot be represented by a bitmap
515 because it contains high-valued characters or Unicode property items, e.g.
516 [\pZ]). Almost always one would set UTF-8 mode when processing such a
517 pattern, but PCRE should not loop if you do not (it no longer does).
518 [Detail: two cases were found: (a) a repeated subpattern containing an
519 extended class; (b) a recursive reference to a subpattern that followed a
520 previous extended class. It wasn't skipping over the extended class
521 correctly when UTF-8 mode was not set.]
522
523 5. A negated single-character class was not being recognized as fixed-length
524 in lookbehind assertions such as (?<=[^f]), leading to an incorrect
525 compile error "lookbehind assertion is not fixed length".
526
527 6. The RunPerlTest auxiliary script was showing an unexpected difference
528 between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
529 write a Perl script that can interpret lines of an input file either as
530 byte characters or as UTF-8, which is what "perltest" was being required to
531 do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
532 can't do is switch easily at run time between having the "use utf8;" pragma
533 or not. In the end, I fudged it by using the RunPerlTest script to insert
534 "use utf8;" explicitly for the UTF-8 tests.
535
536 7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
537 the end of the subject string, contrary to the documentation and to what
538 Perl does. This was true of both matching functions. Now it matches only at
539 the start of the subject and immediately after *internal* newlines.
540
541 8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
542 a pointer to an int instead of a pointer to an unsigned long int. This
543 caused problems on 64-bit systems.
544
545 9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
546 instance of the 'standard' template library not being so standard".
547
548 10. There was no check on the number of named subpatterns nor the maximum
549 length of a subpattern name. The product of these values is used to compute
550 the size of the memory block for a compiled pattern. By supplying a very
551 long subpattern name and a large number of named subpatterns, the size
552 computation could be caused to overflow. This is now prevented by limiting
553 the length of names to 32 characters, and the number of named subpatterns
554 to 10,000.
555
556 11. Subpatterns that are repeated with specific counts have to be replicated in
557 the compiled pattern. The size of memory for this was computed from the
558 length of the subpattern and the repeat count. The latter is limited to
559 65535, but there was no limit on the former, meaning that integer overflow
560 could in principle occur. The compiled length of a repeated subpattern is
561 now limited to 30,000 bytes in order to prevent this.
562
563 12. Added the optional facility to have named substrings with the same name.
564
565 13. Added the ability to use a named substring as a condition, using the
566 Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
567 are numbers (not recommended). Forward references are permitted.
568
569 14. Added forward references in named backreferences (if you see what I mean).
570
571 15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
572 pattern could run off the end of the subject. For example, the pattern
573 "(?s)(.{1,5})"8 did this with the subject "ab".
574
575 16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
576 PCRE_CASELESS was set when matching characters that were quantified with ?
577 or *.
578
579 17. A character class other than a single negated character that had a minimum
580 but no maximum quantifier - for example [ab]{6,} - was not handled
581 correctly by pce_dfa_exec(). It would match only one character.
582
583 18. A valid (though odd) pattern that looked like a POSIX character
584 class but used an invalid character after [ (for example [[,abc,]]) caused
585 pcre_compile() to give the error "Failed: internal error: code overflow" or
586 in some cases to crash with a glibc free() error. This could even happen if
587 the pattern terminated after [[ but there just happened to be a sequence of
588 letters, a binary zero, and a closing ] in the memory that followed.
589
590 19. Perl's treatment of octal escapes in the range \400 to \777 has changed
591 over the years. Originally (before any Unicode support), just the bottom 8
592 bits were taken. Thus, for example, \500 really meant \100. Nowadays the
593 output from "man perlunicode" includes this:
594
595 The regular expression compiler produces polymorphic opcodes. That
596 is, the pattern adapts to the data and automatically switches to
597 the Unicode character scheme when presented with Unicode data--or
598 instead uses a traditional byte scheme when presented with byte
599 data.
600
601 Sadly, a wide octal escape does not cause a switch, and in a string with
602 no other multibyte characters, these octal escapes are treated as before.
603 Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
604 /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
605 Unicode string.
606
607 I have not perpetrated such confusion in PCRE. Up till now, it took just
608 the bottom 8 bits, as in old Perl. I have now made octal escapes with
609 values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
610 translate to the appropriate multibyte character.
611
612 29. Applied some refactoring to reduce the number of warnings from Microsoft
613 and Borland compilers. This has included removing the fudge introduced
614 seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
615 a warning about an unused variable.
616
617 21. PCRE has not included VT (character 0x0b) in the set of whitespace
618 characters since release 4.0, because Perl (from release 5.004) does not.
619 [Or at least, is documented not to: some releases seem to be in conflict
620 with the documentation.] However, when a pattern was studied with
621 pcre_study() and all its branches started with \s, PCRE still included VT
622 as a possible starting character. Of course, this did no harm; it just
623 caused an unnecessary match attempt.
624
625 22. Removed a now-redundant internal flag bit that recorded the fact that case
626 dependency changed within the pattern. This was once needed for "required
627 byte" processing, but is no longer used. This recovers a now-scarce options
628 bit. Also moved the least significant internal flag bit to the most-
629 significant bit of the word, which was not previously used (hangover from
630 the days when it was an int rather than a uint) to free up another bit for
631 the future.
632
633 23. Added support for CRLF line endings as well as CR and LF. As well as the
634 default being selectable at build time, it can now be changed at runtime
635 via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
636 specify that it is scanning data with non-default line endings.
637
638 24. Changed the definition of CXXLINK to make it agree with the definition of
639 LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
640
641 25. Applied Ian Taylor's patches to avoid using another stack frame for tail
642 recursions. This makes a big different to stack usage for some patterns.
643
644 26. If a subpattern containing a named recursion or subroutine reference such
645 as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
646 the space required for the compiled pattern went wrong and gave too small a
647 value. Depending on the environment, this could lead to "Failed: internal
648 error: code overflow at offset 49" or "glibc detected double free or
649 corruption" errors.
650
651 27. Applied patches from Google (a) to support the new newline modes and (b) to
652 advance over multibyte UTF-8 characters in GlobalReplace.
653
654 28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
655 difference for some implementation of PCRE in some Windows version.
656
657 29. Added some extra testing facilities to pcretest:
658
659 \q<number> in a data line sets the "match limit" value
660 \Q<number> in a data line sets the "match recursion limt" value
661 -S <number> sets the stack size, where <number> is in megabytes
662
663 The -S option isn't available for Windows.
664
665
666 Version 6.6 06-Feb-06
667 ---------------------
668
669 1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
670 in pcreposix.h. I have copied the definition from pcre.h.
671
672 2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
673 because pcre.h is no longer a built file.
674
675 3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
676 not normally included in the compiled code.
677
678
679 Version 6.5 01-Feb-06
680 ---------------------
681
682 1. When using the partial match feature with pcre_dfa_exec(), it was not
683 anchoring the second and subsequent partial matches at the new starting
684 point. This could lead to incorrect results. For example, with the pattern
685 /1234/, partially matching against "123" and then "a4" gave a match.
686
687 2. Changes to pcregrep:
688
689 (a) All non-match returns from pcre_exec() were being treated as failures
690 to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
691 error message is output. Some extra information is given for the
692 PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
693 probably the only errors that are likely to be caused by users (by
694 specifying a regex that has nested indefinite repeats, for instance).
695 If there are more than 20 of these errors, pcregrep is abandoned.
696
697 (b) A binary zero was treated as data while matching, but terminated the
698 output line if it was written out. This has been fixed: binary zeroes
699 are now no different to any other data bytes.
700
701 (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
702 used to set a locale for matching. The --locale=xxxx long option has
703 been added (no short equivalent) to specify a locale explicitly on the
704 pcregrep command, overriding the environment variables.
705
706 (d) When -B was used with -n, some line numbers in the output were one less
707 than they should have been.
708
709 (e) Added the -o (--only-matching) option.
710
711 (f) If -A or -C was used with -c (count only), some lines of context were
712 accidentally printed for the final match.
713
714 (g) Added the -H (--with-filename) option.
715
716 (h) The combination of options -rh failed to suppress file names for files
717 that were found from directory arguments.
718
719 (i) Added the -D (--devices) and -d (--directories) options.
720
721 (j) Added the -F (--fixed-strings) option.
722
723 (k) Allow "-" to be used as a file name for -f as well as for a data file.
724
725 (l) Added the --colo(u)r option.
726
727 (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
728 is not present by default.
729
730 3. A nasty bug was discovered in the handling of recursive patterns, that is,
731 items such as (?R) or (?1), when the recursion could match a number of
732 alternatives. If it matched one of the alternatives, but subsequently,
733 outside the recursion, there was a failure, the code tried to back up into
734 the recursion. However, because of the way PCRE is implemented, this is not
735 possible, and the result was an incorrect result from the match.
736
737 In order to prevent this happening, the specification of recursion has
738 been changed so that all such subpatterns are automatically treated as
739 atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
740
741 4. I had overlooked the fact that, in some locales, there are characters for
742 which isalpha() is true but neither isupper() nor islower() are true. In
743 the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
744 and ordfeminine) are like this. This affected the treatment of \w and \W
745 when they appeared in character classes, but not when they appeared outside
746 a character class. The bit map for "word" characters is now created
747 separately from the results of isalnum() instead of just taking it from the
748 upper, lower, and digit maps. (Plus the underscore character, of course.)
749
750 5. The above bug also affected the handling of POSIX character classes such as
751 [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
752 permanent tables. Instead, the bit maps for such a class were previously
753 created as the appropriate unions of the upper, lower, and digit bitmaps.
754 Now they are created by subtraction from the [[:word:]] class, which has
755 its own bitmap.
756
757 6. The [[:blank:]] character class matches horizontal, but not vertical space.
758 It is created by subtracting the vertical space characters (\x09, \x0a,
759 \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
760 subtraction was done in the overall bitmap for a character class, meaning
761 that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
762 be recognized. This bug has been fixed.
763
764 7. Patches from the folks at Google:
765
766 (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
767 real life, but is still worth protecting against".
768
769 (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
770 regular expressions".
771
772 (c) pcre_scanner.cc: avoid use of std::count() because not all systems
773 have it.
