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Revision 474 - (hide annotations) (download)
Sat Jan 2 16:30:46 2010 UTC (5 years, 3 months ago) by ph10
File size: 176290 byte(s)
Fix C++ wrapper GlobalReplace function for empty matches.

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
29 ph10 474
30     5. The C++ GlobalReplace function was not working like Perl for the special
31     situation when an empty string is matched. It now does the fancy magic
32     stuff that is necessary.
33 ph10 473
35 ph10 469 Version 8.00 19-Oct-09
36 ph10 418 ----------------------
38     1. The table for translating pcre_compile() error codes into POSIX error codes
39 ph10 461 was out-of-date, and there was no check on the pcre_compile() error code
40     being within the table. This could lead to an OK return being given in
41 ph10 418 error.
42 ph10 461
43     2. Changed the call to open a subject file in pcregrep from fopen(pathname,
44     "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
45     in a Windows environment.
47 ph10 420 3. The pcregrep --count option prints the count for each file even when it is
48     zero, as does GNU grep. However, pcregrep was also printing all files when
49     --files-with-matches was added. Now, when both options are given, it prints
50     counts only for those files that have at least one match. (GNU grep just
51 ph10 461 prints the file name in this circumstance, but including the count seems
52     more useful - otherwise, why use --count?) Also ensured that the
53 ph10 420 combination -clh just lists non-zero counts, with no names.
54 ph10 461
55     4. The long form of the pcregrep -F option was incorrectly implemented as
56     --fixed_strings instead of --fixed-strings. This is an incompatible change,
57     but it seems right to fix it, and I didn't think it was worth preserving
58     the old behaviour.
60     5. The command line items --regex=pattern and --regexp=pattern were not
61 ph10 422 recognized by pcregrep, which required --regex pattern or --regexp pattern
62 ph10 461 (with a space rather than an '='). The man page documented the '=' forms,
63 ph10 422 which are compatible with GNU grep; these now work.
64 ph10 461
65     6. No libpcreposix.pc file was created for pkg-config; there was just
66 ph10 423 libpcre.pc and libpcrecpp.pc. The omission has been rectified.
67 ph10 461
68 ph10 425 7. Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
69 ph10 461 when UCP support is not needed, by modifying the Python script that
70 ph10 425 generates it from Unicode data files. This should not matter if the module
71     is correctly used as a library, but I received one complaint about 50K of
72     unwanted data. My guess is that the person linked everything into his
73     program rather than using a library. Anyway, it does no harm.
74 ph10 461
75 ph10 426 8. A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
76 ph10 461 was a minimum greater than 1 for a wide character in a possessive
77 ph10 431 repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
78     which had an unlimited repeat of a nested, fixed maximum repeat of a wide
79     character. Chaos in the form of incorrect output or a compiling loop could
80     result.
81 ph10 461
82 ph10 426 9. The restrictions on what a pattern can contain when partial matching is
83 ph10 461 requested for pcre_exec() have been removed. All patterns can now be
84 ph10 426 partially matched by this function. In addition, if there are at least two
85 ph10 435 slots in the offset vector, the offset of the earliest inspected character
86     for the match and the offset of the end of the subject are set in them when
87 ph10 461 PCRE_ERROR_PARTIAL is returned.
89 ph10 428 10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
90     synonymous with PCRE_PARTIAL, for backwards compatibility, and
91     PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
92 ph10 462 and may be more useful for multi-segment matching.
93 ph10 461
94     11. Partial matching with pcre_exec() is now more intuitive. A partial match
95     used to be given if ever the end of the subject was reached; now it is
96     given only if matching could not proceed because another character was
97     needed. This makes a difference in some odd cases such as Z(*FAIL) with the
98     string "Z", which now yields "no match" instead of "partial match". In the
99     case of pcre_dfa_exec(), "no match" is given if every matching path for the
100     final character ended with (*FAIL).
102 ph10 428 12. Restarting a match using pcre_dfa_exec() after a partial match did not work
103 ph10 461 if the pattern had a "must contain" character that was already found in the
104 ph10 428 earlier partial match, unless partial matching was again requested. For
105     example, with the pattern /dog.(body)?/, the "must contain" character is
106     "g". If the first part-match was for the string "dog", restarting with
107 ph10 435 "sbody" failed. This bug has been fixed.
108 ph10 461
109     13. The string returned by pcre_dfa_exec() after a partial match has been
110     changed so that it starts at the first inspected character rather than the
111     first character of the match. This makes a difference only if the pattern
112     starts with a lookbehind assertion or \b or \B (\K is not supported by
113     pcre_dfa_exec()). It's an incompatible change, but it makes the two
114 ph10 435 matching functions compatible, and I think it's the right thing to do.
115 ph10 461
116 ph10 435 14. Added a pcredemo man page, created automatically from the pcredemo.c file,
117 ph10 461 so that the demonstration program is easily available in environments where
118     PCRE has not been installed from source.
120 ph10 435 15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
121 ph10 430 libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
122     library.
123 ph10 461
124 ph10 435 16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
125 ph10 432 It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
126 ph10 461 is not the first non-POSIX option to be added. Clearly some people find
127 ph10 433 these options useful.
128 ph10 461
129     17. If a caller to the POSIX matching function regexec() passes a non-zero
130 ph10 438 value for nmatch with a NULL value for pmatch, the value of
131 ph10 461 nmatch is forced to zero.
133 ph10 437 18. RunGrepTest did not have a test for the availability of the -u option of
134 ph10 461 the diff command, as RunTest does. It now checks in the same way as
135 ph10 437 RunTest, and also checks for the -b option.
136 ph10 461
137 ph10 438 19. If an odd number of negated classes containing just a single character
138     interposed, within parentheses, between a forward reference to a named
139 ph10 461 subpattern and the definition of the subpattern, compilation crashed with
140     an internal error, complaining that it could not find the referenced
141 ph10 438 subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
142 ph10 461 [The bug was that it was starting one character too far in when skipping
143     over the character class, thus treating the ] as data rather than
144     terminating the class. This meant it could skip too much.]
146 ph10 442 20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
147 ph10 461 /g option in pcretest when the pattern contains \K, which makes it possible
148 ph10 442 to have an empty string match not at the start, even when the pattern is
149 ph10 461 anchored. Updated pcretest and pcredemo to use this option.
151 ph10 446 21. If the maximum number of capturing subpatterns in a recursion was greater
152 ph10 461 than the maximum at the outer level, the higher number was returned, but
153     with unset values at the outer level. The correct (outer level) value is
154 ph10 446 now given.
155 ph10 461
156 ph10 447 22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
157     PCRE did not set those parentheses (unlike Perl). I have now found a way to
158     make it do so. The string so far is captured, making this feature
159     compatible with Perl.
160 ph10 461
161     23. The tests have been re-organized, adding tests 11 and 12, to make it
162 ph10 448 possible to check the Perl 5.10 features against Perl 5.10.
163 ph10 461
164 ph10 454 24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
165 ph10 461 pattern matches a fixed length string. PCRE did not allow this; now it
166     does. Neither allows recursion.
168     25. I finally figured out how to implement a request to provide the minimum
169     length of subject string that was needed in order to match a given pattern.
170     (It was back references and recursion that I had previously got hung up
171     on.) This code has now been added to pcre_study(); it finds a lower bound
172 ph10 455 to the length of subject needed. It is not necessarily the greatest lower
173     bound, but using it to avoid searching strings that are too short does give
174     some useful speed-ups. The value is available to calling programs via
175     pcre_fullinfo().
176 ph10 461
177 ph10 455 26. While implementing 25, I discovered to my embarrassment that pcretest had
178     not been passing the result of pcre_study() to pcre_dfa_exec(), so the
179     study optimizations had never been tested with that matching function.
180     Oops. What is worse, even when it was passed study data, there was a bug in
181     pcre_dfa_exec() that meant it never actually used it. Double oops. There
182     were also very few tests of studied patterns with pcre_dfa_exec().
183 ph10 461
184 ph10 457 27. If (?| is used to create subpatterns with duplicate numbers, they are now
185     allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
186     on the other side of the coin, they are no longer allowed to have different
187     names, because these cannot be distinguished in PCRE, and this has caused
188     confusion. (This is a difference from Perl.)
189 ph10 461
190     28. When duplicate subpattern names are present (necessarily with different
191     numbers, as required by 27 above), and a test is made by name in a
192     conditional pattern, either for a subpattern having been matched, or for
193     recursion in such a pattern, all the associated numbered subpatterns are
194 ph10 459 tested, and the overall condition is true if the condition is true for any
195     one of them. This is the way Perl works, and is also more like the way
196     testing by number works.
197 ph10 418
198 ph10 461
199 ph10 412 Version 7.9 11-Apr-09
200 ph10 376 ---------------------
202 ph10 392 1. When building with support for bzlib/zlib (pcregrep) and/or readline
203 ph10 376 (pcretest), all targets were linked against these libraries. This included
204     libpcre, libpcreposix, and libpcrecpp, even though they do not use these
205     libraries. This caused unwanted dependencies to be created. This problem
206 ph10 392 has been fixed, and now only pcregrep is linked with bzlib/zlib and only
207 ph10 376 pcretest is linked with readline.
208 ph10 392
209 ph10 376 2. The "typedef int BOOL" in pcre_internal.h that was included inside the
210     "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
211     moved outside it again, because FALSE and TRUE are already defined in AIX,
212     but BOOL is not.
213 ph10 392
214     3. The pcre_config() function was treating the PCRE_MATCH_LIMIT and
215 ph10 409 PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
216 ph10 392
217 ph10 376 4. The pcregrep documentation said spaces were inserted as well as colons (or
218     hyphens) following file names and line numbers when outputting matching
219 ph10 392 lines. This is not true; no spaces are inserted. I have also clarified the
220 ph10 376 wording for the --colour (or --color) option.
221 ph10 392
222 ph10 378 5. In pcregrep, when --colour was used with -o, the list of matching strings
223     was not coloured; this is different to GNU grep, so I have changed it to be
224     the same.
225 ph10 392
226 ph10 378 6. When --colo(u)r was used in pcregrep, only the first matching substring in
227 ph10 392 each matching line was coloured. Now it goes on to look for further matches
228     of any of the test patterns, which is the same behaviour as GNU grep.
230     7. A pattern that could match an empty string could cause pcregrep to loop; it
231     doesn't make sense to accept an empty string match in pcregrep, so I have
232 ph10 379 locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
233     seems to be how GNU grep behaves.
234 ph10 392
235 ph10 380 8. The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
236 ph10 392 start or after a newline", because the conditional assertion was not being
237     correctly handled. The rule now is that both the assertion and what follows
238     in the first alternative must satisfy the test.
240 ph10 405 9. If auto-callout was enabled in a pattern with a conditional group whose
241 ph10 399 condition was an assertion, PCRE could crash during matching, both with
242     pcre_exec() and pcre_dfa_exec().
243 ph10 392
244     10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
245     used for matching.
247     11. Unicode property support in character classes was not working for
248 ph10 385 characters (bytes) greater than 127 when not in UTF-8 mode.
249 ph10 388
250 ph10 392 12. Added the -M command line option to pcretest.
252 ph10 388 14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
253 ph10 389
254     15. Added the PCRE_NO_START_OPTIMIZE match-time option.
255 ph10 390
256 ph10 392 16. Added comments and documentation about mis-use of no_arg in the C++
257 ph10 390 wrapper.
258 ph10 392
259 ph10 391 17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
260 ph10 392 from Martin Jerabek that uses macro names for all relevant character and
261 ph10 391 string constants.
262 ph10 405
263 ph10 393 18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
264     SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
265 ph10 405 SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
266     these, but not everybody uses configure.
268     19. A conditional group that had only one branch was not being correctly
269     recognized as an item that could match an empty string. This meant that an
270     enclosing group might also not be so recognized, causing infinite looping
271     (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
272     with the subject "ab", where knowledge that the repeated group can match
273 ph10 396 nothing is needed in order to break the loop.
274 ph10 405
275 ph10 397 20. If a pattern that was compiled with callouts was matched using pcre_dfa_
276 ph10 405 exec(), but without supplying a callout function, matching went wrong.
278     21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
279     leak if the size of the offset vector was greater than 30. When the vector
280     is smaller, the saved offsets during recursion go onto a local stack
281     vector, but for larger vectors malloc() is used. It was failing to free
282     when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
283 ph10 400 error, in fact).
284 ph10 405
285 ph10 402 22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
286 ph10 405 heapframe that is used only when UTF-8 support is enabled. This caused no
287     problem, but was untidy.
288 ph10 376
289 ph10 405 23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
290     CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
291     included within another project.
292 ph10 411
293 ph10 407 24. Steven Van Ingelgem's patches to add more options to the CMake support,
294     slightly modified by me:
295 ph10 411
296     (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
297     not building pcregrep.
299 ph10 407 (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
300 ph10 411 if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
302 ph10 408 25. Forward references, both numeric and by name, in patterns that made use of
303     duplicate group numbers, could behave incorrectly or give incorrect errors,
304     because when scanning forward to find the reference group, PCRE was not
305     taking into account the duplicate group numbers. A pattern such as
306     ^X(?3)(a)(?|(b)|(q))(Y) is an example.
307 ph10 411
308     26. Changed a few more instances of "const unsigned char *" to USPTR, making
309     the feature of a custom pointer more persuasive (as requested by a user).
310 ph10 416
311 ph10 411 27. Wrapped the definitions of fileno and isatty for Windows, which appear in
312 ph10 416 pcretest.c, inside #ifndefs, because it seems they are sometimes already
313     pre-defined.
314 ph10 392
315 ph10 416 28. Added support for (*UTF8) at the start of a pattern.
317 ph10 413 29. Arrange for flags added by the "release type" setting in CMake to be shown
318     in the configuration summary.
319 ph10 405
320 ph10 411
321 ph10 374 Version 7.8 05-Sep-08
322 ph10 349 ---------------------
324     1. Replaced UCP searching code with optimized version as implemented for Ad
325     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
326 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
327     to 5 times on some simple patterns that I tested. Permission was given to
328     distribute the MultiStage2.py script that generates the tables (it's not in
329     the tarball, but is in the Subversion repository).
330 ph10 349
331 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
332     scripts.
333 ph10 358
334 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
335     a group with a zero qualifier. The result of the study could be incorrect,
336 ph10 358 or the function might crash, depending on the pattern.
338     4. Caseless matching was not working for non-ASCII characters in back
339 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
340 ph10 358 It now works when Unicode Property Support is available.
342 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
343     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
344     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
345 ph10 358 truncation.
346 ph10 349
347 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
349 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
350     pointers, in case they are 64-bit values.
351 ph10 371
352     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
353     test 2 if it fails.
355 ph10 359 9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
356 ph10 371 and a #define of that name to empty if it is not externally set. This is to
357     allow users of MSVC to set it if necessary.
359     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
360 ph10 359 the convenience functions in the pcre_get.c source file.
361 ph10 371
362 ph10 360 11. An option change at the start of a pattern that had top-level alternatives
363     could cause overwriting and/or a crash. This command provoked a crash in
364 ph10 371 some environments:
366     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
368 ph10 360 This potential security problem was recorded as CVE-2008-2371.
369 ph10 371
370 ph10 361 12. For a pattern where the match had to start at the beginning or immediately
371     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
372 ph10 371 pcre_dfa_exec() could read past the end of the passed subject if there was
373 ph10 361 no match. To help with detecting such bugs (e.g. with valgrind), I modified
374     pcretest so that it places the subject at the end of its malloc-ed buffer.
375 ph10 371
376 ph10 364 13. The change to pcretest in 12 above threw up a couple more cases when pcre_
377 ph10 371 exec() might read past the end of the data buffer in UTF-8 mode.
