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Revision 471 - (hide annotations) (download)
Fri Dec 11 15:11:55 2009 UTC (5 years, 3 months ago) by ph10
File size: 175088 byte(s)
Fix study bug with single-branch conditions, including (DEFINE).

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     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     subpatterns).
13 ph10 469 Version 8.00 19-Oct-09
14 ph10 418 ----------------------
16     1. The table for translating pcre_compile() error codes into POSIX error codes
17 ph10 461 was out-of-date, and there was no check on the pcre_compile() error code
18     being within the table. This could lead to an OK return being given in
19 ph10 418 error.
20 ph10 461
21     2. Changed the call to open a subject file in pcregrep from fopen(pathname,
22     "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
23     in a Windows environment.
25 ph10 420 3. The pcregrep --count option prints the count for each file even when it is
26     zero, as does GNU grep. However, pcregrep was also printing all files when
27     --files-with-matches was added. Now, when both options are given, it prints
28     counts only for those files that have at least one match. (GNU grep just
29 ph10 461 prints the file name in this circumstance, but including the count seems
30     more useful - otherwise, why use --count?) Also ensured that the
31 ph10 420 combination -clh just lists non-zero counts, with no names.
32 ph10 461
33     4. The long form of the pcregrep -F option was incorrectly implemented as
34     --fixed_strings instead of --fixed-strings. This is an incompatible change,
35     but it seems right to fix it, and I didn't think it was worth preserving
36     the old behaviour.
38     5. The command line items --regex=pattern and --regexp=pattern were not
39 ph10 422 recognized by pcregrep, which required --regex pattern or --regexp pattern
40 ph10 461 (with a space rather than an '='). The man page documented the '=' forms,
41 ph10 422 which are compatible with GNU grep; these now work.
42 ph10 461
43     6. No libpcreposix.pc file was created for pkg-config; there was just
44 ph10 423 libpcre.pc and libpcrecpp.pc. The omission has been rectified.
45 ph10 461
46 ph10 425 7. Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
47 ph10 461 when UCP support is not needed, by modifying the Python script that
48 ph10 425 generates it from Unicode data files. This should not matter if the module
49     is correctly used as a library, but I received one complaint about 50K of
50     unwanted data. My guess is that the person linked everything into his
51     program rather than using a library. Anyway, it does no harm.
52 ph10 461
53 ph10 426 8. A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
54 ph10 461 was a minimum greater than 1 for a wide character in a possessive
55 ph10 431 repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
56     which had an unlimited repeat of a nested, fixed maximum repeat of a wide
57     character. Chaos in the form of incorrect output or a compiling loop could
58     result.
59 ph10 461
60 ph10 426 9. The restrictions on what a pattern can contain when partial matching is
61 ph10 461 requested for pcre_exec() have been removed. All patterns can now be
62 ph10 426 partially matched by this function. In addition, if there are at least two
63 ph10 435 slots in the offset vector, the offset of the earliest inspected character
64     for the match and the offset of the end of the subject are set in them when
65 ph10 461 PCRE_ERROR_PARTIAL is returned.
67 ph10 428 10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
68     synonymous with PCRE_PARTIAL, for backwards compatibility, and
69     PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
70 ph10 462 and may be more useful for multi-segment matching.
71 ph10 461
72     11. Partial matching with pcre_exec() is now more intuitive. A partial match
73     used to be given if ever the end of the subject was reached; now it is
74     given only if matching could not proceed because another character was
75     needed. This makes a difference in some odd cases such as Z(*FAIL) with the
76     string "Z", which now yields "no match" instead of "partial match". In the
77     case of pcre_dfa_exec(), "no match" is given if every matching path for the
78     final character ended with (*FAIL).
80 ph10 428 12. Restarting a match using pcre_dfa_exec() after a partial match did not work
81 ph10 461 if the pattern had a "must contain" character that was already found in the
82 ph10 428 earlier partial match, unless partial matching was again requested. For
83     example, with the pattern /dog.(body)?/, the "must contain" character is
84     "g". If the first part-match was for the string "dog", restarting with
85 ph10 435 "sbody" failed. This bug has been fixed.
86 ph10 461
87     13. The string returned by pcre_dfa_exec() after a partial match has been
88     changed so that it starts at the first inspected character rather than the
89     first character of the match. This makes a difference only if the pattern
90     starts with a lookbehind assertion or \b or \B (\K is not supported by
91     pcre_dfa_exec()). It's an incompatible change, but it makes the two
92 ph10 435 matching functions compatible, and I think it's the right thing to do.
93 ph10 461
94 ph10 435 14. Added a pcredemo man page, created automatically from the pcredemo.c file,
95 ph10 461 so that the demonstration program is easily available in environments where
96     PCRE has not been installed from source.
98 ph10 435 15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
99 ph10 430 libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
100     library.
101 ph10 461
102 ph10 435 16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
103 ph10 432 It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
104 ph10 461 is not the first non-POSIX option to be added. Clearly some people find
105 ph10 433 these options useful.
106 ph10 461
107     17. If a caller to the POSIX matching function regexec() passes a non-zero
108 ph10 438 value for nmatch with a NULL value for pmatch, the value of
109 ph10 461 nmatch is forced to zero.
111 ph10 437 18. RunGrepTest did not have a test for the availability of the -u option of
112 ph10 461 the diff command, as RunTest does. It now checks in the same way as
113 ph10 437 RunTest, and also checks for the -b option.
114 ph10 461
115 ph10 438 19. If an odd number of negated classes containing just a single character
116     interposed, within parentheses, between a forward reference to a named
117 ph10 461 subpattern and the definition of the subpattern, compilation crashed with
118     an internal error, complaining that it could not find the referenced
119 ph10 438 subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
120 ph10 461 [The bug was that it was starting one character too far in when skipping
121     over the character class, thus treating the ] as data rather than
122     terminating the class. This meant it could skip too much.]
124 ph10 442 20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
125 ph10 461 /g option in pcretest when the pattern contains \K, which makes it possible
126 ph10 442 to have an empty string match not at the start, even when the pattern is
127 ph10 461 anchored. Updated pcretest and pcredemo to use this option.
129 ph10 446 21. If the maximum number of capturing subpatterns in a recursion was greater
130 ph10 461 than the maximum at the outer level, the higher number was returned, but
131     with unset values at the outer level. The correct (outer level) value is
132 ph10 446 now given.
133 ph10 461
134 ph10 447 22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
135     PCRE did not set those parentheses (unlike Perl). I have now found a way to
136     make it do so. The string so far is captured, making this feature
137     compatible with Perl.
138 ph10 461
139     23. The tests have been re-organized, adding tests 11 and 12, to make it
140 ph10 448 possible to check the Perl 5.10 features against Perl 5.10.
141 ph10 461
142 ph10 454 24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
143 ph10 461 pattern matches a fixed length string. PCRE did not allow this; now it
144     does. Neither allows recursion.
146     25. I finally figured out how to implement a request to provide the minimum
147     length of subject string that was needed in order to match a given pattern.
148     (It was back references and recursion that I had previously got hung up
149     on.) This code has now been added to pcre_study(); it finds a lower bound
150 ph10 455 to the length of subject needed. It is not necessarily the greatest lower
151     bound, but using it to avoid searching strings that are too short does give
152     some useful speed-ups. The value is available to calling programs via
153     pcre_fullinfo().
154 ph10 461
155 ph10 455 26. While implementing 25, I discovered to my embarrassment that pcretest had
156     not been passing the result of pcre_study() to pcre_dfa_exec(), so the
157     study optimizations had never been tested with that matching function.
158     Oops. What is worse, even when it was passed study data, there was a bug in
159     pcre_dfa_exec() that meant it never actually used it. Double oops. There
160     were also very few tests of studied patterns with pcre_dfa_exec().
161 ph10 461
162 ph10 457 27. If (?| is used to create subpatterns with duplicate numbers, they are now
163     allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
164     on the other side of the coin, they are no longer allowed to have different
165     names, because these cannot be distinguished in PCRE, and this has caused
166     confusion. (This is a difference from Perl.)
167 ph10 461
168     28. When duplicate subpattern names are present (necessarily with different
169     numbers, as required by 27 above), and a test is made by name in a
170     conditional pattern, either for a subpattern having been matched, or for
171     recursion in such a pattern, all the associated numbered subpatterns are
172 ph10 459 tested, and the overall condition is true if the condition is true for any
173     one of them. This is the way Perl works, and is also more like the way
174     testing by number works.
175 ph10 418
176 ph10 461
177 ph10 412 Version 7.9 11-Apr-09
178 ph10 376 ---------------------
180 ph10 392 1. When building with support for bzlib/zlib (pcregrep) and/or readline
181 ph10 376 (pcretest), all targets were linked against these libraries. This included
182     libpcre, libpcreposix, and libpcrecpp, even though they do not use these
183     libraries. This caused unwanted dependencies to be created. This problem
184 ph10 392 has been fixed, and now only pcregrep is linked with bzlib/zlib and only
185 ph10 376 pcretest is linked with readline.
186 ph10 392
187 ph10 376 2. The "typedef int BOOL" in pcre_internal.h that was included inside the
188     "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
189     moved outside it again, because FALSE and TRUE are already defined in AIX,
190     but BOOL is not.
191 ph10 392
192     3. The pcre_config() function was treating the PCRE_MATCH_LIMIT and
193 ph10 409 PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
194 ph10 392
195 ph10 376 4. The pcregrep documentation said spaces were inserted as well as colons (or
196     hyphens) following file names and line numbers when outputting matching
197 ph10 392 lines. This is not true; no spaces are inserted. I have also clarified the
198 ph10 376 wording for the --colour (or --color) option.
199 ph10 392
200 ph10 378 5. In pcregrep, when --colour was used with -o, the list of matching strings
201     was not coloured; this is different to GNU grep, so I have changed it to be
202     the same.
203 ph10 392
204 ph10 378 6. When --colo(u)r was used in pcregrep, only the first matching substring in
205 ph10 392 each matching line was coloured. Now it goes on to look for further matches
206     of any of the test patterns, which is the same behaviour as GNU grep.
208     7. A pattern that could match an empty string could cause pcregrep to loop; it
209     doesn't make sense to accept an empty string match in pcregrep, so I have
210 ph10 379 locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
211     seems to be how GNU grep behaves.
212 ph10 392
213 ph10 380 8. The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
214 ph10 392 start or after a newline", because the conditional assertion was not being
215     correctly handled. The rule now is that both the assertion and what follows
216     in the first alternative must satisfy the test.
218 ph10 405 9. If auto-callout was enabled in a pattern with a conditional group whose
219 ph10 399 condition was an assertion, PCRE could crash during matching, both with
220     pcre_exec() and pcre_dfa_exec().
221 ph10 392
222     10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
223     used for matching.
225     11. Unicode property support in character classes was not working for
226 ph10 385 characters (bytes) greater than 127 when not in UTF-8 mode.
227 ph10 388
228 ph10 392 12. Added the -M command line option to pcretest.