774
775 (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
776 "configure" and the latter not, in order to fix a problem somebody had
777 with compiling the Arg class on HP-UX.
778
779 (e) Improve the error-handling of the C++ wrapper a little bit.
780
781 (f) New tests for checking recursion limiting.
782
783 8. The pcre_memmove() function, which is used only if the environment does not
784 have a standard memmove() function (and is therefore rarely compiled),
785 contained two bugs: (a) use of int instead of size_t, and (b) it was not
786 returning a result (though PCRE never actually uses the result).
787
788 9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
789 large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
790 returned instead of calling malloc() with an overflowing number that would
791 most likely cause subsequent chaos.
792
793 10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
794
795 11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
796 with this option is matched, the nmatch and pmatch options of regexec() are
797 ignored.
798
799 12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
800 provided in case anyone wants to the the POSIX interface with UTF-8
801 strings.
802
803 13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
804 C++ linking (needed for some HP-UX environments).
805
806 14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
807 (unused parameter) and in the pcre_printint() function (omitted "default"
808 switch label when the default is to do nothing).
809
810 15. Added some code to make it possible, when PCRE is compiled as a C++
811 library, to replace subject pointers for pcre_exec() with a smart pointer
812 class, thus making it possible to process discontinuous strings.
813
814 16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
815 much the same function. They were added by different people who were trying
816 to make PCRE easy to compile on non-Unix systems. It has been suggested
817 that PCRE_EXPORT be abolished now that there is more automatic apparatus
818 for compiling on Windows systems. I have therefore replaced it with
819 PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
820 defaults to "extern" for C or "extern C" for C++, which works fine on
821 Unix-like systems. It is now possible to override the value of PCRE_DATA_
822 SCOPE with something explicit in config.h. In addition:
823
824 (a) pcreposix.h still had just "extern" instead of either of these macros;
825 I have replaced it with PCRE_DATA_SCOPE.
826
827 (b) Functions such as _pcre_xclass(), which are internal to the library,
828 but external in the C sense, all had PCRE_EXPORT in their definitions.
829 This is apparently wrong for the Windows case, so I have removed it.
830 (It makes no difference on Unix-like systems.)
831
832 17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
833 of recursive calls to match(). This is different to MATCH_LIMIT because
834 that limits the total number of calls to match(), not all of which increase
835 the depth of recursion. Limiting the recursion depth limits the amount of
836 stack (or heap if NO_RECURSE is set) that is used. The default can be set
837 when PCRE is compiled, and changed at run time. A patch from Google adds
838 this functionality to the C++ interface.
839
840 18. Changes to the handling of Unicode character properties:
841
842 (a) Updated the table to Unicode 4.1.0.
843
844 (b) Recognize characters that are not in the table as "Cn" (undefined).
845
846 (c) I revised the way the table is implemented to a much improved format
847 which includes recognition of ranges. It now supports the ranges that
848 are defined in UnicodeData.txt, and it also amalgamates other
849 characters into ranges. This has reduced the number of entries in the
850 table from around 16,000 to around 3,000, thus reducing its size
851 considerably. I realized I did not need to use a tree structure after
852 all - a binary chop search is just as efficient. Having reduced the
853 number of entries, I extended their size from 6 bytes to 8 bytes to
854 allow for more data.
855
856 (d) Added support for Unicode script names via properties such as \p{Han}.
857
858 19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
859 matching that character.
860
861 20. When matching a repeated Unicode property with a minimum greater than zero,
862 (for example \pL{2,}), PCRE could look past the end of the subject if it
863 reached it while seeking the minimum number of characters. This could
864 happen only if some of the characters were more than one byte long, because
865 there is a check for at least the minimum number of bytes.
866
867 21. Refactored the implementation of \p and \P so as to be more general, to
868 allow for more different types of property in future. This has changed the
869 compiled form incompatibly. Anybody with saved compiled patterns that use
870 \p or \P will have to recompile them.
871
872 22. Added "Any" and "L&" to the supported property types.
873
874 23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
875 but give a compile time error if the value is greater than 0xff.
876
877 24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
878 accidentally not being installed or uninstalled.
879
880 25. The pcre.h file was built from pcre.h.in, but the only changes that were
881 made were to insert the current release number. This seemed silly, because
882 it made things harder for people building PCRE on systems that don't run
883 "configure". I have turned pcre.h into a distributed file, no longer built
884 by "configure", with the version identification directly included. There is
885 no longer a pcre.h.in file.
886
887 However, this change necessitated a change to the pcre-config script as
888 well. It is built from pcre-config.in, and one of the substitutions was the
889 release number. I have updated configure.ac so that ./configure now finds
890 the release number by grepping pcre.h.
891
892 26. Added the ability to run the tests under valgrind.
893
894
895 Version 6.4 05-Sep-05
896 ---------------------
897
898 1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
899 "--" to be printed when multiple files were scanned, even when none of the
900 -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
901 consider it to be a bug, and have restored the previous behaviour.
902
903 2. A couple of code tidies to get rid of compiler warnings.
904
905 3. The pcretest program used to cheat by referring to symbols in the library
906 whose names begin with _pcre_. These are internal symbols that are not
907 really supposed to be visible externally, and in some environments it is
908 possible to suppress them. The cheating is now confined to including
909 certain files from the library's source, which is a bit cleaner.
910
911 4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
912 file's purpose clearer.
913
914 5. Reorganized pcre_ucp_findchar().
915
916
917 Version 6.3 15-Aug-05
918 ---------------------
919
920 1. The file libpcre.pc.in did not have general read permission in the tarball.
921
922 2. There were some problems when building without C++ support:
923
924 (a) If C++ support was not built, "make install" and "make test" still
925 tried to test it.
926
927 (b) There were problems when the value of CXX was explicitly set. Some
928 changes have been made to try to fix these, and ...
929
930 (c) --disable-cpp can now be used to explicitly disable C++ support.
931
932 (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
933 backslash in a target when C++ was disabled. This confuses some
934 versions of "make", apparently. Using an intermediate variable solves
935 this. (Same for CPP_LOBJ.)
936
937 3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
938 (non-Windows) now includes $(CFLAGS) because these flags are sometimes
939 necessary on certain architectures.
940
941 4. Added a setting of -export-symbols-regex to the link command to remove
942 those symbols that are exported in the C sense, but actually are local
943 within the library, and not documented. Their names all begin with
944 "_pcre_". This is not a perfect job, because (a) we have to except some
945 symbols that pcretest ("illegally") uses, and (b) the facility isn't always
946 available (and never for static libraries). I have made a note to try to
947 find a way round (a) in the future.
948
949
950 Version 6.2 01-Aug-05
951 ---------------------
952
953 1. There was no test for integer overflow of quantifier values. A construction
954 such as {1111111111111111} would give undefined results. What is worse, if
955 a minimum quantifier for a parenthesized subpattern overflowed and became
956 negative, the calculation of the memory size went wrong. This could have
957 led to memory overwriting.
958
959 2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
960
961 3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
962 operating environments where this matters.
963
964 4. Applied Giuseppe Maxia's patch to add additional features for controlling
965 PCRE options from within the C++ wrapper.
966
967 5. Named capturing subpatterns were not being correctly counted when a pattern
968 was compiled. This caused two problems: (a) If there were more than 100
969 such subpatterns, the calculation of the memory needed for the whole
970 compiled pattern went wrong, leading to an overflow error. (b) Numerical
971 back references of the form \12, where the number was greater than 9, were
972 not recognized as back references, even though there were sufficient
973 previous subpatterns.
974
975 6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
976 versions of gcc, e.g. 2.95.4.
977
978
979 Version 6.1 21-Jun-05
980 ---------------------
981
982 1. There was one reference to the variable "posix" in pcretest.c that was not
983 surrounded by "#if !defined NOPOSIX".
984
985 2. Make it possible to compile pcretest without DFA support, UTF8 support, or
986 the cross-check on the old pcre_info() function, for the benefit of the
987 cut-down version of PCRE that is currently imported into Exim.
988
989 3. A (silly) pattern starting with (?i)(?-i) caused an internal space
990 allocation error. I've done the easy fix, which wastes 2 bytes for sensible
991 patterns that start (?i) but I don't think that matters. The use of (?i) is
992 just an example; this all applies to the other options as well.
993
994 4. Since libtool seems to echo the compile commands it is issuing, the output
995 from "make" can be reduced a bit by putting "@" in front of each libtool
996 compile command.
997
998 5. Patch from the folks at Google for configure.in to be a bit more thorough
999 in checking for a suitable C++ installation before trying to compile the
1000 C++ stuff. This should fix a reported problem when a compiler was present,
1001 but no suitable headers.
1002
1003 6. The man pages all had just "PCRE" as their title. I have changed them to
1004 be the relevant file name. I have also arranged that these names are
1005 retained in the file doc/pcre.txt, which is a concatenation in text format
1006 of all the man pages except the little individual ones for each function.
1007
1008 7. The NON-UNIX-USE file had not been updated for the different set of source
1009 files that come with release 6. I also added a few comments about the C++
1010 wrapper.
1011
1012
1013 Version 6.0 07-Jun-05
1014 ---------------------
1015
1016 1. Some minor internal re-organization to help with my DFA experiments.
1017
1018 2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1019 didn't matter for the library itself when fully configured, but did matter
1020 when compiling without UCP support, or within Exim, where the ucp files are
1021 not imported.
1022
1023 3. Refactoring of the library code to split up the various functions into
1024 different source modules. The addition of the new DFA matching code (see
1025 below) to a single monolithic source would have made it really too
1026 unwieldy, quite apart from causing all the code to be include in a
1027 statically linked application, when only some functions are used. This is
1028 relevant even without the DFA addition now that patterns can be compiled in
1029 one application and matched in another.
1030
1031 The downside of splitting up is that there have to be some external
1032 functions and data tables that are used internally in different modules of
1033 the library but which are not part of the API. These have all had their
1034 names changed to start with "_pcre_" so that they are unlikely to clash
1035 with other external names.
1036
1037 4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1038 a different (DFA) algorithm. Although it is slower than the original
1039 function, it does have some advantages for certain types of matching
1040 problem.
1041
1042 5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1043 including restarting after a partial match.