379 ph10 364 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
380 ph10 371 the data contained the byte 0x85 as part of a UTF-8 character within its
381     first line. This applied both to normal and DFA matching.
383 ph10 366 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
384 ph10 371 /^[^d]*?$/8 failed to match "abc".
385 ph10 351
386 ph10 371 16. Added a missing copyright notice to pcrecpp_internal.h.
388     17. Make it more clear in the documentation that values returned from
389 ph10 368 pcre_exec() in ovector are byte offsets, not character counts.
390 ph10 357
391 ph10 371 18. Tidied a few places to stop certain compilers from issuing warnings.
392 ph10 368
393 ph10 373 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
394     supplied by Stefan Weber. I made a further small update for 7.8 because
395 ph10 374 there is a change of source arrangements: the pcre_searchfuncs.c module is
396     replaced by pcre_ucd.c.
397 ph10 371
398 ph10 373
399 ph10 347 Version 7.7 07-May-08
400 ph10 321 ---------------------
402     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
403 ph10 345 a string to a long long, pretend we don't even have a long long." This is
404 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
405 ph10 345
406 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
407     pre-7.6 versions, which defined a global no_arg variable instead of putting
408 ph10 332 it in the RE class. (See also #8 below.)
409 ph10 345
410     3. Remove a line of dead code, identified by coverity and reported by Nuno
411     Lopes.
413 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
414 ph10 321
415 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
416 ph10 345 of files, instead of just to the final components.
418 ph10 324 (2) If there was more than one level of directory, the subdirectories were
419     skipped unless they satisfied the include/exclude conditions. This is
420     inconsistent with GNU grep (and could even be seen as contrary to the
421     pcregrep specification - which I improved to make it absolutely clear).
422     The action now is always to scan all levels of directory, and just
423     apply the include/exclude patterns to regular files.
424 ph10 345
425 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
426 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
428 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
429 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
430 ph10 326 doesn't support NULs in patterns.
431 ph10 345
432     7. Added some missing "const"s to declarations of static tables in
433     pcre_compile.c and pcre_dfa_exec.c.
435 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
436 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
437 ph10 345 first patch. And a third patch - this was a messy problem.)
438 ph10 321
439 ph10 345 9. Applied Craig's patch to remove the use of push_back().
441 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
442     matching function regexec().
443 ph10 345
444     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
445     which, however, unlike Perl's \g{...}, are subroutine calls, not back
446 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
447     Oniguruma does).
448 ph10 345
449     12. Previously, a group with a zero repeat such as (...){0} was completely
450 ph10 335 omitted from the compiled regex. However, this means that if the group
451     was called as a subroutine from elsewhere in the pattern, things went wrong
452 ph10 345 (an internal error was given). Such groups are now left in the compiled
453     pattern, with a new opcode that causes them to be skipped at execution
454 ph10 335 time.
455 ph10 345
456 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
457     to the way PCRE behaves:
458 ph10 345
459 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
460 ph10 345
461     (b) A back reference to an unmatched subpattern matches an empty string
462 ph10 336 (Perl fails the current match path).
463 ph10 345
464 ph10 341 (c) A data ] in a character class must be notated as \] because if the
465 ph10 345 first data character in a class is ], it defines an empty class. (In
466 ph10 341 Perl it is not possible to have an empty class.) The empty class []
467     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
468     The negative empty class [^] matches any one character, independently
469     of the DOTALL setting.
470 ph10 345
471     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
472 ph10 340 non-existent subpattern following a character class starting with ']' and
473     containing () gave an internal compiling error instead of "reference to
474     non-existent subpattern". Fortunately, when the pattern did exist, the
475 ph10 345 compiled code was correct. (When scanning forwards to check for the
476 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
477 ph10 345 the class, so got the count wrong. When actually compiling, the reference
478 ph10 340 was subsequently set up correctly.)
479 ph10 345
480 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
481 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
482     other assertions are supported. I have made pcre_dfa_exec() support
483     (*FAIL).
485 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
486 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
487     cannot be changed at match time, I realized I could make a small
488     improvement to matching performance by compiling OP_ALLANY instead of
489     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
490     on the OP_ANY path.
492     17. Compiling pcretest on Windows with readline support failed without the
493 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
494 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
496 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
497 ph10 345 ncurses library to be included for pcretest when ReadLine support is
498     requested, but also to allow for it to be overridden. This patch came from
499     Daniel Bergström.
500 ph10 347
501 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
502 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
503     any errors with the current Unicode tables. Thanks to Peter Kankowski for
504     spotting this.
505 ph10 324
506 ph10 332
507 ph10 319 Version 7.6 28-Jan-08
508 ph10 300 ---------------------
510 ph10 302 1. A character class containing a very large number of characters with
511     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
512     overflow.
513 ph10 309
514     2. Patch to cut out the "long long" test in pcrecpp_unittest when
515     HAVE_LONG_LONG is not defined.
517 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
518 ph10 304 bring them up to date and include new features. This patch includes:
519 ph10 309
520 ph10 304 - Fixed PH's badly added libz and libbz2 support.
521     - Fixed a problem with static linking.
522 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
523 ph10 304 - Fixed dftables problem and added an option.
524     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
526     - Added readline support for pcretest.
527 ph10 309 - Added an listing of the option settings after cmake has run.
529 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
530     "pcre.dll" under mingw when using Configure/Make. I added stuff to
531     Makefile.am that cause it to include this special target, without
532     affecting anything else. Note that the same mingw target plus all
533     the other distribution libraries and programs are now supported
534     when configuring with CMake (see 6 below) instead of with
535     Configure/Make.
536 ph10 309
537 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
538     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
539 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
540     solves the problem, but it does no harm.
541 ph10 313
542 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
543 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
544 ph10 314 with CMake, and also correct the comment about stack recursion.
545 ph10 313
546 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
547 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
548     of a program that users should build themselves after PCRE is installed, so
549     building it automatically is not really right. What is more, it gave
550 ph10 312 trouble in some build environments.
551 ph10 300
552 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
553 ph10 308
554 ph10 319
555 ph10 298 Version 7.5 10-Jan-08
556 ph10 263 ---------------------
558     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
559     values in parens when parsing an RE using the C++ wrapper."
560 ph10 286
561 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
562     Characters greater than 255 were excluded from the class instead of being
563     included.
564 ph10 286
565     3. The same bug as (2) above applied to negated POSIX classes such as
566 ph10 265 [:^space:].
567 ph10 286
568 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
569     defined or documented. It seems to have been a typo for PCRE_STATIC, so
570 ph10 286 I have changed it.
572 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
573 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
574     first named subpattern whose name started with "a" (in other words, the
575 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
576     expected" is now given for (?&) (a zero-length name), and this patch also
577     makes it give the same error for \k'' (previously it complained that that
578     was a reference to a non-existent subpattern).
579 ph10 286
580 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
581 ph10 286 this is right because (?- can be followed by option settings as well as by
582 ph10 269 digits. I have, however, made the messages clearer.
583 ph10 286
584 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
585     than the number used in the conditional) now cause a compile-time error.
586     This is actually not compatible with Perl, which accepts such patterns, but
587     treats the conditional as always being FALSE (as PCRE used to), but it
588     seems to me that giving a diagnostic is better.
589 ph10 286
590 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
591 ph10 275 and messages.
592 ph10 286
593     9. Fix two occurrences of "backslash" in comments that should have been
594     "backspace".
596     10. Remove two redundant lines of code that can never be obeyed (their function
597     was moved elsewhere).
599     11. The program that makes PCRE's Unicode character property table had a bug
600     which caused it to generate incorrect table entries for sequences of
601 ph10 277 characters that have the same character type, but are in different scripts.
602 ph10 286 It amalgamated them into a single range, with the script of the first of
603 ph10 277 them. In other words, some characters were in the wrong script. There were
604     thirteen such cases, affecting characters in the following ranges:
605 ph10 286
606 ph10 277 U+002b0 - U+002c1
607     U+0060c - U+0060d
608 ph10 286 U+0061e - U+00612
609 ph10 277 U+0064b - U+0065e
610     U+0074d - U+0076d
611     U+01800 - U+01805
612     U+01d00 - U+01d77
613     U+01d9b - U+01dbf
614     U+0200b - U+0200f
615     U+030fc - U+030fe
616     U+03260 - U+0327f
617     U+0fb46 - U+0fbb1
618     U+10450 - U+1049d
619 ph10 286
620 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
621     compatible with GNU grep in that, if there was more than one match in a
622     line, it showed only the first of them. It now behaves in the same way as
623     GNU grep.
624 ph10 286
625     13. If the -o and -v options were combined for pcregrep, it printed a blank
626     line for every non-matching line. GNU grep prints nothing, and pcregrep now
627     does the same. The return code can be used to tell if there were any
628     non-matching lines.
630 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
632     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
633 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
634 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
635     and both kinds of lookbehind were skipped).
637 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
638 ph10 284 inclusion of <windows.h> to before rather than after the definition of
639     INVALID_FILE_ATTRIBUTES (patch from David Byron).
640 ph10 263
641 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
642 ph10 286 character property caused pcre_compile() to compile bad code, which led at
643     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
644     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
645     caused the error; without that there was no problem.
646 ph10 263
647 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
648 ph10 286
649 ph10 289 19. Added --enable-pcretest-libreadline.
650 ph10 286
651 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
652 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
653 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
654     later patch that removed the other one (the right fix) and added unit tests
655     that check the return values (which was not done before).
656 ph10 292
657 ph10 291 21. Several CMake things:
658 ph10 287
659 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
660 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
661 ph10 288
662 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
663     linked with the newly-built libraries, not previously installed ones.
664 ph10 291
666 ph10 298
667     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
668     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
669     UTF-8 newline character). The key issue is that the pattern starts .*;
670     this means that the match must be either at the beginning, or after a
671     newline. The bug was in the code for advancing after a failed match and
672     checking that the new position followed a newline. It was not taking
673 ph10 294 account of UTF-8 characters correctly.
674 ph10 298
675     23. PCRE was behaving differently from Perl in the way it recognized POSIX
676     character classes. PCRE was not treating the sequence [:...:] as a
677     character class unless the ... were all letters. Perl, however, seems to
678     allow any characters between [: and :], though of course it rejects as
679     unknown any "names" that contain non-letters, because all the known class
680     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
681     for example, whereas PCRE did not - it did not recognize a POSIX character
682     class. This seemed a bit dangerous, so the code has been changed to be
683     closer to Perl. The behaviour is not identical to Perl, because PCRE will
684     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
685     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
686     Perl does, and where it didn't before.
688 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
689     Windows environments %n is disabled by default.
690 ph10 292
692 ph10 260 Version 7.4 21-Sep-07
693 ph10 230 ---------------------
695     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
696 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
697     LF". That isn't really right - the whole point of the change was to try to
698     help when there was an actual mention of one of the two characters. So now
699     the change happens only if \r or \n (or a literal CR or LF) character is
700 ph10 230 encountered.
701 ph10 231
702     2. The 32-bit options word was also used for 6 internal flags, but the numbers
703     of both had grown to the point where there were only 3 bits left.
704     Fortunately, there was spare space in the data structure, and so I have
705     moved the internal flags into a new 16-bit field to free up more option
706 ph10 230 bits.
707 ph10 231
708     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
709     but did not set the internal JCHANGED flag - either of these is enough to
710     control the way the "get" function works - but the PCRE_INFO_JCHANGED
711     facility is supposed to tell if (?J) was ever used, so now (?J) at the
712 ph10 230 start sets both bits.
714 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
715     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
716 ph10 230
717 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
719     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
720 ph10 233 compatibility, even though it is no longer used.
721 ph10 243
722     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
723 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
724 ph10 259 windows.h file is present (where different names are used). [This was
725 ph10 257 reversed later after testing - see 16 below.]
726 ph10 243
727     8. Changed all #include <config.h> to #include "config.h". There were also
728 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
729 ph10 243
730 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
731 ph10 243 sequence off the lines that it output.
733     10. It was pointed out to me that arrays of string pointers cause lots of
734     relocations when a shared library is dynamically loaded. A technique of
735     using a single long string with a table of offsets can drastically reduce
736     these. I have refactored PCRE in four places to do this. The result is
737 ph10 240 dramatic:
738 ph10 243
739 ph10 240 Originally: 290
740     After changing UCP table: 187
741 ph10 243 After changing error message table: 43
742 ph10 240 After changing table of "verbs" 36
743     After changing table of Posix names 22
744 ph10 243
745 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
746 ph10 247
747 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
748 ph10 247 unicode-properties was also set.
750 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
751 ph10 231
752 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
753     checked only for CRLF.
754 ph10 233
755 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
757 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
758 ph10 253
759 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
760 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
761     entirely. This removes changes made in 7 above.
762 ph10 256
763 ph10 261 17. The CMake files have been updated, and there is now more information about
764     building with CMake in the NON-UNIX-USE document.
765 ph10 257
766 ph10 261
767 ph10 228 Version 7.3 28-Aug-07
768 ph10 157 ---------------------
770 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
771     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
772     brackets there is not right, since it causes compilers to look for an
773     installed pcre.h, not the version that is in the source that is being
774     compiled (which of course may be different). I have changed it back to:
775 ph10 197
776 ph10 189 #include "pcre.h"
777 ph10 197
778     I have a vague recollection that the change was concerned with compiling in
779     different directories, but in the new build system, that is taken care of
780     by the VPATH setting the Makefile.
782 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
783     when the subject happened to end in the byte 0x85 (e.g. if the last
784     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
785     characters but of course it shouldn't be taken as a newline when it is part
786     of another character. The bug was that, for an unlimited repeat of . in
787     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
788     characters when looking for a newline.
789 ph10 197
790     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
792     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
793     in debug output.
795 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
796     long printing in the pcrecpp unittest when running under MinGW.
797 ph10 189
798 ph10 197 6. ESC_K was left out of the EBCDIC table.
799 ph10 189
800 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
801     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
802     limit also applies to "virtual nesting" when a pattern is recursive, and in
803     this case 1000 isn't so big. I have been able to remove this limit at the
804     expense of backing off one optimization in certain circumstances. Normally,
805     when pcre_exec() would call its internal match() function recursively and
806     immediately return the result unconditionally, it uses a "tail recursion"
807     feature to save stack. However, when a subpattern that can match an empty
808     string has an unlimited repetition quantifier, it no longer makes this
809     optimization. That gives it a stack frame in which to save the data for
810     checking that an empty string has been matched. Previously this was taken
811     from the 1000-entry workspace that had been reserved. So now there is no
812     explicit limit, but more stack is used.
813 ph10 189
814 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
815     syntax that is required for Windows, and which was going wrong for the
816     pcreposix and pcrecpp parts of the library. These were overlooked when this
817     problem was solved for the main library.
818 ph10 197
819 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
820     the size of patterns that contain repeated groups with explicit upper
821     limits. As the maximum quantifier is 65535, the maximum group length was
822     set at 30,000 so that the product of these two numbers did not overflow a
823     32-bit integer. However, it turns out that people want to use groups that
824     are longer than 30,000 bytes (though not repeat them that many times).
825     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
826     made it possible to implement the integer overflow checks in a much more
827     dynamic way, which I have now done. The artificial limitation on group
828     length has been removed - we now have only the limit on the total length of
829     the compiled pattern, which depends on the LINK_SIZE setting.
830 ph10 208
831     10. Fixed a bug in the documentation for get/copy named substring when
832     duplicate names are permitted. If none of the named substrings are set, the
833     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
834     empty string.
836     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
837     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
838     because the ] is interpreted as the first data character and the
839     terminating ] is not found. PCRE has been made compatible with Perl in this
840     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
841     cause memory overwriting.