230 ph10 388 14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
231 ph10 389
232     15. Added the PCRE_NO_START_OPTIMIZE match-time option.
233 ph10 390
234 ph10 392 16. Added comments and documentation about mis-use of no_arg in the C++
235 ph10 390 wrapper.
236 ph10 392
237 ph10 391 17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
238 ph10 392 from Martin Jerabek that uses macro names for all relevant character and
239 ph10 391 string constants.
240 ph10 405
241 ph10 393 18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
242     SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
243 ph10 405 SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
244     these, but not everybody uses configure.
246     19. A conditional group that had only one branch was not being correctly
247     recognized as an item that could match an empty string. This meant that an
248     enclosing group might also not be so recognized, causing infinite looping
249     (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
250     with the subject "ab", where knowledge that the repeated group can match
251 ph10 396 nothing is needed in order to break the loop.
252 ph10 405
253 ph10 397 20. If a pattern that was compiled with callouts was matched using pcre_dfa_
254 ph10 405 exec(), but without supplying a callout function, matching went wrong.
256     21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
257     leak if the size of the offset vector was greater than 30. When the vector
258     is smaller, the saved offsets during recursion go onto a local stack
259     vector, but for larger vectors malloc() is used. It was failing to free
260     when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
261 ph10 400 error, in fact).
262 ph10 405
263 ph10 402 22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
264 ph10 405 heapframe that is used only when UTF-8 support is enabled. This caused no
265     problem, but was untidy.
266 ph10 376
267 ph10 405 23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
268     CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
269     included within another project.
270 ph10 411
271 ph10 407 24. Steven Van Ingelgem's patches to add more options to the CMake support,
272     slightly modified by me:
273 ph10 411
274     (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
275     not building pcregrep.
277 ph10 407 (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
278 ph10 411 if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
280 ph10 408 25. Forward references, both numeric and by name, in patterns that made use of
281     duplicate group numbers, could behave incorrectly or give incorrect errors,
282     because when scanning forward to find the reference group, PCRE was not
283     taking into account the duplicate group numbers. A pattern such as
284     ^X(?3)(a)(?|(b)|(q))(Y) is an example.
285 ph10 411
286     26. Changed a few more instances of "const unsigned char *" to USPTR, making
287     the feature of a custom pointer more persuasive (as requested by a user).
288 ph10 416
289 ph10 411 27. Wrapped the definitions of fileno and isatty for Windows, which appear in
290 ph10 416 pcretest.c, inside #ifndefs, because it seems they are sometimes already
291     pre-defined.
292 ph10 392
293 ph10 416 28. Added support for (*UTF8) at the start of a pattern.
295 ph10 413 29. Arrange for flags added by the "release type" setting in CMake to be shown
296     in the configuration summary.
297 ph10 405
298 ph10 411
299 ph10 374 Version 7.8 05-Sep-08
300 ph10 349 ---------------------
302     1. Replaced UCP searching code with optimized version as implemented for Ad
303     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
304 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
305     to 5 times on some simple patterns that I tested. Permission was given to
306     distribute the MultiStage2.py script that generates the tables (it's not in
307     the tarball, but is in the Subversion repository).
308 ph10 349
309 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
310     scripts.
311 ph10 358
312 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
313     a group with a zero qualifier. The result of the study could be incorrect,
314 ph10 358 or the function might crash, depending on the pattern.
316     4. Caseless matching was not working for non-ASCII characters in back
317 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
318 ph10 358 It now works when Unicode Property Support is available.
320 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
321     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
322     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
323 ph10 358 truncation.
324 ph10 349
325 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
327 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
328     pointers, in case they are 64-bit values.
329 ph10 371
330     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
331     test 2 if it fails.
333 ph10 359 9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
334 ph10 371 and a #define of that name to empty if it is not externally set. This is to
335     allow users of MSVC to set it if necessary.
337     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
338 ph10 359 the convenience functions in the pcre_get.c source file.
339 ph10 371
340 ph10 360 11. An option change at the start of a pattern that had top-level alternatives
341     could cause overwriting and/or a crash. This command provoked a crash in
342 ph10 371 some environments:
344     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
346 ph10 360 This potential security problem was recorded as CVE-2008-2371.
347 ph10 371
348 ph10 361 12. For a pattern where the match had to start at the beginning or immediately
349     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
350 ph10 371 pcre_dfa_exec() could read past the end of the passed subject if there was
351 ph10 361 no match. To help with detecting such bugs (e.g. with valgrind), I modified
352     pcretest so that it places the subject at the end of its malloc-ed buffer.
353 ph10 371
354 ph10 364 13. The change to pcretest in 12 above threw up a couple more cases when pcre_
355 ph10 371 exec() might read past the end of the data buffer in UTF-8 mode.
357 ph10 364 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
358 ph10 371 the data contained the byte 0x85 as part of a UTF-8 character within its
359     first line. This applied both to normal and DFA matching.
361 ph10 366 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
362 ph10 371 /^[^d]*?$/8 failed to match "abc".
363 ph10 351
364 ph10 371 16. Added a missing copyright notice to pcrecpp_internal.h.
366     17. Make it more clear in the documentation that values returned from
367 ph10 368 pcre_exec() in ovector are byte offsets, not character counts.
368 ph10 357
369 ph10 371 18. Tidied a few places to stop certain compilers from issuing warnings.
370 ph10 368
371 ph10 373 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
372     supplied by Stefan Weber. I made a further small update for 7.8 because
373 ph10 374 there is a change of source arrangements: the pcre_searchfuncs.c module is
374     replaced by pcre_ucd.c.
375 ph10 371
376 ph10 373
377 ph10 347 Version 7.7 07-May-08
378 ph10 321 ---------------------
380     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
381 ph10 345 a string to a long long, pretend we don't even have a long long." This is
382 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
383 ph10 345
384 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
385     pre-7.6 versions, which defined a global no_arg variable instead of putting
386 ph10 332 it in the RE class. (See also #8 below.)
387 ph10 345
388     3. Remove a line of dead code, identified by coverity and reported by Nuno
389     Lopes.
391 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
392 ph10 321
393 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
394 ph10 345 of files, instead of just to the final components.
396 ph10 324 (2) If there was more than one level of directory, the subdirectories were
397     skipped unless they satisfied the include/exclude conditions. This is
398     inconsistent with GNU grep (and could even be seen as contrary to the
399     pcregrep specification - which I improved to make it absolutely clear).
400     The action now is always to scan all levels of directory, and just
401     apply the include/exclude patterns to regular files.
402 ph10 345
403 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
404 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
406 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
407 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
408 ph10 326 doesn't support NULs in patterns.
409 ph10 345
410     7. Added some missing "const"s to declarations of static tables in
411     pcre_compile.c and pcre_dfa_exec.c.
413 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
414 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
415 ph10 345 first patch. And a third patch - this was a messy problem.)
416 ph10 321
417 ph10 345 9. Applied Craig's patch to remove the use of push_back().
419 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
420     matching function regexec().
421 ph10 345
422     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
423     which, however, unlike Perl's \g{...}, are subroutine calls, not back
424 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
425     Oniguruma does).
426 ph10 345
427     12. Previously, a group with a zero repeat such as (...){0} was completely
428 ph10 335 omitted from the compiled regex. However, this means that if the group
429     was called as a subroutine from elsewhere in the pattern, things went wrong
430 ph10 345 (an internal error was given). Such groups are now left in the compiled
431     pattern, with a new opcode that causes them to be skipped at execution
432 ph10 335 time.
433 ph10 345
434 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
435     to the way PCRE behaves:
436 ph10 345
437 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
438 ph10 345
439     (b) A back reference to an unmatched subpattern matches an empty string
440 ph10 336 (Perl fails the current match path).
441 ph10 345
442 ph10 341 (c) A data ] in a character class must be notated as \] because if the
443 ph10 345 first data character in a class is ], it defines an empty class. (In
444 ph10 341 Perl it is not possible to have an empty class.) The empty class []
445     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
446     The negative empty class [^] matches any one character, independently
447     of the DOTALL setting.
448 ph10 345
449     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
450 ph10 340 non-existent subpattern following a character class starting with ']' and
451     containing () gave an internal compiling error instead of "reference to
452     non-existent subpattern". Fortunately, when the pattern did exist, the
453 ph10 345 compiled code was correct. (When scanning forwards to check for the
454 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
455 ph10 345 the class, so got the count wrong. When actually compiling, the reference
456 ph10 340 was subsequently set up correctly.)
457 ph10 345
458 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
459 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
460     other assertions are supported. I have made pcre_dfa_exec() support
461     (*FAIL).
463 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
464 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
465     cannot be changed at match time, I realized I could make a small
466     improvement to matching performance by compiling OP_ALLANY instead of
467     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
468     on the OP_ANY path.
470     17. Compiling pcretest on Windows with readline support failed without the
471 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
472 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
474 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
475 ph10 345 ncurses library to be included for pcretest when ReadLine support is
476     requested, but also to allow for it to be overridden. This patch came from
477     Daniel Bergström.
478 ph10 347
479 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
480 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
481     any errors with the current Unicode tables. Thanks to Peter Kankowski for
482     spotting this.
483 ph10 324
484 ph10 332
485 ph10 319 Version 7.6 28-Jan-08
486 ph10 300 ---------------------
488 ph10 302 1. A character class containing a very large number of characters with
489     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
490     overflow.
491 ph10 309
492     2. Patch to cut out the "long long" test in pcrecpp_unittest when
493     HAVE_LONG_LONG is not defined.
495 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
496 ph10 304 bring them up to date and include new features. This patch includes:
497 ph10 309
498 ph10 304 - Fixed PH's badly added libz and libbz2 support.
499     - Fixed a problem with static linking.
500 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
501 ph10 304 - Fixed dftables problem and added an option.
502     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
504     - Added readline support for pcretest.
505 ph10 309 - Added an listing of the option settings after cmake has run.
507 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
508     "pcre.dll" under mingw when using Configure/Make. I added stuff to
509     Makefile.am that cause it to include this special target, without
510     affecting anything else. Note that the same mingw target plus all
511     the other distribution libraries and programs are now supported
512     when configuring with CMake (see 6 below) instead of with
513     Configure/Make.
514 ph10 309
515 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
516     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
517 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
518     solves the problem, but it does no harm.
519 ph10 313
520 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
521 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
522 ph10 314 with CMake, and also correct the comment about stack recursion.
523 ph10 313
524 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
525 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
526     of a program that users should build themselves after PCRE is installed, so
527     building it automatically is not really right. What is more, it gave
528 ph10 312 trouble in some build environments.
529 ph10 300
530 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
531 ph10 308
532 ph10 319
533 ph10 298 Version 7.5 10-Jan-08
534 ph10 263 ---------------------
536     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
537     values in parens when parsing an RE using the C++ wrapper."
538 ph10 286
539 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
540     Characters greater than 255 were excluded from the class instead of being
541     included.