1044
1045 6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1046 defined when compiling for Windows was sent to me. I have put it into the
1047 code, though I have no means of testing or verifying it.
1048
1049 7. Added the pcre_refcount() auxiliary function.
1050
1051 8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1052 match before or at the first newline in the subject string. In pcretest,
1053 the /f option on a pattern can be used to set this.
1054
1055 9. A repeated \w when used in UTF-8 mode with characters greater than 256
1056 would behave wrongly. This has been present in PCRE since release 4.0.
1057
1058 10. A number of changes to the pcregrep command:
1059
1060 (a) Refactored how -x works; insert ^(...)$ instead of setting
1061 PCRE_ANCHORED and checking the length, in preparation for adding
1062 something similar for -w.
1063
1064 (b) Added the -w (match as a word) option.
1065
1066 (c) Refactored the way lines are read and buffered so as to have more
1067 than one at a time available.
1068
1069 (d) Implemented a pcregrep test script.
1070
1071 (e) Added the -M (multiline match) option. This allows patterns to match
1072 over several lines of the subject. The buffering ensures that at least
1073 8K, or the rest of the document (whichever is the shorter) is available
1074 for matching (and similarly the previous 8K for lookbehind assertions).
1075
1076 (f) Changed the --help output so that it now says
1077
1078 -w, --word-regex(p)
1079
1080 instead of two lines, one with "regex" and the other with "regexp"
1081 because that confused at least one person since the short forms are the
1082 same. (This required a bit of code, as the output is generated
1083 automatically from a table. It wasn't just a text change.)
1084
1085 (g) -- can be used to terminate pcregrep options if the next thing isn't an
1086 option but starts with a hyphen. Could be a pattern or a path name
1087 starting with a hyphen, for instance.
1088
1089 (h) "-" can be given as a file name to represent stdin.
1090
1091 (i) When file names are being printed, "(standard input)" is used for
1092 the standard input, for compatibility with GNU grep. Previously
1093 "<stdin>" was used.
1094
1095 (j) The option --label=xxx can be used to supply a name to be used for
1096 stdin when file names are being printed. There is no short form.
1097
1098 (k) Re-factored the options decoding logic because we are going to add
1099 two more options that take data. Such options can now be given in four
1100 different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1101
1102 (l) Added the -A, -B, and -C options for requesting that lines of context
1103 around matches be printed.
1104
1105 (m) Added the -L option to print the names of files that do not contain
1106 any matching lines, that is, the complement of -l.
1107
1108 (n) The return code is 2 if any file cannot be opened, but pcregrep does
1109 continue to scan other files.
1110
1111 (o) The -s option was incorrectly implemented. For compatibility with other
1112 greps, it now suppresses the error message for a non-existent or non-
1113 accessible file (but not the return code). There is a new option called
1114 -q that suppresses the output of matching lines, which was what -s was
1115 previously doing.
1116
1117 (p) Added --include and --exclude options to specify files for inclusion
1118 and exclusion when recursing.
1119
1120 11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1121 Hopefully, it now does.
1122
1123 12. Missing cast in pcre_study().
1124
1125 13. Added an "uninstall" target to the makefile.
1126
1127 14. Replaced "extern" in the function prototypes in Makefile.in with
1128 "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1129 world, but is set differently for Windows.
1130
1131 15. Added a second compiling function called pcre_compile2(). The only
1132 difference is that it has an extra argument, which is a pointer to an
1133 integer error code. When there is a compile-time failure, this is set
1134 non-zero, in addition to the error test pointer being set to point to an
1135 error message. The new argument may be NULL if no error number is required
1136 (but then you may as well call pcre_compile(), which is now just a
1137 wrapper). This facility is provided because some applications need a
1138 numeric error indication, but it has also enabled me to tidy up the way
1139 compile-time errors are handled in the POSIX wrapper.
1140
1141 16. Added VPATH=.libs to the makefile; this should help when building with one
1142 prefix path and installing with another. (Or so I'm told by someone who
1143 knows more about this stuff than I do.)
1144
1145 17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1146 passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1147 match everything, including newlines. This is not POSIX-compatible, but
1148 somebody wanted the feature. From pcretest it can be activated by using
1149 both the P and the s flags.
1150
1151 18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1152
1153 19. libpcre.pc was being incorrectly installed as executable.
1154
1155 20. A couple of places in pcretest check for end-of-line by looking for '\n';
1156 it now also looks for '\r' so that it will work unmodified on Windows.
1157
1158 21. Added Google's contributed C++ wrapper to the distribution.
1159
1160 22. Added some untidy missing memory free() calls in pcretest, to keep
1161 Electric Fence happy when testing.
1162
1163
1164
1165 Version 5.0 13-Sep-04
1166 ---------------------
1167
1168 1. Internal change: literal characters are no longer packed up into items
1169 containing multiple characters in a single byte-string. Each character
1170 is now matched using a separate opcode. However, there may be more than one
1171 byte in the character in UTF-8 mode.
1172
1173 2. The pcre_callout_block structure has two new fields: pattern_position and
1174 next_item_length. These contain the offset in the pattern to the next match
1175 item, and its length, respectively.
1176
1177 3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1178 insertion of callouts before each pattern item. Added the /C option to
1179 pcretest to make use of this.
1180
1181 4. On the advice of a Windows user, the lines
1182
1183 #if defined(_WIN32) || defined(WIN32)
1184 _setmode( _fileno( stdout ), 0x8000 );
1185 #endif /* defined(_WIN32) || defined(WIN32) */
1186
1187 have been added to the source of pcretest. This apparently does useful
1188 magic in relation to line terminators.
1189
1190 5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1191 for the benefit of those environments where the "b" makes a difference.
1192
1193 6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1194 to know about it. I have put a hack into configure.in that adds in code
1195 to set GCC=yes if CC=icc. This seems to end up at a point in the
1196 generated configure script that is early enough to affect the setting of
1197 compiler options, which is what is needed, but I have no means of testing
1198 whether it really works. (The user who reported this had patched the
1199 generated configure script, which of course I cannot do.)
1200
1201 LATER: After change 22 below (new libtool files), the configure script
1202 seems to know about icc (and also ecc). Therefore, I have commented out
1203 this hack in configure.in.
1204
1205 7. Added support for pkg-config (2 patches were sent in).
1206
1207 8. Negated POSIX character classes that used a combination of internal tables
1208 were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1209 [[:^ascii]]. Typically, they would match almost any characters. The other
1210 POSIX classes were not broken in this way.
1211
1212 9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1213 to find the match, as PCRE was deluded into thinking that the match had to
1214 start at the start point or following a newline. The same bug applied to
1215 patterns with negative forward assertions or any backward assertions
1216 preceding ".*" at the start, unless the pattern required a fixed first
1217 character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1218
1219 10. In UTF-8 mode, when moving forwards in the subject after a failed match
1220 starting at the last subject character, bytes beyond the end of the subject
1221 string were read.
1222
1223 11. Renamed the variable "class" as "classbits" to make life easier for C++
1224 users. (Previously there was a macro definition, but it apparently wasn't
1225 enough.)
1226
1227 12. Added the new field "tables" to the extra data so that tables can be passed
1228 in at exec time, or the internal tables can be re-selected. This allows
1229 a compiled regex to be saved and re-used at a later time by a different
1230 program that might have everything at different addresses.
1231
1232 13. Modified the pcre-config script so that, when run on Solaris, it shows a
1233 -R library as well as a -L library.
1234
1235 14. The debugging options of pcretest (-d on the command line or D on a
1236 pattern) showed incorrect output for anything following an extended class
1237 that contained multibyte characters and which was followed by a quantifier.
1238
1239 15. Added optional support for general category Unicode character properties
1240 via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1241 support. It adds about 90K to the size of the library. The meanings of the
1242 inbuilt class escapes such as \d and \s have NOT been changed.
1243
1244 16. Updated pcredemo.c to include calls to free() to release the memory for the
1245 compiled pattern.
1246
1247 17. The generated file chartables.c was being created in the source directory
1248 instead of in the building directory. This caused the build to fail if the
1249 source directory was different from the building directory, and was
1250 read-only.
1251
1252 18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1253 file. No doubt somebody will tell me if they don't make sense... Also added
1254 Dan Mooney's comments about building on OpenVMS.
1255
1256 19. Added support for partial matching via the PCRE_PARTIAL option for
1257 pcre_exec() and the \P data escape in pcretest.
1258
1259 20. Extended pcretest with 3 new pattern features:
1260
1261 (i) A pattern option of the form ">rest-of-line" causes pcretest to
1262 write the compiled pattern to the file whose name is "rest-of-line".
1263 This is a straight binary dump of the data, with the saved pointer to
1264 the character tables forced to be NULL. The study data, if any, is
1265 written too. After writing, pcretest reads a new pattern.
1266
1267 (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1268 compiled pattern from the given file. There must not be any
1269 occurrences of "<" in the file name (pretty unlikely); if there are,
1270 pcretest will instead treat the initial "<" as a pattern delimiter.
1271 After reading in the pattern, pcretest goes on to read data lines as
1272 usual.
1273
1274 (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1275 and 16-bit fields in a compiled pattern, to simulate a pattern that
1276 was compiled on a host of opposite endianness.
1277
1278 21. The pcre-exec() function can now cope with patterns that were compiled on
1279 hosts of opposite endianness, with this restriction:
1280
1281 As for any compiled expression that is saved and used later, the tables
1282 pointer field cannot be preserved; the extra_data field in the arguments
1283 to pcre_exec() should be used to pass in a tables address if a value
1284 other than the default internal tables were used at compile time.
1285
1286 22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1287 now diagnosed as an error. Previously, most of the time, a negative number
1288 would have been treated as zero, but if in addition "ovector" was passed as
1289 NULL, a crash could occur.
1290
1291 23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1292 new versions from the libtool 1.5 distribution (the last one is a copy of
1293 a file called libtool.m4). This seems to have fixed the need to patch
1294 "configure" to support Darwin 1.3 (which I used to do). However, I still
1295 had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1296 workstation).
1297
1298 24. Changed the PCRE licence to be the more standard "BSD" licence.
1299
1300
1301 Version 4.5 01-Dec-03
1302 ---------------------
1303
1304 1. There has been some re-arrangement of the code for the match() function so
1305 that it can be compiled in a version that does not call itself recursively.