843 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
844     string has been matched (to stop an infinite loop). It was not recognizing
845 ph10 208 a conditional subpattern that could match an empty string if that
846 ph10 206 subpattern was within another subpattern. For example, it looped when
847 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
848 ph10 206 condition was not nested. This bug has been fixed.
849 ph10 208
850 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
851     past the start of the subject in the presence of bytes with the top bit
852     set, for example "\x8aBCD".
853 ph10 211
854 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
855     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
856 ph10 200
857 ph10 211 14. Optimized (?!) to (*FAIL).
858 ph10 202
859 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
860     This restricts code points to be within the range 0 to 0x10FFFF, excluding
861     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
862     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
863     does: it's just the validity check that is more restrictive.
864 ph10 220
865     16. Inserted checks for integer overflows during escape sequence (backslash)
866     processing, and also fixed erroneous offset values for syntax errors during
867     backslash processing.
869 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
870 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
872 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
873     caused an overrun.
874 ph10 220
875     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
876     something other than just ASCII characters) inside a group that had an
877     unlimited repeat caused a loop at compile time (while checking to see
878     whether the group could match an empty string).
880 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
881     [\P{Any}] did so. (Error in the code for printing property names.)
882 ph10 210
883 ph10 220 21. An orphan \E inside a character class could cause a crash.
885     22. A repeated capturing bracket such as (A)? could cause a wild memory
886 ph10 218 reference during compilation.
887 ph10 220
888     23. There are several functions in pcre_compile() that scan along a compiled
889     expression for various reasons (e.g. to see if it's fixed length for look
890 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
891 ph10 220 present in the pattern. These operators have additional parameters compared
892     with \d, etc, and these were not being taken into account when moving along
893 ph10 218 the compiled data. Specifically:
894 ph10 220
895     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
896     length.
898     (b) An item such as \pL+ within a repeated group could cause crashes or
899 ph10 218 loops.
900 ph10 220
901 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
902 ph10 220 "reference to non-existent subpattern" error.
904 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
906 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
907 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
908 ph10 211
909 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
910 ph10 218
911 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
912 ph10 223 character were causing crashes (broken optimization).
913 ph10 227
914 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
915 ph10 227 \p or \P) caused a compile-time loop.
917 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
918     break. For example, the unstudied pattern [\r\n]A does not match the string
919     "\r\nA" because change 7.0/46 below moves the current point on by two
920     characters after failing to match at the start. However, the pattern \nA
921 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
922     the same is true. There doesn't seem any very clean way out of this, but
923     what I have chosen to do makes the common cases work: PCRE now takes note
924     of whether there can be an explicit match for \r or \n anywhere in the
925     pattern, and if so, 7.0/46 no longer applies. As part of this change,
926     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
927     pattern has explicit CR or LF references.
928 ph10 222
929 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
930 ph10 223
931 ph10 227
932 ph10 189 Version 7.2 19-Jun-07
933     ---------------------
935 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
936     which is apparently normally available under Windows.
937 ph10 159
938     2. Re-jig the pcregrep tests with different newline settings in an attempt
939     to make them independent of the local environment's newline setting.
940 ph10 157
941 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
942 ph10 165
943 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
944     was not 2, because the output contained actual offsets. The recent new
945 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
946     usable with all link sizes.
948 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
949     stack recursion. This gives a massive performance boost under BSD, but just
950 ph10 165 a small improvement under Linux. However, it saves one field in the frame
951 ph10 164 in all cases.
952 ph10 172
953 ph10 166 6. Added more features from the forthcoming Perl 5.10:
954 ph10 172
955 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
956     recursion call. It refers to the nth most recently opened parentheses.
957 ph10 172
958 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
959 ph10 172 to be opened parentheses.
961     (c) Conditions that refer to capturing parentheses can be specified
962 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
963 ph10 172
964 ph10 168 (d) \K resets the start of the current match so that everything before
965 ph10 172 is not part of it.
967 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
968 ph10 172
969 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
970 ph10 172 reference syntax.
971 ph10 182
972 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
973 ph10 182 alternative starts with the same number.
974 ph10 172
975 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
977 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
980     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
981     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
982 ph10 170 for detecting groups that can match an empty string.
983 ph10 159
984 ph10 172 9. A pattern with a very large number of alternatives (more than several
985     hundred) was running out of internal workspace during the pre-compile
986     phase, where pcre_compile() figures out how much memory will be needed. A
987     bit of new cunning has reduced the workspace needed for groups with
988     alternatives. The 1000-alternative test pattern now uses 12 bytes of
989     workspace instead of running out of the 4096 that are available.
990 ph10 182
991 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
992 ph10 172
993 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
994     The report of the bug said:
995 ph10 182
996 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
997     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
998 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
999 ph10 185
1000 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1001 ph10 185 it matched the wrong number of bytes.
1002 ph10 172
1003 ph10 179
1004 ph10 155 Version 7.1 24-Apr-07
1005 ph10 98 ---------------------
1007 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1008 ph10 122 that is more "standard", making use of automake and other Autotools. There
1009 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
1010     on this.
1011 ph10 111
1012     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1013     for recursive directory scanning broke on some systems because the files
1014     are not scanned in any specific order and on different systems the order
1015     was different. A call to "sort" has been inserted into RunGrepTest for the
1016     approprate test as a short-term fix. In the longer term there may be an
1017 ph10 100 alternative.
1018 ph10 111
1019 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
1020 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
1021     people do their own conversions for various reasons). The problems
1022     concerned the use of low-level troff macros .br and .in. I have therefore
1023     removed all such uses from the man pages (some were redundant, some could
1024 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
1025     HTML has been updated to handle .nf/.fi and to complain if it encounters
1026     .br or .in.
1027 ph10 111
1028 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
1029 ph10 123 arranged for config.h to be included in the distribution, with the name
1030 ph10 111 config.h.generic, for the benefit of those who have to compile without
1031     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1033     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1034     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1035 ph10 127 makevp.bat for the current PCRE, using the additional files
1036 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1037 ph10 111
1038     6. A Windows user reported a minor discrepancy with test 2, which turned out
1039     to be caused by a trailing space on an input line that had got lost in his
1040 ph10 102 copy. The trailing space was an accident, so I've just removed it.
1041 ph10 111
1042 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1043 ph10 111 that is needed.
1045 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1046     as "const" (a) because they are and (b) because it helps the PHP
1047     maintainers who have recently made a script to detect big data structures
1048 ph10 111 in the php code that should be moved to the .rodata section. I remembered
1049     to update Builducptable as well, so it won't revert if ucptable.h is ever
1050 ph10 105 re-created.
1051 ph10 111
1052     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1053 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1054 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
1055     support is not required. This saves 1.5-2K of code, which is important in
1056 ph10 107 some applications.
1057 ph10 111
1058 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1059 ph10 111 so as not to refer to the tables, even though these functions will never be
1060     called when UTF-8 support is disabled. Otherwise there are problems with a
1061     shared library.
1063 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1065     (a) It was defining its arguments as char * instead of void *.
1067 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
1068     a long time ago when I wrote it, but is no longer the case.
1070 ph10 118 The emulated memove() is provided for those environments that have neither
1071 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
1072 ph10 118 is clearly not the case, as these two bugs were recently reported.
1073 ph10 123
1074 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1075 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
1076     pages, and it removes trailing spaces from listed files. It also creates
1077     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1078     case, it wraps all the #defines with #ifndefs. This script should be run
1079 ph10 111 before "make dist".
1080 ph10 123
1081 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1082     with Unicode property support.
1083 ph10 123
1084     (a) For a maximizing quantifier, if the two different cases of the
1085     character were of different lengths in their UTF-8 codings (there are
1086     some cases like this - I found 11), and the matching function had to
1087 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
1088     were both the same length.
1089 ph10 123
1090     (b) When PCRE was configured to use the heap rather than the stack for
1091     recursion during matching, it was not correctly preserving the data for
1092     the other case of a UTF-8 character when checking ahead for a match
1093     while processing a minimizing repeat. If the check also involved
1094 ph10 115 matching a wide character, but failed, corruption could cause an
1095     erroneous result when trying to check for a repeat of the original
1096     character.
1097 ph10 123
1098 ph10 116 13. Some tidying changes to the testing mechanism:
1099 ph10 98
1100 ph10 116 (a) The RunTest script now detects the internal link size and whether there
1101     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1102 ph10 123 values substituted by "configure". (The RunGrepTest script already did
1103     this for UTF-8.) The configure.ac script no longer substitutes the
1104     relevant variables.
1106 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
1107     with length and offset values. This means that the output is different
1108     for different internal link sizes. Test 2 is skipped for link sizes
1109     other than 2 because of this, bypassing the problem. Unfortunately,
1110     there was also a test in test 3 (the locale tests) that used /B and
1111 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
1112     I have added a new /Z option to pcretest that replaces the length and
1113     offset values with spaces. This is now used to make test 3 independent
1114 ph10 122 of link size. (Test 2 will be tidied up later.)
1115 ph10 123
1116     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1117 ph10 122 segmentation fault instead of returning the appropriate error message.
1118 ph10 134
1119 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
1120 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1121     This doesn't seem right; it now treats the CRLF combination as the line
1122     ending, and so does not match in that case. It's only a pattern such as ^$
1123     that would hit this one: something like ^ABC$ would have failed after \r
1124     and then tried again after \r\n.
1126 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1127 ph10 134 in an attempt to make files that differ only in their line terminators
1128     compare equal. This works on Linux.
1129 ph10 142
1130 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
1131     as it exited. This is now fixed, thanks to valgrind.
1132 ph10 142
1133 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1134 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1135     was because its rules for how to advance for /g after matching an empty
1136 ph10 143 string at the end of a line did not allow for this case. They now check for
1137     it specially.
1138 ph10 150
1139     20. pcretest is supposed to handle patterns and data of any length, by
1140     extending its buffers when necessary. It was getting this wrong when the
1141 ph10 147 buffer for a data line had to be extended.
1142 ph10 150
1143 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1144 ph10 150 CRLF as a newline sequence.
1145 ph10 152
1146 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1147 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1148     I have nevertheless tidied it up.
1149 ph10 111
1150 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
1151 ph10 123
1152 ph10 153 24. Added a man page for pcre-config.
1153 ph10 152
1154 ph10 153
1155 nigel 93 Version 7.0 19-Dec-06
1156     ---------------------
1158     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1159     moving to gcc 4.1.1.
1161     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1162     sys/time.h, which is documented as needed for this function. It doesn't
1163     seem to matter on Linux, but it showed up on some releases of OS X.
1165     3. It seems that there are systems where bytes whose values are greater than
1166     127 match isprint() in the "C" locale. The "C" locale should be the
1167     default when a C program starts up. In most systems, only ASCII printing
1168     characters match isprint(). This difference caused the output from pcretest
1169     to vary, making some of the tests fail. I have changed pcretest so that:
1171     (a) When it is outputting text in the compiled version of a pattern, bytes
1172     other than 32-126 are always shown as hex escapes.
1174     (b) When it is outputting text that is a matched part of a subject string,
1175     it does the same, unless a different locale has been set for the match
1176     (using the /L modifier). In this case, it uses isprint() to decide.
1178     4. Fixed a major bug that caused incorrect computation of the amount of memory
1179     required for a compiled pattern when options that changed within the
1180     pattern affected the logic of the preliminary scan that determines the
1181     length. The relevant options are -x, and -i in UTF-8 mode. The result was
1182     that the computed length was too small. The symptoms of this bug were
1183     either the PCRE error "internal error: code overflow" from pcre_compile(),
1184     or a glibc crash with a message such as "pcretest: free(): invalid next
1185     size (fast)". Examples of patterns that provoked this bug (shown in
1186     pcretest format) are:
1188     /(?-x: )/x
1189     /(?x)(?-x: \s*#\s*)/
1190     /((?i)[\x{c0}])/8
1191     /(?i:[\x{c0}])/8
1193     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1194     is now done differently.
1196     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1197     wrapper classes; (b) implement a new function in the C++ scanner that is
1198     more efficient than the old way of doing things because it avoids levels of
1199     recursion in the regex matching; (c) add a paragraph to the documentation
1200     for the FullMatch() function.
1202     6. The escape sequence \n was being treated as whatever was defined as
1203     "newline". Not only was this contrary to the documentation, which states
1204     that \n is character 10 (hex 0A), but it also went horribly wrong when
1205     "newline" was defined as CRLF. This has been fixed.
1207     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1208     was being set to -1 for the "end of line" case (supposedly a value that no
1209     character can have). Though this value is never used (the check for end of
1210     line is "zero bytes in current character"), it caused compiler complaints.
1211     I've changed it to 0xffffffff.
1213     8. In pcre_version.c, the version string was being built by a sequence of
1214     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1215     string (as it is for production releases) called a macro with an empty
1216     argument. The C standard says the result of this is undefined. The gcc
1217     compiler treats it as an empty string (which was what was wanted) but it is
1218     reported that Visual C gives an error. The source has been hacked around to
1219     avoid this problem.
1221     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1222     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1223     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1224     of them did).
1226     10. Originally, pcretest opened its input and output without "b"; then I was
1227     told that "b" was needed in some environments, so it was added for release
1228     5.0 to both the input and output. (It makes no difference on Unix-like
1229     systems.) Later I was told that it is wrong for the input on Windows. I've
1230     now abstracted the modes into two macros, to make it easier to fiddle with
1231     them, and removed "b" from the input mode under Windows.
1233     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1235     12. Added -help and --help to pcretest as an official way of being reminded
1236     of the options.
1238     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1239     and pcrecpp.cc because they annoy compilers at high warning levels.
1241     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1243     15. Fixed an occurrence of == in configure.ac that should have been = (shell
1244     scripts are not C programs :-) and which was not noticed because it works
1245     on Linux.
1247     16. pcretest is supposed to handle any length of pattern and data line (as one
1248     line or as a continued sequence of lines) by extending its input buffer if
1249     necessary. This feature was broken for very long pattern lines, leading to
1250     a string of junk being passed to pcre_compile() if the pattern was longer
1251     than about 50K.
1253     17. I have done a major re-factoring of the way pcre_compile() computes the
1254     amount of memory needed for a compiled pattern. Previously, there was code
1255     that made a preliminary scan of the pattern in order to do this. That was
1256     OK when PCRE was new, but as the facilities have expanded, it has become
1257     harder and harder to keep it in step with the real compile phase, and there
1258     have been a number of bugs (see for example, 4 above). I have now found a
1259     cunning way of running the real compile function in a "fake" mode that
1260     enables it to compute how much memory it would need, while actually only
1261     ever using a few hundred bytes of working memory and without too many
1262     tests of the mode. This should make future maintenance and development
1263     easier. A side effect of this work is that the limit of 200 on the nesting
1264     depth of parentheses has been removed (though this was never a serious
1265     limitation, I suspect). However, there is a downside: pcre_compile() now
1266     runs more slowly than before (30% or more, depending on the pattern). I
1267     hope this isn't a big issue. There is no effect on runtime performance.
1269     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1270     newline (only possible for the last line of a file) and it was a
1271     pattern that set a locale (followed by /Lsomething), pcretest crashed.
1273     19. Added additional timing features to pcretest. (1) The -tm option now times
1274     matching only, not compiling. (2) Both -t and -tm can be followed, as a
1275     separate command line item, by a number that specifies the number of
1276     repeats to use when timing. The default is 50000; this gives better
1277     precision, but takes uncomfortably long for very large patterns.
1279     20. Extended pcre_study() to be more clever in cases where a branch of a
1280     subpattern has no definite first character. For example, (a*|b*)[cd] would
1281     previously give no result from pcre_study(). Now it recognizes that the
1282     first character must be a, b, c, or d.
1284     21. There was an incorrect error "recursive call could loop indefinitely" if
1285     a subpattern (or the entire pattern) that was being tested for matching an
1286     empty string contained only one non-empty item after a nested subpattern.