542 ph10 286
543     3. The same bug as (2) above applied to negated POSIX classes such as
544 ph10 265 [:^space:].
545 ph10 286
546 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
547     defined or documented. It seems to have been a typo for PCRE_STATIC, so
548 ph10 286 I have changed it.
550 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
551 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
552     first named subpattern whose name started with "a" (in other words, the
553 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
554     expected" is now given for (?&) (a zero-length name), and this patch also
555     makes it give the same error for \k'' (previously it complained that that
556     was a reference to a non-existent subpattern).
557 ph10 286
558 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
559 ph10 286 this is right because (?- can be followed by option settings as well as by
560 ph10 269 digits. I have, however, made the messages clearer.
561 ph10 286
562 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
563     than the number used in the conditional) now cause a compile-time error.
564     This is actually not compatible with Perl, which accepts such patterns, but
565     treats the conditional as always being FALSE (as PCRE used to), but it
566     seems to me that giving a diagnostic is better.
567 ph10 286
568 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
569 ph10 275 and messages.
570 ph10 286
571     9. Fix two occurrences of "backslash" in comments that should have been
572     "backspace".
574     10. Remove two redundant lines of code that can never be obeyed (their function
575     was moved elsewhere).
577     11. The program that makes PCRE's Unicode character property table had a bug
578     which caused it to generate incorrect table entries for sequences of
579 ph10 277 characters that have the same character type, but are in different scripts.
580 ph10 286 It amalgamated them into a single range, with the script of the first of
581 ph10 277 them. In other words, some characters were in the wrong script. There were
582     thirteen such cases, affecting characters in the following ranges:
583 ph10 286
584 ph10 277 U+002b0 - U+002c1
585     U+0060c - U+0060d
586 ph10 286 U+0061e - U+00612
587 ph10 277 U+0064b - U+0065e
588     U+0074d - U+0076d
589     U+01800 - U+01805
590     U+01d00 - U+01d77
591     U+01d9b - U+01dbf
592     U+0200b - U+0200f
593     U+030fc - U+030fe
594     U+03260 - U+0327f
595     U+0fb46 - U+0fbb1
596     U+10450 - U+1049d
597 ph10 286
598 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
599     compatible with GNU grep in that, if there was more than one match in a
600     line, it showed only the first of them. It now behaves in the same way as
601     GNU grep.
602 ph10 286
603     13. If the -o and -v options were combined for pcregrep, it printed a blank
604     line for every non-matching line. GNU grep prints nothing, and pcregrep now
605     does the same. The return code can be used to tell if there were any
606     non-matching lines.
608 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
610     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
611 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
612 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
613     and both kinds of lookbehind were skipped).
615 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
616 ph10 284 inclusion of <windows.h> to before rather than after the definition of
617     INVALID_FILE_ATTRIBUTES (patch from David Byron).
618 ph10 263
619 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
620 ph10 286 character property caused pcre_compile() to compile bad code, which led at
621     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
622     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
623     caused the error; without that there was no problem.
624 ph10 263
625 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
626 ph10 286
627 ph10 289 19. Added --enable-pcretest-libreadline.
628 ph10 286
629 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
630 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
631 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
632     later patch that removed the other one (the right fix) and added unit tests
633     that check the return values (which was not done before).
634 ph10 292
635 ph10 291 21. Several CMake things:
636 ph10 287
637 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
638 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
639 ph10 288
640 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
641     linked with the newly-built libraries, not previously installed ones.
642 ph10 291
644 ph10 298
645     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
646     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
647     UTF-8 newline character). The key issue is that the pattern starts .*;
648     this means that the match must be either at the beginning, or after a
649     newline. The bug was in the code for advancing after a failed match and
650     checking that the new position followed a newline. It was not taking
651 ph10 294 account of UTF-8 characters correctly.
652 ph10 298
653     23. PCRE was behaving differently from Perl in the way it recognized POSIX
654     character classes. PCRE was not treating the sequence [:...:] as a
655     character class unless the ... were all letters. Perl, however, seems to
656     allow any characters between [: and :], though of course it rejects as
657     unknown any "names" that contain non-letters, because all the known class
658     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
659     for example, whereas PCRE did not - it did not recognize a POSIX character
660     class. This seemed a bit dangerous, so the code has been changed to be
661     closer to Perl. The behaviour is not identical to Perl, because PCRE will
662     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
663     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
664     Perl does, and where it didn't before.
666 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
667     Windows environments %n is disabled by default.
668 ph10 292
670 ph10 260 Version 7.4 21-Sep-07
671 ph10 230 ---------------------
673     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
674 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
675     LF". That isn't really right - the whole point of the change was to try to
676     help when there was an actual mention of one of the two characters. So now
677     the change happens only if \r or \n (or a literal CR or LF) character is
678 ph10 230 encountered.
679 ph10 231
680     2. The 32-bit options word was also used for 6 internal flags, but the numbers
681     of both had grown to the point where there were only 3 bits left.
682     Fortunately, there was spare space in the data structure, and so I have
683     moved the internal flags into a new 16-bit field to free up more option
684 ph10 230 bits.
685 ph10 231
686     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
687     but did not set the internal JCHANGED flag - either of these is enough to
688     control the way the "get" function works - but the PCRE_INFO_JCHANGED
689     facility is supposed to tell if (?J) was ever used, so now (?J) at the
690 ph10 230 start sets both bits.
692 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
693     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
694 ph10 230
695 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
697     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
698 ph10 233 compatibility, even though it is no longer used.
699 ph10 243
700     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
701 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
702 ph10 259 windows.h file is present (where different names are used). [This was
703 ph10 257 reversed later after testing - see 16 below.]
704 ph10 243
705     8. Changed all #include <config.h> to #include "config.h". There were also
706 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
707 ph10 243
708 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
709 ph10 243 sequence off the lines that it output.
711     10. It was pointed out to me that arrays of string pointers cause lots of
712     relocations when a shared library is dynamically loaded. A technique of
713     using a single long string with a table of offsets can drastically reduce
714     these. I have refactored PCRE in four places to do this. The result is
715 ph10 240 dramatic:
716 ph10 243
717 ph10 240 Originally: 290
718     After changing UCP table: 187
719 ph10 243 After changing error message table: 43
720 ph10 240 After changing table of "verbs" 36
721     After changing table of Posix names 22
722 ph10 243
723 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
724 ph10 247
725 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
726 ph10 247 unicode-properties was also set.
728 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
729 ph10 231
730 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
731     checked only for CRLF.
732 ph10 233
733 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
735 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
736 ph10 253
737 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
738 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
739     entirely. This removes changes made in 7 above.
740 ph10 256
741 ph10 261 17. The CMake files have been updated, and there is now more information about
742     building with CMake in the NON-UNIX-USE document.
743 ph10 257
744 ph10 261
745 ph10 228 Version 7.3 28-Aug-07
746 ph10 157 ---------------------
748 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
749     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
750     brackets there is not right, since it causes compilers to look for an
751     installed pcre.h, not the version that is in the source that is being
752     compiled (which of course may be different). I have changed it back to:
753 ph10 197
754 ph10 189 #include "pcre.h"
755 ph10 197
756     I have a vague recollection that the change was concerned with compiling in
757     different directories, but in the new build system, that is taken care of
758     by the VPATH setting the Makefile.
760 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
761     when the subject happened to end in the byte 0x85 (e.g. if the last
762     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
763     characters but of course it shouldn't be taken as a newline when it is part
764     of another character. The bug was that, for an unlimited repeat of . in
765     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
766     characters when looking for a newline.
767 ph10 197
768     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
770     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
771     in debug output.
773 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
774     long printing in the pcrecpp unittest when running under MinGW.
775 ph10 189
776 ph10 197 6. ESC_K was left out of the EBCDIC table.
777 ph10 189
778 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
779     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
780     limit also applies to "virtual nesting" when a pattern is recursive, and in
781     this case 1000 isn't so big. I have been able to remove this limit at the
782     expense of backing off one optimization in certain circumstances. Normally,
783     when pcre_exec() would call its internal match() function recursively and
784     immediately return the result unconditionally, it uses a "tail recursion"
785     feature to save stack. However, when a subpattern that can match an empty
786     string has an unlimited repetition quantifier, it no longer makes this
787     optimization. That gives it a stack frame in which to save the data for
788     checking that an empty string has been matched. Previously this was taken
789     from the 1000-entry workspace that had been reserved. So now there is no
790     explicit limit, but more stack is used.
791 ph10 189
792 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
793     syntax that is required for Windows, and which was going wrong for the
794     pcreposix and pcrecpp parts of the library. These were overlooked when this
795     problem was solved for the main library.
796 ph10 197
797 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
798     the size of patterns that contain repeated groups with explicit upper
799     limits. As the maximum quantifier is 65535, the maximum group length was
800     set at 30,000 so that the product of these two numbers did not overflow a
801     32-bit integer. However, it turns out that people want to use groups that
802     are longer than 30,000 bytes (though not repeat them that many times).
803     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
804     made it possible to implement the integer overflow checks in a much more
805     dynamic way, which I have now done. The artificial limitation on group
806     length has been removed - we now have only the limit on the total length of
807     the compiled pattern, which depends on the LINK_SIZE setting.
808 ph10 208
809     10. Fixed a bug in the documentation for get/copy named substring when
810     duplicate names are permitted. If none of the named substrings are set, the
811     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
812     empty string.
814     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
815     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
816     because the ] is interpreted as the first data character and the
817     terminating ] is not found. PCRE has been made compatible with Perl in this
818     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
819     cause memory overwriting.
821 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
822     string has been matched (to stop an infinite loop). It was not recognizing
823 ph10 208 a conditional subpattern that could match an empty string if that
824 ph10 206 subpattern was within another subpattern. For example, it looped when
825 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
826 ph10 206 condition was not nested. This bug has been fixed.
827 ph10 208
828 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
829     past the start of the subject in the presence of bytes with the top bit
830     set, for example "\x8aBCD".
831 ph10 211
832 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
833     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
834 ph10 200
835 ph10 211 14. Optimized (?!) to (*FAIL).
836 ph10 202
837 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
838     This restricts code points to be within the range 0 to 0x10FFFF, excluding
839     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
840     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
841     does: it's just the validity check that is more restrictive.
842 ph10 220
843     16. Inserted checks for integer overflows during escape sequence (backslash)
844     processing, and also fixed erroneous offset values for syntax errors during
845     backslash processing.
847 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
848 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
850 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
851     caused an overrun.
852 ph10 220
853     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
854     something other than just ASCII characters) inside a group that had an
855     unlimited repeat caused a loop at compile time (while checking to see
856     whether the group could match an empty string).
858 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
859     [\P{Any}] did so. (Error in the code for printing property names.)
860 ph10 210
861 ph10 220 21. An orphan \E inside a character class could cause a crash.
863     22. A repeated capturing bracket such as (A)? could cause a wild memory
864 ph10 218 reference during compilation.