1306 Instead, it keeps those local variables that need separate instances for
1307 each "recursion" in a frame on the heap, and gets/frees frames whenever it
1308 needs to "recurse". Keeping track of where control must go is done by means
1309 of setjmp/longjmp. The whole thing is implemented by a set of macros that
1310 hide most of the details from the main code, and operates only if
1311 NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1312 "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1313 operating.
1314
1315 To make it easier for callers to provide specially tailored get/free
1316 functions for this usage, two new functions, pcre_stack_malloc, and
1317 pcre_stack_free, are used. They are always called in strict stacking order,
1318 and the size of block requested is always the same.
1319
1320 The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1321 PCRE has been compiled to use the stack or the heap for recursion. The
1322 -C option of pcretest uses this to show which version is compiled.
1323
1324 A new data escape \S, is added to pcretest; it causes the amounts of store
1325 obtained and freed by both kinds of malloc/free at match time to be added
1326 to the output.
1327
1328 2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1329 what's available on my current Linux desktop machine.
1330
1331 3. When matching a UTF-8 string, the test for a valid string at the start has
1332 been extended. If start_offset is not zero, PCRE now checks that it points
1333 to a byte that is the start of a UTF-8 character. If not, it returns
1334 PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1335 this is necessary because there may be backward assertions in the pattern.
1336 When matching the same subject several times, it may save resources to use
1337 PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1338
1339 4. The code for checking the validity of UTF-8 strings has been tightened so
1340 that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1341 containing "overlong sequences".
1342
1343 5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1344 I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1345 should have been "&", but it just so happened that all the cases this let
1346 through by mistake were picked up later in the function.
1347
1348 6. I had used a variable called "isblank" - this is a C99 function, causing
1349 some compilers to warn. To avoid this, I renamed it (as "blankclass").
1350
1351 7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1352 prompting; (b) run "./pcretest /dev/null" at the start of the test script
1353 so the version is shown; (c) stop "make test" echoing "./RunTest".
1354
1355 8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1356
1357 9. The prototype for memmove() for systems that don't have it was using
1358 size_t, but the inclusion of the header that defines size_t was later. I've
1359 moved the #includes for the C headers earlier to avoid this.
1360
1361 10. Added some adjustments to the code to make it easier to compiler on certain
1362 special systems:
1363
1364 (a) Some "const" qualifiers were missing.
1365 (b) Added the macro EXPORT before all exported functions; by default this
1366 is defined to be empty.
1367 (c) Changed the dftables auxiliary program (that builds chartables.c) so
1368 that it reads its output file name as an argument instead of writing
1369 to the standard output and assuming this can be redirected.
1370
1371 11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1372 class containing characters with values greater than 255, PCRE compilation
1373 went into a loop.
1374
1375 12. A recursive reference to a subpattern that was within another subpattern
1376 that had a minimum quantifier of zero caused PCRE to crash. For example,
1377 (x(y(?2))z)? provoked this bug with a subject that got as far as the
1378 recursion. If the recursively-called subpattern itself had a zero repeat,
1379 that was OK.
1380
1381 13. In pcretest, the buffer for reading a data line was set at 30K, but the
1382 buffer into which it was copied (for escape processing) was still set at
1383 1024, so long lines caused crashes.
1384
1385 14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1386 "internal error: code overflow...". This applied to any character class
1387 that was followed by a possessive quantifier.
1388
1389 15. Modified the Makefile to add libpcre.la as a prerequisite for
1390 libpcreposix.la because I was told this is needed for a parallel build to
1391 work.
1392
1393 16. If a pattern that contained .* following optional items at the start was
1394 studied, the wrong optimizing data was generated, leading to matching
1395 errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1396 matching string must start with a or b or c. The correct conclusion for
1397 this pattern is that a match can start with any character.
1398
1399
1400 Version 4.4 13-Aug-03
1401 ---------------------
1402
1403 1. In UTF-8 mode, a character class containing characters with values between
1404 127 and 255 was not handled correctly if the compiled pattern was studied.
1405 In fixing this, I have also improved the studying algorithm for such
1406 classes (slightly).
1407
1408 2. Three internal functions had redundant arguments passed to them. Removal
1409 might give a very teeny performance improvement.
1410
1411 3. Documentation bug: the value of the capture_top field in a callout is *one
1412 more than* the number of the hightest numbered captured substring.
1413
1414 4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1415 in incorrectly linking with a previously installed version. They now link
1416 explicitly with libpcre.la.
1417
1418 5. configure.in no longer needs to recognize Cygwin specially.
1419
1420 6. A problem in pcre.in for Windows platforms is fixed.
1421
1422 7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1423 pcretest, it used to include the size of the study block as part of its
1424 output. Unfortunately, the structure contains a field that has a different
1425 size on different hardware architectures. This meant that the tests that
1426 showed this size failed. As the block is currently always of a fixed size,
1427 this information isn't actually particularly useful in pcretest output, so
1428 I have just removed it.
1429
1430 8. Three pre-processor statements accidentally did not start in column 1.
1431 Sadly, there are *still* compilers around that complain, even though
1432 standard C has not required this for well over a decade. Sigh.
1433
1434 9. In pcretest, the code for checking callouts passed small integers in the
1435 callout_data field, which is a void * field. However, some picky compilers
1436 complained about the casts involved for this on 64-bit systems. Now
1437 pcretest passes the address of the small integer instead, which should get
1438 rid of the warnings.
1439
1440 10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1441 both compile and run time, and gives an error if an invalid UTF-8 sequence
1442 is found. There is a option for disabling this check in cases where the
1443 string is known to be correct and/or the maximum performance is wanted.
1444
1445 11. In response to a bug report, I changed one line in Makefile.in from
1446
1447 -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1448 to
1449 -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1450
1451 to look similar to other lines, but I have no way of telling whether this
1452 is the right thing to do, as I do not use Windows. No doubt I'll get told
1453 if it's wrong...
1454
1455
1456 Version 4.3 21-May-03
1457 ---------------------
1458
1459 1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1460 Makefile.
1461
1462 2. Some refactoring to improve the quality of the code:
1463
1464 (i) The utf8_table... variables are now declared "const".
1465
1466 (ii) The code for \cx, which used the "case flipping" table to upper case
1467 lower case letters, now just substracts 32. This is ASCII-specific,
1468 but the whole concept of \cx is ASCII-specific, so it seems
1469 reasonable.
1470
1471 (iii) PCRE was using its character types table to recognize decimal and
1472 hexadecimal digits in the pattern. This is silly, because it handles
1473 only 0-9, a-f, and A-F, but the character types table is locale-
1474 specific, which means strange things might happen. A private
1475 table is now used for this - though it costs 256 bytes, a table is
1476 much faster than multiple explicit tests. Of course, the standard
1477 character types table is still used for matching digits in subject
1478 strings against \d.
1479
1480 (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1481 ending in _t are). So I've renamed it as ESC_tee.
1482
1483 3. The first argument for regexec() in the POSIX wrapper should have been
1484 defined as "const".
1485
1486 4. Changed pcretest to use malloc() for its buffers so that they can be
1487 Electric Fenced for debugging.
1488
1489 5. There were several places in the code where, in UTF-8 mode, PCRE would try
1490 to read one or more bytes before the start of the subject string. Often this
1491 had no effect on PCRE's behaviour, but in some circumstances it could
1492 provoke a segmentation fault.
1493
1494 6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1495 to try to read one or more bytes before the start of the subject string.
1496
1497 7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1498 UTF-8 support could misbehave in various ways if the subject string
1499 contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1500 area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1501 back over UTF-8 characters.)
1502
1503
1504 Version 4.2 14-Apr-03
1505 ---------------------
1506
1507 1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1508
1509 2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1510 [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1511 [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1512 [WIN_PREFIX]: new variable, "cyg" for Cygwin
1513 * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1514 and BUILD_EXEEXT
1515 Note: automatic setting of the BUILD variables is not yet working
1516 set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1517 compile-time but not at link-time
1518 [LINK]: use for linking executables only
1519 make different versions for Windows and non-Windows
1520 [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1521 libraries
1522 [LINK_FOR_BUILD]: new variable
1523 [OBJEXT]: use throughout
1524 [EXEEXT]: use throughout
1525 <winshared>: new target
1526 <wininstall>: new target
1527 <dftables.o>: use native compiler
1528 <dftables>: use native linker
1529 <install>: handle Windows platform correctly
1530 <clean>: ditto
1531 <check>: ditto
1532 copy DLL to top builddir before testing
1533
1534 As part of these changes, -no-undefined was removed again. This was reported
1535 to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1536 in any case.
1537
1538 3. Some tidies to get rid of compiler warnings:
1539
1540 . In the match_data structure, match_limit was an unsigned long int, whereas
1541 match_call_count was an int. I've made them both unsigned long ints.
1542
1543 . In pcretest the fact that a const uschar * doesn't automatically cast to
1544 a void * provoked a warning.
1545
1546 . Turning on some more compiler warnings threw up some "shadow" variables
1547 and a few more missing casts.
1548
1549 4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1550 option, a class that contained a single character with a value between 128
1551 and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1552
1553 5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1554 option, a class that contained several characters, but with at least one
1555 whose value was between 128 and 255 caused PCRE to crash.
1556
1557
1558 Version 4.1 12-Mar-03
1559 ---------------------
1560
1561 1. Compiling with gcc -pedantic found a couple of places where casts were
1562 needed, and a string in dftables.c that was longer than standard compilers are
1563 required to support.
1564
1565 2. Compiling with Sun's compiler found a few more places where the code could
1566 be tidied up in order to avoid warnings.
1567
1568 3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1569 first of these names is deprecated in the latest Autoconf in favour of the name
1570 CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1571 compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1572 analogy I have changed it to CFLAGS_FOR_BUILD.
1573
1574 4. Added -no-undefined to the linking command in the Makefile, because this is
1575 apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1576 linking step for the pcreposix library.
1577
1578 5. PCRE was failing to diagnose the case of two named groups with the same
1579 name.