1287     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1288     incorrectly, because the \d was being skipped in the check.
1290     22. The pcretest program now has a new pattern option /B and a command line
1291     option -b, which is equivalent to adding /B to every pattern. This causes
1292     it to show the compiled bytecode, without the additional information that
1293     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1294     is the same as /B/I).
1296     23. A new optimization is now able automatically to treat some sequences such
1297     as a*b as a*+b. More specifically, if something simple (such as a character
1298     or a simple class like \d) has an unlimited quantifier, and is followed by
1299     something that cannot possibly match the quantified thing, the quantifier
1300     is automatically "possessified".
1302     24. A recursive reference to a subpattern whose number was greater than 39
1303     went wrong under certain circumstances in UTF-8 mode. This bug could also
1304     have affected the operation of pcre_study().
1306     25. Realized that a little bit of performance could be had by replacing
1307     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1309     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1311     27. Possessive quantifiers such as a++ were previously implemented by turning
1312     them into atomic groups such as ($>a+). Now they have their own opcodes,
1313     which improves performance. This includes the automatically created ones
1314     from 23 above.
1316     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1317     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1318     the first matched character to be a colon. This applied both to named and
1319     numbered groups.
1321     29. The ucpinternal.h header file was missing its idempotency #ifdef.
1323     30. I was sent a "project" file called libpcre.a.dev which I understand makes
1324     building PCRE on Windows easier, so I have included it in the distribution.
1326     31. There is now a check in pcretest against a ridiculously large number being
1327     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1328     loop, the loop is abandoned.
1330     32. Forward references to subpatterns in conditions such as (?(2)...) where
1331     subpattern 2 is defined later cause pcre_compile() to search forwards in
1332     the pattern for the relevant set of parentheses. This search went wrong
1333     when there were unescaped parentheses in a character class, parentheses
1334     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1336     33. "Subroutine" calls and backreferences were previously restricted to
1337     referencing subpatterns earlier in the regex. This restriction has now
1338     been removed.
1340     34. Added a number of extra features that are going to be in Perl 5.10. On the
1341     whole, these are just syntactic alternatives for features that PCRE had
1342     previously implemented using the Python syntax or my own invention. The
1343     other formats are all retained for compatibility.
1345     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1346     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1347     also .NET compatible.
1349     (b) A recursion or subroutine call to a named group can now be defined as
1350     (?&name) as well as (?P>name).
1352     (c) A backreference to a named group can now be defined as \k<name> or
1353     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1354     5.10, are also .NET compatible.
1356     (d) A conditional reference to a named group can now use the syntax
1357     (?(<name>) or (?('name') as well as (?(name).
1359     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1360     groups (named and numbered) that are never evaluated inline, but can be
1361     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1362     is always false. There may be only one alternative in such a group.
1364     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1365     as the simple (?(R). The condition is true only if the most recent
1366     recursion is that of the given number or name. It does not search out
1367     through the entire recursion stack.
1369     (g) The escape \gN or \g{N} has been added, where N is a positive or
1370     negative number, specifying an absolute or relative reference.
1372     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1373     some "unreachable code" warnings.
1375     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1376     things, this adds five new scripts.
1378     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1379     There were also incompatibilities regarding the handling of \Q..\E inside
1380     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1381     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1383     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1384     matches an empty string, and forcibly breaks the loop. There were bugs in
1385     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1386     against aaaa the result was just "a" rather than "aaaa", for example. Two
1387     separate and independent bugs (that affected different cases) have been
1388     fixed.
1390     39. Refactored the code to abolish the use of different opcodes for small
1391     capturing bracket numbers. This is a tidy that I avoided doing when I
1392     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1393     The new approach is not only tidier, it makes it possible to reduce the
1394     memory needed to fix the previous bug (38).
1396     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1397     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1398     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1399     mode.
1401     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1402     report.
1404     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1405     copy construction and assignment in the C++ wrapper.
1407     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1408     couple of bugs that could have given wrong results in the "--newline=crlf"
1409     case.
1411     44. Added a number of casts and did some reorganization of signed/unsigned int
1412     variables following suggestions from Dair Grant. Also renamed the variable
1413     "this" as "item" because it is a C++ keyword.
1415     45. Arranged for dftables to add
1417     #include "pcre_internal.h"
1419     to pcre_chartables.c because without it, gcc 4.x may remove the array
1420     definition from the final binary if PCRE is built into a static library and
1421     dead code stripping is activated.
1423     46. For an unanchored pattern, if a match attempt fails at the start of a
1424     newline sequence, and the newline setting is CRLF or ANY, and the next two
1425     characters are CRLF, advance by two characters instead of one.
1428 nigel 91 Version 6.7 04-Jul-06
1429     ---------------------
1431     1. In order to handle tests when input lines are enormously long, pcretest has
1432     been re-factored so that it automatically extends its buffers when
1433     necessary. The code is crude, but this _is_ just a test program. The
1434     default size has been increased from 32K to 50K.
1436     2. The code in pcre_study() was using the value of the re argument before
1437     testing it for NULL. (Of course, in any sensible call of the function, it
1438     won't be NULL.)
1440     3. The memmove() emulation function in pcre_internal.h, which is used on
1441     systems that lack both memmove() and bcopy() - that is, hardly ever -
1442     was missing a "static" storage class specifier.
1444     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1445     containing an extended class (one that cannot be represented by a bitmap
1446     because it contains high-valued characters or Unicode property items, e.g.
1447     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1448     pattern, but PCRE should not loop if you do not (it no longer does).
1449     [Detail: two cases were found: (a) a repeated subpattern containing an
1450     extended class; (b) a recursive reference to a subpattern that followed a
1451     previous extended class. It wasn't skipping over the extended class
1452     correctly when UTF-8 mode was not set.]
1454     5. A negated single-character class was not being recognized as fixed-length
1455     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1456     compile error "lookbehind assertion is not fixed length".
1458     6. The RunPerlTest auxiliary script was showing an unexpected difference
1459     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1460     write a Perl script that can interpret lines of an input file either as
1461     byte characters or as UTF-8, which is what "perltest" was being required to
1462     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1463     can't do is switch easily at run time between having the "use utf8;" pragma
1464     or not. In the end, I fudged it by using the RunPerlTest script to insert
1465     "use utf8;" explicitly for the UTF-8 tests.
1467     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1468     the end of the subject string, contrary to the documentation and to what
1469     Perl does. This was true of both matching functions. Now it matches only at
1470     the start of the subject and immediately after *internal* newlines.
1472     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1473     a pointer to an int instead of a pointer to an unsigned long int. This
1474     caused problems on 64-bit systems.
1476     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1477     instance of the 'standard' template library not being so standard".
1479     10. There was no check on the number of named subpatterns nor the maximum
1480     length of a subpattern name. The product of these values is used to compute
1481     the size of the memory block for a compiled pattern. By supplying a very
1482     long subpattern name and a large number of named subpatterns, the size
1483     computation could be caused to overflow. This is now prevented by limiting
1484     the length of names to 32 characters, and the number of named subpatterns
1485     to 10,000.
1487     11. Subpatterns that are repeated with specific counts have to be replicated in
1488     the compiled pattern. The size of memory for this was computed from the
1489     length of the subpattern and the repeat count. The latter is limited to
1490     65535, but there was no limit on the former, meaning that integer overflow
1491     could in principle occur. The compiled length of a repeated subpattern is
1492     now limited to 30,000 bytes in order to prevent this.
1494     12. Added the optional facility to have named substrings with the same name.
1496     13. Added the ability to use a named substring as a condition, using the
1497     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1498     are numbers (not recommended). Forward references are permitted.
1500     14. Added forward references in named backreferences (if you see what I mean).
1502     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1503     pattern could run off the end of the subject. For example, the pattern
1504     "(?s)(.{1,5})"8 did this with the subject "ab".
1506     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1507     PCRE_CASELESS was set when matching characters that were quantified with ?
1508     or *.
1510     17. A character class other than a single negated character that had a minimum
1511     but no maximum quantifier - for example [ab]{6,} - was not handled
1512     correctly by pce_dfa_exec(). It would match only one character.
1514     18. A valid (though odd) pattern that looked like a POSIX character
1515     class but used an invalid character after [ (for example [[,abc,]]) caused
1516     pcre_compile() to give the error "Failed: internal error: code overflow" or
1517     in some cases to crash with a glibc free() error. This could even happen if
1518     the pattern terminated after [[ but there just happened to be a sequence of
1519     letters, a binary zero, and a closing ] in the memory that followed.
1521     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1522     over the years. Originally (before any Unicode support), just the bottom 8
1523     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1524     output from "man perlunicode" includes this:
1526     The regular expression compiler produces polymorphic opcodes. That
1527     is, the pattern adapts to the data and automatically switches to
1528     the Unicode character scheme when presented with Unicode data--or
1529     instead uses a traditional byte scheme when presented with byte
1530     data.
1532     Sadly, a wide octal escape does not cause a switch, and in a string with
1533     no other multibyte characters, these octal escapes are treated as before.
1534     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1535     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1536     Unicode string.
1538     I have not perpetrated such confusion in PCRE. Up till now, it took just
1539     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1540     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1541     translate to the appropriate multibyte character.
1543     29. Applied some refactoring to reduce the number of warnings from Microsoft
1544     and Borland compilers. This has included removing the fudge introduced
1545     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1546     a warning about an unused variable.
1548     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1549     characters since release 4.0, because Perl (from release 5.004) does not.
1550     [Or at least, is documented not to: some releases seem to be in conflict
1551     with the documentation.] However, when a pattern was studied with
1552     pcre_study() and all its branches started with \s, PCRE still included VT
1553     as a possible starting character. Of course, this did no harm; it just
1554     caused an unnecessary match attempt.
1556     22. Removed a now-redundant internal flag bit that recorded the fact that case
1557     dependency changed within the pattern. This was once needed for "required
1558     byte" processing, but is no longer used. This recovers a now-scarce options
1559     bit. Also moved the least significant internal flag bit to the most-
1560     significant bit of the word, which was not previously used (hangover from
1561     the days when it was an int rather than a uint) to free up another bit for
1562     the future.
1564     23. Added support for CRLF line endings as well as CR and LF. As well as the
1565     default being selectable at build time, it can now be changed at runtime
1566     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1567     specify that it is scanning data with non-default line endings.
1569     24. Changed the definition of CXXLINK to make it agree with the definition of
1570     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1572     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1573     recursions. This makes a big different to stack usage for some patterns.
1575     26. If a subpattern containing a named recursion or subroutine reference such
1576     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1577     the space required for the compiled pattern went wrong and gave too small a
1578     value. Depending on the environment, this could lead to "Failed: internal
1579     error: code overflow at offset 49" or "glibc detected double free or
1580     corruption" errors.
1582     27. Applied patches from Google (a) to support the new newline modes and (b) to
1583     advance over multibyte UTF-8 characters in GlobalReplace.
1585     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1586     difference for some implementation of PCRE in some Windows version.
1588     29. Added some extra testing facilities to pcretest:
1590     \q<number> in a data line sets the "match limit" value
1591     \Q<number> in a data line sets the "match recursion limt" value
1592     -S <number> sets the stack size, where <number> is in megabytes
1594     The -S option isn't available for Windows.
1597 nigel 89 Version 6.6 06-Feb-06
1598     ---------------------
1600     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1601     in pcreposix.h. I have copied the definition from pcre.h.
1603     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1604     because pcre.h is no longer a built file.
1606     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1607     not normally included in the compiled code.
1610 nigel 87 Version 6.5 01-Feb-06
1611     ---------------------
1613     1. When using the partial match feature with pcre_dfa_exec(), it was not
1614     anchoring the second and subsequent partial matches at the new starting
1615     point. This could lead to incorrect results. For example, with the pattern
1616     /1234/, partially matching against "123" and then "a4" gave a match.
1618     2. Changes to pcregrep:
1620     (a) All non-match returns from pcre_exec() were being treated as failures
1621     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1622     error message is output. Some extra information is given for the
1624     probably the only errors that are likely to be caused by users (by
1625     specifying a regex that has nested indefinite repeats, for instance).
1626     If there are more than 20 of these errors, pcregrep is abandoned.
1628     (b) A binary zero was treated as data while matching, but terminated the
1629     output line if it was written out. This has been fixed: binary zeroes
1630     are now no different to any other data bytes.
1632     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1633     used to set a locale for matching. The --locale=xxxx long option has
1634     been added (no short equivalent) to specify a locale explicitly on the
1635     pcregrep command, overriding the environment variables.
1637     (d) When -B was used with -n, some line numbers in the output were one less
1638     than they should have been.
1640     (e) Added the -o (--only-matching) option.
1642     (f) If -A or -C was used with -c (count only), some lines of context were
1643     accidentally printed for the final match.
1645     (g) Added the -H (--with-filename) option.
1647     (h) The combination of options -rh failed to suppress file names for files
1648     that were found from directory arguments.
1650     (i) Added the -D (--devices) and -d (--directories) options.
1652     (j) Added the -F (--fixed-strings) option.
1654     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1656     (l) Added the --colo(u)r option.
1658     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1659     is not present by default.
1661     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1662     items such as (?R) or (?1), when the recursion could match a number of
1663     alternatives. If it matched one of the alternatives, but subsequently,
1664     outside the recursion, there was a failure, the code tried to back up into
1665     the recursion. However, because of the way PCRE is implemented, this is not
1666     possible, and the result was an incorrect result from the match.
1668     In order to prevent this happening, the specification of recursion has
1669     been changed so that all such subpatterns are automatically treated as
1670     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1672     4. I had overlooked the fact that, in some locales, there are characters for
1673     which isalpha() is true but neither isupper() nor islower() are true. In
1674     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1675     and ordfeminine) are like this. This affected the treatment of \w and \W
1676     when they appeared in character classes, but not when they appeared outside
1677     a character class. The bit map for "word" characters is now created
1678     separately from the results of isalnum() instead of just taking it from the
1679     upper, lower, and digit maps. (Plus the underscore character, of course.)
1681     5. The above bug also affected the handling of POSIX character classes such as
1682     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1683     permanent tables. Instead, the bit maps for such a class were previously
1684     created as the appropriate unions of the upper, lower, and digit bitmaps.
1685     Now they are created by subtraction from the [[:word:]] class, which has
1686     its own bitmap.
1688     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1689     It is created by subtracting the vertical space characters (\x09, \x0a,
1690     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1691     subtraction was done in the overall bitmap for a character class, meaning
1692     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1693     be recognized. This bug has been fixed.
1695     7. Patches from the folks at Google:
1697     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1698     real life, but is still worth protecting against".
1700     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1701     regular expressions".
1703     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1704     have it.
1706     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1707     "configure" and the latter not, in order to fix a problem somebody had
1708     with compiling the Arg class on HP-UX.
1710     (e) Improve the error-handling of the C++ wrapper a little bit.
1712     (f) New tests for checking recursion limiting.
1714     8. The pcre_memmove() function, which is used only if the environment does not
1715     have a standard memmove() function (and is therefore rarely compiled),
1716     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1717     returning a result (though PCRE never actually uses the result).
1719     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1720     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1721     returned instead of calling malloc() with an overflowing number that would
1722     most likely cause subsequent chaos.
1724     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1726     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1727     with this option is matched, the nmatch and pmatch options of regexec() are
1728     ignored.
1730     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1731     provided in case anyone wants to the the POSIX interface with UTF-8
1732     strings.
1734     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1735     C++ linking (needed for some HP-UX environments).
1737     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1738     (unused parameter) and in the pcre_printint() function (omitted "default"
1739     switch label when the default is to do nothing).
1741     15. Added some code to make it possible, when PCRE is compiled as a C++
1742     library, to replace subject pointers for pcre_exec() with a smart pointer
1743     class, thus making it possible to process discontinuous strings.
