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Revision 473 - (hide annotations) (download)
Sat Jan 2 12:40:07 2010 UTC (5 years, 3 months ago) by ph10
File size: 176103 byte(s)
Fix bugs relating to the use of (*SKIP) etc in assertions.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 471 Version 8.01 11-Dec-09
5     ----------------------
7     1. If a pattern contained a conditional subpattern with only one branch (in
8 ph10 473 particular, this includes all (DEFINE) patterns), a call to pcre_study()
9     computed the wrong minimum data length (which is of course zero for such
10 ph10 471 subpatterns).
11 ph10 473
12     2. For patterns such as (?i)a(?-i)b|c where an option setting at the start of
13 ph10 472 the pattern is reset in the first branch, pcre_compile() failed with
14     "internal error: code overflow at offset...". This happened only when
15 ph10 473 the reset was to the original external option setting. (An optimization
16     abstracts leading options settings into an external setting, which was the
17 ph10 472 cause of this.)
18 ph10 471
19 ph10 473 3. A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
20     of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
21     assertion pattern did not match (meaning that the assertion was true), it
22     was incorrectly treated as false if the SKIP had been reached during the
23     matching. This also applied to assertions used as conditions.
24 ph10 471
25 ph10 473 4. If an item that is not supported by pcre_dfa_exec() was encountered in an
26     assertion subpattern, including such a pattern used as a condition,
27     unpredictable results occurred, instead of the error return
31 ph10 469 Version 8.00 19-Oct-09
32 ph10 418 ----------------------
34     1. The table for translating pcre_compile() error codes into POSIX error codes
35 ph10 461 was out-of-date, and there was no check on the pcre_compile() error code
36     being within the table. This could lead to an OK return being given in
37 ph10 418 error.
38 ph10 461
39     2. Changed the call to open a subject file in pcregrep from fopen(pathname,
40     "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
41     in a Windows environment.
43 ph10 420 3. The pcregrep --count option prints the count for each file even when it is
44     zero, as does GNU grep. However, pcregrep was also printing all files when
45     --files-with-matches was added. Now, when both options are given, it prints
46     counts only for those files that have at least one match. (GNU grep just
47 ph10 461 prints the file name in this circumstance, but including the count seems
48     more useful - otherwise, why use --count?) Also ensured that the
49 ph10 420 combination -clh just lists non-zero counts, with no names.
50 ph10 461
51     4. The long form of the pcregrep -F option was incorrectly implemented as
52     --fixed_strings instead of --fixed-strings. This is an incompatible change,
53     but it seems right to fix it, and I didn't think it was worth preserving
54     the old behaviour.
56     5. The command line items --regex=pattern and --regexp=pattern were not
57 ph10 422 recognized by pcregrep, which required --regex pattern or --regexp pattern
58 ph10 461 (with a space rather than an '='). The man page documented the '=' forms,
59 ph10 422 which are compatible with GNU grep; these now work.
60 ph10 461
61     6. No libpcreposix.pc file was created for pkg-config; there was just
62 ph10 423 libpcre.pc and libpcrecpp.pc. The omission has been rectified.
63 ph10 461
64 ph10 425 7. Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
65 ph10 461 when UCP support is not needed, by modifying the Python script that
66 ph10 425 generates it from Unicode data files. This should not matter if the module
67     is correctly used as a library, but I received one complaint about 50K of
68     unwanted data. My guess is that the person linked everything into his
69     program rather than using a library. Anyway, it does no harm.
70 ph10 461
71 ph10 426 8. A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
72 ph10 461 was a minimum greater than 1 for a wide character in a possessive
73 ph10 431 repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
74     which had an unlimited repeat of a nested, fixed maximum repeat of a wide
75     character. Chaos in the form of incorrect output or a compiling loop could
76     result.
77 ph10 461
78 ph10 426 9. The restrictions on what a pattern can contain when partial matching is
79 ph10 461 requested for pcre_exec() have been removed. All patterns can now be
80 ph10 426 partially matched by this function. In addition, if there are at least two
81 ph10 435 slots in the offset vector, the offset of the earliest inspected character
82     for the match and the offset of the end of the subject are set in them when
83 ph10 461 PCRE_ERROR_PARTIAL is returned.
85 ph10 428 10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
86     synonymous with PCRE_PARTIAL, for backwards compatibility, and
87     PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
88 ph10 462 and may be more useful for multi-segment matching.
89 ph10 461
90     11. Partial matching with pcre_exec() is now more intuitive. A partial match
91     used to be given if ever the end of the subject was reached; now it is
92     given only if matching could not proceed because another character was
93     needed. This makes a difference in some odd cases such as Z(*FAIL) with the
94     string "Z", which now yields "no match" instead of "partial match". In the
95     case of pcre_dfa_exec(), "no match" is given if every matching path for the
96     final character ended with (*FAIL).
98 ph10 428 12. Restarting a match using pcre_dfa_exec() after a partial match did not work
99 ph10 461 if the pattern had a "must contain" character that was already found in the
100 ph10 428 earlier partial match, unless partial matching was again requested. For
101     example, with the pattern /dog.(body)?/, the "must contain" character is
102     "g". If the first part-match was for the string "dog", restarting with
103 ph10 435 "sbody" failed. This bug has been fixed.
104 ph10 461
105     13. The string returned by pcre_dfa_exec() after a partial match has been
106     changed so that it starts at the first inspected character rather than the
107     first character of the match. This makes a difference only if the pattern
108     starts with a lookbehind assertion or \b or \B (\K is not supported by
109     pcre_dfa_exec()). It's an incompatible change, but it makes the two
110 ph10 435 matching functions compatible, and I think it's the right thing to do.
111 ph10 461
112 ph10 435 14. Added a pcredemo man page, created automatically from the pcredemo.c file,
113 ph10 461 so that the demonstration program is easily available in environments where
114     PCRE has not been installed from source.
116 ph10 435 15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
117 ph10 430 libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
118     library.
119 ph10 461
120 ph10 435 16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
121 ph10 432 It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
122 ph10 461 is not the first non-POSIX option to be added. Clearly some people find
123 ph10 433 these options useful.
124 ph10 461
125     17. If a caller to the POSIX matching function regexec() passes a non-zero
126 ph10 438 value for nmatch with a NULL value for pmatch, the value of
127 ph10 461 nmatch is forced to zero.
129 ph10 437 18. RunGrepTest did not have a test for the availability of the -u option of
130 ph10 461 the diff command, as RunTest does. It now checks in the same way as
131 ph10 437 RunTest, and also checks for the -b option.
132 ph10 461
133 ph10 438 19. If an odd number of negated classes containing just a single character
134     interposed, within parentheses, between a forward reference to a named
135 ph10 461 subpattern and the definition of the subpattern, compilation crashed with
136     an internal error, complaining that it could not find the referenced
137 ph10 438 subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
138 ph10 461 [The bug was that it was starting one character too far in when skipping
139     over the character class, thus treating the ] as data rather than
140     terminating the class. This meant it could skip too much.]
142 ph10 442 20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
143 ph10 461 /g option in pcretest when the pattern contains \K, which makes it possible
144 ph10 442 to have an empty string match not at the start, even when the pattern is
145 ph10 461 anchored. Updated pcretest and pcredemo to use this option.
147 ph10 446 21. If the maximum number of capturing subpatterns in a recursion was greater
148 ph10 461 than the maximum at the outer level, the higher number was returned, but
149     with unset values at the outer level. The correct (outer level) value is
150 ph10 446 now given.
151 ph10 461
152 ph10 447 22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
153     PCRE did not set those parentheses (unlike Perl). I have now found a way to
154     make it do so. The string so far is captured, making this feature
155     compatible with Perl.
156 ph10 461
157     23. The tests have been re-organized, adding tests 11 and 12, to make it
158 ph10 448 possible to check the Perl 5.10 features against Perl 5.10.
159 ph10 461
160 ph10 454 24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
161 ph10 461 pattern matches a fixed length string. PCRE did not allow this; now it
162     does. Neither allows recursion.
164     25. I finally figured out how to implement a request to provide the minimum
165     length of subject string that was needed in order to match a given pattern.
166     (It was back references and recursion that I had previously got hung up
167     on.) This code has now been added to pcre_study(); it finds a lower bound
168 ph10 455 to the length of subject needed. It is not necessarily the greatest lower
169     bound, but using it to avoid searching strings that are too short does give
170     some useful speed-ups. The value is available to calling programs via
171     pcre_fullinfo().
172 ph10 461
173 ph10 455 26. While implementing 25, I discovered to my embarrassment that pcretest had
174     not been passing the result of pcre_study() to pcre_dfa_exec(), so the
175     study optimizations had never been tested with that matching function.
176     Oops. What is worse, even when it was passed study data, there was a bug in
177     pcre_dfa_exec() that meant it never actually used it. Double oops. There
178     were also very few tests of studied patterns with pcre_dfa_exec().
179 ph10 461
180 ph10 457 27. If (?| is used to create subpatterns with duplicate numbers, they are now
181     allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
182     on the other side of the coin, they are no longer allowed to have different
183     names, because these cannot be distinguished in PCRE, and this has caused
184     confusion. (This is a difference from Perl.)
185 ph10 461
186     28. When duplicate subpattern names are present (necessarily with different
187     numbers, as required by 27 above), and a test is made by name in a
188     conditional pattern, either for a subpattern having been matched, or for
189     recursion in such a pattern, all the associated numbered subpatterns are
190 ph10 459 tested, and the overall condition is true if the condition is true for any
191     one of them. This is the way Perl works, and is also more like the way
192     testing by number works.
193 ph10 418
194 ph10 461
195 ph10 412 Version 7.9 11-Apr-09
196 ph10 376 ---------------------
198 ph10 392 1. When building with support for bzlib/zlib (pcregrep) and/or readline
199 ph10 376 (pcretest), all targets were linked against these libraries. This included
200     libpcre, libpcreposix, and libpcrecpp, even though they do not use these
201     libraries. This caused unwanted dependencies to be created. This problem
202 ph10 392 has been fixed, and now only pcregrep is linked with bzlib/zlib and only
203 ph10 376 pcretest is linked with readline.
204 ph10 392
205 ph10 376 2. The "typedef int BOOL" in pcre_internal.h that was included inside the
206     "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
207     moved outside it again, because FALSE and TRUE are already defined in AIX,
208     but BOOL is not.
209 ph10 392
210     3. The pcre_config() function was treating the PCRE_MATCH_LIMIT and
211 ph10 409 PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
212 ph10 392
213 ph10 376 4. The pcregrep documentation said spaces were inserted as well as colons (or
214     hyphens) following file names and line numbers when outputting matching
215 ph10 392 lines. This is not true; no spaces are inserted. I have also clarified the
216 ph10 376 wording for the --colour (or --color) option.
217 ph10 392
218 ph10 378 5. In pcregrep, when --colour was used with -o, the list of matching strings
219     was not coloured; this is different to GNU grep, so I have changed it to be
220     the same.
221 ph10 392
222 ph10 378 6. When --colo(u)r was used in pcregrep, only the first matching substring in
223 ph10 392 each matching line was coloured. Now it goes on to look for further matches
224     of any of the test patterns, which is the same behaviour as GNU grep.
226     7. A pattern that could match an empty string could cause pcregrep to loop; it
227     doesn't make sense to accept an empty string match in pcregrep, so I have
228 ph10 379 locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
229     seems to be how GNU grep behaves.
230 ph10 392
231 ph10 380 8. The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
232 ph10 392 start or after a newline", because the conditional assertion was not being
233     correctly handled. The rule now is that both the assertion and what follows
234     in the first alternative must satisfy the test.
236 ph10 405 9. If auto-callout was enabled in a pattern with a conditional group whose
237 ph10 399 condition was an assertion, PCRE could crash during matching, both with
238     pcre_exec() and pcre_dfa_exec().
239 ph10 392
240     10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
241     used for matching.
243     11. Unicode property support in character classes was not working for
244 ph10 385 characters (bytes) greater than 127 when not in UTF-8 mode.
245 ph10 388
246 ph10 392 12. Added the -M command line option to pcretest.
248 ph10 388 14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
249 ph10 389
250     15. Added the PCRE_NO_START_OPTIMIZE match-time option.
251 ph10 390
252 ph10 392 16. Added comments and documentation about mis-use of no_arg in the C++
253 ph10 390 wrapper.
254 ph10 392
255 ph10 391 17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
256 ph10 392 from Martin Jerabek that uses macro names for all relevant character and
257 ph10 391 string constants.
258 ph10 405
259 ph10 393 18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
260     SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
261 ph10 405 SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
262     these, but not everybody uses configure.
264     19. A conditional group that had only one branch was not being correctly
265     recognized as an item that could match an empty string. This meant that an
266     enclosing group might also not be so recognized, causing infinite looping
267     (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
268     with the subject "ab", where knowledge that the repeated group can match
269 ph10 396 nothing is needed in order to break the loop.
270 ph10 405
271 ph10 397 20. If a pattern that was compiled with callouts was matched using pcre_dfa_
272 ph10 405 exec(), but without supplying a callout function, matching went wrong.
274     21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
275     leak if the size of the offset vector was greater than 30. When the vector
276     is smaller, the saved offsets during recursion go onto a local stack
277     vector, but for larger vectors malloc() is used. It was failing to free
278     when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
279 ph10 400 error, in fact).
280 ph10 405
281 ph10 402 22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
282 ph10 405 heapframe that is used only when UTF-8 support is enabled. This caused no
283     problem, but was untidy.
284 ph10 376
285 ph10 405 23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
286     CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
287     included within another project.
288 ph10 411
289 ph10 407 24. Steven Van Ingelgem's patches to add more options to the CMake support,
290     slightly modified by me:
291 ph10 411
292     (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
293     not building pcregrep.
295 ph10 407 (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
296 ph10 411 if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
298 ph10 408 25. Forward references, both numeric and by name, in patterns that made use of
299     duplicate group numbers, could behave incorrectly or give incorrect errors,
300     because when scanning forward to find the reference group, PCRE was not
301     taking into account the duplicate group numbers. A pattern such as
302     ^X(?3)(a)(?|(b)|(q))(Y) is an example.
303 ph10 411
304     26. Changed a few more instances of "const unsigned char *" to USPTR, making
305     the feature of a custom pointer more persuasive (as requested by a user).
306 ph10 416
307 ph10 411 27. Wrapped the definitions of fileno and isatty for Windows, which appear in
308 ph10 416 pcretest.c, inside #ifndefs, because it seems they are sometimes already
309     pre-defined.
310 ph10 392
311 ph10 416 28. Added support for (*UTF8) at the start of a pattern.
313 ph10 413 29. Arrange for flags added by the "release type" setting in CMake to be shown
314     in the configuration summary.
315 ph10 405
316 ph10 411
317 ph10 374 Version 7.8 05-Sep-08
318 ph10 349 ---------------------
320     1. Replaced UCP searching code with optimized version as implemented for Ad
321     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
322 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
323     to 5 times on some simple patterns that I tested. Permission was given to
324     distribute the MultiStage2.py script that generates the tables (it's not in
325     the tarball, but is in the Subversion repository).
326 ph10 349
327 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
328     scripts.
329 ph10 358
330 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
331     a group with a zero qualifier. The result of the study could be incorrect,
332 ph10 358 or the function might crash, depending on the pattern.
334     4. Caseless matching was not working for non-ASCII characters in back
335 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
336 ph10 358 It now works when Unicode Property Support is available.
338 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
339     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
340     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
341 ph10 358 truncation.
342 ph10 349
343 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
345 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
346     pointers, in case they are 64-bit values.
347 ph10 371
348     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
349     test 2 if it fails.
351 ph10 359 9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
352 ph10 371 and a #define of that name to empty if it is not externally set. This is to
353     allow users of MSVC to set it if necessary.
355     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
356 ph10 359 the convenience functions in the pcre_get.c source file.