1580
1581 6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1582 literal character that is needed in the subject for a match, and scans along to
1583 ensure that it is present before embarking on the full matching process. This
1584 saves time in cases of nested unlimited repeats that are never going to match.
1585 Problem: the scan can take a lot of time if the subject is very long (e.g.
1586 megabytes), thus penalizing straightforward matches. It is now done only if the
1587 amount of subject to be scanned is less than 1000 bytes.
1588
1589 7. A lesser problem with the same optimization is that it was recording the
1590 first character of an anchored pattern as "needed", thus provoking a search
1591 right along the subject, even when the first match of the pattern was going to
1592 fail. The "needed" character is now not set for anchored patterns, unless it
1593 follows something in the pattern that is of non-fixed length. Thus, it still
1594 fulfils its original purpose of finding quick non-matches in cases of nested
1595 unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1596
1597
1598 Version 4.0 17-Feb-03
1599 ---------------------
1600
1601 1. If a comment in an extended regex that started immediately after a meta-item
1602 extended to the end of string, PCRE compiled incorrect data. This could lead to
1603 all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1604
1605 2. Moved to autoconf 2.53 and libtool 1.4.2.
1606
1607 3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1608 the special perltest8 script is no longer needed - all the tests can be run
1609 from a single perltest script.
1610
1611 4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1612 by \s. It has now been removed in PCRE. This means it isn't recognized as
1613 whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1614 class [:space:] *does* include VT, thereby creating a mess.
1615
1616 5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1617 space and tab.
1618
1619 6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1620 its new features into the main test script, reducing the number of scripts.
1621
1622 7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1623 were backward compatible, and made the (?i) apply to the whole pattern, as if
1624 /i were given. Now it behaves more logically, and applies the option setting
1625 only to what follows. PCRE has been changed to follow suit. However, if it
1626 finds options settings right at the start of the pattern, it extracts them into
1627 the global options, as before. Thus, they show up in the info data.
1628
1629 8. Added support for the \Q...\E escape sequence. Characters in between are
1630 treated as literals. This is slightly different from Perl in that $ and @ are
1631 also handled as literals inside the quotes. In Perl, they will cause variable
1632 interpolation. Note the following examples:
1633
1634 Pattern PCRE matches Perl matches
1635
1636 \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1637 \Qabc\$xyz\E abc\$xyz abc\$xyz
1638 \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1639
1640 For compatibility with Perl, \Q...\E sequences are recognized inside character
1641 classes as well as outside them.
1642
1643 9. Re-organized 3 code statements in pcretest to avoid "overflow in
1644 floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1645 (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1646 signed/unsigned warnings.
1647
1648 10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1649 option for pcretest, so I've replaced it by a simple function that does just
1650 that job.
1651
1652 11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1653 "pcregrep -".
1654
1655 12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1656 Java package. This provides some syntactic sugar for simple cases of what my
1657 documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1658 as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1659 item, you can use this simplified notation. Note that only makes sense with
1660 greedy quantifiers. Consequently, the use of the possessive quantifier forces
1661 greediness, whatever the setting of the PCRE_UNGREEDY option.
1662
1663 13. A change of greediness default within a pattern was not taking effect at
1664 the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1665 subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1666 was abstracted outside.
1667
1668 14. PCRE now supports the \G assertion. It is true when the current matching
1669 position is at the start point of the match. This differs from \A when the
1670 starting offset is non-zero. Used with the /g option of pcretest (or similar
1671 code), it works in the same way as it does for Perl's /g option. If all
1672 alternatives of a regex begin with \G, the expression is anchored to the start
1673 match position, and the "anchored" flag is set in the compiled expression.
1674
1675 15. Some bugs concerning the handling of certain option changes within patterns
1676 have been fixed. These applied to options other than (?ims). For example,
1677 "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1678 been the other way round. Some of this was related to change 7 above.
1679
1680 16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1681 features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1682 and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1683 POSIX classes only within a class (e.g. /[[:alpha:]]/).
1684
1685 17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1686 mode. Unlike ".", it always matches newline, whatever the setting of
1687 PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1688 assertions. Perl allows it, but it doesn't (in general) work because it can't
1689 calculate the length of the lookbehind. At least, that's the case for Perl
1690 5.8.0 - I've been told they are going to document that it doesn't work in
1691 future.
1692
1693 18. Added an error diagnosis for escapes that PCRE does not support: these are
1694 \L, \l, \N, \P, \p, \U, \u, and \X.
1695
1696 19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1697 reading past the end of the pattern in cases such as /[abcd/.
1698
1699 20. PCRE was getting more memory than necessary for patterns with classes that
1700 contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1701
1702 21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1703 compiling PCRE for use with Virtual Pascal.
1704
1705 22. Small fix to the Makefile to make it work properly if the build is done
1706 outside the source tree.
1707
1708 23. Added a new extension: a condition to go with recursion. If a conditional
1709 subpattern starts with (?(R) the "true" branch is used if recursion has
1710 happened, whereas the "false" branch is used only at the top level.
1711
1712 24. When there was a very long string of literal characters (over 255 bytes
1713 without UTF support, over 250 bytes with UTF support), the computation of how
1714 much memory was required could be incorrect, leading to segfaults or other
1715 strange effects.
1716
1717 25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1718 start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1719 there was a subsequent back reference to those brackets. This meant that, for
1720 example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1721 possible to check for precisely this case. All we can do is abandon the
1722 optimization if .* occurs inside capturing brackets when there are any back
1723 references whatsoever. (See below for a better fix that came later.)
1724
1725 26. The handling of the optimization for finding the first character of a
1726 non-anchored pattern, and for finding a character that is required later in the
1727 match were failing in some cases. This didn't break the matching; it just
1728 failed to optimize when it could. The way this is done has been re-implemented.
1729
1730 27. Fixed typo in error message for invalid (?R item (it said "(?p").
1731
1732 28. Added a new feature that provides some of the functionality that Perl
1733 provides with (?{...}). The facility is termed a "callout". The way it is done
1734 in PCRE is for the caller to provide an optional function, by setting
1735 pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1736 global variable. By default it is unset, which disables all calling out. To get
1737 the function called, the regex must include (?C) at appropriate points. This
1738 is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1739 This provides a means of identifying different callout points. When PCRE
1740 reaches such a point in the regex, if pcre_callout has been set, the external
1741 function is called. It is provided with data in a structure called
1742 pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1743 matching continues; if it returns a non-zero value, the match at the current
1744 point fails. However, backtracking will occur if possible. [This was changed
1745 later and other features added - see item 49 below.]
1746
1747 29. pcretest is upgraded to test the callout functionality. It provides a
1748 callout function that displays information. By default, it shows the start of
1749 the match and the current position in the text. There are some new data escapes
1750 to vary what happens:
1751
1752 \C+ in addition, show current contents of captured substrings
1753 \C- do not supply a callout function
1754 \C!n return 1 when callout number n is reached
1755 \C!n!m return 1 when callout number n is reached for the mth time
1756
1757 30. If pcregrep was called with the -l option and just a single file name, it
1758 output "<stdin>" if a match was found, instead of the file name.
1759
1760 31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1761 slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1762 pcre_exec(). This saves a malloc/free per call. The default value of
1763 POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1764 when configuring.
1765
1766 32. The default maximum size of a compiled pattern is 64K. There have been a
1767 few cases of people hitting this limit. The code now uses macros to handle the
1768 storing of links as offsets within the compiled pattern. It defaults to 2-byte
1769 links, but this can be changed to 3 or 4 bytes by --with-link-size when
1770 configuring. Tests 2 and 5 work only with 2-byte links because they output
1771 debugging information about compiled patterns.
1772
1773 33. Internal code re-arrangements:
1774
1775 (a) Moved the debugging function for printing out a compiled regex into
1776 its own source file (printint.c) and used #include to pull it into
1777 pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1778 separate copies.
1779
1780 (b) Defined the list of op-code names for debugging as a macro in
1781 internal.h so that it is next to the definition of the opcodes.
1782
1783 (c) Defined a table of op-code lengths for simpler skipping along compiled
1784 code. This is again a macro in internal.h so that it is next to the
1785 definition of the opcodes.
1786
1787 34. Added support for recursive calls to individual subpatterns, along the
1788 lines of Robin Houston's patch (but implemented somewhat differently).
1789
1790 35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1791 allow it to read and process whole directories in Win32. This code was
1792 contributed by Lionel Fourquaux; it has not been tested by me.
1793
1794 36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1795 used to name a group. Names consist of alphanumerics and underscores, and must
1796 be unique. Back references use the syntax (?P=name) and recursive calls use
1797 (?P>name) which is a PCRE extension to the Python extension. Groups still have
1798 numbers. The function pcre_fullinfo() can be used after compilation to extract
1799 a name/number map. There are three relevant calls:
1800
1801 PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1802 PCRE_INFO_NAMECOUNT yields the number of entries
1803 PCRE_INFO_NAMETABLE yields a pointer to the map.
1804
1805 The map is a vector of fixed-size entries. The size of each entry depends on
1806 the length of the longest name used. The first two bytes of each entry are the
1807 group number, most significant byte first. There follows the corresponding
1808 name, zero terminated. The names are in alphabetical order.
1809
1810 37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1811 case instead of 255. Making it the same both with and without UTF-8 support
1812 means that the same test output works with both.
1813
1814 38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1815 calling malloc() with a zero argument.
1816
1817 39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1818 optimization. I've improved things by keeping a bitmap of backreferences with
1819 numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1820 fact referenced, the optimization can be applied. It is unlikely that a
1821 relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1822 the match to follow \n) will appear inside brackets with a number greater than
1823 31, but if it does, any back reference > 31 suppresses the optimization.
1824
1825 40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1826 of disabling numbered capturing parentheses. Any opening parenthesis that is
1827 not followed by ? behaves as if it were followed by ?: but named parentheses
1828 can still be used for capturing (and they will acquire numbers in the usual
1829 way).