1745     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1746     much the same function. They were added by different people who were trying
1747     to make PCRE easy to compile on non-Unix systems. It has been suggested
1748     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1749     for compiling on Windows systems. I have therefore replaced it with
1750     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1751     defaults to "extern" for C or "extern C" for C++, which works fine on
1752     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1753     SCOPE with something explicit in config.h. In addition:
1755     (a) pcreposix.h still had just "extern" instead of either of these macros;
1756     I have replaced it with PCRE_DATA_SCOPE.
1758     (b) Functions such as _pcre_xclass(), which are internal to the library,
1759     but external in the C sense, all had PCRE_EXPORT in their definitions.
1760     This is apparently wrong for the Windows case, so I have removed it.
1761     (It makes no difference on Unix-like systems.)
1763     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1764     of recursive calls to match(). This is different to MATCH_LIMIT because
1765     that limits the total number of calls to match(), not all of which increase
1766     the depth of recursion. Limiting the recursion depth limits the amount of
1767     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1768     when PCRE is compiled, and changed at run time. A patch from Google adds
1769     this functionality to the C++ interface.
1771     18. Changes to the handling of Unicode character properties:
1773     (a) Updated the table to Unicode 4.1.0.
1775     (b) Recognize characters that are not in the table as "Cn" (undefined).
1777     (c) I revised the way the table is implemented to a much improved format
1778     which includes recognition of ranges. It now supports the ranges that
1779     are defined in UnicodeData.txt, and it also amalgamates other
1780     characters into ranges. This has reduced the number of entries in the
1781     table from around 16,000 to around 3,000, thus reducing its size
1782     considerably. I realized I did not need to use a tree structure after
1783     all - a binary chop search is just as efficient. Having reduced the
1784     number of entries, I extended their size from 6 bytes to 8 bytes to
1785     allow for more data.
1787     (d) Added support for Unicode script names via properties such as \p{Han}.
1789     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1790     matching that character.
1792     20. When matching a repeated Unicode property with a minimum greater than zero,
1793     (for example \pL{2,}), PCRE could look past the end of the subject if it
1794     reached it while seeking the minimum number of characters. This could
1795     happen only if some of the characters were more than one byte long, because
1796     there is a check for at least the minimum number of bytes.
1798     21. Refactored the implementation of \p and \P so as to be more general, to
1799     allow for more different types of property in future. This has changed the
1800     compiled form incompatibly. Anybody with saved compiled patterns that use
1801     \p or \P will have to recompile them.
1803     22. Added "Any" and "L&" to the supported property types.
1805     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1806     but give a compile time error if the value is greater than 0xff.
1808     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1809     accidentally not being installed or uninstalled.
1811     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1812     made were to insert the current release number. This seemed silly, because
1813     it made things harder for people building PCRE on systems that don't run
1814     "configure". I have turned pcre.h into a distributed file, no longer built
1815     by "configure", with the version identification directly included. There is
1816     no longer a pcre.h.in file.
1818     However, this change necessitated a change to the pcre-config script as
1819     well. It is built from pcre-config.in, and one of the substitutions was the
1820     release number. I have updated configure.ac so that ./configure now finds
1821     the release number by grepping pcre.h.
1823     26. Added the ability to run the tests under valgrind.
1826 nigel 85 Version 6.4 05-Sep-05
1827     ---------------------
1829     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1830     "--" to be printed when multiple files were scanned, even when none of the
1831     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1832     consider it to be a bug, and have restored the previous behaviour.
1834     2. A couple of code tidies to get rid of compiler warnings.
1836     3. The pcretest program used to cheat by referring to symbols in the library
1837     whose names begin with _pcre_. These are internal symbols that are not
1838     really supposed to be visible externally, and in some environments it is
1839     possible to suppress them. The cheating is now confined to including
1840     certain files from the library's source, which is a bit cleaner.
1842     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1843     file's purpose clearer.
1845     5. Reorganized pcre_ucp_findchar().
1848 nigel 83 Version 6.3 15-Aug-05
1849     ---------------------
1851     1. The file libpcre.pc.in did not have general read permission in the tarball.
1853     2. There were some problems when building without C++ support:
1855     (a) If C++ support was not built, "make install" and "make test" still
1856     tried to test it.
1858     (b) There were problems when the value of CXX was explicitly set. Some
1859     changes have been made to try to fix these, and ...
1861     (c) --disable-cpp can now be used to explicitly disable C++ support.
1863     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1864     backslash in a target when C++ was disabled. This confuses some
1865     versions of "make", apparently. Using an intermediate variable solves
1866     this. (Same for CPP_LOBJ.)
1868     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1869     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1870     necessary on certain architectures.
1872     4. Added a setting of -export-symbols-regex to the link command to remove
1873     those symbols that are exported in the C sense, but actually are local
1874     within the library, and not documented. Their names all begin with
1875     "_pcre_". This is not a perfect job, because (a) we have to except some
1876     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1877     available (and never for static libraries). I have made a note to try to
1878     find a way round (a) in the future.
1881 nigel 81 Version 6.2 01-Aug-05
1882     ---------------------
1884     1. There was no test for integer overflow of quantifier values. A construction
1885     such as {1111111111111111} would give undefined results. What is worse, if
1886     a minimum quantifier for a parenthesized subpattern overflowed and became
1887     negative, the calculation of the memory size went wrong. This could have
1888     led to memory overwriting.
1890     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1892     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1893     operating environments where this matters.
1895     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1896     PCRE options from within the C++ wrapper.
1898     5. Named capturing subpatterns were not being correctly counted when a pattern
1899     was compiled. This caused two problems: (a) If there were more than 100
1900     such subpatterns, the calculation of the memory needed for the whole
1901     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1902     back references of the form \12, where the number was greater than 9, were
1903     not recognized as back references, even though there were sufficient
1904     previous subpatterns.
1906     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1907     versions of gcc, e.g. 2.95.4.
1910 nigel 79 Version 6.1 21-Jun-05
1911     ---------------------
1913     1. There was one reference to the variable "posix" in pcretest.c that was not
1914     surrounded by "#if !defined NOPOSIX".
1916     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1917     the cross-check on the old pcre_info() function, for the benefit of the
1918     cut-down version of PCRE that is currently imported into Exim.
1920     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1921     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1922     patterns that start (?i) but I don't think that matters. The use of (?i) is
1923     just an example; this all applies to the other options as well.
1925     4. Since libtool seems to echo the compile commands it is issuing, the output
1926     from "make" can be reduced a bit by putting "@" in front of each libtool
1927     compile command.
1929     5. Patch from the folks at Google for configure.in to be a bit more thorough
1930     in checking for a suitable C++ installation before trying to compile the
1931     C++ stuff. This should fix a reported problem when a compiler was present,
1932     but no suitable headers.
1934     6. The man pages all had just "PCRE" as their title. I have changed them to
1935     be the relevant file name. I have also arranged that these names are
1936     retained in the file doc/pcre.txt, which is a concatenation in text format
1937     of all the man pages except the little individual ones for each function.
1939     7. The NON-UNIX-USE file had not been updated for the different set of source
1940     files that come with release 6. I also added a few comments about the C++
1941     wrapper.
1944 nigel 77 Version 6.0 07-Jun-05
1945     ---------------------
1947     1. Some minor internal re-organization to help with my DFA experiments.
1949     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1950     didn't matter for the library itself when fully configured, but did matter
1951     when compiling without UCP support, or within Exim, where the ucp files are
1952     not imported.
1954     3. Refactoring of the library code to split up the various functions into
1955     different source modules. The addition of the new DFA matching code (see
1956     below) to a single monolithic source would have made it really too
1957     unwieldy, quite apart from causing all the code to be include in a
1958     statically linked application, when only some functions are used. This is
1959     relevant even without the DFA addition now that patterns can be compiled in
1960     one application and matched in another.
1962     The downside of splitting up is that there have to be some external
1963     functions and data tables that are used internally in different modules of
1964     the library but which are not part of the API. These have all had their
1965     names changed to start with "_pcre_" so that they are unlikely to clash
1966     with other external names.
1968     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1969     a different (DFA) algorithm. Although it is slower than the original
1970     function, it does have some advantages for certain types of matching
1971     problem.
1973     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1974     including restarting after a partial match.
1976     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1977     defined when compiling for Windows was sent to me. I have put it into the
1978     code, though I have no means of testing or verifying it.
1980     7. Added the pcre_refcount() auxiliary function.
1982     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1983     match before or at the first newline in the subject string. In pcretest,
1984     the /f option on a pattern can be used to set this.
1986     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1987     would behave wrongly. This has been present in PCRE since release 4.0.
1989     10. A number of changes to the pcregrep command:
1991     (a) Refactored how -x works; insert ^(...)$ instead of setting
1992     PCRE_ANCHORED and checking the length, in preparation for adding
1993     something similar for -w.
1995     (b) Added the -w (match as a word) option.
1997     (c) Refactored the way lines are read and buffered so as to have more
1998     than one at a time available.
2000     (d) Implemented a pcregrep test script.
2002     (e) Added the -M (multiline match) option. This allows patterns to match
2003     over several lines of the subject. The buffering ensures that at least
2004     8K, or the rest of the document (whichever is the shorter) is available
2005     for matching (and similarly the previous 8K for lookbehind assertions).
2007     (f) Changed the --help output so that it now says
2009     -w, --word-regex(p)
2011     instead of two lines, one with "regex" and the other with "regexp"
2012     because that confused at least one person since the short forms are the
2013     same. (This required a bit of code, as the output is generated
2014     automatically from a table. It wasn't just a text change.)
2016     (g) -- can be used to terminate pcregrep options if the next thing isn't an
2017     option but starts with a hyphen. Could be a pattern or a path name
2018     starting with a hyphen, for instance.
2020     (h) "-" can be given as a file name to represent stdin.
2022     (i) When file names are being printed, "(standard input)" is used for
2023     the standard input, for compatibility with GNU grep. Previously
2024     "<stdin>" was used.
2026     (j) The option --label=xxx can be used to supply a name to be used for
2027     stdin when file names are being printed. There is no short form.
2029     (k) Re-factored the options decoding logic because we are going to add
2030     two more options that take data. Such options can now be given in four
2031     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2033     (l) Added the -A, -B, and -C options for requesting that lines of context
2034     around matches be printed.
2036     (m) Added the -L option to print the names of files that do not contain
2037     any matching lines, that is, the complement of -l.
2039     (n) The return code is 2 if any file cannot be opened, but pcregrep does
2040     continue to scan other files.
2042     (o) The -s option was incorrectly implemented. For compatibility with other
2043     greps, it now suppresses the error message for a non-existent or non-
2044     accessible file (but not the return code). There is a new option called
2045     -q that suppresses the output of matching lines, which was what -s was
2046     previously doing.
2048     (p) Added --include and --exclude options to specify files for inclusion
2049     and exclusion when recursing.
2051     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2052     Hopefully, it now does.
2054     12. Missing cast in pcre_study().
2056     13. Added an "uninstall" target to the makefile.
2058     14. Replaced "extern" in the function prototypes in Makefile.in with
2059     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2060     world, but is set differently for Windows.
2062     15. Added a second compiling function called pcre_compile2(). The only
2063     difference is that it has an extra argument, which is a pointer to an
2064     integer error code. When there is a compile-time failure, this is set
2065     non-zero, in addition to the error test pointer being set to point to an
2066     error message. The new argument may be NULL if no error number is required
2067     (but then you may as well call pcre_compile(), which is now just a
2068     wrapper). This facility is provided because some applications need a
2069     numeric error indication, but it has also enabled me to tidy up the way
2070     compile-time errors are handled in the POSIX wrapper.
2072     16. Added VPATH=.libs to the makefile; this should help when building with one
2073     prefix path and installing with another. (Or so I'm told by someone who
2074     knows more about this stuff than I do.)
2076     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2077     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2078     match everything, including newlines. This is not POSIX-compatible, but
2079     somebody wanted the feature. From pcretest it can be activated by using
2080     both the P and the s flags.
2082     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2084     19. libpcre.pc was being incorrectly installed as executable.
2086     20. A couple of places in pcretest check for end-of-line by looking for '\n';
2087     it now also looks for '\r' so that it will work unmodified on Windows.
2089     21. Added Google's contributed C++ wrapper to the distribution.
2091     22. Added some untidy missing memory free() calls in pcretest, to keep
2092     Electric Fence happy when testing.
2096 nigel 75 Version 5.0 13-Sep-04
2097     ---------------------
2099     1. Internal change: literal characters are no longer packed up into items
2100     containing multiple characters in a single byte-string. Each character
2101     is now matched using a separate opcode. However, there may be more than one
2102     byte in the character in UTF-8 mode.
2104     2. The pcre_callout_block structure has two new fields: pattern_position and
2105     next_item_length. These contain the offset in the pattern to the next match
2106     item, and its length, respectively.
2108     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2109     insertion of callouts before each pattern item. Added the /C option to
2110     pcretest to make use of this.
2112     4. On the advice of a Windows user, the lines
2114     #if defined(_WIN32) || defined(WIN32)
2115     _setmode( _fileno( stdout ), 0x8000 );
2116     #endif /* defined(_WIN32) || defined(WIN32) */
2118     have been added to the source of pcretest. This apparently does useful
2119     magic in relation to line terminators.
2121     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2122     for the benefit of those environments where the "b" makes a difference.
2124     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2125     to know about it. I have put a hack into configure.in that adds in code
2126     to set GCC=yes if CC=icc. This seems to end up at a point in the
2127     generated configure script that is early enough to affect the setting of
2128     compiler options, which is what is needed, but I have no means of testing
2129     whether it really works. (The user who reported this had patched the
2130     generated configure script, which of course I cannot do.)
2132     LATER: After change 22 below (new libtool files), the configure script
2133     seems to know about icc (and also ecc). Therefore, I have commented out
2134     this hack in configure.in.
2136     7. Added support for pkg-config (2 patches were sent in).
2138     8. Negated POSIX character classes that used a combination of internal tables
2139     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2140     [[:^ascii]]. Typically, they would match almost any characters. The other
2141     POSIX classes were not broken in this way.
2143     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2144     to find the match, as PCRE was deluded into thinking that the match had to
2145     start at the start point or following a newline. The same bug applied to
2146     patterns with negative forward assertions or any backward assertions
2147     preceding ".*" at the start, unless the pattern required a fixed first
2148     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2150     10. In UTF-8 mode, when moving forwards in the subject after a failed match
2151     starting at the last subject character, bytes beyond the end of the subject
2152     string were read.
2154     11. Renamed the variable "class" as "classbits" to make life easier for C++
2155     users. (Previously there was a macro definition, but it apparently wasn't
2156     enough.)
2158     12. Added the new field "tables" to the extra data so that tables can be passed
2159     in at exec time, or the internal tables can be re-selected. This allows
2160     a compiled regex to be saved and re-used at a later time by a different
2161     program that might have everything at different addresses.
2163     13. Modified the pcre-config script so that, when run on Solaris, it shows a
2164     -R library as well as a -L library.
2166     14. The debugging options of pcretest (-d on the command line or D on a
2167     pattern) showed incorrect output for anything following an extended class
2168     that contained multibyte characters and which was followed by a quantifier.
2170     15. Added optional support for general category Unicode character properties
2171     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2172     support. It adds about 90K to the size of the library. The meanings of the
2173     inbuilt class escapes such as \d and \s have NOT been changed.
2175     16. Updated pcredemo.c to include calls to free() to release the memory for the
2176     compiled pattern.
2178     17. The generated file chartables.c was being created in the source directory
2179     instead of in the building directory. This caused the build to fail if the
2180     source directory was different from the building directory, and was
2181     read-only.