865 ph10 220
866     23. There are several functions in pcre_compile() that scan along a compiled
867     expression for various reasons (e.g. to see if it's fixed length for look
868 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
869 ph10 220 present in the pattern. These operators have additional parameters compared
870     with \d, etc, and these were not being taken into account when moving along
871 ph10 218 the compiled data. Specifically:
872 ph10 220
873     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
874     length.
876     (b) An item such as \pL+ within a repeated group could cause crashes or
877 ph10 218 loops.
878 ph10 220
879 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
880 ph10 220 "reference to non-existent subpattern" error.
882 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
884 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
885 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
886 ph10 211
887 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
888 ph10 218
889 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
890 ph10 223 character were causing crashes (broken optimization).
891 ph10 227
892 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
893 ph10 227 \p or \P) caused a compile-time loop.
895 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
896     break. For example, the unstudied pattern [\r\n]A does not match the string
897     "\r\nA" because change 7.0/46 below moves the current point on by two
898     characters after failing to match at the start. However, the pattern \nA
899 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
900     the same is true. There doesn't seem any very clean way out of this, but
901     what I have chosen to do makes the common cases work: PCRE now takes note
902     of whether there can be an explicit match for \r or \n anywhere in the
903     pattern, and if so, 7.0/46 no longer applies. As part of this change,
904     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
905     pattern has explicit CR or LF references.
906 ph10 222
907 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
908 ph10 223
909 ph10 227
910 ph10 189 Version 7.2 19-Jun-07
911     ---------------------
913 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
914     which is apparently normally available under Windows.
915 ph10 159
916     2. Re-jig the pcregrep tests with different newline settings in an attempt
917     to make them independent of the local environment's newline setting.
918 ph10 157
919 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
920 ph10 165
921 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
922     was not 2, because the output contained actual offsets. The recent new
923 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
924     usable with all link sizes.
926 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
927     stack recursion. This gives a massive performance boost under BSD, but just
928 ph10 165 a small improvement under Linux. However, it saves one field in the frame
929 ph10 164 in all cases.
930 ph10 172
931 ph10 166 6. Added more features from the forthcoming Perl 5.10:
932 ph10 172
933 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
934     recursion call. It refers to the nth most recently opened parentheses.
935 ph10 172
936 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
937 ph10 172 to be opened parentheses.
939     (c) Conditions that refer to capturing parentheses can be specified
940 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
941 ph10 172
942 ph10 168 (d) \K resets the start of the current match so that everything before
943 ph10 172 is not part of it.
945 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
946 ph10 172
947 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
948 ph10 172 reference syntax.
949 ph10 182
950 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
951 ph10 182 alternative starts with the same number.
952 ph10 172
953 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
955 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
958     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
959     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
960 ph10 170 for detecting groups that can match an empty string.
961 ph10 159
962 ph10 172 9. A pattern with a very large number of alternatives (more than several
963     hundred) was running out of internal workspace during the pre-compile
964     phase, where pcre_compile() figures out how much memory will be needed. A
965     bit of new cunning has reduced the workspace needed for groups with
966     alternatives. The 1000-alternative test pattern now uses 12 bytes of
967     workspace instead of running out of the 4096 that are available.
968 ph10 182
969 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
970 ph10 172
971 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
972     The report of the bug said:
973 ph10 182
974 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
975     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
976 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
977 ph10 185
978 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
979 ph10 185 it matched the wrong number of bytes.
980 ph10 172
981 ph10 179
982 ph10 155 Version 7.1 24-Apr-07
983 ph10 98 ---------------------
985 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
986 ph10 122 that is more "standard", making use of automake and other Autotools. There
987 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
988     on this.
989 ph10 111
990     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
991     for recursive directory scanning broke on some systems because the files
992     are not scanned in any specific order and on different systems the order
993     was different. A call to "sort" has been inserted into RunGrepTest for the
994     approprate test as a short-term fix. In the longer term there may be an
995 ph10 100 alternative.
996 ph10 111
997 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
998 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
999     people do their own conversions for various reasons). The problems
1000     concerned the use of low-level troff macros .br and .in. I have therefore
1001     removed all such uses from the man pages (some were redundant, some could
1002 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
1003     HTML has been updated to handle .nf/.fi and to complain if it encounters
1004     .br or .in.
1005 ph10 111
1006 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
1007 ph10 123 arranged for config.h to be included in the distribution, with the name
1008 ph10 111 config.h.generic, for the benefit of those who have to compile without
1009     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1011     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1012     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1013 ph10 127 makevp.bat for the current PCRE, using the additional files
1014 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1015 ph10 111
1016     6. A Windows user reported a minor discrepancy with test 2, which turned out
1017     to be caused by a trailing space on an input line that had got lost in his
1018 ph10 102 copy. The trailing space was an accident, so I've just removed it.
1019 ph10 111
1020 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1021 ph10 111 that is needed.
1023 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1024     as "const" (a) because they are and (b) because it helps the PHP
1025     maintainers who have recently made a script to detect big data structures
1026 ph10 111 in the php code that should be moved to the .rodata section. I remembered
1027     to update Builducptable as well, so it won't revert if ucptable.h is ever
1028 ph10 105 re-created.
1029 ph10 111
1030     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1031 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1032 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
1033     support is not required. This saves 1.5-2K of code, which is important in
1034 ph10 107 some applications.
1035 ph10 111
1036 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1037 ph10 111 so as not to refer to the tables, even though these functions will never be
1038     called when UTF-8 support is disabled. Otherwise there are problems with a
1039     shared library.
1041 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1043     (a) It was defining its arguments as char * instead of void *.
1045 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
1046     a long time ago when I wrote it, but is no longer the case.
1048 ph10 118 The emulated memove() is provided for those environments that have neither
1049 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
1050 ph10 118 is clearly not the case, as these two bugs were recently reported.
1051 ph10 123
1052 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1053 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
1054     pages, and it removes trailing spaces from listed files. It also creates
1055     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1056     case, it wraps all the #defines with #ifndefs. This script should be run
1057 ph10 111 before "make dist".
1058 ph10 123
1059 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1060     with Unicode property support.
1061 ph10 123
1062     (a) For a maximizing quantifier, if the two different cases of the
1063     character were of different lengths in their UTF-8 codings (there are
1064     some cases like this - I found 11), and the matching function had to
1065 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
1066     were both the same length.
1067 ph10 123
1068     (b) When PCRE was configured to use the heap rather than the stack for
1069     recursion during matching, it was not correctly preserving the data for
1070     the other case of a UTF-8 character when checking ahead for a match
1071     while processing a minimizing repeat. If the check also involved
1072 ph10 115 matching a wide character, but failed, corruption could cause an
1073     erroneous result when trying to check for a repeat of the original
1074     character.
1075 ph10 123
1076 ph10 116 13. Some tidying changes to the testing mechanism:
1077 ph10 98
1078 ph10 116 (a) The RunTest script now detects the internal link size and whether there
1079     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1080 ph10 123 values substituted by "configure". (The RunGrepTest script already did
1081     this for UTF-8.) The configure.ac script no longer substitutes the
1082     relevant variables.
1084 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
1085     with length and offset values. This means that the output is different
1086     for different internal link sizes. Test 2 is skipped for link sizes
1087     other than 2 because of this, bypassing the problem. Unfortunately,
1088     there was also a test in test 3 (the locale tests) that used /B and
1089 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
1090     I have added a new /Z option to pcretest that replaces the length and
1091     offset values with spaces. This is now used to make test 3 independent
1092 ph10 122 of link size. (Test 2 will be tidied up later.)
1093 ph10 123
1094     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1095 ph10 122 segmentation fault instead of returning the appropriate error message.
1096 ph10 134
1097 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
1098 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1099     This doesn't seem right; it now treats the CRLF combination as the line
1100     ending, and so does not match in that case. It's only a pattern such as ^$
1101     that would hit this one: something like ^ABC$ would have failed after \r
1102     and then tried again after \r\n.
1104 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1105 ph10 134 in an attempt to make files that differ only in their line terminators
1106     compare equal. This works on Linux.
1107 ph10 142
1108 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
1109     as it exited. This is now fixed, thanks to valgrind.
1110 ph10 142
1111 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1112 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1113     was because its rules for how to advance for /g after matching an empty
1114 ph10 143 string at the end of a line did not allow for this case. They now check for
1115     it specially.
1116 ph10 150
1117     20. pcretest is supposed to handle patterns and data of any length, by
1118     extending its buffers when necessary. It was getting this wrong when the
1119 ph10 147 buffer for a data line had to be extended.
1120 ph10 150
1121 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1122 ph10 150 CRLF as a newline sequence.
1123 ph10 152
1124 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1125 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1126     I have nevertheless tidied it up.
1127 ph10 111
1128 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
1129 ph10 123
1130 ph10 153 24. Added a man page for pcre-config.
1131 ph10 152
1132 ph10 153
1133 nigel 93 Version 7.0 19-Dec-06
1134     ---------------------
1136     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1137     moving to gcc 4.1.1.
1139     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1140     sys/time.h, which is documented as needed for this function. It doesn't
1141     seem to matter on Linux, but it showed up on some releases of OS X.
1143     3. It seems that there are systems where bytes whose values are greater than
1144     127 match isprint() in the "C" locale. The "C" locale should be the
1145     default when a C program starts up. In most systems, only ASCII printing
1146     characters match isprint(). This difference caused the output from pcretest
1147     to vary, making some of the tests fail. I have changed pcretest so that:
1149     (a) When it is outputting text in the compiled version of a pattern, bytes
1150     other than 32-126 are always shown as hex escapes.
1152     (b) When it is outputting text that is a matched part of a subject string,
1153     it does the same, unless a different locale has been set for the match
1154     (using the /L modifier). In this case, it uses isprint() to decide.
1156     4. Fixed a major bug that caused incorrect computation of the amount of memory
1157     required for a compiled pattern when options that changed within the
1158     pattern affected the logic of the preliminary scan that determines the
1159     length. The relevant options are -x, and -i in UTF-8 mode. The result was
1160     that the computed length was too small. The symptoms of this bug were
1161     either the PCRE error "internal error: code overflow" from pcre_compile(),
1162     or a glibc crash with a message such as "pcretest: free(): invalid next
1163     size (fast)". Examples of patterns that provoked this bug (shown in
1164     pcretest format) are:
1166     /(?-x: )/x
1167     /(?x)(?-x: \s*#\s*)/
1168     /((?i)[\x{c0}])/8
1169     /(?i:[\x{c0}])/8
1171     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1172     is now done differently.
1174     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1175     wrapper classes; (b) implement a new function in the C++ scanner that is
1176     more efficient than the old way of doing things because it avoids levels of
1177     recursion in the regex matching; (c) add a paragraph to the documentation
1178     for the FullMatch() function.
1180     6. The escape sequence \n was being treated as whatever was defined as
1181     "newline". Not only was this contrary to the documentation, which states
1182     that \n is character 10 (hex 0A), but it also went horribly wrong when
1183     "newline" was defined as CRLF. This has been fixed.