357 ph10 371
358 ph10 360 11. An option change at the start of a pattern that had top-level alternatives
359     could cause overwriting and/or a crash. This command provoked a crash in
360 ph10 371 some environments:
362     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
364 ph10 360 This potential security problem was recorded as CVE-2008-2371.
365 ph10 371
366 ph10 361 12. For a pattern where the match had to start at the beginning or immediately
367     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
368 ph10 371 pcre_dfa_exec() could read past the end of the passed subject if there was
369 ph10 361 no match. To help with detecting such bugs (e.g. with valgrind), I modified
370     pcretest so that it places the subject at the end of its malloc-ed buffer.
371 ph10 371
372 ph10 364 13. The change to pcretest in 12 above threw up a couple more cases when pcre_
373 ph10 371 exec() might read past the end of the data buffer in UTF-8 mode.
375 ph10 364 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
376 ph10 371 the data contained the byte 0x85 as part of a UTF-8 character within its
377     first line. This applied both to normal and DFA matching.
379 ph10 366 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
380 ph10 371 /^[^d]*?$/8 failed to match "abc".
381 ph10 351
382 ph10 371 16. Added a missing copyright notice to pcrecpp_internal.h.
384     17. Make it more clear in the documentation that values returned from
385 ph10 368 pcre_exec() in ovector are byte offsets, not character counts.
386 ph10 357
387 ph10 371 18. Tidied a few places to stop certain compilers from issuing warnings.
388 ph10 368
389 ph10 373 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
390     supplied by Stefan Weber. I made a further small update for 7.8 because
391 ph10 374 there is a change of source arrangements: the pcre_searchfuncs.c module is
392     replaced by pcre_ucd.c.
393 ph10 371
394 ph10 373
395 ph10 347 Version 7.7 07-May-08
396 ph10 321 ---------------------
398     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
399 ph10 345 a string to a long long, pretend we don't even have a long long." This is
400 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
401 ph10 345
402 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
403     pre-7.6 versions, which defined a global no_arg variable instead of putting
404 ph10 332 it in the RE class. (See also #8 below.)
405 ph10 345
406     3. Remove a line of dead code, identified by coverity and reported by Nuno
407     Lopes.
409 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
410 ph10 321
411 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
412 ph10 345 of files, instead of just to the final components.
414 ph10 324 (2) If there was more than one level of directory, the subdirectories were
415     skipped unless they satisfied the include/exclude conditions. This is
416     inconsistent with GNU grep (and could even be seen as contrary to the
417     pcregrep specification - which I improved to make it absolutely clear).
418     The action now is always to scan all levels of directory, and just
419     apply the include/exclude patterns to regular files.
420 ph10 345
421 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
422 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
424 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
425 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
426 ph10 326 doesn't support NULs in patterns.
427 ph10 345
428     7. Added some missing "const"s to declarations of static tables in
429     pcre_compile.c and pcre_dfa_exec.c.
431 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
432 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
433 ph10 345 first patch. And a third patch - this was a messy problem.)
434 ph10 321
435 ph10 345 9. Applied Craig's patch to remove the use of push_back().
437 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
438     matching function regexec().
439 ph10 345
440     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
441     which, however, unlike Perl's \g{...}, are subroutine calls, not back
442 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
443     Oniguruma does).
444 ph10 345
445     12. Previously, a group with a zero repeat such as (...){0} was completely
446 ph10 335 omitted from the compiled regex. However, this means that if the group
447     was called as a subroutine from elsewhere in the pattern, things went wrong
448 ph10 345 (an internal error was given). Such groups are now left in the compiled
449     pattern, with a new opcode that causes them to be skipped at execution
450 ph10 335 time.
451 ph10 345
452 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
453     to the way PCRE behaves:
454 ph10 345
455 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
456 ph10 345
457     (b) A back reference to an unmatched subpattern matches an empty string
458 ph10 336 (Perl fails the current match path).
459 ph10 345
460 ph10 341 (c) A data ] in a character class must be notated as \] because if the
461 ph10 345 first data character in a class is ], it defines an empty class. (In
462 ph10 341 Perl it is not possible to have an empty class.) The empty class []
463     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
464     The negative empty class [^] matches any one character, independently
465     of the DOTALL setting.
466 ph10 345
467     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
468 ph10 340 non-existent subpattern following a character class starting with ']' and
469     containing () gave an internal compiling error instead of "reference to
470     non-existent subpattern". Fortunately, when the pattern did exist, the
471 ph10 345 compiled code was correct. (When scanning forwards to check for the
472 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
473 ph10 345 the class, so got the count wrong. When actually compiling, the reference
474 ph10 340 was subsequently set up correctly.)
475 ph10 345
476 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
477 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
478     other assertions are supported. I have made pcre_dfa_exec() support
479     (*FAIL).
481 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
482 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
483     cannot be changed at match time, I realized I could make a small
484     improvement to matching performance by compiling OP_ALLANY instead of
485     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
486     on the OP_ANY path.
488     17. Compiling pcretest on Windows with readline support failed without the
489 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
490 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
492 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
493 ph10 345 ncurses library to be included for pcretest when ReadLine support is
494     requested, but also to allow for it to be overridden. This patch came from
495     Daniel Bergström.
496 ph10 347
497 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
498 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
499     any errors with the current Unicode tables. Thanks to Peter Kankowski for
500     spotting this.
501 ph10 324
502 ph10 332
503 ph10 319 Version 7.6 28-Jan-08
504 ph10 300 ---------------------
506 ph10 302 1. A character class containing a very large number of characters with
507     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
508     overflow.
509 ph10 309
510     2. Patch to cut out the "long long" test in pcrecpp_unittest when
511     HAVE_LONG_LONG is not defined.
513 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
514 ph10 304 bring them up to date and include new features. This patch includes:
515 ph10 309
516 ph10 304 - Fixed PH's badly added libz and libbz2 support.
517     - Fixed a problem with static linking.
518 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
519 ph10 304 - Fixed dftables problem and added an option.
520     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
522     - Added readline support for pcretest.
523 ph10 309 - Added an listing of the option settings after cmake has run.
525 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
526     "pcre.dll" under mingw when using Configure/Make. I added stuff to
527     Makefile.am that cause it to include this special target, without
528     affecting anything else. Note that the same mingw target plus all
529     the other distribution libraries and programs are now supported
530     when configuring with CMake (see 6 below) instead of with
531     Configure/Make.
532 ph10 309
533 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
534     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
535 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
536     solves the problem, but it does no harm.
537 ph10 313
538 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
539 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
540 ph10 314 with CMake, and also correct the comment about stack recursion.
541 ph10 313
542 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
543 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
544     of a program that users should build themselves after PCRE is installed, so
545     building it automatically is not really right. What is more, it gave
546 ph10 312 trouble in some build environments.
547 ph10 300
548 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
549 ph10 308
550 ph10 319
551 ph10 298 Version 7.5 10-Jan-08
552 ph10 263 ---------------------
554     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
555     values in parens when parsing an RE using the C++ wrapper."
556 ph10 286
557 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
558     Characters greater than 255 were excluded from the class instead of being
559     included.
560 ph10 286
561     3. The same bug as (2) above applied to negated POSIX classes such as
562 ph10 265 [:^space:].
563 ph10 286
564 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
565     defined or documented. It seems to have been a typo for PCRE_STATIC, so
566 ph10 286 I have changed it.
568 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
569 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
570     first named subpattern whose name started with "a" (in other words, the
571 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
572     expected" is now given for (?&) (a zero-length name), and this patch also
573     makes it give the same error for \k'' (previously it complained that that
574     was a reference to a non-existent subpattern).
575 ph10 286
576 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
577 ph10 286 this is right because (?- can be followed by option settings as well as by
578 ph10 269 digits. I have, however, made the messages clearer.
579 ph10 286
580 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
581     than the number used in the conditional) now cause a compile-time error.
582     This is actually not compatible with Perl, which accepts such patterns, but
583     treats the conditional as always being FALSE (as PCRE used to), but it
584     seems to me that giving a diagnostic is better.
585 ph10 286
586 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
587 ph10 275 and messages.
588 ph10 286
589     9. Fix two occurrences of "backslash" in comments that should have been
590     "backspace".
592     10. Remove two redundant lines of code that can never be obeyed (their function
593     was moved elsewhere).
595     11. The program that makes PCRE's Unicode character property table had a bug
596     which caused it to generate incorrect table entries for sequences of
597 ph10 277 characters that have the same character type, but are in different scripts.
598 ph10 286 It amalgamated them into a single range, with the script of the first of
599 ph10 277 them. In other words, some characters were in the wrong script. There were
600     thirteen such cases, affecting characters in the following ranges:
601 ph10 286
602 ph10 277 U+002b0 - U+002c1
603     U+0060c - U+0060d
604 ph10 286 U+0061e - U+00612
605 ph10 277 U+0064b - U+0065e
606     U+0074d - U+0076d
607     U+01800 - U+01805
608     U+01d00 - U+01d77
609     U+01d9b - U+01dbf
610     U+0200b - U+0200f
611     U+030fc - U+030fe
612     U+03260 - U+0327f
613     U+0fb46 - U+0fbb1
614     U+10450 - U+1049d
615 ph10 286
616 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
617     compatible with GNU grep in that, if there was more than one match in a
618     line, it showed only the first of them. It now behaves in the same way as
619     GNU grep.
620 ph10 286
621     13. If the -o and -v options were combined for pcregrep, it printed a blank
622     line for every non-matching line. GNU grep prints nothing, and pcregrep now
623     does the same. The return code can be used to tell if there were any
624     non-matching lines.
626 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
628     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
629 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
630 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
631     and both kinds of lookbehind were skipped).
633 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
634 ph10 284 inclusion of <windows.h> to before rather than after the definition of
635     INVALID_FILE_ATTRIBUTES (patch from David Byron).
636 ph10 263
637 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
638 ph10 286 character property caused pcre_compile() to compile bad code, which led at
639     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
640     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
641     caused the error; without that there was no problem.
642 ph10 263
643 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
644 ph10 286
645 ph10 289 19. Added --enable-pcretest-libreadline.
646 ph10 286
647 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
648 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
649 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
650     later patch that removed the other one (the right fix) and added unit tests
651     that check the return values (which was not done before).
652 ph10 292
653 ph10 291 21. Several CMake things:
654 ph10 287
655 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
656 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
657 ph10 288
658 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
659     linked with the newly-built libraries, not previously installed ones.
660 ph10 291
662 ph10 298
663     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
664     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
665     UTF-8 newline character). The key issue is that the pattern starts .*;
666     this means that the match must be either at the beginning, or after a
667     newline. The bug was in the code for advancing after a failed match and
668     checking that the new position followed a newline. It was not taking
669 ph10 294 account of UTF-8 characters correctly.
670 ph10 298
671     23. PCRE was behaving differently from Perl in the way it recognized POSIX
672     character classes. PCRE was not treating the sequence [:...:] as a
673     character class unless the ... were all letters. Perl, however, seems to
674     allow any characters between [: and :], though of course it rejects as
675     unknown any "names" that contain non-letters, because all the known class
676     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
677     for example, whereas PCRE did not - it did not recognize a POSIX character
678     class. This seemed a bit dangerous, so the code has been changed to be
679     closer to Perl. The behaviour is not identical to Perl, because PCRE will
680     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
681     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
682     Perl does, and where it didn't before.
684 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
685     Windows environments %n is disabled by default.
686 ph10 292
688 ph10 260 Version 7.4 21-Sep-07
689 ph10 230 ---------------------
691     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
692 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
693     LF". That isn't really right - the whole point of the change was to try to
694     help when there was an actual mention of one of the two characters. So now
695     the change happens only if \r or \n (or a literal CR or LF) character is
696 ph10 230 encountered.
697 ph10 231
698     2. The 32-bit options word was also used for 6 internal flags, but the numbers
699     of both had grown to the point where there were only 3 bits left.
700     Fortunately, there was spare space in the data structure, and so I have
701     moved the internal flags into a new 16-bit field to free up more option
702 ph10 230 bits.
703 ph10 231
704     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
705     but did not set the internal JCHANGED flag - either of these is enough to
706     control the way the "get" function works - but the PCRE_INFO_JCHANGED
707     facility is supposed to tell if (?J) was ever used, so now (?J) at the
708 ph10 230 start sets both bits.
710 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
711     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
712 ph10 230
713 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
715     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
716 ph10 233 compatibility, even though it is no longer used.
717 ph10 243
718     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
719 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
720 ph10 259 windows.h file is present (where different names are used). [This was
721 ph10 257 reversed later after testing - see 16 below.]
722 ph10 243
723     8. Changed all #include <config.h> to #include "config.h". There were also
724 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
725 ph10 243
726 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
727 ph10 243 sequence off the lines that it output.
729     10. It was pointed out to me that arrays of string pointers cause lots of
730     relocations when a shared library is dynamically loaded. A technique of
731     using a single long string with a table of offsets can drastically reduce
732     these. I have refactored PCRE in four places to do this. The result is
733 ph10 240 dramatic:
734 ph10 243
735 ph10 240 Originally: 290
736     After changing UCP table: 187
737 ph10 243 After changing error message table: 43
738 ph10 240 After changing table of "verbs" 36
739     After changing table of Posix names 22
740 ph10 243
741 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
742 ph10 247
743 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
744 ph10 247 unicode-properties was also set.
746 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
747 ph10 231
748 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
749     checked only for CRLF.
750 ph10 233
751 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
753 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
754 ph10 253
755 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
756 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
757     entirely. This removes changes made in 7 above.
758 ph10 256
759 ph10 261 17. The CMake files have been updated, and there is now more information about
760     building with CMake in the NON-UNIX-USE document.
761 ph10 257
762 ph10 261
763 ph10 228 Version 7.3 28-Aug-07
764 ph10 157 ---------------------
766 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
767     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
768     brackets there is not right, since it causes compilers to look for an
769     installed pcre.h, not the version that is in the source that is being
770     compiled (which of course may be different). I have changed it back to:
771 ph10 197
772 ph10 189 #include "pcre.h"
773 ph10 197
774     I have a vague recollection that the change was concerned with compiling in
775     different directories, but in the new build system, that is taken care of
776     by the VPATH setting the Makefile.
778 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
779     when the subject happened to end in the byte 0x85 (e.g. if the last
780     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
781     characters but of course it shouldn't be taken as a newline when it is part
782     of another character. The bug was that, for an unlimited repeat of . in
783     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
784     characters when looking for a newline.
785 ph10 197
786     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
788     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
789     in debug output.
791 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
792     long printing in the pcrecpp unittest when running under MinGW.
793 ph10 189
794 ph10 197 6. ESC_K was left out of the EBCDIC table.
795 ph10 189
796 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
797     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
798     limit also applies to "virtual nesting" when a pattern is recursive, and in
799     this case 1000 isn't so big. I have been able to remove this limit at the
800     expense of backing off one optimization in certain circumstances. Normally,
801     when pcre_exec() would call its internal match() function recursively and
802     immediately return the result unconditionally, it uses a "tail recursion"
803     feature to save stack. However, when a subpattern that can match an empty
804     string has an unlimited repetition quantifier, it no longer makes this
805     optimization. That gives it a stack frame in which to save the data for
806     checking that an empty string has been matched. Previously this was taken
807     from the 1000-entry workspace that had been reserved. So now there is no
808     explicit limit, but more stack is used.
809 ph10 189
810 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
811     syntax that is required for Windows, and which was going wrong for the
812     pcreposix and pcrecpp parts of the library. These were overlooked when this
813     problem was solved for the main library.
814 ph10 197
815 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
816     the size of patterns that contain repeated groups with explicit upper
817     limits. As the maximum quantifier is 65535, the maximum group length was
818     set at 30,000 so that the product of these two numbers did not overflow a
819     32-bit integer. However, it turns out that people want to use groups that
820     are longer than 30,000 bytes (though not repeat them that many times).