2183     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2184     file. No doubt somebody will tell me if they don't make sense... Also added
2185     Dan Mooney's comments about building on OpenVMS.
2187     19. Added support for partial matching via the PCRE_PARTIAL option for
2188     pcre_exec() and the \P data escape in pcretest.
2190     20. Extended pcretest with 3 new pattern features:
2192     (i) A pattern option of the form ">rest-of-line" causes pcretest to
2193     write the compiled pattern to the file whose name is "rest-of-line".
2194     This is a straight binary dump of the data, with the saved pointer to
2195     the character tables forced to be NULL. The study data, if any, is
2196     written too. After writing, pcretest reads a new pattern.
2198     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2199     compiled pattern from the given file. There must not be any
2200     occurrences of "<" in the file name (pretty unlikely); if there are,
2201     pcretest will instead treat the initial "<" as a pattern delimiter.
2202     After reading in the pattern, pcretest goes on to read data lines as
2203     usual.
2205     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2206     and 16-bit fields in a compiled pattern, to simulate a pattern that
2207     was compiled on a host of opposite endianness.
2209     21. The pcre-exec() function can now cope with patterns that were compiled on
2210     hosts of opposite endianness, with this restriction:
2212     As for any compiled expression that is saved and used later, the tables
2213     pointer field cannot be preserved; the extra_data field in the arguments
2214     to pcre_exec() should be used to pass in a tables address if a value
2215     other than the default internal tables were used at compile time.
2217     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2218     now diagnosed as an error. Previously, most of the time, a negative number
2219     would have been treated as zero, but if in addition "ovector" was passed as
2220     NULL, a crash could occur.
2222     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2223     new versions from the libtool 1.5 distribution (the last one is a copy of
2224     a file called libtool.m4). This seems to have fixed the need to patch
2225     "configure" to support Darwin 1.3 (which I used to do). However, I still
2226     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2227     workstation).
2229     24. Changed the PCRE licence to be the more standard "BSD" licence.
2232 nigel 73 Version 4.5 01-Dec-03
2233     ---------------------
2235     1. There has been some re-arrangement of the code for the match() function so
2236     that it can be compiled in a version that does not call itself recursively.
2237     Instead, it keeps those local variables that need separate instances for
2238     each "recursion" in a frame on the heap, and gets/frees frames whenever it
2239     needs to "recurse". Keeping track of where control must go is done by means
2240     of setjmp/longjmp. The whole thing is implemented by a set of macros that
2241     hide most of the details from the main code, and operates only if
2242     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2243     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2244     operating.
2246     To make it easier for callers to provide specially tailored get/free
2247     functions for this usage, two new functions, pcre_stack_malloc, and
2248     pcre_stack_free, are used. They are always called in strict stacking order,
2249     and the size of block requested is always the same.
2251     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2252     PCRE has been compiled to use the stack or the heap for recursion. The
2253     -C option of pcretest uses this to show which version is compiled.
2255     A new data escape \S, is added to pcretest; it causes the amounts of store
2256     obtained and freed by both kinds of malloc/free at match time to be added
2257     to the output.
2259     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2260     what's available on my current Linux desktop machine.
2262     3. When matching a UTF-8 string, the test for a valid string at the start has
2263     been extended. If start_offset is not zero, PCRE now checks that it points
2264     to a byte that is the start of a UTF-8 character. If not, it returns
2265     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2266     this is necessary because there may be backward assertions in the pattern.
2267     When matching the same subject several times, it may save resources to use
2268     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2270     4. The code for checking the validity of UTF-8 strings has been tightened so
2271     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2272     containing "overlong sequences".
2274     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2275     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2276     should have been "&", but it just so happened that all the cases this let
2277     through by mistake were picked up later in the function.
2279     6. I had used a variable called "isblank" - this is a C99 function, causing
2280     some compilers to warn. To avoid this, I renamed it (as "blankclass").
2282     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2283     prompting; (b) run "./pcretest /dev/null" at the start of the test script
2284     so the version is shown; (c) stop "make test" echoing "./RunTest".
2286     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2288     9. The prototype for memmove() for systems that don't have it was using
2289     size_t, but the inclusion of the header that defines size_t was later. I've
2290     moved the #includes for the C headers earlier to avoid this.
2292     10. Added some adjustments to the code to make it easier to compiler on certain
2293     special systems:
2295     (a) Some "const" qualifiers were missing.
2296     (b) Added the macro EXPORT before all exported functions; by default this
2297     is defined to be empty.
2298     (c) Changed the dftables auxiliary program (that builds chartables.c) so
2299     that it reads its output file name as an argument instead of writing
2300     to the standard output and assuming this can be redirected.
2302     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2303     class containing characters with values greater than 255, PCRE compilation
2304     went into a loop.
2306     12. A recursive reference to a subpattern that was within another subpattern
2307     that had a minimum quantifier of zero caused PCRE to crash. For example,
2308     (x(y(?2))z)? provoked this bug with a subject that got as far as the
2309     recursion. If the recursively-called subpattern itself had a zero repeat,
2310     that was OK.
2312     13. In pcretest, the buffer for reading a data line was set at 30K, but the
2313     buffer into which it was copied (for escape processing) was still set at
2314     1024, so long lines caused crashes.
2316     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2317     "internal error: code overflow...". This applied to any character class
2318     that was followed by a possessive quantifier.
2320     15. Modified the Makefile to add libpcre.la as a prerequisite for
2321     libpcreposix.la because I was told this is needed for a parallel build to
2322     work.
2324     16. If a pattern that contained .* following optional items at the start was
2325     studied, the wrong optimizing data was generated, leading to matching
2326     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2327     matching string must start with a or b or c. The correct conclusion for
2328     this pattern is that a match can start with any character.
2331 nigel 71 Version 4.4 13-Aug-03
2332     ---------------------
2334     1. In UTF-8 mode, a character class containing characters with values between
2335     127 and 255 was not handled correctly if the compiled pattern was studied.
2336     In fixing this, I have also improved the studying algorithm for such
2337     classes (slightly).
2339     2. Three internal functions had redundant arguments passed to them. Removal
2340     might give a very teeny performance improvement.
2342     3. Documentation bug: the value of the capture_top field in a callout is *one
2343     more than* the number of the hightest numbered captured substring.
2345     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2346     in incorrectly linking with a previously installed version. They now link
2347     explicitly with libpcre.la.
2349     5. configure.in no longer needs to recognize Cygwin specially.
2351     6. A problem in pcre.in for Windows platforms is fixed.
2353     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2354     pcretest, it used to include the size of the study block as part of its
2355     output. Unfortunately, the structure contains a field that has a different
2356     size on different hardware architectures. This meant that the tests that
2357     showed this size failed. As the block is currently always of a fixed size,
2358     this information isn't actually particularly useful in pcretest output, so
2359     I have just removed it.
2361     8. Three pre-processor statements accidentally did not start in column 1.
2362     Sadly, there are *still* compilers around that complain, even though
2363     standard C has not required this for well over a decade. Sigh.
2365     9. In pcretest, the code for checking callouts passed small integers in the
2366     callout_data field, which is a void * field. However, some picky compilers
2367     complained about the casts involved for this on 64-bit systems. Now
2368     pcretest passes the address of the small integer instead, which should get
2369     rid of the warnings.
2371     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2372     both compile and run time, and gives an error if an invalid UTF-8 sequence
2373     is found. There is a option for disabling this check in cases where the
2374     string is known to be correct and/or the maximum performance is wanted.
2376     11. In response to a bug report, I changed one line in Makefile.in from
2378     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2379     to
2380     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2382     to look similar to other lines, but I have no way of telling whether this
2383     is the right thing to do, as I do not use Windows. No doubt I'll get told
2384     if it's wrong...
2387 nigel 69 Version 4.3 21-May-03
2388     ---------------------
2390     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2391     Makefile.
2393     2. Some refactoring to improve the quality of the code:
2395     (i) The utf8_table... variables are now declared "const".
2397     (ii) The code for \cx, which used the "case flipping" table to upper case
2398     lower case letters, now just substracts 32. This is ASCII-specific,
2399     but the whole concept of \cx is ASCII-specific, so it seems
2400     reasonable.
2402     (iii) PCRE was using its character types table to recognize decimal and
2403     hexadecimal digits in the pattern. This is silly, because it handles
2404     only 0-9, a-f, and A-F, but the character types table is locale-
2405     specific, which means strange things might happen. A private
2406     table is now used for this - though it costs 256 bytes, a table is
2407     much faster than multiple explicit tests. Of course, the standard
2408     character types table is still used for matching digits in subject
2409     strings against \d.
2411     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2412     ending in _t are). So I've renamed it as ESC_tee.
2414     3. The first argument for regexec() in the POSIX wrapper should have been
2415     defined as "const".
2417     4. Changed pcretest to use malloc() for its buffers so that they can be
2418     Electric Fenced for debugging.
2420     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2421     to read one or more bytes before the start of the subject string. Often this
2422     had no effect on PCRE's behaviour, but in some circumstances it could
2423     provoke a segmentation fault.
2425     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2426     to try to read one or more bytes before the start of the subject string.
2428     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2429     UTF-8 support could misbehave in various ways if the subject string
2430     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2431     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2432     back over UTF-8 characters.)
2435 nigel 67 Version 4.2 14-Apr-03
2436     ---------------------
2438     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2440     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2441     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2442     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2443     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2444     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2445     and BUILD_EXEEXT
2446     Note: automatic setting of the BUILD variables is not yet working
2447     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2448     compile-time but not at link-time
2449     [LINK]: use for linking executables only
2450     make different versions for Windows and non-Windows
2451     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2452     libraries
2453     [LINK_FOR_BUILD]: new variable
2454     [OBJEXT]: use throughout
2455     [EXEEXT]: use throughout
2456     <winshared>: new target
2457     <wininstall>: new target
2458     <dftables.o>: use native compiler
2459     <dftables>: use native linker
2460     <install>: handle Windows platform correctly
2461     <clean>: ditto
2462     <check>: ditto
2463     copy DLL to top builddir before testing
2465     As part of these changes, -no-undefined was removed again. This was reported
2466     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2467     in any case.
2469     3. Some tidies to get rid of compiler warnings:
2471     . In the match_data structure, match_limit was an unsigned long int, whereas
2472     match_call_count was an int. I've made them both unsigned long ints.
2474     . In pcretest the fact that a const uschar * doesn't automatically cast to
2475     a void * provoked a warning.
2477     . Turning on some more compiler warnings threw up some "shadow" variables
2478     and a few more missing casts.
2480     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2481     option, a class that contained a single character with a value between 128
2482     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2484     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2485     option, a class that contained several characters, but with at least one
2486     whose value was between 128 and 255 caused PCRE to crash.
2489 nigel 65 Version 4.1 12-Mar-03
2490     ---------------------
2491 nigel 63
2492 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2493     needed, and a string in dftables.c that was longer than standard compilers are
2494     required to support.
2496     2. Compiling with Sun's compiler found a few more places where the code could
2497     be tidied up in order to avoid warnings.
2499     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2500     first of these names is deprecated in the latest Autoconf in favour of the name
2501     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2502     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2503     analogy I have changed it to CFLAGS_FOR_BUILD.
2505     4. Added -no-undefined to the linking command in the Makefile, because this is
2506     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2507     linking step for the pcreposix library.
2509     5. PCRE was failing to diagnose the case of two named groups with the same
2510     name.
2512     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2513     literal character that is needed in the subject for a match, and scans along to
2514     ensure that it is present before embarking on the full matching process. This
2515     saves time in cases of nested unlimited repeats that are never going to match.
2516     Problem: the scan can take a lot of time if the subject is very long (e.g.
2517     megabytes), thus penalizing straightforward matches. It is now done only if the
2518     amount of subject to be scanned is less than 1000 bytes.
2520     7. A lesser problem with the same optimization is that it was recording the
2521     first character of an anchored pattern as "needed", thus provoking a search
2522     right along the subject, even when the first match of the pattern was going to
2523     fail. The "needed" character is now not set for anchored patterns, unless it
2524     follows something in the pattern that is of non-fixed length. Thus, it still
2525     fulfils its original purpose of finding quick non-matches in cases of nested
2526     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2529     Version 4.0 17-Feb-03
2530     ---------------------
2532 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2533     extended to the end of string, PCRE compiled incorrect data. This could lead to
2534     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2536     2. Moved to autoconf 2.53 and libtool 1.4.2.
2538     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2539     the special perltest8 script is no longer needed - all the tests can be run
2540     from a single perltest script.
2542     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2543     by \s. It has now been removed in PCRE. This means it isn't recognized as
2544     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2545     class [:space:] *does* include VT, thereby creating a mess.
2547     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2548     space and tab.
2550     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2551     its new features into the main test script, reducing the number of scripts.
2553     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2554     were backward compatible, and made the (?i) apply to the whole pattern, as if
2555     /i were given. Now it behaves more logically, and applies the option setting
2556     only to what follows. PCRE has been changed to follow suit. However, if it
2557     finds options settings right at the start of the pattern, it extracts them into
2558     the global options, as before. Thus, they show up in the info data.
2560     8. Added support for the \Q...\E escape sequence. Characters in between are
2561     treated as literals. This is slightly different from Perl in that $ and @ are
2562     also handled as literals inside the quotes. In Perl, they will cause variable
2563     interpolation. Note the following examples:
2565     Pattern PCRE matches Perl matches
2567     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2568     \Qabc\$xyz\E abc\$xyz abc\$xyz
2569     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2571     For compatibility with Perl, \Q...\E sequences are recognized inside character
2572     classes as well as outside them.
2574     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2575     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2576     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2577     signed/unsigned warnings.
2579     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2580     option for pcretest, so I've replaced it by a simple function that does just
2581     that job.
2583     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2584     "pcregrep -".
2586     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2587     Java package. This provides some syntactic sugar for simple cases of what my
2588     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2589     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2590     item, you can use this simplified notation. Note that only makes sense with
2591     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2592     greediness, whatever the setting of the PCRE_UNGREEDY option.
2594     13. A change of greediness default within a pattern was not taking effect at
2595     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2596     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2597     was abstracted outside.
2599     14. PCRE now supports the \G assertion. It is true when the current matching
2600     position is at the start point of the match. This differs from \A when the
2601     starting offset is non-zero. Used with the /g option of pcretest (or similar
2602     code), it works in the same way as it does for Perl's /g option. If all
2603     alternatives of a regex begin with \G, the expression is anchored to the start
2604     match position, and the "anchored" flag is set in the compiled expression.
2606     15. Some bugs concerning the handling of certain option changes within patterns
2607     have been fixed. These applied to options other than (?ims). For example,
2608     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2609     been the other way round. Some of this was related to change 7 above.
2611     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2612     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2613     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2614     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2616     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2617     mode. Unlike ".", it always matches newline, whatever the setting of
2618     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2619     assertions. Perl allows it, but it doesn't (in general) work because it can't
2620     calculate the length of the lookbehind. At least, that's the case for Perl
2621     5.8.0 - I've been told they are going to document that it doesn't work in
2622     future.
2624     18. Added an error diagnosis for escapes that PCRE does not support: these are
2625     \L, \l, \N, \P, \p, \U, \u, and \X.
2627     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2628     reading past the end of the pattern in cases such as /[abcd/.
2630     20. PCRE was getting more memory than necessary for patterns with classes that
2631     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2633     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2634     compiling PCRE for use with Virtual Pascal.
2636     22. Small fix to the Makefile to make it work properly if the build is done
2637     outside the source tree.
2639     23. Added a new extension: a condition to go with recursion. If a conditional
2640     subpattern starts with (?(R) the "true" branch is used if recursion has
2641     happened, whereas the "false" branch is used only at the top level.
2643     24. When there was a very long string of literal characters (over 255 bytes
2644     without UTF support, over 250 bytes with UTF support), the computation of how
2645     much memory was required could be incorrect, leading to segfaults or other
2646     strange effects.