1185     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1186     was being set to -1 for the "end of line" case (supposedly a value that no
1187     character can have). Though this value is never used (the check for end of
1188     line is "zero bytes in current character"), it caused compiler complaints.
1189     I've changed it to 0xffffffff.
1191     8. In pcre_version.c, the version string was being built by a sequence of
1192     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1193     string (as it is for production releases) called a macro with an empty
1194     argument. The C standard says the result of this is undefined. The gcc
1195     compiler treats it as an empty string (which was what was wanted) but it is
1196     reported that Visual C gives an error. The source has been hacked around to
1197     avoid this problem.
1199     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1200     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1201     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1202     of them did).
1204     10. Originally, pcretest opened its input and output without "b"; then I was
1205     told that "b" was needed in some environments, so it was added for release
1206     5.0 to both the input and output. (It makes no difference on Unix-like
1207     systems.) Later I was told that it is wrong for the input on Windows. I've
1208     now abstracted the modes into two macros, to make it easier to fiddle with
1209     them, and removed "b" from the input mode under Windows.
1211     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1213     12. Added -help and --help to pcretest as an official way of being reminded
1214     of the options.
1216     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1217     and pcrecpp.cc because they annoy compilers at high warning levels.
1219     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1221     15. Fixed an occurrence of == in configure.ac that should have been = (shell
1222     scripts are not C programs :-) and which was not noticed because it works
1223     on Linux.
1225     16. pcretest is supposed to handle any length of pattern and data line (as one
1226     line or as a continued sequence of lines) by extending its input buffer if
1227     necessary. This feature was broken for very long pattern lines, leading to
1228     a string of junk being passed to pcre_compile() if the pattern was longer
1229     than about 50K.
1231     17. I have done a major re-factoring of the way pcre_compile() computes the
1232     amount of memory needed for a compiled pattern. Previously, there was code
1233     that made a preliminary scan of the pattern in order to do this. That was
1234     OK when PCRE was new, but as the facilities have expanded, it has become
1235     harder and harder to keep it in step with the real compile phase, and there
1236     have been a number of bugs (see for example, 4 above). I have now found a
1237     cunning way of running the real compile function in a "fake" mode that
1238     enables it to compute how much memory it would need, while actually only
1239     ever using a few hundred bytes of working memory and without too many
1240     tests of the mode. This should make future maintenance and development
1241     easier. A side effect of this work is that the limit of 200 on the nesting
1242     depth of parentheses has been removed (though this was never a serious
1243     limitation, I suspect). However, there is a downside: pcre_compile() now
1244     runs more slowly than before (30% or more, depending on the pattern). I
1245     hope this isn't a big issue. There is no effect on runtime performance.
1247     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1248     newline (only possible for the last line of a file) and it was a
1249     pattern that set a locale (followed by /Lsomething), pcretest crashed.
1251     19. Added additional timing features to pcretest. (1) The -tm option now times
1252     matching only, not compiling. (2) Both -t and -tm can be followed, as a
1253     separate command line item, by a number that specifies the number of
1254     repeats to use when timing. The default is 50000; this gives better
1255     precision, but takes uncomfortably long for very large patterns.
1257     20. Extended pcre_study() to be more clever in cases where a branch of a
1258     subpattern has no definite first character. For example, (a*|b*)[cd] would
1259     previously give no result from pcre_study(). Now it recognizes that the
1260     first character must be a, b, c, or d.
1262     21. There was an incorrect error "recursive call could loop indefinitely" if
1263     a subpattern (or the entire pattern) that was being tested for matching an
1264     empty string contained only one non-empty item after a nested subpattern.
1265     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1266     incorrectly, because the \d was being skipped in the check.
1268     22. The pcretest program now has a new pattern option /B and a command line
1269     option -b, which is equivalent to adding /B to every pattern. This causes
1270     it to show the compiled bytecode, without the additional information that
1271     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1272     is the same as /B/I).
1274     23. A new optimization is now able automatically to treat some sequences such
1275     as a*b as a*+b. More specifically, if something simple (such as a character
1276     or a simple class like \d) has an unlimited quantifier, and is followed by
1277     something that cannot possibly match the quantified thing, the quantifier
1278     is automatically "possessified".
1280     24. A recursive reference to a subpattern whose number was greater than 39
1281     went wrong under certain circumstances in UTF-8 mode. This bug could also
1282     have affected the operation of pcre_study().
1284     25. Realized that a little bit of performance could be had by replacing
1285     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1287     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1289     27. Possessive quantifiers such as a++ were previously implemented by turning
1290     them into atomic groups such as ($>a+). Now they have their own opcodes,
1291     which improves performance. This includes the automatically created ones
1292     from 23 above.
1294     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1295     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1296     the first matched character to be a colon. This applied both to named and
1297     numbered groups.
1299     29. The ucpinternal.h header file was missing its idempotency #ifdef.
1301     30. I was sent a "project" file called libpcre.a.dev which I understand makes
1302     building PCRE on Windows easier, so I have included it in the distribution.
1304     31. There is now a check in pcretest against a ridiculously large number being
1305     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1306     loop, the loop is abandoned.
1308     32. Forward references to subpatterns in conditions such as (?(2)...) where
1309     subpattern 2 is defined later cause pcre_compile() to search forwards in
1310     the pattern for the relevant set of parentheses. This search went wrong
1311     when there were unescaped parentheses in a character class, parentheses
1312     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1314     33. "Subroutine" calls and backreferences were previously restricted to
1315     referencing subpatterns earlier in the regex. This restriction has now
1316     been removed.
1318     34. Added a number of extra features that are going to be in Perl 5.10. On the
1319     whole, these are just syntactic alternatives for features that PCRE had
1320     previously implemented using the Python syntax or my own invention. The
1321     other formats are all retained for compatibility.
1323     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1324     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1325     also .NET compatible.
1327     (b) A recursion or subroutine call to a named group can now be defined as
1328     (?&name) as well as (?P>name).
1330     (c) A backreference to a named group can now be defined as \k<name> or
1331     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1332     5.10, are also .NET compatible.
1334     (d) A conditional reference to a named group can now use the syntax
1335     (?(<name>) or (?('name') as well as (?(name).
1337     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1338     groups (named and numbered) that are never evaluated inline, but can be
1339     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1340     is always false. There may be only one alternative in such a group.
1342     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1343     as the simple (?(R). The condition is true only if the most recent
1344     recursion is that of the given number or name. It does not search out
1345     through the entire recursion stack.
1347     (g) The escape \gN or \g{N} has been added, where N is a positive or
1348     negative number, specifying an absolute or relative reference.
1350     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1351     some "unreachable code" warnings.
1353     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1354     things, this adds five new scripts.
1356     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1357     There were also incompatibilities regarding the handling of \Q..\E inside
1358     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1359     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1361     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1362     matches an empty string, and forcibly breaks the loop. There were bugs in
1363     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1364     against aaaa the result was just "a" rather than "aaaa", for example. Two
1365     separate and independent bugs (that affected different cases) have been
1366     fixed.
1368     39. Refactored the code to abolish the use of different opcodes for small
1369     capturing bracket numbers. This is a tidy that I avoided doing when I
1370     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1371     The new approach is not only tidier, it makes it possible to reduce the
1372     memory needed to fix the previous bug (38).
1374     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1375     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1376     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1377     mode.
1379     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1380     report.
1382     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1383     copy construction and assignment in the C++ wrapper.
1385     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1386     couple of bugs that could have given wrong results in the "--newline=crlf"
1387     case.
1389     44. Added a number of casts and did some reorganization of signed/unsigned int
1390     variables following suggestions from Dair Grant. Also renamed the variable
1391     "this" as "item" because it is a C++ keyword.
1393     45. Arranged for dftables to add
1395     #include "pcre_internal.h"
1397     to pcre_chartables.c because without it, gcc 4.x may remove the array
1398     definition from the final binary if PCRE is built into a static library and
1399     dead code stripping is activated.
1401     46. For an unanchored pattern, if a match attempt fails at the start of a
1402     newline sequence, and the newline setting is CRLF or ANY, and the next two
1403     characters are CRLF, advance by two characters instead of one.
1406 nigel 91 Version 6.7 04-Jul-06
1407     ---------------------
1409     1. In order to handle tests when input lines are enormously long, pcretest has
1410     been re-factored so that it automatically extends its buffers when
1411     necessary. The code is crude, but this _is_ just a test program. The
1412     default size has been increased from 32K to 50K.
1414     2. The code in pcre_study() was using the value of the re argument before
1415     testing it for NULL. (Of course, in any sensible call of the function, it
1416     won't be NULL.)
1418     3. The memmove() emulation function in pcre_internal.h, which is used on
1419     systems that lack both memmove() and bcopy() - that is, hardly ever -
1420     was missing a "static" storage class specifier.
1422     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1423     containing an extended class (one that cannot be represented by a bitmap
1424     because it contains high-valued characters or Unicode property items, e.g.
1425     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1426     pattern, but PCRE should not loop if you do not (it no longer does).
1427     [Detail: two cases were found: (a) a repeated subpattern containing an
1428     extended class; (b) a recursive reference to a subpattern that followed a
1429     previous extended class. It wasn't skipping over the extended class
1430     correctly when UTF-8 mode was not set.]
1432     5. A negated single-character class was not being recognized as fixed-length
1433     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1434     compile error "lookbehind assertion is not fixed length".
1436     6. The RunPerlTest auxiliary script was showing an unexpected difference
1437     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1438     write a Perl script that can interpret lines of an input file either as
1439     byte characters or as UTF-8, which is what "perltest" was being required to
1440     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1441     can't do is switch easily at run time between having the "use utf8;" pragma
1442     or not. In the end, I fudged it by using the RunPerlTest script to insert
1443     "use utf8;" explicitly for the UTF-8 tests.
1445     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1446     the end of the subject string, contrary to the documentation and to what
1447     Perl does. This was true of both matching functions. Now it matches only at
1448     the start of the subject and immediately after *internal* newlines.
1450     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1451     a pointer to an int instead of a pointer to an unsigned long int. This
1452     caused problems on 64-bit systems.
1454     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1455     instance of the 'standard' template library not being so standard".
1457     10. There was no check on the number of named subpatterns nor the maximum
1458     length of a subpattern name. The product of these values is used to compute
1459     the size of the memory block for a compiled pattern. By supplying a very
1460     long subpattern name and a large number of named subpatterns, the size
1461     computation could be caused to overflow. This is now prevented by limiting
1462     the length of names to 32 characters, and the number of named subpatterns
1463     to 10,000.
1465     11. Subpatterns that are repeated with specific counts have to be replicated in
1466     the compiled pattern. The size of memory for this was computed from the
1467     length of the subpattern and the repeat count. The latter is limited to
1468     65535, but there was no limit on the former, meaning that integer overflow
1469     could in principle occur. The compiled length of a repeated subpattern is
1470     now limited to 30,000 bytes in order to prevent this.
1472     12. Added the optional facility to have named substrings with the same name.