821     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
822     made it possible to implement the integer overflow checks in a much more
823     dynamic way, which I have now done. The artificial limitation on group
824     length has been removed - we now have only the limit on the total length of
825     the compiled pattern, which depends on the LINK_SIZE setting.
826 ph10 208
827     10. Fixed a bug in the documentation for get/copy named substring when
828     duplicate names are permitted. If none of the named substrings are set, the
829     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
830     empty string.
832     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
833     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
834     because the ] is interpreted as the first data character and the
835     terminating ] is not found. PCRE has been made compatible with Perl in this
836     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
837     cause memory overwriting.
839 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
840     string has been matched (to stop an infinite loop). It was not recognizing
841 ph10 208 a conditional subpattern that could match an empty string if that
842 ph10 206 subpattern was within another subpattern. For example, it looped when
843 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
844 ph10 206 condition was not nested. This bug has been fixed.
845 ph10 208
846 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
847     past the start of the subject in the presence of bytes with the top bit
848     set, for example "\x8aBCD".
849 ph10 211
850 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
851     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
852 ph10 200
853 ph10 211 14. Optimized (?!) to (*FAIL).
854 ph10 202
855 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
856     This restricts code points to be within the range 0 to 0x10FFFF, excluding
857     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
858     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
859     does: it's just the validity check that is more restrictive.
860 ph10 220
861     16. Inserted checks for integer overflows during escape sequence (backslash)
862     processing, and also fixed erroneous offset values for syntax errors during
863     backslash processing.
865 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
866 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
868 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
869     caused an overrun.
870 ph10 220
871     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
872     something other than just ASCII characters) inside a group that had an
873     unlimited repeat caused a loop at compile time (while checking to see
874     whether the group could match an empty string).
876 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
877     [\P{Any}] did so. (Error in the code for printing property names.)
878 ph10 210
879 ph10 220 21. An orphan \E inside a character class could cause a crash.
881     22. A repeated capturing bracket such as (A)? could cause a wild memory
882 ph10 218 reference during compilation.
883 ph10 220
884     23. There are several functions in pcre_compile() that scan along a compiled
885     expression for various reasons (e.g. to see if it's fixed length for look
886 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
887 ph10 220 present in the pattern. These operators have additional parameters compared
888     with \d, etc, and these were not being taken into account when moving along
889 ph10 218 the compiled data. Specifically:
890 ph10 220
891     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
892     length.
894     (b) An item such as \pL+ within a repeated group could cause crashes or
895 ph10 218 loops.
896 ph10 220
897 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
898 ph10 220 "reference to non-existent subpattern" error.
900 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
902 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
903 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
904 ph10 211
905 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
906 ph10 218
907 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
908 ph10 223 character were causing crashes (broken optimization).
909 ph10 227
910 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
911 ph10 227 \p or \P) caused a compile-time loop.
913 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
914     break. For example, the unstudied pattern [\r\n]A does not match the string
915     "\r\nA" because change 7.0/46 below moves the current point on by two
916     characters after failing to match at the start. However, the pattern \nA
917 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
918     the same is true. There doesn't seem any very clean way out of this, but
919     what I have chosen to do makes the common cases work: PCRE now takes note
920     of whether there can be an explicit match for \r or \n anywhere in the
921     pattern, and if so, 7.0/46 no longer applies. As part of this change,
922     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
923     pattern has explicit CR or LF references.
924 ph10 222
925 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
926 ph10 223
927 ph10 227
928 ph10 189 Version 7.2 19-Jun-07
929     ---------------------
931 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
932     which is apparently normally available under Windows.
933 ph10 159
934     2. Re-jig the pcregrep tests with different newline settings in an attempt
935     to make them independent of the local environment's newline setting.
936 ph10 157
937 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
938 ph10 165
939 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
940     was not 2, because the output contained actual offsets. The recent new
941 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
942     usable with all link sizes.
944 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
945     stack recursion. This gives a massive performance boost under BSD, but just
946 ph10 165 a small improvement under Linux. However, it saves one field in the frame
947 ph10 164 in all cases.
948 ph10 172
949 ph10 166 6. Added more features from the forthcoming Perl 5.10:
950 ph10 172
951 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
952     recursion call. It refers to the nth most recently opened parentheses.
953 ph10 172
954 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
955 ph10 172 to be opened parentheses.
957     (c) Conditions that refer to capturing parentheses can be specified
958 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
959 ph10 172
960 ph10 168 (d) \K resets the start of the current match so that everything before
961 ph10 172 is not part of it.
963 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
964 ph10 172
965 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
966 ph10 172 reference syntax.
967 ph10 182
968 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
969 ph10 182 alternative starts with the same number.
970 ph10 172
971 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
973 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
976     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
977     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
978 ph10 170 for detecting groups that can match an empty string.
979 ph10 159
980 ph10 172 9. A pattern with a very large number of alternatives (more than several
981     hundred) was running out of internal workspace during the pre-compile
982     phase, where pcre_compile() figures out how much memory will be needed. A
983     bit of new cunning has reduced the workspace needed for groups with
984     alternatives. The 1000-alternative test pattern now uses 12 bytes of
985     workspace instead of running out of the 4096 that are available.
986 ph10 182
987 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
988 ph10 172
989 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
990     The report of the bug said:
991 ph10 182
992 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
993     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
994 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
995 ph10 185
996 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
997 ph10 185 it matched the wrong number of bytes.
998 ph10 172
999 ph10 179
1000 ph10 155 Version 7.1 24-Apr-07
1001 ph10 98 ---------------------
1003 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1004 ph10 122 that is more "standard", making use of automake and other Autotools. There
1005 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
1006     on this.
1007 ph10 111
1008     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1009     for recursive directory scanning broke on some systems because the files
1010     are not scanned in any specific order and on different systems the order
1011     was different. A call to "sort" has been inserted into RunGrepTest for the
1012     approprate test as a short-term fix. In the longer term there may be an
1013 ph10 100 alternative.
1014 ph10 111
1015 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
1016 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
1017     people do their own conversions for various reasons). The problems
1018     concerned the use of low-level troff macros .br and .in. I have therefore
1019     removed all such uses from the man pages (some were redundant, some could
1020 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
1021     HTML has been updated to handle .nf/.fi and to complain if it encounters
1022     .br or .in.
1023 ph10 111
1024 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
1025 ph10 123 arranged for config.h to be included in the distribution, with the name
1026 ph10 111 config.h.generic, for the benefit of those who have to compile without
1027     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1029     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1030     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1031 ph10 127 makevp.bat for the current PCRE, using the additional files
1032 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1033 ph10 111
1034     6. A Windows user reported a minor discrepancy with test 2, which turned out
1035     to be caused by a trailing space on an input line that had got lost in his
1036 ph10 102 copy. The trailing space was an accident, so I've just removed it.
1037 ph10 111
1038 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1039 ph10 111 that is needed.
1041 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1042     as "const" (a) because they are and (b) because it helps the PHP
1043     maintainers who have recently made a script to detect big data structures
1044 ph10 111 in the php code that should be moved to the .rodata section. I remembered
1045     to update Builducptable as well, so it won't revert if ucptable.h is ever
1046 ph10 105 re-created.
1047 ph10 111
1048     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1049 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1050 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
1051     support is not required. This saves 1.5-2K of code, which is important in
1052 ph10 107 some applications.
1053 ph10 111
1054 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1055 ph10 111 so as not to refer to the tables, even though these functions will never be
1056     called when UTF-8 support is disabled. Otherwise there are problems with a
1057     shared library.
1059 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1061     (a) It was defining its arguments as char * instead of void *.
1063 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
1064     a long time ago when I wrote it, but is no longer the case.
1066 ph10 118 The emulated memove() is provided for those environments that have neither
1067 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
1068 ph10 118 is clearly not the case, as these two bugs were recently reported.
1069 ph10 123
1070 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1071 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
1072     pages, and it removes trailing spaces from listed files. It also creates
1073     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1074     case, it wraps all the #defines with #ifndefs. This script should be run
1075 ph10 111 before "make dist".
1076 ph10 123
1077 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1078     with Unicode property support.
1079 ph10 123
1080     (a) For a maximizing quantifier, if the two different cases of the
1081     character were of different lengths in their UTF-8 codings (there are
1082     some cases like this - I found 11), and the matching function had to
1083 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
1084     were both the same length.
1085 ph10 123
1086     (b) When PCRE was configured to use the heap rather than the stack for
1087     recursion during matching, it was not correctly preserving the data for
1088     the other case of a UTF-8 character when checking ahead for a match
1089     while processing a minimizing repeat. If the check also involved
1090 ph10 115 matching a wide character, but failed, corruption could cause an
1091     erroneous result when trying to check for a repeat of the original
1092     character.
1093 ph10 123
1094 ph10 116 13. Some tidying changes to the testing mechanism:
1095 ph10 98
1096 ph10 116 (a) The RunTest script now detects the internal link size and whether there
1097     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1098 ph10 123 values substituted by "configure". (The RunGrepTest script already did
1099     this for UTF-8.) The configure.ac script no longer substitutes the
1100     relevant variables.
1102 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
1103     with length and offset values. This means that the output is different
1104     for different internal link sizes. Test 2 is skipped for link sizes
1105     other than 2 because of this, bypassing the problem. Unfortunately,
1106     there was also a test in test 3 (the locale tests) that used /B and
1107 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
1108     I have added a new /Z option to pcretest that replaces the length and
1109     offset values with spaces. This is now used to make test 3 independent
1110 ph10 122 of link size. (Test 2 will be tidied up later.)
1111 ph10 123
1112     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1113 ph10 122 segmentation fault instead of returning the appropriate error message.
1114 ph10 134
1115 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
1116 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1117     This doesn't seem right; it now treats the CRLF combination as the line
1118     ending, and so does not match in that case. It's only a pattern such as ^$
1119     that would hit this one: something like ^ABC$ would have failed after \r
1120     and then tried again after \r\n.
1122 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1123 ph10 134 in an attempt to make files that differ only in their line terminators
1124     compare equal. This works on Linux.
1125 ph10 142
1126 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
1127     as it exited. This is now fixed, thanks to valgrind.
1128 ph10 142
1129 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1130 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1131     was because its rules for how to advance for /g after matching an empty
1132 ph10 143 string at the end of a line did not allow for this case. They now check for
1133     it specially.
1134 ph10 150
1135     20. pcretest is supposed to handle patterns and data of any length, by
1136     extending its buffers when necessary. It was getting this wrong when the
1137 ph10 147 buffer for a data line had to be extended.
1138 ph10 150
1139 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1140 ph10 150 CRLF as a newline sequence.
1141 ph10 152
1142 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1143 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1144     I have nevertheless tidied it up.
1145 ph10 111
1146 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
1147 ph10 123
1148 ph10 153 24. Added a man page for pcre-config.
1149 ph10 152
1150 ph10 153
1151 nigel 93 Version 7.0 19-Dec-06
1152     ---------------------
1154     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1155     moving to gcc 4.1.1.
1157     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1158     sys/time.h, which is documented as needed for this function. It doesn't
1159     seem to matter on Linux, but it showed up on some releases of OS X.
1161     3. It seems that there are systems where bytes whose values are greater than
1162     127 match isprint() in the "C" locale. The "C" locale should be the
1163     default when a C program starts up. In most systems, only ASCII printing
1164     characters match isprint(). This difference caused the output from pcretest
1165     to vary, making some of the tests fail. I have changed pcretest so that:
1167     (a) When it is outputting text in the compiled version of a pattern, bytes
1168     other than 32-126 are always shown as hex escapes.
1170     (b) When it is outputting text that is a matched part of a subject string,
1171     it does the same, unless a different locale has been set for the match
1172     (using the /L modifier). In this case, it uses isprint() to decide.
1174     4. Fixed a major bug that caused incorrect computation of the amount of memory
1175     required for a compiled pattern when options that changed within the
1176     pattern affected the logic of the preliminary scan that determines the
1177     length. The relevant options are -x, and -i in UTF-8 mode. The result was
1178     that the computed length was too small. The symptoms of this bug were
1179     either the PCRE error "internal error: code overflow" from pcre_compile(),
1180     or a glibc crash with a message such as "pcretest: free(): invalid next
1181     size (fast)". Examples of patterns that provoked this bug (shown in
1182     pcretest format) are:
1184     /(?-x: )/x
1185     /(?x)(?-x: \s*#\s*)/
1186     /((?i)[\x{c0}])/8
1187     /(?i:[\x{c0}])/8
1189     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1190     is now done differently.
1192     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1193     wrapper classes; (b) implement a new function in the C++ scanner that is
1194     more efficient than the old way of doing things because it avoids levels of
1195     recursion in the regex matching; (c) add a paragraph to the documentation
1196     for the FullMatch() function.
1198     6. The escape sequence \n was being treated as whatever was defined as
1199     "newline". Not only was this contrary to the documentation, which states
1200     that \n is character 10 (hex 0A), but it also went horribly wrong when
1201     "newline" was defined as CRLF. This has been fixed.
1203     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1204     was being set to -1 for the "end of line" case (supposedly a value that no
1205     character can have). Though this value is never used (the check for end of
1206     line is "zero bytes in current character"), it caused compiler complaints.
1207     I've changed it to 0xffffffff.
1209     8. In pcre_version.c, the version string was being built by a sequence of
1210     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1211     string (as it is for production releases) called a macro with an empty
1212     argument. The C standard says the result of this is undefined. The gcc
1213     compiler treats it as an empty string (which was what was wanted) but it is
1214     reported that Visual C gives an error. The source has been hacked around to
1215     avoid this problem.
1217     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1218     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1219     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1220     of them did).
1222     10. Originally, pcretest opened its input and output without "b"; then I was
1223     told that "b" was needed in some environments, so it was added for release
1224     5.0 to both the input and output. (It makes no difference on Unix-like
1225     systems.) Later I was told that it is wrong for the input on Windows. I've
1226     now abstracted the modes into two macros, to make it easier to fiddle with
1227     them, and removed "b" from the input mode under Windows.
1229     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1231     12. Added -help and --help to pcretest as an official way of being reminded
1232     of the options.
1234     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1235     and pcrecpp.cc because they annoy compilers at high warning levels.
1237     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1239     15. Fixed an occurrence of == in configure.ac that should have been = (shell
1240     scripts are not C programs :-) and which was not noticed because it works
1241     on Linux.
1243     16. pcretest is supposed to handle any length of pattern and data line (as one
1244     line or as a continued sequence of lines) by extending its input buffer if
1245     necessary. This feature was broken for very long pattern lines, leading to
1246     a string of junk being passed to pcre_compile() if the pattern was longer
1247     than about 50K.
1249     17. I have done a major re-factoring of the way pcre_compile() computes the
1250     amount of memory needed for a compiled pattern. Previously, there was code
1251     that made a preliminary scan of the pattern in order to do this. That was
1252     OK when PCRE was new, but as the facilities have expanded, it has become
1253     harder and harder to keep it in step with the real compile phase, and there
1254     have been a number of bugs (see for example, 4 above). I have now found a
1255     cunning way of running the real compile function in a "fake" mode that
1256     enables it to compute how much memory it would need, while actually only
1257     ever using a few hundred bytes of working memory and without too many
1258     tests of the mode. This should make future maintenance and development
1259     easier. A side effect of this work is that the limit of 200 on the nesting
1260     depth of parentheses has been removed (though this was never a serious
1261     limitation, I suspect). However, there is a downside: pcre_compile() now
1262     runs more slowly than before (30% or more, depending on the pattern). I
1263     hope this isn't a big issue. There is no effect on runtime performance.
1265     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1266     newline (only possible for the last line of a file) and it was a
1267     pattern that set a locale (followed by /Lsomething), pcretest crashed.
1269     19. Added additional timing features to pcretest. (1) The -tm option now times
1270     matching only, not compiling. (2) Both -t and -tm can be followed, as a
1271     separate command line item, by a number that specifies the number of
1272     repeats to use when timing. The default is 50000; this gives better
1273     precision, but takes uncomfortably long for very large patterns.