2648     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2649     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2650     there was a subsequent back reference to those brackets. This meant that, for
2651     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2652     possible to check for precisely this case. All we can do is abandon the
2653     optimization if .* occurs inside capturing brackets when there are any back
2654     references whatsoever. (See below for a better fix that came later.)
2656     26. The handling of the optimization for finding the first character of a
2657     non-anchored pattern, and for finding a character that is required later in the
2658     match were failing in some cases. This didn't break the matching; it just
2659     failed to optimize when it could. The way this is done has been re-implemented.
2661     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2663     28. Added a new feature that provides some of the functionality that Perl
2664     provides with (?{...}). The facility is termed a "callout". The way it is done
2665     in PCRE is for the caller to provide an optional function, by setting
2666     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2667     global variable. By default it is unset, which disables all calling out. To get
2668     the function called, the regex must include (?C) at appropriate points. This
2669     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2670     This provides a means of identifying different callout points. When PCRE
2671     reaches such a point in the regex, if pcre_callout has been set, the external
2672     function is called. It is provided with data in a structure called
2673     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2674     matching continues; if it returns a non-zero value, the match at the current
2675     point fails. However, backtracking will occur if possible. [This was changed
2676     later and other features added - see item 49 below.]
2678     29. pcretest is upgraded to test the callout functionality. It provides a
2679     callout function that displays information. By default, it shows the start of
2680     the match and the current position in the text. There are some new data escapes
2681     to vary what happens:
2683     \C+ in addition, show current contents of captured substrings
2684     \C- do not supply a callout function
2685     \C!n return 1 when callout number n is reached
2686     \C!n!m return 1 when callout number n is reached for the mth time
2688     30. If pcregrep was called with the -l option and just a single file name, it
2689     output "<stdin>" if a match was found, instead of the file name.
2691     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2692     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2693     pcre_exec(). This saves a malloc/free per call. The default value of
2694     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2695     when configuring.
2697     32. The default maximum size of a compiled pattern is 64K. There have been a
2698     few cases of people hitting this limit. The code now uses macros to handle the
2699     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2700     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2701     configuring. Tests 2 and 5 work only with 2-byte links because they output
2702     debugging information about compiled patterns.
2704     33. Internal code re-arrangements:
2706     (a) Moved the debugging function for printing out a compiled regex into
2707     its own source file (printint.c) and used #include to pull it into
2708     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2709     separate copies.
2711     (b) Defined the list of op-code names for debugging as a macro in
2712     internal.h so that it is next to the definition of the opcodes.
2714     (c) Defined a table of op-code lengths for simpler skipping along compiled
2715     code. This is again a macro in internal.h so that it is next to the
2716     definition of the opcodes.
2718     34. Added support for recursive calls to individual subpatterns, along the
2719     lines of Robin Houston's patch (but implemented somewhat differently).
2721     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2722     allow it to read and process whole directories in Win32. This code was
2723     contributed by Lionel Fourquaux; it has not been tested by me.
2725     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2726     used to name a group. Names consist of alphanumerics and underscores, and must
2727     be unique. Back references use the syntax (?P=name) and recursive calls use
2728     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2729     numbers. The function pcre_fullinfo() can be used after compilation to extract
2730     a name/number map. There are three relevant calls:
2732     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2733     PCRE_INFO_NAMECOUNT yields the number of entries
2734     PCRE_INFO_NAMETABLE yields a pointer to the map.
2736     The map is a vector of fixed-size entries. The size of each entry depends on
2737     the length of the longest name used. The first two bytes of each entry are the
2738     group number, most significant byte first. There follows the corresponding
2739     name, zero terminated. The names are in alphabetical order.
2741     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2742     case instead of 255. Making it the same both with and without UTF-8 support
2743     means that the same test output works with both.
2745     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2746     calling malloc() with a zero argument.
2748     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2749     optimization. I've improved things by keeping a bitmap of backreferences with
2750     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2751     fact referenced, the optimization can be applied. It is unlikely that a
2752     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2753     the match to follow \n) will appear inside brackets with a number greater than
2754     31, but if it does, any back reference > 31 suppresses the optimization.
2756     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2757     of disabling numbered capturing parentheses. Any opening parenthesis that is
2758     not followed by ? behaves as if it were followed by ?: but named parentheses
2759     can still be used for capturing (and they will acquire numbers in the usual
2760     way).
2762     41. Redesigned the return codes from the match() function into yes/no/error so
2763     that errors can be passed back from deep inside the nested calls. A malloc
2764     failure while inside a recursive subpattern call now causes the
2765     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2767     42. It is now possible to set a limit on the number of times the match()
2768     function is called in a call to pcre_exec(). This facility makes it possible to
2769     limit the amount of recursion and backtracking, though not in a directly
2770     obvious way, because the match() function is used in a number of different
2771     circumstances. The count starts from zero for each position in the subject
2772     string (for non-anchored patterns). The default limit is, for compatibility, a
2773     large number, namely 10 000 000. You can change this in two ways:
2775     (a) When configuring PCRE before making, you can use --with-match-limit=n
2776     to set a default value for the compiled library.
2778     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2779     a different value is set. See 45 below.
2781     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2783     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2784     of things that can be changed at compile time. The first argument specifies
2785     what is wanted and the second points to where the information is to be placed.
2786     The current list of available information is:
2790     The output is an integer that is set to one if UTF-8 support is available;
2791     otherwise it is set to zero.
2795     The output is an integer that it set to the value of the code that is used for
2796     newline. It is either LF (10) or CR (13).
2800     The output is an integer that contains the number of bytes used for internal
2801     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2805     The output is an integer that contains the threshold above which the POSIX
2806     interface uses malloc() for output vectors. See item 31 above.
2810     The output is an unsigned integer that contains the default limit of the number
2811     of match() calls in a pcre_exec() execution. See 42 above.
2813     44. pcretest has been upgraded by the addition of the -C option. This causes it
2814     to extract all the available output from the new pcre_config() function, and to
2815     output it. The program then exits immediately.
2817     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2818     order to support additional features. One way would have been to define
2819     pcre_exec2() (for example) with extra arguments, but this would not have been
2820     extensible, and would also have required all calls to the original function to
2821     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2822     is used for passing in "extra" data from pcre_study().
2824     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2825     contains the following fields:
2827     flags a bitmap indicating which of the following fields are set
2828     study_data opaque data from pcre_study()
2829     match_limit a way of specifying a limit on match() calls for a specific
2830     call to pcre_exec()
2831     callout_data data for callouts (see 49 below)
2833     The flag bits are also defined in pcre.h, and are
2839     The pcre_study() function now returns one of these new pcre_extra blocks, with
2840     the actual study data pointed to by the study_data field, and the
2841     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2842     before. That is, this change is entirely upwards-compatible and requires no
2843     change to existing code.
2845     If you want to pass in additional data to pcre_exec(), you can either place it
2846     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2847     block.
2849     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2850     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2851     times with different match limits, until it finds the minimum value needed for
2852     pcre_exec() to complete. The value is then output. This can be instructive; for
2853     most simple matches the number is quite small, but for pathological cases it
2854     gets very large very quickly.
2856     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2857     returns the size of the data block pointed to by the study_data field in a
2858     pcre_extra block, that is, the value that was passed as the argument to
2859     pcre_malloc() when PCRE was getting memory in which to place the information
2860     created by pcre_study(). The fourth argument should point to a size_t variable.
2861     pcretest has been extended so that this information is shown after a successful
2862     pcre_study() call when information about the compiled regex is being displayed.
2864     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2865     because what follows is always an absolute path. (Later: it turns out that this
2866     is more than cosmetic for MinGW, because it doesn't like empty path
2867     components.)
2869     49. Some changes have been made to the callout feature (see 28 above):
2871     (i) A callout function now has three choices for what it returns:
2873     0 => success, carry on matching
2874     > 0 => failure at this point, but backtrack if possible
2875     < 0 => serious error, return this value from pcre_exec()
2877     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2878     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2879     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2880     use by callout functions. It will never be used by PCRE itself.
2882     (ii) The pcre_extra structure (see 45 above) has a void * field called
2883     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2884     pcre_callout_block structure has a field of the same name. The contents of
2885     the field passed in the pcre_extra structure are passed to the callout
2886     function in the corresponding field in the callout block. This makes it
2887     easier to use the same callout-containing regex from multiple threads. For
2888     testing, the pcretest program has a new data escape
2890     \C*n pass the number n (may be negative) as callout_data
2892     If the callout function in pcretest receives a non-zero value as
2893     callout_data, it returns that value.
2895     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2896     there were some redundant $(CFLAGS) in commands that are now specified as
2897     $(LINK), which already includes $(CFLAGS).
2899     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2900     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2901     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2902     one-byte characters throughout. Note that case-insensitive matching applies
2903     only to characters whose values are less than 256. PCRE doesn't support the
2904     notion of cases for higher-valued characters.
2906     (i) A character class whose characters are all within 0-255 is handled as
2907     a bit map, and the map is inverted for negative classes. Previously, a
2908     character > 255 always failed to match such a class; however it should
2909     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2911     (ii) A negated character class with a single character < 255 is coded as
2912     "not this character" (OP_NOT). This wasn't working properly when the test
2913     character was multibyte, either singly or repeated.
2915     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2916     mode, for example: \x{100}{2,3}.
2918     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2919     singly or repeated) now correctly test multibyte characters. However,
2920     PCRE doesn't recognize any characters with values greater than 255 as
2921     digits, spaces, or word characters. Such characters always match \D, \S,
2922     and \W, and never match \d, \s, or \w.
2924     (v) Classes may now contain characters and character ranges with values
2925     greater than 255. For example: [ab\x{100}-\x{400}].
2927     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2928     PCRE in UTF-8 mode.
2930     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2931     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2932     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2933     value.)
2935     53. The single man page has become too large. I have therefore split it up into
2936     a number of separate man pages. These also give rise to individual HTML pages;
2937     these are now put in a separate directory, and there is an index.html page that
2938     lists them all. Some hyperlinking between the pages has been installed.
2940     54. Added convenience functions for handling named capturing parentheses.
2942     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2943     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2944     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2945     are faulted.
2947     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2948     calling configure. These values are used when compiling the dftables.c program
2949     which is run to generate the source of the default character tables. They
2950     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2951     you will need to set these values.
2953     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2956     Version 3.9 02-Jan-02
2957 nigel 61 ---------------------
2959     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2961     2. If --disable-static was given, the building process failed when trying to
2962     build pcretest and pcregrep. (For some reason it was using libtool to compile
2963     them, which is not right, as they aren't part of the library.)
2966 nigel 59 Version 3.8 18-Dec-01
2967     ---------------------
2969     1. The experimental UTF-8 code was completely screwed up. It was packing the
2970     bytes in the wrong order. How dumb can you get?
2973 nigel 57 Version 3.7 29-Oct-01
2974     ---------------------
2976     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2977     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2978     this didn't happen under Solaris 8, where I normally test things.
2980 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2981     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2982     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2983     this fix an hour or so after the initial 3.7 release.)
2984 nigel 57
2985 nigel 59
2986 nigel 55 Version 3.6 23-Oct-01
2987     ---------------------
2989     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2990     offsets passed as NULL with zero offset count.
2992     2. The config.guess and config.sub files had not been updated when I moved to
2993     the latest autoconf.
2996 nigel 53 Version 3.5 15-Aug-01
2997     ---------------------
2998 nigel 5
2999 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
3000     had been forgotten.
3002     2. By using declared but undefined structures, we can avoid using "void"
3003     definitions in pcre.h while keeping the internal definitions of the structures
3004     private.
3006     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3007     user point of view, this means that both static and shared libraries are built
3008     by default, but this can be individually controlled. More of the work of
3009     handling this static/shared cases is now inside libtool instead of PCRE's make
3010     file.
3012     4. The pcretest utility is now installed along with pcregrep because it is
3013     useful for users (to test regexs) and by doing this, it automatically gets
3014     relinked by libtool. The documentation has been turned into a man page, so
3015     there are now .1, .txt, and .html versions in /doc.
3017     5. Upgrades to pcregrep:
3018     (i) Added long-form option names like gnu grep.
3019     (ii) Added --help to list all options with an explanatory phrase.
3020     (iii) Added -r, --recursive to recurse into sub-directories.
3021     (iv) Added -f, --file to read patterns from a file.
3023     6. pcre_exec() was referring to its "code" argument before testing that
3024     argument for NULL (and giving an error if it was NULL).
3026     7. Upgraded Makefile.in to allow for compiling in a different directory from
3027     the source directory.
3029     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3030     options bits, the pointer it was passed was to an int instead of to an unsigned
3031     long int. This mattered only on 64-bit systems.
3033     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3034     generated) instead of pcre.in, which it its source. Also made the same change
3035     in several of the .c files.
3037     10. A new release of gcc defines printf() as a macro, which broke pcretest
3038     because it had an ifdef in the middle of a string argument for printf(). Fixed
3039     by using separate calls to printf().
3041     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3042     script, to force use of CR or LF instead of \n in the source. On non-Unix
3043     systems, the value can be set in config.h.
3045     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3046     absolute limit. Changed the text of the error message to make this clear, and
3047     likewise updated the man page.
3049     13. The limit of 99 on the number of capturing subpatterns has been removed.
3050     The new limit is 65535, which I hope will not be a "real" limit.
3053 nigel 51 Version 3.4 22-Aug-00
3054     ---------------------
3056     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3058     2. Diagnose condition (?(0) as an error instead of crashing on matching.
3061 nigel 49 Version 3.3 01-Aug-00
3062     ---------------------
3064     1. If an octal character was given, but the value was greater than \377, it
3065     was not getting masked to the least significant bits, as documented. This could
3066     lead to crashes in some systems.
3068     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3069     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3071     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3072     These just pass their arguments on to (pcre_free)(), but they are provided
3073     because some uses of PCRE bind it to non-C systems that can call its functions,
3074     but cannot call free() or pcre_free() directly.
3076     4. Add "make test" as a synonym for "make check". Corrected some comments in
3077     the Makefile.
3079     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3080     Makefile.
3082     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3083     command called pgrep for grepping around the active processes.
3085     7. Added the beginnings of support for UTF-8 character strings.
3087     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3088     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3089     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3090     out for the ar command.)
3093 nigel 47 Version 3.2 12-May-00
3094     ---------------------
3096     This is purely a bug fixing release.
3098     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3099     of ZA. This was just one example of several cases that could provoke this bug,
3100     which was introduced by change 9 of version 2.00. The code for breaking
3101     infinite loops after an iteration that matches an empty string was't working
3102     correctly.
3104     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3105     when matched against abbab (for example). After matching an empty string, it
3106     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3107     caused it to match further down the string than it should.
3109     3. The code contained an inclusion of sys/types.h. It isn't clear why this
3110     was there because it doesn't seem to be needed, and it causes trouble on some
3111     systems, as it is not a Standard C header. It has been removed.
3113     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3114     were reported on the Macintosh. The changes were from
3116     while ((c = *(++ptr)) != 0 && c != '\n');
3117     to
3118     while ((c = *(++ptr)) != 0 && c != '\n') ;
3120     Totally extraordinary, but if that's what it takes...
3122     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3123     available. Added HAVE_BCOPY and an autoconf test for it; if neither
3124     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3125     assumes the way PCRE uses memmove() (always moving upwards).
3127     6. PCRE is being used in one environment where strchr() is not available. There
3128     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3129     faster code anyway.
3132 nigel 45 Version 3.1 09-Feb-00
3133     ---------------------
3135     The only change in this release is the fixing of some bugs in Makefile.in for
3136     the "install" target:
3138     (1) It was failing to install pcreposix.h.