1474     13. Added the ability to use a named substring as a condition, using the
1475     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1476     are numbers (not recommended). Forward references are permitted.
1478     14. Added forward references in named backreferences (if you see what I mean).
1480     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1481     pattern could run off the end of the subject. For example, the pattern
1482     "(?s)(.{1,5})"8 did this with the subject "ab".
1484     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1485     PCRE_CASELESS was set when matching characters that were quantified with ?
1486     or *.
1488     17. A character class other than a single negated character that had a minimum
1489     but no maximum quantifier - for example [ab]{6,} - was not handled
1490     correctly by pce_dfa_exec(). It would match only one character.
1492     18. A valid (though odd) pattern that looked like a POSIX character
1493     class but used an invalid character after [ (for example [[,abc,]]) caused
1494     pcre_compile() to give the error "Failed: internal error: code overflow" or
1495     in some cases to crash with a glibc free() error. This could even happen if
1496     the pattern terminated after [[ but there just happened to be a sequence of
1497     letters, a binary zero, and a closing ] in the memory that followed.
1499     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1500     over the years. Originally (before any Unicode support), just the bottom 8
1501     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1502     output from "man perlunicode" includes this:
1504     The regular expression compiler produces polymorphic opcodes. That
1505     is, the pattern adapts to the data and automatically switches to
1506     the Unicode character scheme when presented with Unicode data--or
1507     instead uses a traditional byte scheme when presented with byte
1508     data.
1510     Sadly, a wide octal escape does not cause a switch, and in a string with
1511     no other multibyte characters, these octal escapes are treated as before.
1512     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1513     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1514     Unicode string.
1516     I have not perpetrated such confusion in PCRE. Up till now, it took just
1517     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1518     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1519     translate to the appropriate multibyte character.
1521     29. Applied some refactoring to reduce the number of warnings from Microsoft
1522     and Borland compilers. This has included removing the fudge introduced
1523     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1524     a warning about an unused variable.
1526     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1527     characters since release 4.0, because Perl (from release 5.004) does not.
1528     [Or at least, is documented not to: some releases seem to be in conflict
1529     with the documentation.] However, when a pattern was studied with
1530     pcre_study() and all its branches started with \s, PCRE still included VT
1531     as a possible starting character. Of course, this did no harm; it just
1532     caused an unnecessary match attempt.
1534     22. Removed a now-redundant internal flag bit that recorded the fact that case
1535     dependency changed within the pattern. This was once needed for "required
1536     byte" processing, but is no longer used. This recovers a now-scarce options
1537     bit. Also moved the least significant internal flag bit to the most-
1538     significant bit of the word, which was not previously used (hangover from
1539     the days when it was an int rather than a uint) to free up another bit for
1540     the future.
1542     23. Added support for CRLF line endings as well as CR and LF. As well as the
1543     default being selectable at build time, it can now be changed at runtime
1544     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1545     specify that it is scanning data with non-default line endings.
1547     24. Changed the definition of CXXLINK to make it agree with the definition of
1548     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1550     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1551     recursions. This makes a big different to stack usage for some patterns.
1553     26. If a subpattern containing a named recursion or subroutine reference such
1554     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1555     the space required for the compiled pattern went wrong and gave too small a
1556     value. Depending on the environment, this could lead to "Failed: internal
1557     error: code overflow at offset 49" or "glibc detected double free or
1558     corruption" errors.
1560     27. Applied patches from Google (a) to support the new newline modes and (b) to
1561     advance over multibyte UTF-8 characters in GlobalReplace.
1563     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1564     difference for some implementation of PCRE in some Windows version.
1566     29. Added some extra testing facilities to pcretest:
1568     \q<number> in a data line sets the "match limit" value
1569     \Q<number> in a data line sets the "match recursion limt" value
1570     -S <number> sets the stack size, where <number> is in megabytes
1572     The -S option isn't available for Windows.
1575 nigel 89 Version 6.6 06-Feb-06
1576     ---------------------
1578     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1579     in pcreposix.h. I have copied the definition from pcre.h.
1581     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1582     because pcre.h is no longer a built file.
1584     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1585     not normally included in the compiled code.
1588 nigel 87 Version 6.5 01-Feb-06
1589     ---------------------
1591     1. When using the partial match feature with pcre_dfa_exec(), it was not
1592     anchoring the second and subsequent partial matches at the new starting
1593     point. This could lead to incorrect results. For example, with the pattern
1594     /1234/, partially matching against "123" and then "a4" gave a match.
1596     2. Changes to pcregrep:
1598     (a) All non-match returns from pcre_exec() were being treated as failures
1599     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1600     error message is output. Some extra information is given for the
1602     probably the only errors that are likely to be caused by users (by
1603     specifying a regex that has nested indefinite repeats, for instance).
1604     If there are more than 20 of these errors, pcregrep is abandoned.
1606     (b) A binary zero was treated as data while matching, but terminated the
1607     output line if it was written out. This has been fixed: binary zeroes
1608     are now no different to any other data bytes.
1610     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1611     used to set a locale for matching. The --locale=xxxx long option has
1612     been added (no short equivalent) to specify a locale explicitly on the
1613     pcregrep command, overriding the environment variables.
1615     (d) When -B was used with -n, some line numbers in the output were one less
1616     than they should have been.
1618     (e) Added the -o (--only-matching) option.
1620     (f) If -A or -C was used with -c (count only), some lines of context were
1621     accidentally printed for the final match.
1623     (g) Added the -H (--with-filename) option.
1625     (h) The combination of options -rh failed to suppress file names for files
1626     that were found from directory arguments.
1628     (i) Added the -D (--devices) and -d (--directories) options.
1630     (j) Added the -F (--fixed-strings) option.
1632     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1634     (l) Added the --colo(u)r option.
1636     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1637     is not present by default.
1639     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1640     items such as (?R) or (?1), when the recursion could match a number of
1641     alternatives. If it matched one of the alternatives, but subsequently,
1642     outside the recursion, there was a failure, the code tried to back up into
1643     the recursion. However, because of the way PCRE is implemented, this is not
1644     possible, and the result was an incorrect result from the match.
1646     In order to prevent this happening, the specification of recursion has
1647     been changed so that all such subpatterns are automatically treated as
1648     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1650     4. I had overlooked the fact that, in some locales, there are characters for
1651     which isalpha() is true but neither isupper() nor islower() are true. In
1652     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1653     and ordfeminine) are like this. This affected the treatment of \w and \W
1654     when they appeared in character classes, but not when they appeared outside
1655     a character class. The bit map for "word" characters is now created
1656     separately from the results of isalnum() instead of just taking it from the
1657     upper, lower, and digit maps. (Plus the underscore character, of course.)
1659     5. The above bug also affected the handling of POSIX character classes such as
1660     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1661     permanent tables. Instead, the bit maps for such a class were previously
1662     created as the appropriate unions of the upper, lower, and digit bitmaps.
1663     Now they are created by subtraction from the [[:word:]] class, which has
1664     its own bitmap.
1666     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1667     It is created by subtracting the vertical space characters (\x09, \x0a,
1668     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1669     subtraction was done in the overall bitmap for a character class, meaning
1670     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1671     be recognized. This bug has been fixed.
1673     7. Patches from the folks at Google:
1675     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1676     real life, but is still worth protecting against".
1678     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1679     regular expressions".
1681     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1682     have it.
1684     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1685     "configure" and the latter not, in order to fix a problem somebody had
1686     with compiling the Arg class on HP-UX.
1688     (e) Improve the error-handling of the C++ wrapper a little bit.
1690     (f) New tests for checking recursion limiting.
1692     8. The pcre_memmove() function, which is used only if the environment does not
1693     have a standard memmove() function (and is therefore rarely compiled),
1694     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1695     returning a result (though PCRE never actually uses the result).
1697     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1698     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1699     returned instead of calling malloc() with an overflowing number that would
1700     most likely cause subsequent chaos.
1702     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1704     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1705     with this option is matched, the nmatch and pmatch options of regexec() are
1706     ignored.
1708     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1709     provided in case anyone wants to the the POSIX interface with UTF-8
1710     strings.
1712     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1713     C++ linking (needed for some HP-UX environments).
1715     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1716     (unused parameter) and in the pcre_printint() function (omitted "default"
1717     switch label when the default is to do nothing).
1719     15. Added some code to make it possible, when PCRE is compiled as a C++
1720     library, to replace subject pointers for pcre_exec() with a smart pointer
1721     class, thus making it possible to process discontinuous strings.
1723     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1724     much the same function. They were added by different people who were trying
1725     to make PCRE easy to compile on non-Unix systems. It has been suggested
1726     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1727     for compiling on Windows systems. I have therefore replaced it with
1728     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1729     defaults to "extern" for C or "extern C" for C++, which works fine on
1730     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1731     SCOPE with something explicit in config.h. In addition:
1733     (a) pcreposix.h still had just "extern" instead of either of these macros;
1734     I have replaced it with PCRE_DATA_SCOPE.
1736     (b) Functions such as _pcre_xclass(), which are internal to the library,
1737     but external in the C sense, all had PCRE_EXPORT in their definitions.
1738     This is apparently wrong for the Windows case, so I have removed it.
1739     (It makes no difference on Unix-like systems.)
1741     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1742     of recursive calls to match(). This is different to MATCH_LIMIT because
1743     that limits the total number of calls to match(), not all of which increase
1744     the depth of recursion. Limiting the recursion depth limits the amount of
1745     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1746     when PCRE is compiled, and changed at run time. A patch from Google adds
1747     this functionality to the C++ interface.
1749     18. Changes to the handling of Unicode character properties:
1751     (a) Updated the table to Unicode 4.1.0.
1753     (b) Recognize characters that are not in the table as "Cn" (undefined).
1755     (c) I revised the way the table is implemented to a much improved format
1756     which includes recognition of ranges. It now supports the ranges that
1757     are defined in UnicodeData.txt, and it also amalgamates other
1758     characters into ranges. This has reduced the number of entries in the
1759     table from around 16,000 to around 3,000, thus reducing its size
1760     considerably. I realized I did not need to use a tree structure after
1761     all - a binary chop search is just as efficient. Having reduced the
1762     number of entries, I extended their size from 6 bytes to 8 bytes to
1763     allow for more data.
1765     (d) Added support for Unicode script names via properties such as \p{Han}.
1767     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1768     matching that character.
1770     20. When matching a repeated Unicode property with a minimum greater than zero,
1771     (for example \pL{2,}), PCRE could look past the end of the subject if it
1772     reached it while seeking the minimum number of characters. This could
1773     happen only if some of the characters were more than one byte long, because
1774     there is a check for at least the minimum number of bytes.
1776     21. Refactored the implementation of \p and \P so as to be more general, to
1777     allow for more different types of property in future. This has changed the
1778     compiled form incompatibly. Anybody with saved compiled patterns that use
1779     \p or \P will have to recompile them.
1781     22. Added "Any" and "L&" to the supported property types.
1783     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1784     but give a compile time error if the value is greater than 0xff.