1830
1831 41. Redesigned the return codes from the match() function into yes/no/error so
1832 that errors can be passed back from deep inside the nested calls. A malloc
1833 failure while inside a recursive subpattern call now causes the
1834 PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1835
1836 42. It is now possible to set a limit on the number of times the match()
1837 function is called in a call to pcre_exec(). This facility makes it possible to
1838 limit the amount of recursion and backtracking, though not in a directly
1839 obvious way, because the match() function is used in a number of different
1840 circumstances. The count starts from zero for each position in the subject
1841 string (for non-anchored patterns). The default limit is, for compatibility, a
1842 large number, namely 10 000 000. You can change this in two ways:
1843
1844 (a) When configuring PCRE before making, you can use --with-match-limit=n
1845 to set a default value for the compiled library.
1846
1847 (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1848 a different value is set. See 45 below.
1849
1850 If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1851
1852 43. Added a new function pcre_config(int, void *) to enable run-time extraction
1853 of things that can be changed at compile time. The first argument specifies
1854 what is wanted and the second points to where the information is to be placed.
1855 The current list of available information is:
1856
1857 PCRE_CONFIG_UTF8
1858
1859 The output is an integer that is set to one if UTF-8 support is available;
1860 otherwise it is set to zero.
1861
1862 PCRE_CONFIG_NEWLINE
1863
1864 The output is an integer that it set to the value of the code that is used for
1865 newline. It is either LF (10) or CR (13).
1866
1867 PCRE_CONFIG_LINK_SIZE
1868
1869 The output is an integer that contains the number of bytes used for internal
1870 linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1871
1872 PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1873
1874 The output is an integer that contains the threshold above which the POSIX
1875 interface uses malloc() for output vectors. See item 31 above.
1876
1877 PCRE_CONFIG_MATCH_LIMIT
1878
1879 The output is an unsigned integer that contains the default limit of the number
1880 of match() calls in a pcre_exec() execution. See 42 above.
1881
1882 44. pcretest has been upgraded by the addition of the -C option. This causes it
1883 to extract all the available output from the new pcre_config() function, and to
1884 output it. The program then exits immediately.
1885
1886 45. A need has arisen to pass over additional data with calls to pcre_exec() in
1887 order to support additional features. One way would have been to define
1888 pcre_exec2() (for example) with extra arguments, but this would not have been
1889 extensible, and would also have required all calls to the original function to
1890 be mapped to the new one. Instead, I have chosen to extend the mechanism that
1891 is used for passing in "extra" data from pcre_study().
1892
1893 The pcre_extra structure is now exposed and defined in pcre.h. It currently
1894 contains the following fields:
1895
1896 flags a bitmap indicating which of the following fields are set
1897 study_data opaque data from pcre_study()
1898 match_limit a way of specifying a limit on match() calls for a specific
1899 call to pcre_exec()
1900 callout_data data for callouts (see 49 below)
1901
1902 The flag bits are also defined in pcre.h, and are
1903
1904 PCRE_EXTRA_STUDY_DATA
1905 PCRE_EXTRA_MATCH_LIMIT
1906 PCRE_EXTRA_CALLOUT_DATA
1907
1908 The pcre_study() function now returns one of these new pcre_extra blocks, with
1909 the actual study data pointed to by the study_data field, and the
1910 PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1911 before. That is, this change is entirely upwards-compatible and requires no
1912 change to existing code.
1913
1914 If you want to pass in additional data to pcre_exec(), you can either place it
1915 in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1916 block.
1917
1918 46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1919 data string contains the escape sequence \M, pcretest calls pcre_exec() several
1920 times with different match limits, until it finds the minimum value needed for
1921 pcre_exec() to complete. The value is then output. This can be instructive; for
1922 most simple matches the number is quite small, but for pathological cases it
1923 gets very large very quickly.
1924
1925 47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1926 returns the size of the data block pointed to by the study_data field in a
1927 pcre_extra block, that is, the value that was passed as the argument to
1928 pcre_malloc() when PCRE was getting memory in which to place the information
1929 created by pcre_study(). The fourth argument should point to a size_t variable.
1930 pcretest has been extended so that this information is shown after a successful
1931 pcre_study() call when information about the compiled regex is being displayed.
1932
1933 48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1934 because what follows is always an absolute path. (Later: it turns out that this
1935 is more than cosmetic for MinGW, because it doesn't like empty path
1936 components.)
1937
1938 49. Some changes have been made to the callout feature (see 28 above):
1939
1940 (i) A callout function now has three choices for what it returns:
1941
1942 0 => success, carry on matching
1943 > 0 => failure at this point, but backtrack if possible
1944 < 0 => serious error, return this value from pcre_exec()
1945
1946 Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1947 values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1948 "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1949 use by callout functions. It will never be used by PCRE itself.
1950
1951 (ii) The pcre_extra structure (see 45 above) has a void * field called
1952 callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1953 pcre_callout_block structure has a field of the same name. The contents of
1954 the field passed in the pcre_extra structure are passed to the callout
1955 function in the corresponding field in the callout block. This makes it
1956 easier to use the same callout-containing regex from multiple threads. For
1957 testing, the pcretest program has a new data escape
1958
1959 \C*n pass the number n (may be negative) as callout_data
1960
1961 If the callout function in pcretest receives a non-zero value as
1962 callout_data, it returns that value.
1963
1964 50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1965 there were some redundant $(CFLAGS) in commands that are now specified as
1966 $(LINK), which already includes $(CFLAGS).
1967
1968 51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1969 has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1970 with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1971 one-byte characters throughout. Note that case-insensitive matching applies
1972 only to characters whose values are less than 256. PCRE doesn't support the
1973 notion of cases for higher-valued characters.
1974
1975 (i) A character class whose characters are all within 0-255 is handled as
1976 a bit map, and the map is inverted for negative classes. Previously, a
1977 character > 255 always failed to match such a class; however it should
1978 match if the class was a negative one (e.g. [^ab]). This has been fixed.
1979
1980 (ii) A negated character class with a single character < 255 is coded as
1981 "not this character" (OP_NOT). This wasn't working properly when the test
1982 character was multibyte, either singly or repeated.
1983
1984 (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1985 mode, for example: \x{100}{2,3}.
1986
1987 (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1988 singly or repeated) now correctly test multibyte characters. However,
1989 PCRE doesn't recognize any characters with values greater than 255 as
1990 digits, spaces, or word characters. Such characters always match \D, \S,
1991 and \W, and never match \d, \s, or \w.
1992
1993 (v) Classes may now contain characters and character ranges with values
1994 greater than 255. For example: [ab\x{100}-\x{400}].
1995
1996 (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1997 PCRE in UTF-8 mode.
1998
1999 52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2000 PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2001 retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2002 value.)
2003
2004 53. The single man page has become too large. I have therefore split it up into
2005 a number of separate man pages. These also give rise to individual HTML pages;
2006 these are now put in a separate directory, and there is an index.html page that
2007 lists them all. Some hyperlinking between the pages has been installed.
2008
2009 54. Added convenience functions for handling named capturing parentheses.
2010
2011 55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2012 aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2013 true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2014 are faulted.
2015
2016 56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2017 calling configure. These values are used when compiling the dftables.c program
2018 which is run to generate the source of the default character tables. They
2019 default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2020 you will need to set these values.
2021
2022 57. Updated the building process for Windows DLL, as provided by Fred Cox.
2023
2024
2025 Version 3.9 02-Jan-02
2026 ---------------------
2027
2028 1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2029
2030 2. If --disable-static was given, the building process failed when trying to
2031 build pcretest and pcregrep. (For some reason it was using libtool to compile
2032 them, which is not right, as they aren't part of the library.)
2033
2034
2035 Version 3.8 18-Dec-01
2036 ---------------------
2037
2038 1. The experimental UTF-8 code was completely screwed up. It was packing the
2039 bytes in the wrong order. How dumb can you get?
2040
2041
2042 Version 3.7 29-Oct-01
2043 ---------------------
2044
2045 1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2046 This caused pcretest, when used on the test data, to segfault. Unfortunately,
2047 this didn't happen under Solaris 8, where I normally test things.
2048
2049 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2050 doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2051 isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2052 this fix an hour or so after the initial 3.7 release.)
2053
2054
2055 Version 3.6 23-Oct-01
2056 ---------------------
2057
2058 1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2059 offsets passed as NULL with zero offset count.
2060
2061 2. The config.guess and config.sub files had not been updated when I moved to
2062 the latest autoconf.
2063
2064
2065 Version 3.5 15-Aug-01
2066 ---------------------
2067
2068 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2069 had been forgotten.
2070
2071 2. By using declared but undefined structures, we can avoid using "void"
2072 definitions in pcre.h while keeping the internal definitions of the structures
2073 private.
2074
2075 3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2076 user point of view, this means that both static and shared libraries are built
2077 by default, but this can be individually controlled. More of the work of
2078 handling this static/shared cases is now inside libtool instead of PCRE's make
2079 file.
2080
2081 4. The pcretest utility is now installed along with pcregrep because it is
2082 useful for users (to test regexs) and by doing this, it automatically gets
2083 relinked by libtool. The documentation has been turned into a man page, so
2084 there are now .1, .txt, and .html versions in /doc.
2085
2086 5. Upgrades to pcregrep:
2087 (i) Added long-form option names like gnu grep.
2088 (ii) Added --help to list all options with an explanatory phrase.
2089 (iii) Added -r, --recursive to recurse into sub-directories.
2090 (iv) Added -f, --file to read patterns from a file.
2091
2092 6. pcre_exec() was referring to its "code" argument before testing that
2093 argument for NULL (and giving an error if it was NULL).
2094
2095 7. Upgraded Makefile.in to allow for compiling in a different directory from
2096 the source directory.
2097
2098 8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2099 options bits, the pointer it was passed was to an int instead of to an unsigned
2100 long int. This mattered only on 64-bit systems.
2101
2102 9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2103 generated) instead of pcre.in, which it its source. Also made the same change
2104 in several of the .c files.
2105
2106 10. A new release of gcc defines printf() as a macro, which broke pcretest
2107 because it had an ifdef in the middle of a string argument for printf(). Fixed
2108 by using separate calls to printf().
2109
2110 11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2111 script, to force use of CR or LF instead of \n in the source. On non-Unix
2112 systems, the value can be set in config.h.
2113
2114 12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2115 absolute limit. Changed the text of the error message to make this clear, and
2116 likewise updated the man page.
2117
2118 13. The limit of 99 on the number of capturing subpatterns has been removed.