3140     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3143 nigel 43 Version 3.0 01-Feb-00
3144     ---------------------
3145 nigel 41
3146     1. Add support for the /+ modifier to perltest (to output $` like it does in
3147     pcretest).
3149     2. Add support for the /g modifier to perltest.
3151     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3152     matches null strings.
3154     4. Fix perltest so that it doesn't do unwanted things when fed an empty
3155     pattern. Perl treats empty patterns specially - it reuses the most recent
3156     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3157     effect.
3159     5. The POSIX interface was broken in that it was just handing over the POSIX
3160     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3161     required a bigger vector, with some working space on the end. This means that
3162     the POSIX wrapper now has to get and free some memory, and copy the results.
3164 nigel 43 6. Added some simple autoconf support, placing the test data and the
3165     documentation in separate directories, re-organizing some of the
3166     information files, and making it build pcre-config (a GNU standard). Also added
3167     libtool support for building PCRE as a shared library, which is now the
3168     default.
3169 nigel 41
3170 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3171     09 are not valid octal constants. Single digits will be used for minor values
3172     less than 10.
3174     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3175     existing programs that set these in the POSIX interface can use PCRE without
3176     modification.
3178     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3179     return all that pcre_info() returns, plus additional data. The pcre_info()
3180     function is retained for compatibility, but is considered to be obsolete.
3182     10. Added experimental recursion feature (?R) to handle one common case that
3183     Perl 5.6 will be able to do with (?p{...}).
3185     11. Added support for POSIX character classes like [:alpha:], which Perl is
3186     adopting.
3189 nigel 39 Version 2.08 31-Aug-99
3190     ----------------------
3192     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3193     trying to match at the startoffset position, but instead was moving forward to
3194     the next newline as if a previous match had failed.
3196     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3197     and could get into a loop if a null string was matched other than at the start
3198     of the subject.
3200     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3201     be distinguished at compile time, and for completeness also added PCRE_DATE.
3203     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3204     in GnuWin32 environments.
3207 nigel 37 Version 2.07 29-Jul-99
3208     ----------------------
3210     1. The documentation is now supplied in plain text form and HTML as well as in
3211     the form of man page sources.
3213     2. C++ compilers don't like assigning (void *) values to other pointer types.
3214     In particular this affects malloc(). Although there is no problem in Standard
3215     C, I've put in casts to keep C++ compilers happy.
3217     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3218     should be (const char *).
3220     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3221     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3222     However, I haven't made this a standard facility. The documentation doesn't
3223     mention it, and the Makefile doesn't support it.
3225     5. The Makefile now contains an "install" target, with editable destinations at
3226     the top of the file. The pcretest program is not installed.
3228     6. pgrep -V now gives the PCRE version number and date.
3230     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3231     causing the entire string to be ignored, instead of just the last character.
3233     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3234     non-matching string, it can take a very, very long time, even for strings of
3235     quite modest length, because of the nested recursion. PCRE now does better in
3236     some of these cases. It does this by remembering the last required literal
3237     character in the pattern, and pre-searching the subject to ensure it is present
3238     before running the real match. In other words, it applies a heuristic to detect
3239     some types of certain failure quickly, and in the above example, if presented
3240     with a string that has no trailing " it gives "no match" very quickly.
3242     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3243     other alternatives are tried instead.
3246 nigel 35 Version 2.06 09-Jun-99
3247     ----------------------
3249     1. Change pcretest's output for amount of store used to show just the code
3250     space, because the remainder (the data block) varies in size between 32-bit and
3251     64-bit systems.
3253     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3254     start matching at. This allows lookbehinds to work when searching for multiple
3255     occurrences in a string.
3257     3. Added additional options to pcretest for testing multiple occurrences:
3259     /+ outputs the rest of the string that follows a match
3260     /g loops for multiple occurrences, using the new startoffset argument
3261     /G loops for multiple occurrences by passing an incremented pointer
3263     4. PCRE wasn't doing the "first character" optimization for patterns starting
3264     with \b or \B, though it was doing it for other lookbehind assertions. That is,
3265     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3266     the letter 'x'. On long subject strings, this gives a significant speed-up.
3269 nigel 33 Version 2.05 21-Apr-99
3270     ----------------------
3272     1. Changed the type of magic_number from int to long int so that it works
3273     properly on 16-bit systems.
3275     2. Fixed a bug which caused patterns starting with .* not to work correctly
3276     when the subject string contained newline characters. PCRE was assuming
3277     anchoring for such patterns in all cases, which is not correct because .* will
3278     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3279     DOTALL is set at top level; otherwise it knows that patterns starting with .*
3280     must be retried after every newline in the subject.
3283 nigel 31 Version 2.04 18-Feb-99
3284     ----------------------
3286     1. For parenthesized subpatterns with repeats whose minimum was zero, the
3287     computation of the store needed to hold the pattern was incorrect (too large).
3288     If such patterns were nested a few deep, this could multiply and become a real
3289     problem.
3291     2. Added /M option to pcretest to show the memory requirement of a specific
3292     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3294     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3295     compiled in such a way that the backtracking after subsequent failure was
3296     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3297     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3300 nigel 29 Version 2.03 02-Feb-99
3301     ----------------------
3303     1. Fixed typo and small mistake in man page.
3305 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
3306     LICENCE file containing the conditions.
3307 nigel 29
3308     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3309     Perl, that is the internal \ allows the delimiter to be included in the
3310     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3311     the final delimiter, add \ to the end of the pattern (to test the error).
3313     4. Added the convenience functions for extracting substrings after a successful
3314     match. Updated pcretest to make it able to test these functions.
3317 nigel 27 Version 2.02 14-Jan-99
3318     ----------------------
3320     1. Initialized the working variables associated with each extraction so that
3321     their saving and restoring doesn't refer to uninitialized store.
3323     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3324     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3325     fix the problem.
3327     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3328     calls, and wasn't printing the correct value for compiling calls. Increased the
3329     default value of LOOPREPEAT, and the number of significant figures in the
3330     times.
3332     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3334     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3335     a building problem on Windows NT with a FAT file system.
3338 nigel 25 Version 2.01 21-Oct-98
3339     ----------------------
3341     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3342     to character tables built by pcre_maketables() in the current locale. If NULL
3343     is passed, the default tables are used.
3346 nigel 23 Version 2.00 24-Sep-98
3347 nigel 21 ----------------------
3349 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3350     it any more.
3352     2. Allow quantification of (?>) groups, and make it work correctly.
3354     3. The first character computation wasn't working for (?>) groups.
3356     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3357     end of the subject) and add 5.005's \z, which really does match only at the
3358     very end of the subject.
3360     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3362     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3363     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3364     localized options. All options to pcre_study() were also removed.
3366     7. Add other new features from 5.005:
3368     $(?<= positive lookbehind
3369     $(?<! negative lookbehind
3370     (?imsx-imsx) added the unsetting capability
3371     such a setting is global if at outer level; local otherwise
3372     (?imsx-imsx:) non-capturing groups with option setting
3373     (?(cond)re|re) conditional pattern matching
3375     A backreference to itself in a repeated group matches the previous
3376     captured string.
3378     8. General tidying up of studying (both automatic and via "study")
3379     consequential on the addition of new assertions.
3381     9. As in 5.005, unlimited repeated groups that could match an empty substring
3382     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3383     runtime if any iteration does actually match an empty substring.
3385     10. Include the RunTest script in the distribution.
3387     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3388     discrepancies, some of which were old and were also with respect to 5.004. They
3389     have now been fixed.
3392     Version 1.09 28-Apr-98
3393     ----------------------
3395 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3396     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3397     program crashes, or just wrong answers. This did not apply to negated classes
3398     containing more than one character, or to minima other than one.
3401 nigel 19 Version 1.08 27-Mar-98
3402     ----------------------
3404     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3406     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3407     latter must appear before anything that relies on it in the pattern.
3410 nigel 17 Version 1.07 16-Feb-98
3411     ----------------------
3413     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3414     repeat of a potentially empty string).
3417 nigel 15 Version 1.06 23-Jan-98
3418     ----------------------
3420     1. Added Markus Oberhumer's little patches for C++.
3422     2. Literal strings longer than 255 characters were broken.
3425 nigel 13 Version 1.05 23-Dec-97
3426     ----------------------
3428     1. Negated character classes containing more than one character were failing if
3429     PCRE_CASELESS was set at run time.
3432 nigel 11 Version 1.04 19-Dec-97
3433     ----------------------
3435     1. Corrected the man page, where some "const" qualifiers had been omitted.
3437     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3438     input syntax.
3440     3. Fixed memory leak which occurred when a regex with back references was
3441     matched with an offsets vector that wasn't big enough. The temporary memory
3442     that is used in this case wasn't being freed if the match failed.
3444     4. Tidied pcretest to ensure it frees memory that it gets.
3446     5. Temporary memory was being obtained in the case where the passed offsets
3447     vector was exactly big enough.
3449     6. Corrected definition of offsetof() from change 5 below.
3451     7. I had screwed up change 6 below and broken the rules for the use of
3452     setjmp(). Now fixed.
3455 nigel 9 Version 1.03 18-Dec-97
3456     ----------------------
3458     1. A erroneous regex with a missing opening parenthesis was correctly
3459     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3460     on some systems.
3462     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3463     it was reported that one broken compiler failed on the former because "code" is
3464     also an independent variable.
3466     3. The erroneous regex a[]b caused an array overrun reference.
3468     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3469     fail on data ending with that character. (It was going on too far, and checking
3470     the next character, typically a binary zero.) This was specific to the
3471     optimized code for single-character negative classes.
3473     5. Added a contributed patch from the TIN world which does the following:
3475     + Add an undef for memmove, in case the the system defines a macro for it.
3477     + Add a definition of offsetof(), in case there isn't one. (I don't know
3478     the reason behind this - offsetof() is part of the ANSI standard - but
3479     it does no harm).
3481     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3482     most of the places where whitespace preceded '#'. I have given up and
3483     allowed the remaining 2 cases to be at the margin.
3485     + Rename some variables in pcre to eliminate shadowing. This seems very
3486     pedantic, but does no harm, of course.
3488     6. Moved the call to setjmp() into its own function, to get rid of warnings
3489     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3491     7. Constructs such as \d{8,} were compiling into the equivalent of
3492 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3493 nigel 9 outcome, but in this particular case used more store than had been allocated,
3494     which caused the bug to be discovered because it threw up an internal error.
3496     8. The debugging code in both pcre and pcretest for outputting the compiled
3497     form of a regex was going wrong in the case of back references followed by
3498     curly-bracketed repeats.
3501 nigel 7 Version 1.02 12-Dec-97
3502     ----------------------
3504     1. Typos in pcre.3 and comments in the source fixed.
3506     2. Applied a contributed patch to get rid of places where it used to remove
3507     'const' from variables, and fixed some signed/unsigned and uninitialized
3508     variable warnings.
3510     3. Added the "runtest" target to Makefile.
3512     4. Set default compiler flag to -O2 rather than just -O.
3515 nigel 5 Version 1.01 19-Nov-97
3516     ----------------------
3518     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3519     like /([ab]*)*/, that is, for classes with more than one character in them.
3521     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3522     as /((?>a*))*/ (a PCRE_EXTRA facility).
3525     Version 1.00 18-Nov-97
3526     ----------------------
3528     1. Added compile-time macros to support systems such as SunOS4 which don't have
3529     memmove() or strerror() but have other things that can be used instead.
3531     2. Arranged that "make clean" removes the executables.
3534 nigel 3 Version 0.99 27-Oct-97
3535     ----------------------
3537     1. Fixed bug in code for optimizing classes with only one character. It was
3538     initializing a 32-byte map regardless, which could cause it to run off the end
3539     of the memory it had got.
3541     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3544     Version 0.98 22-Oct-97
3545     ----------------------
3547     1. Fixed bug in code for handling temporary memory usage when there are more
3548     back references than supplied space in the ovector. This could cause segfaults.
3551     Version 0.97 21-Oct-97
3552     ----------------------
3554     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3556     2. Optimized negated single characters not to use a bit map.
3558     3. Brought error texts together as macro definitions; clarified some of them;
3559     fixed one that was wrong - it said "range out of order" when it meant "invalid
3560     escape sequence".
3562     4. Changed some char * arguments to const char *.
3564     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3566     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3567     pcretest.
3570     Version 0.96 16-Oct-97
3571     ----------------------
3573     1. Added a simple "pgrep" utility to the distribution.
3575     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3576     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3577     where "ddd" means "one or more decimal digits".
3579     3. Fixed serious bug. If a pattern had a back reference, but the call to
3580     pcre_exec() didn't supply a large enough ovector to record the related
3581     identifying subpattern, the match always failed. PCRE now remembers the number
3582     of the largest back reference, and gets some temporary memory in which to save
3583     the offsets during matching if necessary, in order to ensure that
3584     backreferences always work.
3586     4. Increased the compatibility with Perl in a number of ways:
3588     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3589     to request this handling. The option can be set at compile or exec time.
3591     (b) $ matches before a terminating newline by default; an option
3592     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3593     mode). The option can be set at compile or exec time.
3595     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3596     the same as Perl's. If the decimal number it represents is less than 10
3597     or there aren't that many previous left capturing parentheses, an octal
3598     escape is read. Inside a character class, it's always an octal escape,
3599     even if it is a single digit.
3601     (d) An escaped but undefined alphabetic character is taken as a literal,
3602     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3603     escapes.
3605     (e) {0} is now permitted. (The previous item is removed from the compiled
3606     pattern).
3608     5. Changed all the names of code files so that the basic parts are no longer
3609     than 10 characters, and abolished the teeny "globals.c" file.
3611     6. Changed the handling of character classes; they are now done with a 32-byte
3612     bit map always.
3614     7. Added the -d and /D options to pcretest to make it possible to look at the
3615     internals of compilation without having to recompile pcre.
3618     Version 0.95 23-Sep-97
3619     ----------------------
3621     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3622     \x20 at the start of a run of normal characters. These were being treated as
3623     real characters, instead of the source characters being re-checked.
3626     Version 0.94 18-Sep-97
3627     ----------------------
3629     1. The functions are now thread-safe, with the caveat that the global variables
3630     containing pointers to malloc() and free() or alternative functions are the
3631     same for all threads.
3633     2. Get pcre_study() to generate a bitmap of initial characters for non-
3634     anchored patterns when this is possible, and use it if passed to pcre_exec().
3637     Version 0.93 15-Sep-97
3638     ----------------------
3640     1. /(b)|(:+)/ was computing an incorrect first character.
3642     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3643     but not actually doing anything yet.
3645     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3646     as Perl does (e.g. [-az] or [az-]).
3648     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3649     all possible positions.
3651     5. Split up into different modules to avoid including unneeded functions in a
3652     compiled binary. However, compile and exec are still in one module. The "study"
3653     function is split off.
3655     6. The character tables are now in a separate module whose source is generated
3656     by an auxiliary program - but can then be edited by hand if required. There are
3657     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3658     toupper() in the code.
3660     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3661     make them global. Abolish the function for setting them, as the caller can now
3662     set them directly.
3665     Version 0.92 11-Sep-97
3666     ----------------------
3668     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3669     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3671     2. Caseless matching was not working in character classes if the characters in
3672     the pattern were in upper case.
3674     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3676     4. Make PCRE_ANCHORED public and accept as a compile option.
3678     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3679     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3680     pass them.
3682     6. Give an error if bad option bits passed at compile or run time.
3684     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3685     pcretest to cause it to pass that flag.
3687     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3688     options, and the first character, if set.
3690     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3693     Version 0.91 10-Sep-97
3694     ----------------------
3696     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3697     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3699     2. PCRE was looping on encountering an indefinitely repeated back reference to
3700     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3701     Perl does - treats the match as successful.
3703     ****


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