1786     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1787     accidentally not being installed or uninstalled.
1789     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1790     made were to insert the current release number. This seemed silly, because
1791     it made things harder for people building PCRE on systems that don't run
1792     "configure". I have turned pcre.h into a distributed file, no longer built
1793     by "configure", with the version identification directly included. There is
1794     no longer a pcre.h.in file.
1796     However, this change necessitated a change to the pcre-config script as
1797     well. It is built from pcre-config.in, and one of the substitutions was the
1798     release number. I have updated configure.ac so that ./configure now finds
1799     the release number by grepping pcre.h.
1801     26. Added the ability to run the tests under valgrind.
1804 nigel 85 Version 6.4 05-Sep-05
1805     ---------------------
1807     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1808     "--" to be printed when multiple files were scanned, even when none of the
1809     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1810     consider it to be a bug, and have restored the previous behaviour.
1812     2. A couple of code tidies to get rid of compiler warnings.
1814     3. The pcretest program used to cheat by referring to symbols in the library
1815     whose names begin with _pcre_. These are internal symbols that are not
1816     really supposed to be visible externally, and in some environments it is
1817     possible to suppress them. The cheating is now confined to including
1818     certain files from the library's source, which is a bit cleaner.
1820     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1821     file's purpose clearer.
1823     5. Reorganized pcre_ucp_findchar().
1826 nigel 83 Version 6.3 15-Aug-05
1827     ---------------------
1829     1. The file libpcre.pc.in did not have general read permission in the tarball.
1831     2. There were some problems when building without C++ support:
1833     (a) If C++ support was not built, "make install" and "make test" still
1834     tried to test it.
1836     (b) There were problems when the value of CXX was explicitly set. Some
1837     changes have been made to try to fix these, and ...
1839     (c) --disable-cpp can now be used to explicitly disable C++ support.
1841     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1842     backslash in a target when C++ was disabled. This confuses some
1843     versions of "make", apparently. Using an intermediate variable solves
1844     this. (Same for CPP_LOBJ.)
1846     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1847     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1848     necessary on certain architectures.
1850     4. Added a setting of -export-symbols-regex to the link command to remove
1851     those symbols that are exported in the C sense, but actually are local
1852     within the library, and not documented. Their names all begin with
1853     "_pcre_". This is not a perfect job, because (a) we have to except some
1854     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1855     available (and never for static libraries). I have made a note to try to
1856     find a way round (a) in the future.
1859 nigel 81 Version 6.2 01-Aug-05
1860     ---------------------
1862     1. There was no test for integer overflow of quantifier values. A construction
1863     such as {1111111111111111} would give undefined results. What is worse, if
1864     a minimum quantifier for a parenthesized subpattern overflowed and became
1865     negative, the calculation of the memory size went wrong. This could have
1866     led to memory overwriting.
1868     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1870     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1871     operating environments where this matters.
1873     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1874     PCRE options from within the C++ wrapper.
1876     5. Named capturing subpatterns were not being correctly counted when a pattern
1877     was compiled. This caused two problems: (a) If there were more than 100
1878     such subpatterns, the calculation of the memory needed for the whole
1879     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1880     back references of the form \12, where the number was greater than 9, were
1881     not recognized as back references, even though there were sufficient
1882     previous subpatterns.
1884     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1885     versions of gcc, e.g. 2.95.4.
1888 nigel 79 Version 6.1 21-Jun-05
1889     ---------------------
1891     1. There was one reference to the variable "posix" in pcretest.c that was not
1892     surrounded by "#if !defined NOPOSIX".
1894     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1895     the cross-check on the old pcre_info() function, for the benefit of the
1896     cut-down version of PCRE that is currently imported into Exim.
1898     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1899     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1900     patterns that start (?i) but I don't think that matters. The use of (?i) is
1901     just an example; this all applies to the other options as well.
1903     4. Since libtool seems to echo the compile commands it is issuing, the output
1904     from "make" can be reduced a bit by putting "@" in front of each libtool
1905     compile command.
1907     5. Patch from the folks at Google for configure.in to be a bit more thorough
1908     in checking for a suitable C++ installation before trying to compile the
1909     C++ stuff. This should fix a reported problem when a compiler was present,
1910     but no suitable headers.
1912     6. The man pages all had just "PCRE" as their title. I have changed them to
1913     be the relevant file name. I have also arranged that these names are
1914     retained in the file doc/pcre.txt, which is a concatenation in text format
1915     of all the man pages except the little individual ones for each function.
1917     7. The NON-UNIX-USE file had not been updated for the different set of source
1918     files that come with release 6. I also added a few comments about the C++
1919     wrapper.
1922 nigel 77 Version 6.0 07-Jun-05
1923     ---------------------
1925     1. Some minor internal re-organization to help with my DFA experiments.
1927     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1928     didn't matter for the library itself when fully configured, but did matter
1929     when compiling without UCP support, or within Exim, where the ucp files are
1930     not imported.
1932     3. Refactoring of the library code to split up the various functions into
1933     different source modules. The addition of the new DFA matching code (see
1934     below) to a single monolithic source would have made it really too
1935     unwieldy, quite apart from causing all the code to be include in a
1936     statically linked application, when only some functions are used. This is
1937     relevant even without the DFA addition now that patterns can be compiled in
1938     one application and matched in another.
1940     The downside of splitting up is that there have to be some external
1941     functions and data tables that are used internally in different modules of
1942     the library but which are not part of the API. These have all had their
1943     names changed to start with "_pcre_" so that they are unlikely to clash
1944     with other external names.
1946     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1947     a different (DFA) algorithm. Although it is slower than the original
1948     function, it does have some advantages for certain types of matching
1949     problem.
1951     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1952     including restarting after a partial match.
1954     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1955     defined when compiling for Windows was sent to me. I have put it into the
1956     code, though I have no means of testing or verifying it.
1958     7. Added the pcre_refcount() auxiliary function.
1960     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1961     match before or at the first newline in the subject string. In pcretest,
1962     the /f option on a pattern can be used to set this.
1964     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1965     would behave wrongly. This has been present in PCRE since release 4.0.
1967     10. A number of changes to the pcregrep command:
1969     (a) Refactored how -x works; insert ^(...)$ instead of setting
1970     PCRE_ANCHORED and checking the length, in preparation for adding
1971     something similar for -w.
1973     (b) Added the -w (match as a word) option.
1975     (c) Refactored the way lines are read and buffered so as to have more
1976     than one at a time available.
1978     (d) Implemented a pcregrep test script.
1980     (e) Added the -M (multiline match) option. This allows patterns to match
1981     over several lines of the subject. The buffering ensures that at least
1982     8K, or the rest of the document (whichever is the shorter) is available
1983     for matching (and similarly the previous 8K for lookbehind assertions).
1985     (f) Changed the --help output so that it now says
1987     -w, --word-regex(p)
1989     instead of two lines, one with "regex" and the other with "regexp"
1990     because that confused at least one person since the short forms are the
1991     same. (This required a bit of code, as the output is generated
1992     automatically from a table. It wasn't just a text change.)
1994     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1995     option but starts with a hyphen. Could be a pattern or a path name
1996     starting with a hyphen, for instance.
1998     (h) "-" can be given as a file name to represent stdin.
2000     (i) When file names are being printed, "(standard input)" is used for
2001     the standard input, for compatibility with GNU grep. Previously
2002     "<stdin>" was used.
2004     (j) The option --label=xxx can be used to supply a name to be used for
2005     stdin when file names are being printed. There is no short form.
2007     (k) Re-factored the options decoding logic because we are going to add
2008     two more options that take data. Such options can now be given in four
2009     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2011     (l) Added the -A, -B, and -C options for requesting that lines of context
2012     around matches be printed.
2014     (m) Added the -L option to print the names of files that do not contain
2015     any matching lines, that is, the complement of -l.
2017     (n) The return code is 2 if any file cannot be opened, but pcregrep does
2018     continue to scan other files.
2020     (o) The -s option was incorrectly implemented. For compatibility with other
2021     greps, it now suppresses the error message for a non-existent or non-
2022     accessible file (but not the return code). There is a new option called
2023     -q that suppresses the output of matching lines, which was what -s was
2024     previously doing.
2026     (p) Added --include and --exclude options to specify files for inclusion
2027     and exclusion when recursing.
2029     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2030     Hopefully, it now does.
2032     12. Missing cast in pcre_study().
2034     13. Added an "uninstall" target to the makefile.
2036     14. Replaced "extern" in the function prototypes in Makefile.in with
2037     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2038     world, but is set differently for Windows.
2040     15. Added a second compiling function called pcre_compile2(). The only
2041     difference is that it has an extra argument, which is a pointer to an
2042     integer error code. When there is a compile-time failure, this is set
2043     non-zero, in addition to the error test pointer being set to point to an
2044     error message. The new argument may be NULL if no error number is required
2045     (but then you may as well call pcre_compile(), which is now just a
2046     wrapper). This facility is provided because some applications need a
2047     numeric error indication, but it has also enabled me to tidy up the way
2048     compile-time errors are handled in the POSIX wrapper.
2050     16. Added VPATH=.libs to the makefile; this should help when building with one
2051     prefix path and installing with another. (Or so I'm told by someone who
2052     knows more about this stuff than I do.)
2054     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2055     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2056     match everything, including newlines. This is not POSIX-compatible, but
2057     somebody wanted the feature. From pcretest it can be activated by using
2058     both the P and the s flags.
2060     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2062     19. libpcre.pc was being incorrectly installed as executable.
2064     20. A couple of places in pcretest check for end-of-line by looking for '\n';
2065     it now also looks for '\r' so that it will work unmodified on Windows.
2067     21. Added Google's contributed C++ wrapper to the distribution.
2069     22. Added some untidy missing memory free() calls in pcretest, to keep
2070     Electric Fence happy when testing.
2074 nigel 75 Version 5.0 13-Sep-04
2075     ---------------------
2077     1. Internal change: literal characters are no longer packed up into items
2078     containing multiple characters in a single byte-string. Each character
2079     is now matched using a separate opcode. However, there may be more than one
2080     byte in the character in UTF-8 mode.
2082     2. The pcre_callout_block structure has two new fields: pattern_position and
2083     next_item_length. These contain the offset in the pattern to the next match
2084     item, and its length, respectively.
2086     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2087     insertion of callouts before each pattern item. Added the /C option to
2088     pcretest to make use of this.
2090     4. On the advice of a Windows user, the lines
2092     #if defined(_WIN32) || defined(WIN32)
2093     _setmode( _fileno( stdout ), 0x8000 );
2094     #endif /* defined(_WIN32) || defined(WIN32) */
2096     have been added to the source of pcretest. This apparently does useful
2097     magic in relation to line terminators.
2099     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2100     for the benefit of those environments where the "b" makes a difference.
2102     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2103     to know about it. I have put a hack into configure.in that adds in code
2104     to set GCC=yes if CC=icc. This seems to end up at a point in the
2105     generated configure script that is early enough to affect the setting of
2106     compiler options, which is what is needed, but I have no means of testing
2107     whether it really works. (The user who reported this had patched the
2108     generated configure script, which of course I cannot do.)