1275     20. Extended pcre_study() to be more clever in cases where a branch of a
1276     subpattern has no definite first character. For example, (a*|b*)[cd] would
1277     previously give no result from pcre_study(). Now it recognizes that the
1278     first character must be a, b, c, or d.
1280     21. There was an incorrect error "recursive call could loop indefinitely" if
1281     a subpattern (or the entire pattern) that was being tested for matching an
1282     empty string contained only one non-empty item after a nested subpattern.
1283     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1284     incorrectly, because the \d was being skipped in the check.
1286     22. The pcretest program now has a new pattern option /B and a command line
1287     option -b, which is equivalent to adding /B to every pattern. This causes
1288     it to show the compiled bytecode, without the additional information that
1289     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1290     is the same as /B/I).
1292     23. A new optimization is now able automatically to treat some sequences such
1293     as a*b as a*+b. More specifically, if something simple (such as a character
1294     or a simple class like \d) has an unlimited quantifier, and is followed by
1295     something that cannot possibly match the quantified thing, the quantifier
1296     is automatically "possessified".
1298     24. A recursive reference to a subpattern whose number was greater than 39
1299     went wrong under certain circumstances in UTF-8 mode. This bug could also
1300     have affected the operation of pcre_study().
1302     25. Realized that a little bit of performance could be had by replacing
1303     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1305     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1307     27. Possessive quantifiers such as a++ were previously implemented by turning
1308     them into atomic groups such as ($>a+). Now they have their own opcodes,
1309     which improves performance. This includes the automatically created ones
1310     from 23 above.
1312     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1313     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1314     the first matched character to be a colon. This applied both to named and
1315     numbered groups.
1317     29. The ucpinternal.h header file was missing its idempotency #ifdef.
1319     30. I was sent a "project" file called libpcre.a.dev which I understand makes
1320     building PCRE on Windows easier, so I have included it in the distribution.
1322     31. There is now a check in pcretest against a ridiculously large number being
1323     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1324     loop, the loop is abandoned.
1326     32. Forward references to subpatterns in conditions such as (?(2)...) where
1327     subpattern 2 is defined later cause pcre_compile() to search forwards in
1328     the pattern for the relevant set of parentheses. This search went wrong
1329     when there were unescaped parentheses in a character class, parentheses
1330     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1332     33. "Subroutine" calls and backreferences were previously restricted to
1333     referencing subpatterns earlier in the regex. This restriction has now
1334     been removed.
1336     34. Added a number of extra features that are going to be in Perl 5.10. On the
1337     whole, these are just syntactic alternatives for features that PCRE had
1338     previously implemented using the Python syntax or my own invention. The
1339     other formats are all retained for compatibility.
1341     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1342     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1343     also .NET compatible.
1345     (b) A recursion or subroutine call to a named group can now be defined as
1346     (?&name) as well as (?P>name).
1348     (c) A backreference to a named group can now be defined as \k<name> or
1349     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1350     5.10, are also .NET compatible.
1352     (d) A conditional reference to a named group can now use the syntax
1353     (?(<name>) or (?('name') as well as (?(name).
1355     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1356     groups (named and numbered) that are never evaluated inline, but can be
1357     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1358     is always false. There may be only one alternative in such a group.
1360     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1361     as the simple (?(R). The condition is true only if the most recent
1362     recursion is that of the given number or name. It does not search out
1363     through the entire recursion stack.
1365     (g) The escape \gN or \g{N} has been added, where N is a positive or
1366     negative number, specifying an absolute or relative reference.
1368     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1369     some "unreachable code" warnings.
1371     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1372     things, this adds five new scripts.
1374     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1375     There were also incompatibilities regarding the handling of \Q..\E inside
1376     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1377     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1379     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1380     matches an empty string, and forcibly breaks the loop. There were bugs in
1381     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1382     against aaaa the result was just "a" rather than "aaaa", for example. Two
1383     separate and independent bugs (that affected different cases) have been
1384     fixed.
1386     39. Refactored the code to abolish the use of different opcodes for small
1387     capturing bracket numbers. This is a tidy that I avoided doing when I
1388     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1389     The new approach is not only tidier, it makes it possible to reduce the
1390     memory needed to fix the previous bug (38).
1392     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1393     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1394     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1395     mode.
1397     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1398     report.
1400     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1401     copy construction and assignment in the C++ wrapper.
1403     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1404     couple of bugs that could have given wrong results in the "--newline=crlf"
1405     case.
1407     44. Added a number of casts and did some reorganization of signed/unsigned int
1408     variables following suggestions from Dair Grant. Also renamed the variable
1409     "this" as "item" because it is a C++ keyword.
1411     45. Arranged for dftables to add
1413     #include "pcre_internal.h"
1415     to pcre_chartables.c because without it, gcc 4.x may remove the array
1416     definition from the final binary if PCRE is built into a static library and
1417     dead code stripping is activated.
1419     46. For an unanchored pattern, if a match attempt fails at the start of a
1420     newline sequence, and the newline setting is CRLF or ANY, and the next two
1421     characters are CRLF, advance by two characters instead of one.
1424 nigel 91 Version 6.7 04-Jul-06
1425     ---------------------
1427     1. In order to handle tests when input lines are enormously long, pcretest has
1428     been re-factored so that it automatically extends its buffers when
1429     necessary. The code is crude, but this _is_ just a test program. The
1430     default size has been increased from 32K to 50K.
1432     2. The code in pcre_study() was using the value of the re argument before
1433     testing it for NULL. (Of course, in any sensible call of the function, it
1434     won't be NULL.)
1436     3. The memmove() emulation function in pcre_internal.h, which is used on
1437     systems that lack both memmove() and bcopy() - that is, hardly ever -
1438     was missing a "static" storage class specifier.
1440     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1441     containing an extended class (one that cannot be represented by a bitmap
1442     because it contains high-valued characters or Unicode property items, e.g.
1443     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1444     pattern, but PCRE should not loop if you do not (it no longer does).
1445     [Detail: two cases were found: (a) a repeated subpattern containing an
1446     extended class; (b) a recursive reference to a subpattern that followed a
1447     previous extended class. It wasn't skipping over the extended class
1448     correctly when UTF-8 mode was not set.]
1450     5. A negated single-character class was not being recognized as fixed-length
1451     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1452     compile error "lookbehind assertion is not fixed length".
1454     6. The RunPerlTest auxiliary script was showing an unexpected difference
1455     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1456     write a Perl script that can interpret lines of an input file either as
1457     byte characters or as UTF-8, which is what "perltest" was being required to
1458     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1459     can't do is switch easily at run time between having the "use utf8;" pragma
1460     or not. In the end, I fudged it by using the RunPerlTest script to insert
1461     "use utf8;" explicitly for the UTF-8 tests.
1463     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1464     the end of the subject string, contrary to the documentation and to what
1465     Perl does. This was true of both matching functions. Now it matches only at
1466     the start of the subject and immediately after *internal* newlines.
1468     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1469     a pointer to an int instead of a pointer to an unsigned long int. This
1470     caused problems on 64-bit systems.
1472     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1473     instance of the 'standard' template library not being so standard".
1475     10. There was no check on the number of named subpatterns nor the maximum
1476     length of a subpattern name. The product of these values is used to compute
1477     the size of the memory block for a compiled pattern. By supplying a very
1478     long subpattern name and a large number of named subpatterns, the size
1479     computation could be caused to overflow. This is now prevented by limiting
1480     the length of names to 32 characters, and the number of named subpatterns
1481     to 10,000.
1483     11. Subpatterns that are repeated with specific counts have to be replicated in
1484     the compiled pattern. The size of memory for this was computed from the
1485     length of the subpattern and the repeat count. The latter is limited to
1486     65535, but there was no limit on the former, meaning that integer overflow
1487     could in principle occur. The compiled length of a repeated subpattern is
1488     now limited to 30,000 bytes in order to prevent this.
1490     12. Added the optional facility to have named substrings with the same name.
1492     13. Added the ability to use a named substring as a condition, using the
1493     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1494     are numbers (not recommended). Forward references are permitted.
1496     14. Added forward references in named backreferences (if you see what I mean).
1498     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1499     pattern could run off the end of the subject. For example, the pattern
1500     "(?s)(.{1,5})"8 did this with the subject "ab".
1502     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1503     PCRE_CASELESS was set when matching characters that were quantified with ?
1504     or *.
1506     17. A character class other than a single negated character that had a minimum
1507     but no maximum quantifier - for example [ab]{6,} - was not handled
1508     correctly by pce_dfa_exec(). It would match only one character.
1510     18. A valid (though odd) pattern that looked like a POSIX character
1511     class but used an invalid character after [ (for example [[,abc,]]) caused
1512     pcre_compile() to give the error "Failed: internal error: code overflow" or
1513     in some cases to crash with a glibc free() error. This could even happen if
1514     the pattern terminated after [[ but there just happened to be a sequence of
1515     letters, a binary zero, and a closing ] in the memory that followed.
1517     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1518     over the years. Originally (before any Unicode support), just the bottom 8
1519     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1520     output from "man perlunicode" includes this:
1522     The regular expression compiler produces polymorphic opcodes. That
1523     is, the pattern adapts to the data and automatically switches to
1524     the Unicode character scheme when presented with Unicode data--or
1525     instead uses a traditional byte scheme when presented with byte
1526     data.
1528     Sadly, a wide octal escape does not cause a switch, and in a string with
1529     no other multibyte characters, these octal escapes are treated as before.
1530     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1531     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1532     Unicode string.
1534     I have not perpetrated such confusion in PCRE. Up till now, it took just
1535     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1536     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1537     translate to the appropriate multibyte character.
1539     29. Applied some refactoring to reduce the number of warnings from Microsoft
1540     and Borland compilers. This has included removing the fudge introduced
1541     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1542     a warning about an unused variable.
1544     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1545     characters since release 4.0, because Perl (from release 5.004) does not.
1546     [Or at least, is documented not to: some releases seem to be in conflict
1547     with the documentation.] However, when a pattern was studied with
1548     pcre_study() and all its branches started with \s, PCRE still included VT
1549     as a possible starting character. Of course, this did no harm; it just
1550     caused an unnecessary match attempt.
1552     22. Removed a now-redundant internal flag bit that recorded the fact that case
1553     dependency changed within the pattern. This was once needed for "required
1554     byte" processing, but is no longer used. This recovers a now-scarce options
1555     bit. Also moved the least significant internal flag bit to the most-
1556     significant bit of the word, which was not previously used (hangover from
1557     the days when it was an int rather than a uint) to free up another bit for
1558     the future.
1560     23. Added support for CRLF line endings as well as CR and LF. As well as the
1561     default being selectable at build time, it can now be changed at runtime
1562     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1563     specify that it is scanning data with non-default line endings.
1565     24. Changed the definition of CXXLINK to make it agree with the definition of
1566     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1568     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1569     recursions. This makes a big different to stack usage for some patterns.
1571     26. If a subpattern containing a named recursion or subroutine reference such
1572     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1573     the space required for the compiled pattern went wrong and gave too small a
1574     value. Depending on the environment, this could lead to "Failed: internal
1575     error: code overflow at offset 49" or "glibc detected double free or
1576     corruption" errors.
1578     27. Applied patches from Google (a) to support the new newline modes and (b) to
1579     advance over multibyte UTF-8 characters in GlobalReplace.
1581     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1582     difference for some implementation of PCRE in some Windows version.
1584     29. Added some extra testing facilities to pcretest:
1586     \q<number> in a data line sets the "match limit" value
1587     \Q<number> in a data line sets the "match recursion limt" value
1588     -S <number> sets the stack size, where <number> is in megabytes
1590     The -S option isn't available for Windows.
1593 nigel 89 Version 6.6 06-Feb-06
1594     ---------------------
1596     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1597     in pcreposix.h. I have copied the definition from pcre.h.
1599     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1600     because pcre.h is no longer a built file.
1602     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1603     not normally included in the compiled code.
1606 nigel 87 Version 6.5 01-Feb-06
1607     ---------------------
1609     1. When using the partial match feature with pcre_dfa_exec(), it was not
1610     anchoring the second and subsequent partial matches at the new starting
1611     point. This could lead to incorrect results. For example, with the pattern
1612     /1234/, partially matching against "123" and then "a4" gave a match.
1614     2. Changes to pcregrep:
1616     (a) All non-match returns from pcre_exec() were being treated as failures
1617     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1618     error message is output. Some extra information is given for the
1620     probably the only errors that are likely to be caused by users (by
1621     specifying a regex that has nested indefinite repeats, for instance).
1622     If there are more than 20 of these errors, pcregrep is abandoned.
1624     (b) A binary zero was treated as data while matching, but terminated the
1625     output line if it was written out. This has been fixed: binary zeroes
1626     are now no different to any other data bytes.
1628     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1629     used to set a locale for matching. The --locale=xxxx long option has
1630     been added (no short equivalent) to specify a locale explicitly on the
1631     pcregrep command, overriding the environment variables.
1633     (d) When -B was used with -n, some line numbers in the output were one less
1634     than they should have been.
1636     (e) Added the -o (--only-matching) option.
1638     (f) If -A or -C was used with -c (count only), some lines of context were
1639     accidentally printed for the final match.
1641     (g) Added the -H (--with-filename) option.
1643     (h) The combination of options -rh failed to suppress file names for files
1644     that were found from directory arguments.
1646     (i) Added the -D (--devices) and -d (--directories) options.
1648     (j) Added the -F (--fixed-strings) option.
1650     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1652     (l) Added the --colo(u)r option.
1654     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1655     is not present by default.
1657     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1658     items such as (?R) or (?1), when the recursion could match a number of
1659     alternatives. If it matched one of the alternatives, but subsequently,
1660     outside the recursion, there was a failure, the code tried to back up into
1661     the recursion. However, because of the way PCRE is implemented, this is not
1662     possible, and the result was an incorrect result from the match.
1664     In order to prevent this happening, the specification of recursion has
1665     been changed so that all such subpatterns are automatically treated as
1666     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1668     4. I had overlooked the fact that, in some locales, there are characters for
1669     which isalpha() is true but neither isupper() nor islower() are true. In
1670     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1671     and ordfeminine) are like this. This affected the treatment of \w and \W
1672     when they appeared in character classes, but not when they appeared outside
1673     a character class. The bit map for "word" characters is now created
1674     separately from the results of isalnum() instead of just taking it from the
1675     upper, lower, and digit maps. (Plus the underscore character, of course.)
1677     5. The above bug also affected the handling of POSIX character classes such as
1678     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1679     permanent tables. Instead, the bit maps for such a class were previously
1680     created as the appropriate unions of the upper, lower, and digit bitmaps.
1681     Now they are created by subtraction from the [[:word:]] class, which has
1682     its own bitmap.
1684     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1685     It is created by subtracting the vertical space characters (\x09, \x0a,
1686     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1687     subtraction was done in the overall bitmap for a character class, meaning
1688     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1689     be recognized. This bug has been fixed.
1691     7. Patches from the folks at Google:
1693     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1694     real life, but is still worth protecting against".
1696     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1697     regular expressions".
1699     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1700     have it.
1702     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1703     "configure" and the latter not, in order to fix a problem somebody had
1704     with compiling the Arg class on HP-UX.
1706     (e) Improve the error-handling of the C++ wrapper a little bit.
1708     (f) New tests for checking recursion limiting.
1710     8. The pcre_memmove() function, which is used only if the environment does not
1711     have a standard memmove() function (and is therefore rarely compiled),
1712     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1713     returning a result (though PCRE never actually uses the result).
1715     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1716     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1717     returned instead of calling malloc() with an overflowing number that would
1718     most likely cause subsequent chaos.
1720     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1722     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1723     with this option is matched, the nmatch and pmatch options of regexec() are
1724     ignored.