2119 The new limit is 65535, which I hope will not be a "real" limit.
2120
2121
2122 Version 3.4 22-Aug-00
2123 ---------------------
2124
2125 1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2126
2127 2. Diagnose condition (?(0) as an error instead of crashing on matching.
2128
2129
2130 Version 3.3 01-Aug-00
2131 ---------------------
2132
2133 1. If an octal character was given, but the value was greater than \377, it
2134 was not getting masked to the least significant bits, as documented. This could
2135 lead to crashes in some systems.
2136
2137 2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2138 the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2139
2140 3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2141 These just pass their arguments on to (pcre_free)(), but they are provided
2142 because some uses of PCRE bind it to non-C systems that can call its functions,
2143 but cannot call free() or pcre_free() directly.
2144
2145 4. Add "make test" as a synonym for "make check". Corrected some comments in
2146 the Makefile.
2147
2148 5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2149 Makefile.
2150
2151 6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2152 command called pgrep for grepping around the active processes.
2153
2154 7. Added the beginnings of support for UTF-8 character strings.
2155
2156 8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2157 RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2158 the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2159 out for the ar command.)
2160
2161
2162 Version 3.2 12-May-00
2163 ---------------------
2164
2165 This is purely a bug fixing release.
2166
2167 1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2168 of ZA. This was just one example of several cases that could provoke this bug,
2169 which was introduced by change 9 of version 2.00. The code for breaking
2170 infinite loops after an iteration that matches an empty string was't working
2171 correctly.
2172
2173 2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2174 when matched against abbab (for example). After matching an empty string, it
2175 wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2176 caused it to match further down the string than it should.
2177
2178 3. The code contained an inclusion of sys/types.h. It isn't clear why this
2179 was there because it doesn't seem to be needed, and it causes trouble on some
2180 systems, as it is not a Standard C header. It has been removed.
2181
2182 4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2183 were reported on the Macintosh. The changes were from
2184
2185 while ((c = *(++ptr)) != 0 && c != '\n');
2186 to
2187 while ((c = *(++ptr)) != 0 && c != '\n') ;
2188
2189 Totally extraordinary, but if that's what it takes...
2190
2191 5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2192 available. Added HAVE_BCOPY and an autoconf test for it; if neither
2193 HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2194 assumes the way PCRE uses memmove() (always moving upwards).
2195
2196 6. PCRE is being used in one environment where strchr() is not available. There
2197 was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2198 faster code anyway.
2199
2200
2201 Version 3.1 09-Feb-00
2202 ---------------------
2203
2204 The only change in this release is the fixing of some bugs in Makefile.in for
2205 the "install" target:
2206
2207 (1) It was failing to install pcreposix.h.
2208
2209 (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2210
2211
2212 Version 3.0 01-Feb-00
2213 ---------------------
2214
2215 1. Add support for the /+ modifier to perltest (to output $` like it does in
2216 pcretest).
2217
2218 2. Add support for the /g modifier to perltest.
2219
2220 3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2221 matches null strings.
2222
2223 4. Fix perltest so that it doesn't do unwanted things when fed an empty
2224 pattern. Perl treats empty patterns specially - it reuses the most recent
2225 pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2226 effect.
2227
2228 5. The POSIX interface was broken in that it was just handing over the POSIX
2229 captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2230 required a bigger vector, with some working space on the end. This means that
2231 the POSIX wrapper now has to get and free some memory, and copy the results.
2232
2233 6. Added some simple autoconf support, placing the test data and the
2234 documentation in separate directories, re-organizing some of the
2235 information files, and making it build pcre-config (a GNU standard). Also added
2236 libtool support for building PCRE as a shared library, which is now the
2237 default.
2238
2239 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2240 09 are not valid octal constants. Single digits will be used for minor values
2241 less than 10.
2242
2243 8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2244 existing programs that set these in the POSIX interface can use PCRE without
2245 modification.
2246
2247 9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2248 return all that pcre_info() returns, plus additional data. The pcre_info()
2249 function is retained for compatibility, but is considered to be obsolete.
2250
2251 10. Added experimental recursion feature (?R) to handle one common case that
2252 Perl 5.6 will be able to do with (?p{...}).
2253
2254 11. Added support for POSIX character classes like [:alpha:], which Perl is
2255 adopting.
2256
2257
2258 Version 2.08 31-Aug-99
2259 ----------------------
2260
2261 1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2262 trying to match at the startoffset position, but instead was moving forward to
2263 the next newline as if a previous match had failed.
2264
2265 2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2266 and could get into a loop if a null string was matched other than at the start
2267 of the subject.
2268
2269 3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2270 be distinguished at compile time, and for completeness also added PCRE_DATE.
2271
2272 5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2273 in GnuWin32 environments.
2274
2275
2276 Version 2.07 29-Jul-99
2277 ----------------------
2278
2279 1. The documentation is now supplied in plain text form and HTML as well as in
2280 the form of man page sources.
2281
2282 2. C++ compilers don't like assigning (void *) values to other pointer types.
2283 In particular this affects malloc(). Although there is no problem in Standard
2284 C, I've put in casts to keep C++ compilers happy.
2285
2286 3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2287 should be (const char *).
2288
2289 4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2290 be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2291 However, I haven't made this a standard facility. The documentation doesn't
2292 mention it, and the Makefile doesn't support it.
2293
2294 5. The Makefile now contains an "install" target, with editable destinations at
2295 the top of the file. The pcretest program is not installed.
2296
2297 6. pgrep -V now gives the PCRE version number and date.
2298
2299 7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2300 causing the entire string to be ignored, instead of just the last character.
2301
2302 8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2303 non-matching string, it can take a very, very long time, even for strings of
2304 quite modest length, because of the nested recursion. PCRE now does better in
2305 some of these cases. It does this by remembering the last required literal
2306 character in the pattern, and pre-searching the subject to ensure it is present
2307 before running the real match. In other words, it applies a heuristic to detect
2308 some types of certain failure quickly, and in the above example, if presented
2309 with a string that has no trailing " it gives "no match" very quickly.
2310
2311 9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2312 other alternatives are tried instead.
2313
2314
2315 Version 2.06 09-Jun-99
2316 ----------------------
2317
2318 1. Change pcretest's output for amount of store used to show just the code
2319 space, because the remainder (the data block) varies in size between 32-bit and
2320 64-bit systems.
2321
2322 2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2323 start matching at. This allows lookbehinds to work when searching for multiple
2324 occurrences in a string.
2325
2326 3. Added additional options to pcretest for testing multiple occurrences:
2327
2328 /+ outputs the rest of the string that follows a match
2329 /g loops for multiple occurrences, using the new startoffset argument
2330 /G loops for multiple occurrences by passing an incremented pointer
2331
2332 4. PCRE wasn't doing the "first character" optimization for patterns starting
2333 with \b or \B, though it was doing it for other lookbehind assertions. That is,
2334 it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2335 the letter 'x'. On long subject strings, this gives a significant speed-up.
2336
2337
2338 Version 2.05 21-Apr-99
2339 ----------------------
2340
2341 1. Changed the type of magic_number from int to long int so that it works
2342 properly on 16-bit systems.
2343
2344 2. Fixed a bug which caused patterns starting with .* not to work correctly
2345 when the subject string contained newline characters. PCRE was assuming
2346 anchoring for such patterns in all cases, which is not correct because .* will
2347 not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2348 DOTALL is set at top level; otherwise it knows that patterns starting with .*
2349 must be retried after every newline in the subject.
2350
2351
2352 Version 2.04 18-Feb-99
2353 ----------------------
2354
2355 1. For parenthesized subpatterns with repeats whose minimum was zero, the
2356 computation of the store needed to hold the pattern was incorrect (too large).
2357 If such patterns were nested a few deep, this could multiply and become a real
2358 problem.
2359
2360 2. Added /M option to pcretest to show the memory requirement of a specific
2361 pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2362
2363 3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2364 compiled in such a way that the backtracking after subsequent failure was
2365 pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2366 ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2367
2368
2369 Version 2.03 02-Feb-99
2370 ----------------------
2371
2372 1. Fixed typo and small mistake in man page.
2373
2374 2. Added 4th condition (GPL supersedes if conflict) and created separate
2375 LICENCE file containing the conditions.
2376
2377 3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2378 Perl, that is the internal \ allows the delimiter to be included in the
2379 pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2380 the final delimiter, add \ to the end of the pattern (to test the error).
2381
2382 4. Added the convenience functions for extracting substrings after a successful
2383 match. Updated pcretest to make it able to test these functions.
2384
2385
2386 Version 2.02 14-Jan-99
2387 ----------------------
2388
2389 1. Initialized the working variables associated with each extraction so that
2390 their saving and restoring doesn't refer to uninitialized store.
2391
2392 2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2393 compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2394 fix the problem.
2395
2396 3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2397 calls, and wasn't printing the correct value for compiling calls. Increased the
2398 default value of LOOPREPEAT, and the number of significant figures in the
2399 times.
2400
2401 4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2402
2403 5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2404 a building problem on Windows NT with a FAT file system.
2405
2406
2407 Version 2.01 21-Oct-98
2408 ----------------------
2409
2410 1. Changed the API for pcre_compile() to allow for the provision of a pointer
2411 to character tables built by pcre_maketables() in the current locale. If NULL
2412 is passed, the default tables are used.
2413
2414
2415 Version 2.00 24-Sep-98
2416 ----------------------
2417
2418 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2419 it any more.
2420
2421 2. Allow quantification of (?>) groups, and make it work correctly.
2422
2423 3. The first character computation wasn't working for (?>) groups.
2424
2425 4. Correct the implementation of \Z (it is permitted to match on the \n at the
2426 end of the subject) and add 5.005's \z, which really does match only at the
2427 very end of the subject.
2428
2429 5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2430
2431 6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2432 DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2433 localized options. All options to pcre_study() were also removed.
2434
2435 7. Add other new features from 5.005:
2436
2437 $(?<= positive lookbehind
2438 $(?<! negative lookbehind
2439 (?imsx-imsx) added the unsetting capability
2440 such a setting is global if at outer level; local otherwise
2441 (?imsx-imsx:) non-capturing groups with option setting
2442 (?(cond)re|re) conditional pattern matching
2443
2444 A backreference to itself in a repeated group matches the previous
2445 captured string.