1726     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1727     provided in case anyone wants to the the POSIX interface with UTF-8
1728     strings.
1730     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1731     C++ linking (needed for some HP-UX environments).
1733     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1734     (unused parameter) and in the pcre_printint() function (omitted "default"
1735     switch label when the default is to do nothing).
1737     15. Added some code to make it possible, when PCRE is compiled as a C++
1738     library, to replace subject pointers for pcre_exec() with a smart pointer
1739     class, thus making it possible to process discontinuous strings.
1741     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1742     much the same function. They were added by different people who were trying
1743     to make PCRE easy to compile on non-Unix systems. It has been suggested
1744     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1745     for compiling on Windows systems. I have therefore replaced it with
1746     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1747     defaults to "extern" for C or "extern C" for C++, which works fine on
1748     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1749     SCOPE with something explicit in config.h. In addition:
1751     (a) pcreposix.h still had just "extern" instead of either of these macros;
1752     I have replaced it with PCRE_DATA_SCOPE.
1754     (b) Functions such as _pcre_xclass(), which are internal to the library,
1755     but external in the C sense, all had PCRE_EXPORT in their definitions.
1756     This is apparently wrong for the Windows case, so I have removed it.
1757     (It makes no difference on Unix-like systems.)
1759     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1760     of recursive calls to match(). This is different to MATCH_LIMIT because
1761     that limits the total number of calls to match(), not all of which increase
1762     the depth of recursion. Limiting the recursion depth limits the amount of
1763     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1764     when PCRE is compiled, and changed at run time. A patch from Google adds
1765     this functionality to the C++ interface.
1767     18. Changes to the handling of Unicode character properties:
1769     (a) Updated the table to Unicode 4.1.0.
1771     (b) Recognize characters that are not in the table as "Cn" (undefined).
1773     (c) I revised the way the table is implemented to a much improved format
1774     which includes recognition of ranges. It now supports the ranges that
1775     are defined in UnicodeData.txt, and it also amalgamates other
1776     characters into ranges. This has reduced the number of entries in the
1777     table from around 16,000 to around 3,000, thus reducing its size
1778     considerably. I realized I did not need to use a tree structure after
1779     all - a binary chop search is just as efficient. Having reduced the
1780     number of entries, I extended their size from 6 bytes to 8 bytes to
1781     allow for more data.
1783     (d) Added support for Unicode script names via properties such as \p{Han}.
1785     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1786     matching that character.
1788     20. When matching a repeated Unicode property with a minimum greater than zero,
1789     (for example \pL{2,}), PCRE could look past the end of the subject if it
1790     reached it while seeking the minimum number of characters. This could
1791     happen only if some of the characters were more than one byte long, because
1792     there is a check for at least the minimum number of bytes.
1794     21. Refactored the implementation of \p and \P so as to be more general, to
1795     allow for more different types of property in future. This has changed the
1796     compiled form incompatibly. Anybody with saved compiled patterns that use
1797     \p or \P will have to recompile them.
1799     22. Added "Any" and "L&" to the supported property types.
1801     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1802     but give a compile time error if the value is greater than 0xff.
1804     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1805     accidentally not being installed or uninstalled.
1807     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1808     made were to insert the current release number. This seemed silly, because
1809     it made things harder for people building PCRE on systems that don't run
1810     "configure". I have turned pcre.h into a distributed file, no longer built
1811     by "configure", with the version identification directly included. There is
1812     no longer a pcre.h.in file.
1814     However, this change necessitated a change to the pcre-config script as
1815     well. It is built from pcre-config.in, and one of the substitutions was the
1816     release number. I have updated configure.ac so that ./configure now finds
1817     the release number by grepping pcre.h.
1819     26. Added the ability to run the tests under valgrind.
1822 nigel 85 Version 6.4 05-Sep-05
1823     ---------------------
1825     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1826     "--" to be printed when multiple files were scanned, even when none of the
1827     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1828     consider it to be a bug, and have restored the previous behaviour.
1830     2. A couple of code tidies to get rid of compiler warnings.
1832     3. The pcretest program used to cheat by referring to symbols in the library
1833     whose names begin with _pcre_. These are internal symbols that are not
1834     really supposed to be visible externally, and in some environments it is
1835     possible to suppress them. The cheating is now confined to including
1836     certain files from the library's source, which is a bit cleaner.
1838     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1839     file's purpose clearer.
1841     5. Reorganized pcre_ucp_findchar().
1844 nigel 83 Version 6.3 15-Aug-05
1845     ---------------------
1847     1. The file libpcre.pc.in did not have general read permission in the tarball.
1849     2. There were some problems when building without C++ support:
1851     (a) If C++ support was not built, "make install" and "make test" still
1852     tried to test it.
1854     (b) There were problems when the value of CXX was explicitly set. Some
1855     changes have been made to try to fix these, and ...
1857     (c) --disable-cpp can now be used to explicitly disable C++ support.
1859     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1860     backslash in a target when C++ was disabled. This confuses some
1861     versions of "make", apparently. Using an intermediate variable solves
1862     this. (Same for CPP_LOBJ.)
1864     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1865     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1866     necessary on certain architectures.
1868     4. Added a setting of -export-symbols-regex to the link command to remove
1869     those symbols that are exported in the C sense, but actually are local
1870     within the library, and not documented. Their names all begin with
1871     "_pcre_". This is not a perfect job, because (a) we have to except some
1872     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1873     available (and never for static libraries). I have made a note to try to
1874     find a way round (a) in the future.
1877 nigel 81 Version 6.2 01-Aug-05
1878     ---------------------
1880     1. There was no test for integer overflow of quantifier values. A construction
1881     such as {1111111111111111} would give undefined results. What is worse, if
1882     a minimum quantifier for a parenthesized subpattern overflowed and became
1883     negative, the calculation of the memory size went wrong. This could have
1884     led to memory overwriting.
1886     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1888     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1889     operating environments where this matters.
1891     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1892     PCRE options from within the C++ wrapper.
1894     5. Named capturing subpatterns were not being correctly counted when a pattern
1895     was compiled. This caused two problems: (a) If there were more than 100
1896     such subpatterns, the calculation of the memory needed for the whole
1897     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1898     back references of the form \12, where the number was greater than 9, were
1899     not recognized as back references, even though there were sufficient
1900     previous subpatterns.
1902     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1903     versions of gcc, e.g. 2.95.4.
1906 nigel 79 Version 6.1 21-Jun-05
1907     ---------------------
1909     1. There was one reference to the variable "posix" in pcretest.c that was not
1910     surrounded by "#if !defined NOPOSIX".
1912     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1913     the cross-check on the old pcre_info() function, for the benefit of the
1914     cut-down version of PCRE that is currently imported into Exim.
1916     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1917     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1918     patterns that start (?i) but I don't think that matters. The use of (?i) is
1919     just an example; this all applies to the other options as well.
1921     4. Since libtool seems to echo the compile commands it is issuing, the output
1922     from "make" can be reduced a bit by putting "@" in front of each libtool
1923     compile command.
1925     5. Patch from the folks at Google for configure.in to be a bit more thorough
1926     in checking for a suitable C++ installation before trying to compile the
1927     C++ stuff. This should fix a reported problem when a compiler was present,
1928     but no suitable headers.
1930     6. The man pages all had just "PCRE" as their title. I have changed them to
1931     be the relevant file name. I have also arranged that these names are
1932     retained in the file doc/pcre.txt, which is a concatenation in text format
1933     of all the man pages except the little individual ones for each function.
1935     7. The NON-UNIX-USE file had not been updated for the different set of source
1936     files that come with release 6. I also added a few comments about the C++
1937     wrapper.
1940 nigel 77 Version 6.0 07-Jun-05
1941     ---------------------
1943     1. Some minor internal re-organization to help with my DFA experiments.
1945     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1946     didn't matter for the library itself when fully configured, but did matter
1947     when compiling without UCP support, or within Exim, where the ucp files are
1948     not imported.
1950     3. Refactoring of the library code to split up the various functions into
1951     different source modules. The addition of the new DFA matching code (see
1952     below) to a single monolithic source would have made it really too
1953     unwieldy, quite apart from causing all the code to be include in a
1954     statically linked application, when only some functions are used. This is
1955     relevant even without the DFA addition now that patterns can be compiled in
1956     one application and matched in another.
1958     The downside of splitting up is that there have to be some external
1959     functions and data tables that are used internally in different modules of
1960     the library but which are not part of the API. These have all had their
1961     names changed to start with "_pcre_" so that they are unlikely to clash
1962     with other external names.
1964     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1965     a different (DFA) algorithm. Although it is slower than the original
1966     function, it does have some advantages for certain types of matching
1967     problem.
1969     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1970     including restarting after a partial match.
1972     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1973     defined when compiling for Windows was sent to me. I have put it into the
1974     code, though I have no means of testing or verifying it.
1976     7. Added the pcre_refcount() auxiliary function.
1978     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1979     match before or at the first newline in the subject string. In pcretest,
1980     the /f option on a pattern can be used to set this.
1982     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1983     would behave wrongly. This has been present in PCRE since release 4.0.
1985     10. A number of changes to the pcregrep command:
1987     (a) Refactored how -x works; insert ^(...)$ instead of setting
1988     PCRE_ANCHORED and checking the length, in preparation for adding
1989     something similar for -w.
1991     (b) Added the -w (match as a word) option.
1993     (c) Refactored the way lines are read and buffered so as to have more
1994     than one at a time available.
1996     (d) Implemented a pcregrep test script.
1998     (e) Added the -M (multiline match) option. This allows patterns to match
1999     over several lines of the subject. The buffering ensures that at least
2000     8K, or the rest of the document (whichever is the shorter) is available
2001     for matching (and similarly the previous 8K for lookbehind assertions).
2003     (f) Changed the --help output so that it now says
2005     -w, --word-regex(p)
2007     instead of two lines, one with "regex" and the other with "regexp"
2008     because that confused at least one person since the short forms are the
2009     same. (This required a bit of code, as the output is generated
2010     automatically from a table. It wasn't just a text change.)
2012     (g) -- can be used to terminate pcregrep options if the next thing isn't an
2013     option but starts with a hyphen. Could be a pattern or a path name
2014     starting with a hyphen, for instance.
2016     (h) "-" can be given as a file name to represent stdin.
2018     (i) When file names are being printed, "(standard input)" is used for
2019     the standard input, for compatibility with GNU grep. Previously
2020     "<stdin>" was used.
2022     (j) The option --label=xxx can be used to supply a name to be used for
2023     stdin when file names are being printed. There is no short form.
2025     (k) Re-factored the options decoding logic because we are going to add
2026     two more options that take data. Such options can now be given in four
2027     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2029     (l) Added the -A, -B, and -C options for requesting that lines of context
2030     around matches be printed.
2032     (m) Added the -L option to print the names of files that do not contain
2033     any matching lines, that is, the complement of -l.
2035     (n) The return code is 2 if any file cannot be opened, but pcregrep does
2036     continue to scan other files.
2038     (o) The -s option was incorrectly implemented. For compatibility with other
2039     greps, it now suppresses the error message for a non-existent or non-
2040     accessible file (but not the return code). There is a new option called
2041     -q that suppresses the output of matching lines, which was what -s was
2042     previously doing.
2044     (p) Added --include and --exclude options to specify files for inclusion
2045     and exclusion when recursing.
2047     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2048     Hopefully, it now does.
2050     12. Missing cast in pcre_study().
2052     13. Added an "uninstall" target to the makefile.
2054     14. Replaced "extern" in the function prototypes in Makefile.in with
2055     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2056     world, but is set differently for Windows.
2058     15. Added a second compiling function called pcre_compile2(). The only
2059     difference is that it has an extra argument, which is a pointer to an
2060     integer error code. When there is a compile-time failure, this is set
2061     non-zero, in addition to the error test pointer being set to point to an
2062     error message. The new argument may be NULL if no error number is required
2063     (but then you may as well call pcre_compile(), which is now just a
2064     wrapper). This facility is provided because some applications need a
2065     numeric error indication, but it has also enabled me to tidy up the way
2066     compile-time errors are handled in the POSIX wrapper.
2068     16. Added VPATH=.libs to the makefile; this should help when building with one
2069     prefix path and installing with another. (Or so I'm told by someone who
2070     knows more about this stuff than I do.)
2072     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2073     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2074     match everything, including newlines. This is not POSIX-compatible, but
2075     somebody wanted the feature. From pcretest it can be activated by using
2076     both the P and the s flags.
2078     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2080     19. libpcre.pc was being incorrectly installed as executable.
2082     20. A couple of places in pcretest check for end-of-line by looking for '\n';
2083     it now also looks for '\r' so that it will work unmodified on Windows.
2085     21. Added Google's contributed C++ wrapper to the distribution.
2087     22. Added some untidy missing memory free() calls in pcretest, to keep
2088     Electric Fence happy when testing.
2092 nigel 75 Version 5.0 13-Sep-04
2093     ---------------------
2095     1. Internal change: literal characters are no longer packed up into items
2096     containing multiple characters in a single byte-string. Each character
2097     is now matched using a separate opcode. However, there may be more than one
2098     byte in the character in UTF-8 mode.
2100     2. The pcre_callout_block structure has two new fields: pattern_position and
2101     next_item_length. These contain the offset in the pattern to the next match
2102     item, and its length, respectively.
2104     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2105     insertion of callouts before each pattern item. Added the /C option to
2106     pcretest to make use of this.
2108     4. On the advice of a Windows user, the lines
2110     #if defined(_WIN32) || defined(WIN32)
2111     _setmode( _fileno( stdout ), 0x8000 );
2112     #endif /* defined(_WIN32) || defined(WIN32) */
2114     have been added to the source of pcretest. This apparently does useful
2115     magic in relation to line terminators.
2117     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2118     for the benefit of those environments where the "b" makes a difference.
2120     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2121     to know about it. I have put a hack into configure.in that adds in code
2122     to set GCC=yes if CC=icc. This seems to end up at a point in the
2123     generated configure script that is early enough to affect the setting of
2124     compiler options, which is what is needed, but I have no means of testing
2125     whether it really works. (The user who reported this had patched the
2126     generated configure script, which of course I cannot do.)
2128     LATER: After change 22 below (new libtool files), the configure script
2129     seems to know about icc (and also ecc). Therefore, I have commented out
2130     this hack in configure.in.
2132     7. Added support for pkg-config (2 patches were sent in).
2134     8. Negated POSIX character classes that used a combination of internal tables
2135     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2136     [[:^ascii]]. Typically, they would match almost any characters. The other
2137     POSIX classes were not broken in this way.
2139     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2140     to find the match, as PCRE was deluded into thinking that the match had to
2141     start at the start point or following a newline. The same bug applied to
2142     patterns with negative forward assertions or any backward assertions
2143     preceding ".*" at the start, unless the pattern required a fixed first
2144     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2146     10. In UTF-8 mode, when moving forwards in the subject after a failed match
2147     starting at the last subject character, bytes beyond the end of the subject
2148     string were read.
2150     11. Renamed the variable "class" as "classbits" to make life easier for C++
2151     users. (Previously there was a macro definition, but it apparently wasn't
2152     enough.)
2154     12. Added the new field "tables" to the extra data so that tables can be passed
2155     in at exec time, or the internal tables can be re-selected. This allows
2156     a compiled regex to be saved and re-used at a later time by a different
2157     program that might have everything at different addresses.
2159     13. Modified the pcre-config script so that, when run on Solaris, it shows a
2160     -R library as well as a -L library.
2162     14. The debugging options of pcretest (-d on the command line or D on a
2163     pattern) showed incorrect output for anything following an extended class
2164     that contained multibyte characters and which was followed by a quantifier.
2166     15. Added optional support for general category Unicode character properties
2167     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2168     support. It adds about 90K to the size of the library. The meanings of the
2169     inbuilt class escapes such as \d and \s have NOT been changed.
2171     16. Updated pcredemo.c to include calls to free() to release the memory for the
2172     compiled pattern.
2174     17. The generated file chartables.c was being created in the source directory
2175     instead of in the building directory. This caused the build to fail if the
2176     source directory was different from the building directory, and was
2177     read-only.
2179     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2180     file. No doubt somebody will tell me if they don't make sense... Also added
2181     Dan Mooney's comments about building on OpenVMS.
2183     19. Added support for partial matching via the PCRE_PARTIAL option for
2184     pcre_exec() and the \P data escape in pcretest.
2186     20. Extended pcretest with 3 new pattern features:
2188     (i) A pattern option of the form ">rest-of-line" causes pcretest to
2189     write the compiled pattern to the file whose name is "rest-of-line".
2190     This is a straight binary dump of the data, with the saved pointer to
2191     the character tables forced to be NULL. The study data, if any, is
2192     written too. After writing, pcretest reads a new pattern.
2194     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2195     compiled pattern from the given file. There must not be any
2196     occurrences of "<" in the file name (pretty unlikely); if there are,
2197     pcretest will instead treat the initial "<" as a pattern delimiter.
2198     After reading in the pattern, pcretest goes on to read data lines as
2199     usual.
2201     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2202     and 16-bit fields in a compiled pattern, to simulate a pattern that
2203     was compiled on a host of opposite endianness.
2205     21. The pcre-exec() function can now cope with patterns that were compiled on
2206     hosts of opposite endianness, with this restriction:
2208     As for any compiled expression that is saved and used later, the tables
2209     pointer field cannot be preserved; the extra_data field in the arguments
2210     to pcre_exec() should be used to pass in a tables address if a value
2211     other than the default internal tables were used at compile time.
2213     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2214     now diagnosed as an error. Previously, most of the time, a negative number
2215     would have been treated as zero, but if in addition "ovector" was passed as
2216     NULL, a crash could occur.
2218     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2219     new versions from the libtool 1.5 distribution (the last one is a copy of
2220     a file called libtool.m4). This seems to have fixed the need to patch
2221     "configure" to support Darwin 1.3 (which I used to do). However, I still
2222     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2223     workstation).
2225     24. Changed the PCRE licence to be the more standard "BSD" licence.
2228 nigel 73 Version 4.5 01-Dec-03
2229     ---------------------
2231     1. There has been some re-arrangement of the code for the match() function so
2232     that it can be compiled in a version that does not call itself recursively.
2233     Instead, it keeps those local variables that need separate instances for
2234     each "recursion" in a frame on the heap, and gets/frees frames whenever it
2235     needs to "recurse". Keeping track of where control must go is done by means
2236     of setjmp/longjmp. The whole thing is implemented by a set of macros that
2237     hide most of the details from the main code, and operates only if
2238     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2239     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2240     operating.
2242     To make it easier for callers to provide specially tailored get/free
2243     functions for this usage, two new functions, pcre_stack_malloc, and
2244     pcre_stack_free, are used. They are always called in strict stacking order,
2245     and the size of block requested is always the same.
2247     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2248     PCRE has been compiled to use the stack or the heap for recursion. The
2249     -C option of pcretest uses this to show which version is compiled.
2251     A new data escape \S, is added to pcretest; it causes the amounts of store
2252     obtained and freed by both kinds of malloc/free at match time to be added
2253     to the output.
2255     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2256     what's available on my current Linux desktop machine.
2258     3. When matching a UTF-8 string, the test for a valid string at the start has
2259     been extended. If start_offset is not zero, PCRE now checks that it points
2260     to a byte that is the start of a UTF-8 character. If not, it returns
2261     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2262     this is necessary because there may be backward assertions in the pattern.
2263     When matching the same subject several times, it may save resources to use
2264     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2266     4. The code for checking the validity of UTF-8 strings has been tightened so
2267     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2268     containing "overlong sequences".
2270     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2271     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2272     should have been "&", but it just so happened that all the cases this let
2273     through by mistake were picked up later in the function.
2275     6. I had used a variable called "isblank" - this is a C99 function, causing
2276     some compilers to warn. To avoid this, I renamed it (as "blankclass").
2278     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2279     prompting; (b) run "./pcretest /dev/null" at the start of the test script
2280     so the version is shown; (c) stop "make test" echoing "./RunTest".
2282     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2284     9. The prototype for memmove() for systems that don't have it was using
2285     size_t, but the inclusion of the header that defines size_t was later. I've
2286     moved the #includes for the C headers earlier to avoid this.
2288     10. Added some adjustments to the code to make it easier to compiler on certain
2289     special systems:
2291     (a) Some "const" qualifiers were missing.
2292     (b) Added the macro EXPORT before all exported functions; by default this
2293     is defined to be empty.
2294     (c) Changed the dftables auxiliary program (that builds chartables.c) so
2295     that it reads its output file name as an argument instead of writing
2296     to the standard output and assuming this can be redirected.
2298     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2299     class containing characters with values greater than 255, PCRE compilation
2300     went into a loop.
2302     12. A recursive reference to a subpattern that was within another subpattern
2303     that had a minimum quantifier of zero caused PCRE to crash. For example,
2304     (x(y(?2))z)? provoked this bug with a subject that got as far as the
2305     recursion. If the recursively-called subpattern itself had a zero repeat,
2306     that was OK.
2308     13. In pcretest, the buffer for reading a data line was set at 30K, but the
2309     buffer into which it was copied (for escape processing) was still set at
2310     1024, so long lines caused crashes.
2312     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2313     "internal error: code overflow...". This applied to any character class
2314     that was followed by a possessive quantifier.
2316     15. Modified the Makefile to add libpcre.la as a prerequisite for
2317     libpcreposix.la because I was told this is needed for a parallel build to
2318     work.
2320     16. If a pattern that contained .* following optional items at the start was
2321     studied, the wrong optimizing data was generated, leading to matching
2322     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2323     matching string must start with a or b or c. The correct conclusion for
2324     this pattern is that a match can start with any character.
2327 nigel 71 Version 4.4 13-Aug-03
2328     ---------------------
2330     1. In UTF-8 mode, a character class containing characters with values between
2331     127 and 255 was not handled correctly if the compiled pattern was studied.
2332     In fixing this, I have also improved the studying algorithm for such
2333     classes (slightly).
2335     2. Three internal functions had redundant arguments passed to them. Removal
2336     might give a very teeny performance improvement.
2338     3. Documentation bug: the value of the capture_top field in a callout is *one
2339     more than* the number of the hightest numbered captured substring.
2341     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2342     in incorrectly linking with a previously installed version. They now link
2343     explicitly with libpcre.la.
2345     5. configure.in no longer needs to recognize Cygwin specially.
2347     6. A problem in pcre.in for Windows platforms is fixed.
2349     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2350     pcretest, it used to include the size of the study block as part of its
2351     output. Unfortunately, the structure contains a field that has a different
2352     size on different hardware architectures. This meant that the tests that
2353     showed this size failed. As the block is currently always of a fixed size,
2354     this information isn't actually particularly useful in pcretest output, so
2355     I have just removed it.
2357     8. Three pre-processor statements accidentally did not start in column 1.
2358     Sadly, there are *still* compilers around that complain, even though
2359     standard C has not required this for well over a decade. Sigh.
2361     9. In pcretest, the code for checking callouts passed small integers in the
2362     callout_data field, which is a void * field. However, some picky compilers
2363     complained about the casts involved for this on 64-bit systems. Now
2364     pcretest passes the address of the small integer instead, which should get
2365     rid of the warnings.
2367     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2368     both compile and run time, and gives an error if an invalid UTF-8 sequence
2369     is found. There is a option for disabling this check in cases where the
2370     string is known to be correct and/or the maximum performance is wanted.
2372     11. In response to a bug report, I changed one line in Makefile.in from
2374     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2375     to
2376     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2378     to look similar to other lines, but I have no way of telling whether this
2379     is the right thing to do, as I do not use Windows. No doubt I'll get told
2380     if it's wrong...
2383 nigel 69 Version 4.3 21-May-03
2384     ---------------------
2386     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2387     Makefile.
2389     2. Some refactoring to improve the quality of the code:
2391     (i) The utf8_table... variables are now declared "const".
2393     (ii) The code for \cx, which used the "case flipping" table to upper case
2394     lower case letters, now just substracts 32. This is ASCII-specific,
2395     but the whole concept of \cx is ASCII-specific, so it seems
2396     reasonable.
2398     (iii) PCRE was using its character types table to recognize decimal and
2399     hexadecimal digits in the pattern. This is silly, because it handles
2400     only 0-9, a-f, and A-F, but the character types table is locale-
2401     specific, which means strange things might happen. A private
2402     table is now used for this - though it costs 256 bytes, a table is
2403     much faster than multiple explicit tests. Of course, the standard
2404     character types table is still used for matching digits in subject
2405     strings against \d.
2407     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2408     ending in _t are). So I've renamed it as ESC_tee.
2410     3. The first argument for regexec() in the POSIX wrapper should have been
2411     defined as "const".
2413     4. Changed pcretest to use malloc() for its buffers so that they can be
2414     Electric Fenced for debugging.
2416     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2417     to read one or more bytes before the start of the subject string. Often this
2418     had no effect on PCRE's behaviour, but in some circumstances it could
2419     provoke a segmentation fault.
2421     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2422     to try to read one or more bytes before the start of the subject string.
2424     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2425     UTF-8 support could misbehave in various ways if the subject string
2426     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2427     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2428     back over UTF-8 characters.)
2431 nigel 67 Version 4.2 14-Apr-03
2432     ---------------------
2434     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2436     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2437     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2438     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2439     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2440     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2441     and BUILD_EXEEXT
2442     Note: automatic setting of the BUILD variables is not yet working
2443     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2444     compile-time but not at link-time
2445     [LINK]: use for linking executables only
2446     make different versions for Windows and non-Windows
2447     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2448     libraries
2449     [LINK_FOR_BUILD]: new variable
2450     [OBJEXT]: use throughout
2451     [EXEEXT]: use throughout
2452     <winshared>: new target
2453     <wininstall>: new target
2454     <dftables.o>: use native compiler
2455     <dftables>: use native linker
2456     <install>: handle Windows platform correctly
2457     <clean>: ditto
2458     <check>: ditto
2459     copy DLL to top builddir before testing
2461     As part of these changes, -no-undefined was removed again. This was reported
2462     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2463     in any case.
2465     3. Some tidies to get rid of compiler warnings:
2467     . In the match_data structure, match_limit was an unsigned long int, whereas
2468     match_call_count was an int. I've made them both unsigned long ints.
2470     . In pcretest the fact that a const uschar * doesn't automatically cast to
2471     a void * provoked a warning.
2473     . Turning on some more compiler warnings threw up some "shadow" variables
2474     and a few more missing casts.
2476     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2477     option, a class that contained a single character with a value between 128
2478     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2480     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2481     option, a class that contained several characters, but with at least one
2482     whose value was between 128 and 255 caused PCRE to crash.
2485 nigel 65 Version 4.1 12-Mar-03
2486     ---------------------
2487 nigel 63
2488 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2489     needed, and a string in dftables.c that was longer than standard compilers are
2490     required to support.
2492     2. Compiling with Sun's compiler found a few more places where the code could
2493     be tidied up in order to avoid warnings.
2495     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2496     first of these names is deprecated in the latest Autoconf in favour of the name
2497     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2498     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2499     analogy I have changed it to CFLAGS_FOR_BUILD.
2501     4. Added -no-undefined to the linking command in the Makefile, because this is
2502     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2503     linking step for the pcreposix library.
2505     5. PCRE was failing to diagnose the case of two named groups with the same
2506     name.
2508     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2509     literal character that is needed in the subject for a match, and scans along to
2510     ensure that it is present before embarking on the full matching process. This
2511     saves time in cases of nested unlimited repeats that are never going to match.
2512     Problem: the scan can take a lot of time if the subject is very long (e.g.
2513     megabytes), thus penalizing straightforward matches. It is now done only if the
2514     amount of subject to be scanned is less than 1000 bytes.
2516     7. A lesser problem with the same optimization is that it was recording the
2517     first character of an anchored pattern as "needed", thus provoking a search
2518     right along the subject, even when the first match of the pattern was going to
2519     fail. The "needed" character is now not set for anchored patterns, unless it
2520     follows something in the pattern that is of non-fixed length. Thus, it still
2521     fulfils its original purpose of finding quick non-matches in cases of nested
2522     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2525     Version 4.0 17-Feb-03
2526     ---------------------
2528 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2529     extended to the end of string, PCRE compiled incorrect data. This could lead to
2530     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2532     2. Moved to autoconf 2.53 and libtool 1.4.2.
2534     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2535     the special perltest8 script is no longer needed - all the tests can be run
2536     from a single perltest script.
2538     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2539     by \s. It has now been removed in PCRE. This means it isn't recognized as
2540     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2541     class [:space:] *does* include VT, thereby creating a mess.
2543     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2544     space and tab.
2546     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2547     its new features into the main test script, reducing the number of scripts.
2549     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2550     were backward compatible, and made the (?i) apply to the whole pattern, as if
2551     /i were given. Now it behaves more logically, and applies the option setting
2552     only to what follows. PCRE has been changed to follow suit. However, if it
2553     finds options settings right at the start of the pattern, it extracts them into
2554     the global options, as before. Thus, they show up in the info data.
2556     8. Added support for the \Q...\E escape sequence. Characters in between are
2557     treated as literals. This is slightly different from Perl in that $ and @ are
2558     also handled as literals inside the quotes. In Perl, they will cause variable
2559     interpolation. Note the following examples:
2561     Pattern PCRE matches Perl matches
2563     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2564     \Qabc\$xyz\E abc\$xyz abc\$xyz
2565     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2567     For compatibility with Perl, \Q...\E sequences are recognized inside character
2568     classes as well as outside them.
2570     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2571     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2572     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2573     signed/unsigned warnings.
2575     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2576     option for pcretest, so I've replaced it by a simple function that does just
2577     that job.
2579     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2580     "pcregrep -".
2582     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2583     Java package. This provides some syntactic sugar for simple cases of what my
2584     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2585     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2586     item, you can use this simplified notation. Note that only makes sense with
2587     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2588     greediness, whatever the setting of the PCRE_UNGREEDY option.
2590     13. A change of greediness default within a pattern was not taking effect at
2591     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2592     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2593     was abstracted outside.
2595     14. PCRE now supports the \G assertion. It is true when the current matching
2596     position is at the start point of the match. This differs from \A when the
2597     starting offset is non-zero. Used with the /g option of pcretest (or similar
2598     code), it works in the same way as it does for Perl's /g option. If all
2599     alternatives of a regex begin with \G, the expression is anchored to the start
2600     match position, and the "anchored" flag is set in the compiled expression.
2602     15. Some bugs concerning the handling of certain option changes within patterns
2603     have been fixed. These applied to options other than (?ims). For example,
2604     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2605     been the other way round. Some of this was related to change 7 above.
2607     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2608     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2609     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2610     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2612     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2613     mode. Unlike ".", it always matches newline, whatever the setting of
2614     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2615     assertions. Perl allows it, but it doesn't (in general) work because it can't
2616     calculate the length of the lookbehind. At least, that's the case for Perl
2617     5.8.0 - I've been told they are going to document that it doesn't work in
2618     future.
2620     18. Added an error diagnosis for escapes that PCRE does not support: these are
2621     \L, \l, \N, \P, \p, \U, \u, and \X.
2623     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2624     reading past the end of the pattern in cases such as /[abcd/.
2626     20. PCRE was getting more memory than necessary for patterns with classes that
2627     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2629     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2630     compiling PCRE for use with Virtual Pascal.
2632     22. Small fix to the Makefile to make it work properly if the build is done
2633     outside the source tree.