2446
2447 8. General tidying up of studying (both automatic and via "study")
2448 consequential on the addition of new assertions.
2449
2450 9. As in 5.005, unlimited repeated groups that could match an empty substring
2451 are no longer faulted at compile time. Instead, the loop is forcibly broken at
2452 runtime if any iteration does actually match an empty substring.
2453
2454 10. Include the RunTest script in the distribution.
2455
2456 11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2457 discrepancies, some of which were old and were also with respect to 5.004. They
2458 have now been fixed.
2459
2460
2461 Version 1.09 28-Apr-98
2462 ----------------------
2463
2464 1. A negated single character class followed by a quantifier with a minimum
2465 value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2466 program crashes, or just wrong answers. This did not apply to negated classes
2467 containing more than one character, or to minima other than one.
2468
2469
2470 Version 1.08 27-Mar-98
2471 ----------------------
2472
2473 1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2474
2475 2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2476 latter must appear before anything that relies on it in the pattern.
2477
2478
2479 Version 1.07 16-Feb-98
2480 ----------------------
2481
2482 1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2483 repeat of a potentially empty string).
2484
2485
2486 Version 1.06 23-Jan-98
2487 ----------------------
2488
2489 1. Added Markus Oberhumer's little patches for C++.
2490
2491 2. Literal strings longer than 255 characters were broken.
2492
2493
2494 Version 1.05 23-Dec-97
2495 ----------------------
2496
2497 1. Negated character classes containing more than one character were failing if
2498 PCRE_CASELESS was set at run time.
2499
2500
2501 Version 1.04 19-Dec-97
2502 ----------------------
2503
2504 1. Corrected the man page, where some "const" qualifiers had been omitted.
2505
2506 2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2507 input syntax.
2508
2509 3. Fixed memory leak which occurred when a regex with back references was
2510 matched with an offsets vector that wasn't big enough. The temporary memory
2511 that is used in this case wasn't being freed if the match failed.
2512
2513 4. Tidied pcretest to ensure it frees memory that it gets.
2514
2515 5. Temporary memory was being obtained in the case where the passed offsets
2516 vector was exactly big enough.
2517
2518 6. Corrected definition of offsetof() from change 5 below.
2519
2520 7. I had screwed up change 6 below and broken the rules for the use of
2521 setjmp(). Now fixed.
2522
2523
2524 Version 1.03 18-Dec-97
2525 ----------------------
2526
2527 1. A erroneous regex with a missing opening parenthesis was correctly
2528 diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2529 on some systems.
2530
2531 2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2532 it was reported that one broken compiler failed on the former because "code" is
2533 also an independent variable.
2534
2535 3. The erroneous regex a[]b caused an array overrun reference.
2536
2537 4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2538 fail on data ending with that character. (It was going on too far, and checking
2539 the next character, typically a binary zero.) This was specific to the
2540 optimized code for single-character negative classes.
2541
2542 5. Added a contributed patch from the TIN world which does the following:
2543
2544 + Add an undef for memmove, in case the the system defines a macro for it.
2545
2546 + Add a definition of offsetof(), in case there isn't one. (I don't know
2547 the reason behind this - offsetof() is part of the ANSI standard - but
2548 it does no harm).
2549
2550 + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2551 most of the places where whitespace preceded '#'. I have given up and
2552 allowed the remaining 2 cases to be at the margin.
2553
2554 + Rename some variables in pcre to eliminate shadowing. This seems very
2555 pedantic, but does no harm, of course.
2556
2557 6. Moved the call to setjmp() into its own function, to get rid of warnings
2558 from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2559
2560 7. Constructs such as \d{8,} were compiling into the equivalent of
2561 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2562 outcome, but in this particular case used more store than had been allocated,
2563 which caused the bug to be discovered because it threw up an internal error.
2564
2565 8. The debugging code in both pcre and pcretest for outputting the compiled
2566 form of a regex was going wrong in the case of back references followed by
2567 curly-bracketed repeats.
2568
2569
2570 Version 1.02 12-Dec-97
2571 ----------------------
2572
2573 1. Typos in pcre.3 and comments in the source fixed.
2574
2575 2. Applied a contributed patch to get rid of places where it used to remove
2576 'const' from variables, and fixed some signed/unsigned and uninitialized
2577 variable warnings.
2578
2579 3. Added the "runtest" target to Makefile.
2580
2581 4. Set default compiler flag to -O2 rather than just -O.
2582
2583
2584 Version 1.01 19-Nov-97
2585 ----------------------
2586
2587 1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2588 like /([ab]*)*/, that is, for classes with more than one character in them.
2589
2590 2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2591 as /((?>a*))*/ (a PCRE_EXTRA facility).
2592
2593
2594 Version 1.00 18-Nov-97
2595 ----------------------
2596
2597 1. Added compile-time macros to support systems such as SunOS4 which don't have
2598 memmove() or strerror() but have other things that can be used instead.
2599
2600 2. Arranged that "make clean" removes the executables.
2601
2602
2603 Version 0.99 27-Oct-97
2604 ----------------------
2605
2606 1. Fixed bug in code for optimizing classes with only one character. It was
2607 initializing a 32-byte map regardless, which could cause it to run off the end
2608 of the memory it had got.
2609
2610 2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2611
2612
2613 Version 0.98 22-Oct-97
2614 ----------------------
2615
2616 1. Fixed bug in code for handling temporary memory usage when there are more
2617 back references than supplied space in the ovector. This could cause segfaults.
2618
2619
2620 Version 0.97 21-Oct-97
2621 ----------------------
2622
2623 1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2624
2625 2. Optimized negated single characters not to use a bit map.
2626
2627 3. Brought error texts together as macro definitions; clarified some of them;
2628 fixed one that was wrong - it said "range out of order" when it meant "invalid
2629 escape sequence".
2630
2631 4. Changed some char * arguments to const char *.
2632
2633 5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2634
2635 6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2636 pcretest.
2637
2638
2639 Version 0.96 16-Oct-97
2640 ----------------------
2641
2642 1. Added a simple "pgrep" utility to the distribution.
2643
2644 2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2645 unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2646 where "ddd" means "one or more decimal digits".
2647
2648 3. Fixed serious bug. If a pattern had a back reference, but the call to
2649 pcre_exec() didn't supply a large enough ovector to record the related
2650 identifying subpattern, the match always failed. PCRE now remembers the number
2651 of the largest back reference, and gets some temporary memory in which to save
2652 the offsets during matching if necessary, in order to ensure that
2653 backreferences always work.
2654
2655 4. Increased the compatibility with Perl in a number of ways:
2656
2657 (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2658 to request this handling. The option can be set at compile or exec time.
2659
2660 (b) $ matches before a terminating newline by default; an option
2661 PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2662 mode). The option can be set at compile or exec time.
2663
2664 (c) The handling of \ followed by a digit other than 0 is now supposed to be
2665 the same as Perl's. If the decimal number it represents is less than 10
2666 or there aren't that many previous left capturing parentheses, an octal
2667 escape is read. Inside a character class, it's always an octal escape,
2668 even if it is a single digit.
2669
2670 (d) An escaped but undefined alphabetic character is taken as a literal,
2671 unless PCRE_EXTRA is set. Currently this just reserves the remaining
2672 escapes.
2673
2674 (e) {0} is now permitted. (The previous item is removed from the compiled
2675 pattern).
2676
2677 5. Changed all the names of code files so that the basic parts are no longer
2678 than 10 characters, and abolished the teeny "globals.c" file.
2679
2680 6. Changed the handling of character classes; they are now done with a 32-byte
2681 bit map always.
2682
2683 7. Added the -d and /D options to pcretest to make it possible to look at the
2684 internals of compilation without having to recompile pcre.
2685
2686
2687 Version 0.95 23-Sep-97
2688 ----------------------
2689
2690 1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2691 \x20 at the start of a run of normal characters. These were being treated as
2692 real characters, instead of the source characters being re-checked.
2693
2694
2695 Version 0.94 18-Sep-97
2696 ----------------------
2697
2698 1. The functions are now thread-safe, with the caveat that the global variables
2699 containing pointers to malloc() and free() or alternative functions are the
2700 same for all threads.
2701
2702 2. Get pcre_study() to generate a bitmap of initial characters for non-
2703 anchored patterns when this is possible, and use it if passed to pcre_exec().
2704
2705
2706 Version 0.93 15-Sep-97
2707 ----------------------
2708
2709 1. /(b)|(:+)/ was computing an incorrect first character.
2710
2711 2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2712 but not actually doing anything yet.
2713
2714 3. Treat "-" characters in classes that cannot be part of ranges as literals,
2715 as Perl does (e.g. [-az] or [az-]).
2716
2717 4. Set the anchored flag if a branch starts with .* or .*? because that tests
2718 all possible positions.
2719
2720 5. Split up into different modules to avoid including unneeded functions in a
2721 compiled binary. However, compile and exec are still in one module. The "study"
2722 function is split off.
2723
2724 6. The character tables are now in a separate module whose source is generated
2725 by an auxiliary program - but can then be edited by hand if required. There are
2726 now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2727 toupper() in the code.
2728
2729 7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2730 make them global. Abolish the function for setting them, as the caller can now
2731 set them directly.
2732
2733
2734 Version 0.92 11-Sep-97
2735 ----------------------
2736
2737 1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2738 (e.g. /a{1,3}/) was broken (I mis-optimized it).
2739
2740 2. Caseless matching was not working in character classes if the characters in
2741 the pattern were in upper case.
2742
2743 3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2744
2745 4. Make PCRE_ANCHORED public and accept as a compile option.
2746
2747 5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2748 PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2749 pass them.
2750
2751 6. Give an error if bad option bits passed at compile or run time.
2752
2753 7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2754 pcretest to cause it to pass that flag.
2755
2756 8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2757 options, and the first character, if set.
2758
2759 9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2760
2761
2762 Version 0.91 10-Sep-97
2763 ----------------------
2764
2765 1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2766 match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2767
2768 2. PCRE was looping on encountering an indefinitely repeated back reference to
2769 a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2770 Perl does - treats the match as successful.
2771
2772 ****

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