2635     23. Added a new extension: a condition to go with recursion. If a conditional
2636     subpattern starts with (?(R) the "true" branch is used if recursion has
2637     happened, whereas the "false" branch is used only at the top level.
2639     24. When there was a very long string of literal characters (over 255 bytes
2640     without UTF support, over 250 bytes with UTF support), the computation of how
2641     much memory was required could be incorrect, leading to segfaults or other
2642     strange effects.
2644     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2645     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2646     there was a subsequent back reference to those brackets. This meant that, for
2647     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2648     possible to check for precisely this case. All we can do is abandon the
2649     optimization if .* occurs inside capturing brackets when there are any back
2650     references whatsoever. (See below for a better fix that came later.)
2652     26. The handling of the optimization for finding the first character of a
2653     non-anchored pattern, and for finding a character that is required later in the
2654     match were failing in some cases. This didn't break the matching; it just
2655     failed to optimize when it could. The way this is done has been re-implemented.
2657     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2659     28. Added a new feature that provides some of the functionality that Perl
2660     provides with (?{...}). The facility is termed a "callout". The way it is done
2661     in PCRE is for the caller to provide an optional function, by setting
2662     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2663     global variable. By default it is unset, which disables all calling out. To get
2664     the function called, the regex must include (?C) at appropriate points. This
2665     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2666     This provides a means of identifying different callout points. When PCRE
2667     reaches such a point in the regex, if pcre_callout has been set, the external
2668     function is called. It is provided with data in a structure called
2669     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2670     matching continues; if it returns a non-zero value, the match at the current
2671     point fails. However, backtracking will occur if possible. [This was changed
2672     later and other features added - see item 49 below.]
2674     29. pcretest is upgraded to test the callout functionality. It provides a
2675     callout function that displays information. By default, it shows the start of
2676     the match and the current position in the text. There are some new data escapes
2677     to vary what happens:
2679     \C+ in addition, show current contents of captured substrings
2680     \C- do not supply a callout function
2681     \C!n return 1 when callout number n is reached
2682     \C!n!m return 1 when callout number n is reached for the mth time
2684     30. If pcregrep was called with the -l option and just a single file name, it
2685     output "<stdin>" if a match was found, instead of the file name.
2687     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2688     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2689     pcre_exec(). This saves a malloc/free per call. The default value of
2690     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2691     when configuring.
2693     32. The default maximum size of a compiled pattern is 64K. There have been a
2694     few cases of people hitting this limit. The code now uses macros to handle the
2695     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2696     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2697     configuring. Tests 2 and 5 work only with 2-byte links because they output
2698     debugging information about compiled patterns.
2700     33. Internal code re-arrangements:
2702     (a) Moved the debugging function for printing out a compiled regex into
2703     its own source file (printint.c) and used #include to pull it into
2704     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2705     separate copies.
2707     (b) Defined the list of op-code names for debugging as a macro in
2708     internal.h so that it is next to the definition of the opcodes.
2710     (c) Defined a table of op-code lengths for simpler skipping along compiled
2711     code. This is again a macro in internal.h so that it is next to the
2712     definition of the opcodes.
2714     34. Added support for recursive calls to individual subpatterns, along the
2715     lines of Robin Houston's patch (but implemented somewhat differently).
2717     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2718     allow it to read and process whole directories in Win32. This code was
2719     contributed by Lionel Fourquaux; it has not been tested by me.
2721     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2722     used to name a group. Names consist of alphanumerics and underscores, and must
2723     be unique. Back references use the syntax (?P=name) and recursive calls use
2724     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2725     numbers. The function pcre_fullinfo() can be used after compilation to extract
2726     a name/number map. There are three relevant calls:
2728     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2729     PCRE_INFO_NAMECOUNT yields the number of entries
2730     PCRE_INFO_NAMETABLE yields a pointer to the map.
2732     The map is a vector of fixed-size entries. The size of each entry depends on
2733     the length of the longest name used. The first two bytes of each entry are the
2734     group number, most significant byte first. There follows the corresponding
2735     name, zero terminated. The names are in alphabetical order.
2737     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2738     case instead of 255. Making it the same both with and without UTF-8 support
2739     means that the same test output works with both.
2741     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2742     calling malloc() with a zero argument.
2744     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2745     optimization. I've improved things by keeping a bitmap of backreferences with
2746     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2747     fact referenced, the optimization can be applied. It is unlikely that a
2748     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2749     the match to follow \n) will appear inside brackets with a number greater than
2750     31, but if it does, any back reference > 31 suppresses the optimization.
2752     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2753     of disabling numbered capturing parentheses. Any opening parenthesis that is
2754     not followed by ? behaves as if it were followed by ?: but named parentheses
2755     can still be used for capturing (and they will acquire numbers in the usual
2756     way).
2758     41. Redesigned the return codes from the match() function into yes/no/error so
2759     that errors can be passed back from deep inside the nested calls. A malloc
2760     failure while inside a recursive subpattern call now causes the
2761     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2763     42. It is now possible to set a limit on the number of times the match()
2764     function is called in a call to pcre_exec(). This facility makes it possible to
2765     limit the amount of recursion and backtracking, though not in a directly
2766     obvious way, because the match() function is used in a number of different
2767     circumstances. The count starts from zero for each position in the subject
2768     string (for non-anchored patterns). The default limit is, for compatibility, a
2769     large number, namely 10 000 000. You can change this in two ways:
2771     (a) When configuring PCRE before making, you can use --with-match-limit=n
2772     to set a default value for the compiled library.
2774     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2775     a different value is set. See 45 below.
2777     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2779     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2780     of things that can be changed at compile time. The first argument specifies
2781     what is wanted and the second points to where the information is to be placed.
2782     The current list of available information is:
2786     The output is an integer that is set to one if UTF-8 support is available;
2787     otherwise it is set to zero.
2791     The output is an integer that it set to the value of the code that is used for
2792     newline. It is either LF (10) or CR (13).
2796     The output is an integer that contains the number of bytes used for internal
2797     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2801     The output is an integer that contains the threshold above which the POSIX
2802     interface uses malloc() for output vectors. See item 31 above.
2806     The output is an unsigned integer that contains the default limit of the number
2807     of match() calls in a pcre_exec() execution. See 42 above.
2809     44. pcretest has been upgraded by the addition of the -C option. This causes it
2810     to extract all the available output from the new pcre_config() function, and to
2811     output it. The program then exits immediately.
2813     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2814     order to support additional features. One way would have been to define
2815     pcre_exec2() (for example) with extra arguments, but this would not have been
2816     extensible, and would also have required all calls to the original function to
2817     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2818     is used for passing in "extra" data from pcre_study().
2820     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2821     contains the following fields:
2823     flags a bitmap indicating which of the following fields are set
2824     study_data opaque data from pcre_study()
2825     match_limit a way of specifying a limit on match() calls for a specific
2826     call to pcre_exec()
2827     callout_data data for callouts (see 49 below)
2829     The flag bits are also defined in pcre.h, and are
2835     The pcre_study() function now returns one of these new pcre_extra blocks, with
2836     the actual study data pointed to by the study_data field, and the
2837     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2838     before. That is, this change is entirely upwards-compatible and requires no
2839     change to existing code.
2841     If you want to pass in additional data to pcre_exec(), you can either place it
2842     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2843     block.
2845     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2846     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2847     times with different match limits, until it finds the minimum value needed for
2848     pcre_exec() to complete. The value is then output. This can be instructive; for
2849     most simple matches the number is quite small, but for pathological cases it
2850     gets very large very quickly.
2852     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2853     returns the size of the data block pointed to by the study_data field in a
2854     pcre_extra block, that is, the value that was passed as the argument to
2855     pcre_malloc() when PCRE was getting memory in which to place the information
2856     created by pcre_study(). The fourth argument should point to a size_t variable.
2857     pcretest has been extended so that this information is shown after a successful
2858     pcre_study() call when information about the compiled regex is being displayed.
2860     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2861     because what follows is always an absolute path. (Later: it turns out that this
2862     is more than cosmetic for MinGW, because it doesn't like empty path
2863     components.)
2865     49. Some changes have been made to the callout feature (see 28 above):
2867     (i) A callout function now has three choices for what it returns:
2869     0 => success, carry on matching
2870     > 0 => failure at this point, but backtrack if possible
2871     < 0 => serious error, return this value from pcre_exec()
2873     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2874     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2875     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2876     use by callout functions. It will never be used by PCRE itself.
2878     (ii) The pcre_extra structure (see 45 above) has a void * field called
2879     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2880     pcre_callout_block structure has a field of the same name. The contents of
2881     the field passed in the pcre_extra structure are passed to the callout
2882     function in the corresponding field in the callout block. This makes it
2883     easier to use the same callout-containing regex from multiple threads. For
2884     testing, the pcretest program has a new data escape
2886     \C*n pass the number n (may be negative) as callout_data
2888     If the callout function in pcretest receives a non-zero value as
2889     callout_data, it returns that value.
2891     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2892     there were some redundant $(CFLAGS) in commands that are now specified as
2893     $(LINK), which already includes $(CFLAGS).
2895     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2896     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2897     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2898     one-byte characters throughout. Note that case-insensitive matching applies
2899     only to characters whose values are less than 256. PCRE doesn't support the
2900     notion of cases for higher-valued characters.
2902     (i) A character class whose characters are all within 0-255 is handled as
2903     a bit map, and the map is inverted for negative classes. Previously, a
2904     character > 255 always failed to match such a class; however it should
2905     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2907     (ii) A negated character class with a single character < 255 is coded as
2908     "not this character" (OP_NOT). This wasn't working properly when the test
2909     character was multibyte, either singly or repeated.
2911     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2912     mode, for example: \x{100}{2,3}.
2914     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2915     singly or repeated) now correctly test multibyte characters. However,
2916     PCRE doesn't recognize any characters with values greater than 255 as
2917     digits, spaces, or word characters. Such characters always match \D, \S,
2918     and \W, and never match \d, \s, or \w.
2920     (v) Classes may now contain characters and character ranges with values
2921     greater than 255. For example: [ab\x{100}-\x{400}].
2923     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2924     PCRE in UTF-8 mode.
2926     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2927     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2928     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2929     value.)
2931     53. The single man page has become too large. I have therefore split it up into
2932     a number of separate man pages. These also give rise to individual HTML pages;
2933     these are now put in a separate directory, and there is an index.html page that
2934     lists them all. Some hyperlinking between the pages has been installed.
2936     54. Added convenience functions for handling named capturing parentheses.
2938     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2939     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2940     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2941     are faulted.
2943     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2944     calling configure. These values are used when compiling the dftables.c program
2945     which is run to generate the source of the default character tables. They
2946     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2947     you will need to set these values.
2949     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2952     Version 3.9 02-Jan-02
2953 nigel 61 ---------------------
2955     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2957     2. If --disable-static was given, the building process failed when trying to
2958     build pcretest and pcregrep. (For some reason it was using libtool to compile
2959     them, which is not right, as they aren't part of the library.)
2962 nigel 59 Version 3.8 18-Dec-01
2963     ---------------------
2965     1. The experimental UTF-8 code was completely screwed up. It was packing the
2966     bytes in the wrong order. How dumb can you get?
2969 nigel 57 Version 3.7 29-Oct-01
2970     ---------------------
2972     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2973     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2974     this didn't happen under Solaris 8, where I normally test things.
2976 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2977     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2978     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2979     this fix an hour or so after the initial 3.7 release.)
2980 nigel 57
2981 nigel 59
2982 nigel 55 Version 3.6 23-Oct-01
2983     ---------------------
2985     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2986     offsets passed as NULL with zero offset count.
2988     2. The config.guess and config.sub files had not been updated when I moved to
2989     the latest autoconf.
2992 nigel 53 Version 3.5 15-Aug-01
2993     ---------------------
2994 nigel 5
2995 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2996     had been forgotten.
2998     2. By using declared but undefined structures, we can avoid using "void"
2999     definitions in pcre.h while keeping the internal definitions of the structures
3000     private.
3002     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3003     user point of view, this means that both static and shared libraries are built
3004     by default, but this can be individually controlled. More of the work of
3005     handling this static/shared cases is now inside libtool instead of PCRE's make
3006     file.
3008     4. The pcretest utility is now installed along with pcregrep because it is
3009     useful for users (to test regexs) and by doing this, it automatically gets
3010     relinked by libtool. The documentation has been turned into a man page, so
3011     there are now .1, .txt, and .html versions in /doc.
3013     5. Upgrades to pcregrep:
3014     (i) Added long-form option names like gnu grep.
3015     (ii) Added --help to list all options with an explanatory phrase.
3016     (iii) Added -r, --recursive to recurse into sub-directories.
3017     (iv) Added -f, --file to read patterns from a file.
3019     6. pcre_exec() was referring to its "code" argument before testing that
3020     argument for NULL (and giving an error if it was NULL).
3022     7. Upgraded Makefile.in to allow for compiling in a different directory from
3023     the source directory.
3025     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3026     options bits, the pointer it was passed was to an int instead of to an unsigned
3027     long int. This mattered only on 64-bit systems.
3029     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3030     generated) instead of pcre.in, which it its source. Also made the same change
3031     in several of the .c files.
3033     10. A new release of gcc defines printf() as a macro, which broke pcretest
3034     because it had an ifdef in the middle of a string argument for printf(). Fixed
3035     by using separate calls to printf().
3037     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3038     script, to force use of CR or LF instead of \n in the source. On non-Unix
3039     systems, the value can be set in config.h.
3041     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3042     absolute limit. Changed the text of the error message to make this clear, and
3043     likewise updated the man page.
3045     13. The limit of 99 on the number of capturing subpatterns has been removed.
3046     The new limit is 65535, which I hope will not be a "real" limit.
3049 nigel 51 Version 3.4 22-Aug-00
3050     ---------------------
3052     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3054     2. Diagnose condition (?(0) as an error instead of crashing on matching.
3057 nigel 49 Version 3.3 01-Aug-00
3058     ---------------------
3060     1. If an octal character was given, but the value was greater than \377, it
3061     was not getting masked to the least significant bits, as documented. This could
3062     lead to crashes in some systems.
3064     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3065     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3067     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3068     These just pass their arguments on to (pcre_free)(), but they are provided
3069     because some uses of PCRE bind it to non-C systems that can call its functions,
3070     but cannot call free() or pcre_free() directly.
3072     4. Add "make test" as a synonym for "make check". Corrected some comments in
3073     the Makefile.
3075     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3076     Makefile.
3078     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3079     command called pgrep for grepping around the active processes.
3081     7. Added the beginnings of support for UTF-8 character strings.
3083     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3084     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3085     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3086     out for the ar command.)
3089 nigel 47 Version 3.2 12-May-00
3090     ---------------------
3092     This is purely a bug fixing release.
3094     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3095     of ZA. This was just one example of several cases that could provoke this bug,
3096     which was introduced by change 9 of version 2.00. The code for breaking
3097     infinite loops after an iteration that matches an empty string was't working
3098     correctly.
3100     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3101     when matched against abbab (for example). After matching an empty string, it
3102     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3103     caused it to match further down the string than it should.
3105     3. The code contained an inclusion of sys/types.h. It isn't clear why this
3106     was there because it doesn't seem to be needed, and it causes trouble on some
3107     systems, as it is not a Standard C header. It has been removed.
3109     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3110     were reported on the Macintosh. The changes were from
3112     while ((c = *(++ptr)) != 0 && c != '\n');
3113     to
3114     while ((c = *(++ptr)) != 0 && c != '\n') ;
3116     Totally extraordinary, but if that's what it takes...
3118     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3119     available. Added HAVE_BCOPY and an autoconf test for it; if neither
3120     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3121     assumes the way PCRE uses memmove() (always moving upwards).
3123     6. PCRE is being used in one environment where strchr() is not available. There
3124     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3125     faster code anyway.
3128 nigel 45 Version 3.1 09-Feb-00
3129     ---------------------
3131     The only change in this release is the fixing of some bugs in Makefile.in for
3132     the "install" target:
3134     (1) It was failing to install pcreposix.h.
3136     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3139 nigel 43 Version 3.0 01-Feb-00
3140     ---------------------
3141 nigel 41
3142     1. Add support for the /+ modifier to perltest (to output $` like it does in
3143     pcretest).
3145     2. Add support for the /g modifier to perltest.
3147     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3148     matches null strings.
3150     4. Fix perltest so that it doesn't do unwanted things when fed an empty
3151     pattern. Perl treats empty patterns specially - it reuses the most recent
3152     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3153     effect.
3155     5. The POSIX interface was broken in that it was just handing over the POSIX
3156     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3157     required a bigger vector, with some working space on the end. This means that
3158     the POSIX wrapper now has to get and free some memory, and copy the results.
3160 nigel 43 6. Added some simple autoconf support, placing the test data and the
3161     documentation in separate directories, re-organizing some of the
3162     information files, and making it build pcre-config (a GNU standard). Also added
3163     libtool support for building PCRE as a shared library, which is now the
3164     default.
3165 nigel 41
3166 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3167     09 are not valid octal constants. Single digits will be used for minor values
3168     less than 10.
3170     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3171     existing programs that set these in the POSIX interface can use PCRE without
3172     modification.
3174     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3175     return all that pcre_info() returns, plus additional data. The pcre_info()
3176     function is retained for compatibility, but is considered to be obsolete.
3178     10. Added experimental recursion feature (?R) to handle one common case that
3179     Perl 5.6 will be able to do with (?p{...}).
3181     11. Added support for POSIX character classes like [:alpha:], which Perl is
3182     adopting.
3185 nigel 39 Version 2.08 31-Aug-99
3186     ----------------------
3188     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3189     trying to match at the startoffset position, but instead was moving forward to
3190     the next newline as if a previous match had failed.
3192     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3193     and could get into a loop if a null string was matched other than at the start
3194     of the subject.
3196     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3197     be distinguished at compile time, and for completeness also added PCRE_DATE.
3199     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3200     in GnuWin32 environments.
3203 nigel 37 Version 2.07 29-Jul-99
3204     ----------------------
3206     1. The documentation is now supplied in plain text form and HTML as well as in
3207     the form of man page sources.
3209     2. C++ compilers don't like assigning (void *) values to other pointer types.
3210     In particular this affects malloc(). Although there is no problem in Standard
3211     C, I've put in casts to keep C++ compilers happy.
3213     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3214     should be (const char *).
3216     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3217     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3218     However, I haven't made this a standard facility. The documentation doesn't
3219     mention it, and the Makefile doesn't support it.
3221     5. The Makefile now contains an "install" target, with editable destinations at
3222     the top of the file. The pcretest program is not installed.
3224     6. pgrep -V now gives the PCRE version number and date.
3226     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3227     causing the entire string to be ignored, instead of just the last character.
3229     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3230     non-matching string, it can take a very, very long time, even for strings of
3231     quite modest length, because of the nested recursion. PCRE now does better in
3232     some of these cases. It does this by remembering the last required literal
3233     character in the pattern, and pre-searching the subject to ensure it is present
3234     before running the real match. In other words, it applies a heuristic to detect
3235     some types of certain failure quickly, and in the above example, if presented
3236     with a string that has no trailing " it gives "no match" very quickly.
3238     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3239     other alternatives are tried instead.
3242 nigel 35 Version 2.06 09-Jun-99
3243     ----------------------
3245     1. Change pcretest's output for amount of store used to show just the code
3246     space, because the remainder (the data block) varies in size between 32-bit and
3247     64-bit systems.
3249     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3250     start matching at. This allows lookbehinds to work when searching for multiple
3251     occurrences in a string.
3253     3. Added additional options to pcretest for testing multiple occurrences:
3255     /+ outputs the rest of the string that follows a match
3256     /g loops for multiple occurrences, using the new startoffset argument
3257     /G loops for multiple occurrences by passing an incremented pointer
3259     4. PCRE wasn't doing the "first character" optimization for patterns starting
3260     with \b or \B, though it was doing it for other lookbehind assertions. That is,
3261     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3262     the letter 'x'. On long subject strings, this gives a significant speed-up.
3265 nigel 33 Version 2.05 21-Apr-99
3266     ----------------------
3268     1. Changed the type of magic_number from int to long int so that it works
3269     properly on 16-bit systems.
3271     2. Fixed a bug which caused patterns starting with .* not to work correctly
3272     when the subject string contained newline characters. PCRE was assuming
3273     anchoring for such patterns in all cases, which is not correct because .* will
3274     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3275     DOTALL is set at top level; otherwise it knows that patterns starting with .*
3276     must be retried after every newline in the subject.
3279 nigel 31 Version 2.04 18-Feb-99
3280     ----------------------
3282     1. For parenthesized subpatterns with repeats whose minimum was zero, the
3283     computation of the store needed to hold the pattern was incorrect (too large).
3284     If such patterns were nested a few deep, this could multiply and become a real
3285     problem.
3287     2. Added /M option to pcretest to show the memory requirement of a specific
3288     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3290     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3291     compiled in such a way that the backtracking after subsequent failure was
3292     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3293     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3296 nigel 29 Version 2.03 02-Feb-99
3297     ----------------------
3299     1. Fixed typo and small mistake in man page.
3301 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
3302     LICENCE file containing the conditions.
3303 nigel 29
3304     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3305     Perl, that is the internal \ allows the delimiter to be included in the
3306     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3307     the final delimiter, add \ to the end of the pattern (to test the error).
3309     4. Added the convenience functions for extracting substrings after a successful
3310     match. Updated pcretest to make it able to test these functions.
3313 nigel 27 Version 2.02 14-Jan-99
3314     ----------------------
3316     1. Initialized the working variables associated with each extraction so that
3317     their saving and restoring doesn't refer to uninitialized store.
3319     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3320     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3321     fix the problem.
3323     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3324     calls, and wasn't printing the correct value for compiling calls. Increased the
3325     default value of LOOPREPEAT, and the number of significant figures in the
3326     times.
3328     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3330     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3331     a building problem on Windows NT with a FAT file system.
3334 nigel 25 Version 2.01 21-Oct-98
3335     ----------------------
3337     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3338     to character tables built by pcre_maketables() in the current locale. If NULL
3339     is passed, the default tables are used.
3342 nigel 23 Version 2.00 24-Sep-98
3343 nigel 21 ----------------------
3345 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3346     it any more.
3348     2. Allow quantification of (?>) groups, and make it work correctly.
3350     3. The first character computation wasn't working for (?>) groups.
3352     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3353     end of the subject) and add 5.005's \z, which really does match only at the
3354     very end of the subject.
3356     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3358     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3359     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3360     localized options. All options to pcre_study() were also removed.
3362     7. Add other new features from 5.005:
3364     $(?<= positive lookbehind
3365     $(?<! negative lookbehind
3366     (?imsx-imsx) added the unsetting capability
3367     such a setting is global if at outer level; local otherwise
3368     (?imsx-imsx:) non-capturing groups with option setting
3369     (?(cond)re|re) conditional pattern matching
3371     A backreference to itself in a repeated group matches the previous
3372     captured string.
3374     8. General tidying up of studying (both automatic and via "study")
3375     consequential on the addition of new assertions.
3377     9. As in 5.005, unlimited repeated groups that could match an empty substring
3378     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3379     runtime if any iteration does actually match an empty substring.
3381     10. Include the RunTest script in the distribution.
3383     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3384     discrepancies, some of which were old and were also with respect to 5.004. They
3385     have now been fixed.
3388     Version 1.09 28-Apr-98
3389     ----------------------
3391 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3392     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3393     program crashes, or just wrong answers. This did not apply to negated classes
3394     containing more than one character, or to minima other than one.
3397 nigel 19 Version 1.08 27-Mar-98
3398     ----------------------
3400     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3402     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3403     latter must appear before anything that relies on it in the pattern.
3406 nigel 17 Version 1.07 16-Feb-98
3407     ----------------------
3409     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3410     repeat of a potentially empty string).
3413 nigel 15 Version 1.06 23-Jan-98
3414     ----------------------
3416     1. Added Markus Oberhumer's little patches for C++.
3418     2. Literal strings longer than 255 characters were broken.
3421 nigel 13 Version 1.05 23-Dec-97
3422     ----------------------
3424     1. Negated character classes containing more than one character were failing if
3425     PCRE_CASELESS was set at run time.
3428 nigel 11 Version 1.04 19-Dec-97
3429     ----------------------
3431     1. Corrected the man page, where some "const" qualifiers had been omitted.
3433     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3434     input syntax.
3436     3. Fixed memory leak which occurred when a regex with back references was
3437     matched with an offsets vector that wasn't big enough. The temporary memory
3438     that is used in this case wasn't being freed if the match failed.
3440     4. Tidied pcretest to ensure it frees memory that it gets.
3442     5. Temporary memory was being obtained in the case where the passed offsets
3443     vector was exactly big enough.
3445     6. Corrected definition of offsetof() from change 5 below.
3447     7. I had screwed up change 6 below and broken the rules for the use of
3448     setjmp(). Now fixed.
3451 nigel 9 Version 1.03 18-Dec-97
3452     ----------------------
3454     1. A erroneous regex with a missing opening parenthesis was correctly
3455     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3456     on some systems.
3458     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3459     it was reported that one broken compiler failed on the former because "code" is
3460     also an independent variable.
3462     3. The erroneous regex a[]b caused an array overrun reference.
3464     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3465     fail on data ending with that character. (It was going on too far, and checking
3466     the next character, typically a binary zero.) This was specific to the
3467     optimized code for single-character negative classes.
3469     5. Added a contributed patch from the TIN world which does the following:
3471     + Add an undef for memmove, in case the the system defines a macro for it.
3473     + Add a definition of offsetof(), in case there isn't one. (I don't know
3474     the reason behind this - offsetof() is part of the ANSI standard - but
3475     it does no harm).
3477     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3478     most of the places where whitespace preceded '#'. I have given up and
3479     allowed the remaining 2 cases to be at the margin.
3481     + Rename some variables in pcre to eliminate shadowing. This seems very
3482     pedantic, but does no harm, of course.
3484     6. Moved the call to setjmp() into its own function, to get rid of warnings
3485     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3487     7. Constructs such as \d{8,} were compiling into the equivalent of
3488 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3489 nigel 9 outcome, but in this particular case used more store than had been allocated,
3490     which caused the bug to be discovered because it threw up an internal error.
3492     8. The debugging code in both pcre and pcretest for outputting the compiled
3493     form of a regex was going wrong in the case of back references followed by
3494     curly-bracketed repeats.
3497 nigel 7 Version 1.02 12-Dec-97
3498     ----------------------
3500     1. Typos in pcre.3 and comments in the source fixed.
3502     2. Applied a contributed patch to get rid of places where it used to remove
3503     'const' from variables, and fixed some signed/unsigned and uninitialized
3504     variable warnings.
3506     3. Added the "runtest" target to Makefile.
3508     4. Set default compiler flag to -O2 rather than just -O.
3511 nigel 5 Version 1.01 19-Nov-97
3512     ----------------------
3514     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3515     like /([ab]*)*/, that is, for classes with more than one character in them.
3517     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3518     as /((?>a*))*/ (a PCRE_EXTRA facility).
3521     Version 1.00 18-Nov-97
3522     ----------------------
3524     1. Added compile-time macros to support systems such as SunOS4 which don't have
3525     memmove() or strerror() but have other things that can be used instead.
3527     2. Arranged that "make clean" removes the executables.
3530 nigel 3 Version 0.99 27-Oct-97
3531     ----------------------
3533     1. Fixed bug in code for optimizing classes with only one character. It was
3534     initializing a 32-byte map regardless, which could cause it to run off the end
3535     of the memory it had got.
3537     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3540     Version 0.98 22-Oct-97
3541     ----------------------
3543     1. Fixed bug in code for handling temporary memory usage when there are more
3544     back references than supplied space in the ovector. This could cause segfaults.
3547     Version 0.97 21-Oct-97
3548     ----------------------
3550     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3552     2. Optimized negated single characters not to use a bit map.
3554     3. Brought error texts together as macro definitions; clarified some of them;
3555     fixed one that was wrong - it said "range out of order" when it meant "invalid
3556     escape sequence".
3558     4. Changed some char * arguments to const char *.
3560     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3562     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3563     pcretest.
3566     Version 0.96 16-Oct-97
3567     ----------------------
3569     1. Added a simple "pgrep" utility to the distribution.
3571     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3572     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3573     where "ddd" means "one or more decimal digits".
3575     3. Fixed serious bug. If a pattern had a back reference, but the call to
3576     pcre_exec() didn't supply a large enough ovector to record the related
3577     identifying subpattern, the match always failed. PCRE now remembers the number
3578     of the largest back reference, and gets some temporary memory in which to save
3579     the offsets during matching if necessary, in order to ensure that
3580     backreferences always work.
3582     4. Increased the compatibility with Perl in a number of ways:
3584     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3585     to request this handling. The option can be set at compile or exec time.
3587     (b) $ matches before a terminating newline by default; an option
3588     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3589     mode). The option can be set at compile or exec time.
3591     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3592     the same as Perl's. If the decimal number it represents is less than 10
3593     or there aren't that many previous left capturing parentheses, an octal
3594     escape is read. Inside a character class, it's always an octal escape,
3595     even if it is a single digit.
3597     (d) An escaped but undefined alphabetic character is taken as a literal,
3598     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3599     escapes.
3601     (e) {0} is now permitted. (The previous item is removed from the compiled
3602     pattern).
3604     5. Changed all the names of code files so that the basic parts are no longer
3605     than 10 characters, and abolished the teeny "globals.c" file.
3607     6. Changed the handling of character classes; they are now done with a 32-byte
3608     bit map always.
3610     7. Added the -d and /D options to pcretest to make it possible to look at the
3611     internals of compilation without having to recompile pcre.
3614     Version 0.95 23-Sep-97
3615     ----------------------
3617     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3618     \x20 at the start of a run of normal characters. These were being treated as
3619     real characters, instead of the source characters being re-checked.
3622     Version 0.94 18-Sep-97
3623     ----------------------
3625     1. The functions are now thread-safe, with the caveat that the global variables
3626     containing pointers to malloc() and free() or alternative functions are the
3627     same for all threads.
3629     2. Get pcre_study() to generate a bitmap of initial characters for non-
3630     anchored patterns when this is possible, and use it if passed to pcre_exec().
3633     Version 0.93 15-Sep-97
3634     ----------------------
3636     1. /(b)|(:+)/ was computing an incorrect first character.
3638     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3639     but not actually doing anything yet.
3641     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3642     as Perl does (e.g. [-az] or [az-]).
3644     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3645     all possible positions.
3647     5. Split up into different modules to avoid including unneeded functions in a
3648     compiled binary. However, compile and exec are still in one module. The "study"
3649     function is split off.
3651     6. The character tables are now in a separate module whose source is generated
3652     by an auxiliary program - but can then be edited by hand if required. There are
3653     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3654     toupper() in the code.
3656     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3657     make them global. Abolish the function for setting them, as the caller can now
3658     set them directly.
3661     Version 0.92 11-Sep-97
3662     ----------------------
3664     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3665     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3667     2. Caseless matching was not working in character classes if the characters in
3668     the pattern were in upper case.
3670     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3672     4. Make PCRE_ANCHORED public and accept as a compile option.
3674     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3675     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3676     pass them.
3678     6. Give an error if bad option bits passed at compile or run time.
3680     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3681     pcretest to cause it to pass that flag.
3683     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3684     options, and the first character, if set.
3686     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3689     Version 0.91 10-Sep-97
3690     ----------------------
3692     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3693     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3695     2. PCRE was looping on encountering an indefinitely repeated back reference to
3696     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3697     Perl does - treats the match as successful.
3699     ****


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