2110     LATER: After change 22 below (new libtool files), the configure script
2111     seems to know about icc (and also ecc). Therefore, I have commented out
2112     this hack in configure.in.
2114     7. Added support for pkg-config (2 patches were sent in).
2116     8. Negated POSIX character classes that used a combination of internal tables
2117     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2118     [[:^ascii]]. Typically, they would match almost any characters. The other
2119     POSIX classes were not broken in this way.
2121     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2122     to find the match, as PCRE was deluded into thinking that the match had to
2123     start at the start point or following a newline. The same bug applied to
2124     patterns with negative forward assertions or any backward assertions
2125     preceding ".*" at the start, unless the pattern required a fixed first
2126     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2128     10. In UTF-8 mode, when moving forwards in the subject after a failed match
2129     starting at the last subject character, bytes beyond the end of the subject
2130     string were read.
2132     11. Renamed the variable "class" as "classbits" to make life easier for C++
2133     users. (Previously there was a macro definition, but it apparently wasn't
2134     enough.)
2136     12. Added the new field "tables" to the extra data so that tables can be passed
2137     in at exec time, or the internal tables can be re-selected. This allows
2138     a compiled regex to be saved and re-used at a later time by a different
2139     program that might have everything at different addresses.
2141     13. Modified the pcre-config script so that, when run on Solaris, it shows a
2142     -R library as well as a -L library.
2144     14. The debugging options of pcretest (-d on the command line or D on a
2145     pattern) showed incorrect output for anything following an extended class
2146     that contained multibyte characters and which was followed by a quantifier.
2148     15. Added optional support for general category Unicode character properties
2149     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2150     support. It adds about 90K to the size of the library. The meanings of the
2151     inbuilt class escapes such as \d and \s have NOT been changed.
2153     16. Updated pcredemo.c to include calls to free() to release the memory for the
2154     compiled pattern.
2156     17. The generated file chartables.c was being created in the source directory
2157     instead of in the building directory. This caused the build to fail if the
2158     source directory was different from the building directory, and was
2159     read-only.
2161     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2162     file. No doubt somebody will tell me if they don't make sense... Also added
2163     Dan Mooney's comments about building on OpenVMS.
2165     19. Added support for partial matching via the PCRE_PARTIAL option for
2166     pcre_exec() and the \P data escape in pcretest.
2168     20. Extended pcretest with 3 new pattern features:
2170     (i) A pattern option of the form ">rest-of-line" causes pcretest to
2171     write the compiled pattern to the file whose name is "rest-of-line".
2172     This is a straight binary dump of the data, with the saved pointer to
2173     the character tables forced to be NULL. The study data, if any, is
2174     written too. After writing, pcretest reads a new pattern.
2176     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2177     compiled pattern from the given file. There must not be any
2178     occurrences of "<" in the file name (pretty unlikely); if there are,
2179     pcretest will instead treat the initial "<" as a pattern delimiter.
2180     After reading in the pattern, pcretest goes on to read data lines as
2181     usual.
2183     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2184     and 16-bit fields in a compiled pattern, to simulate a pattern that
2185     was compiled on a host of opposite endianness.
2187     21. The pcre-exec() function can now cope with patterns that were compiled on
2188     hosts of opposite endianness, with this restriction:
2190     As for any compiled expression that is saved and used later, the tables
2191     pointer field cannot be preserved; the extra_data field in the arguments
2192     to pcre_exec() should be used to pass in a tables address if a value
2193     other than the default internal tables were used at compile time.
2195     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2196     now diagnosed as an error. Previously, most of the time, a negative number
2197     would have been treated as zero, but if in addition "ovector" was passed as
2198     NULL, a crash could occur.
2200     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2201     new versions from the libtool 1.5 distribution (the last one is a copy of
2202     a file called libtool.m4). This seems to have fixed the need to patch
2203     "configure" to support Darwin 1.3 (which I used to do). However, I still
2204     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2205     workstation).
2207     24. Changed the PCRE licence to be the more standard "BSD" licence.
2210 nigel 73 Version 4.5 01-Dec-03
2211     ---------------------
2213     1. There has been some re-arrangement of the code for the match() function so
2214     that it can be compiled in a version that does not call itself recursively.
2215     Instead, it keeps those local variables that need separate instances for
2216     each "recursion" in a frame on the heap, and gets/frees frames whenever it
2217     needs to "recurse". Keeping track of where control must go is done by means
2218     of setjmp/longjmp. The whole thing is implemented by a set of macros that
2219     hide most of the details from the main code, and operates only if
2220     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2221     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2222     operating.
2224     To make it easier for callers to provide specially tailored get/free
2225     functions for this usage, two new functions, pcre_stack_malloc, and
2226     pcre_stack_free, are used. They are always called in strict stacking order,
2227     and the size of block requested is always the same.
2229     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2230     PCRE has been compiled to use the stack or the heap for recursion. The
2231     -C option of pcretest uses this to show which version is compiled.
2233     A new data escape \S, is added to pcretest; it causes the amounts of store
2234     obtained and freed by both kinds of malloc/free at match time to be added
2235     to the output.
2237     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2238     what's available on my current Linux desktop machine.
2240     3. When matching a UTF-8 string, the test for a valid string at the start has
2241     been extended. If start_offset is not zero, PCRE now checks that it points
2242     to a byte that is the start of a UTF-8 character. If not, it returns
2243     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2244     this is necessary because there may be backward assertions in the pattern.
2245     When matching the same subject several times, it may save resources to use
2246     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2248     4. The code for checking the validity of UTF-8 strings has been tightened so
2249     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2250     containing "overlong sequences".
2252     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2253     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2254     should have been "&", but it just so happened that all the cases this let
2255     through by mistake were picked up later in the function.
2257     6. I had used a variable called "isblank" - this is a C99 function, causing
2258     some compilers to warn. To avoid this, I renamed it (as "blankclass").
2260     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2261     prompting; (b) run "./pcretest /dev/null" at the start of the test script
2262     so the version is shown; (c) stop "make test" echoing "./RunTest".
2264     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2266     9. The prototype for memmove() for systems that don't have it was using
2267     size_t, but the inclusion of the header that defines size_t was later. I've
2268     moved the #includes for the C headers earlier to avoid this.
2270     10. Added some adjustments to the code to make it easier to compiler on certain
2271     special systems:
2273     (a) Some "const" qualifiers were missing.
2274     (b) Added the macro EXPORT before all exported functions; by default this
2275     is defined to be empty.
2276     (c) Changed the dftables auxiliary program (that builds chartables.c) so
2277     that it reads its output file name as an argument instead of writing
2278     to the standard output and assuming this can be redirected.
2280     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2281     class containing characters with values greater than 255, PCRE compilation
2282     went into a loop.
2284     12. A recursive reference to a subpattern that was within another subpattern
2285     that had a minimum quantifier of zero caused PCRE to crash. For example,
2286     (x(y(?2))z)? provoked this bug with a subject that got as far as the
2287     recursion. If the recursively-called subpattern itself had a zero repeat,
2288     that was OK.
2290     13. In pcretest, the buffer for reading a data line was set at 30K, but the
2291     buffer into which it was copied (for escape processing) was still set at
2292     1024, so long lines caused crashes.
2294     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2295     "internal error: code overflow...". This applied to any character class
2296     that was followed by a possessive quantifier.
2298     15. Modified the Makefile to add libpcre.la as a prerequisite for
2299     libpcreposix.la because I was told this is needed for a parallel build to
2300     work.
2302     16. If a pattern that contained .* following optional items at the start was
2303     studied, the wrong optimizing data was generated, leading to matching
2304     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2305     matching string must start with a or b or c. The correct conclusion for
2306     this pattern is that a match can start with any character.
2309 nigel 71 Version 4.4 13-Aug-03
2310     ---------------------
2312     1. In UTF-8 mode, a character class containing characters with values between
2313     127 and 255 was not handled correctly if the compiled pattern was studied.
2314     In fixing this, I have also improved the studying algorithm for such
2315     classes (slightly).
2317     2. Three internal functions had redundant arguments passed to them. Removal
2318     might give a very teeny performance improvement.
2320     3. Documentation bug: the value of the capture_top field in a callout is *one
2321     more than* the number of the hightest numbered captured substring.
2323     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2324     in incorrectly linking with a previously installed version. They now link
2325     explicitly with libpcre.la.
2327     5. configure.in no longer needs to recognize Cygwin specially.
2329     6. A problem in pcre.in for Windows platforms is fixed.
2331     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2332     pcretest, it used to include the size of the study block as part of its
2333     output. Unfortunately, the structure contains a field that has a different
2334     size on different hardware architectures. This meant that the tests that
2335     showed this size failed. As the block is currently always of a fixed size,
2336     this information isn't actually particularly useful in pcretest output, so
2337     I have just removed it.
2339     8. Three pre-processor statements accidentally did not start in column 1.
2340     Sadly, there are *still* compilers around that complain, even though
2341     standard C has not required this for well over a decade. Sigh.
2343     9. In pcretest, the code for checking callouts passed small integers in the
2344     callout_data field, which is a void * field. However, some picky compilers
2345     complained about the casts involved for this on 64-bit systems. Now
2346     pcretest passes the address of the small integer instead, which should get
2347     rid of the warnings.
2349     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2350     both compile and run time, and gives an error if an invalid UTF-8 sequence
2351     is found. There is a option for disabling this check in cases where the
2352     string is known to be correct and/or the maximum performance is wanted.
2354     11. In response to a bug report, I changed one line in Makefile.in from
2356     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2357     to
2358     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2360     to look similar to other lines, but I have no way of telling whether this
2361     is the right thing to do, as I do not use Windows. No doubt I'll get told
2362     if it's wrong...
2365 nigel 69 Version 4.3 21-May-03
2366     ---------------------
2368     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2369     Makefile.
2371     2. Some refactoring to improve the quality of the code:
2373     (i) The utf8_table... variables are now declared "const".
2375     (ii) The code for \cx, which used the "case flipping" table to upper case
2376     lower case letters, now just substracts 32. This is ASCII-specific,
2377     but the whole concept of \cx is ASCII-specific, so it seems
2378     reasonable.
2380     (iii) PCRE was using its character types table to recognize decimal and
2381     hexadecimal digits in the pattern. This is silly, because it handles
2382     only 0-9, a-f, and A-F, but the character types table is locale-
2383     specific, which means strange things might happen. A private
2384     table is now used for this - though it costs 256 bytes, a table is
2385     much faster than multiple explicit tests. Of course, the standard
2386     character types table is still used for matching digits in subject
2387     strings against \d.
2389     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2390     ending in _t are). So I've renamed it as ESC_tee.
2392     3. The first argument for regexec() in the POSIX wrapper should have been
2393     defined as "const".
2395     4. Changed pcretest to use malloc() for its buffers so that they can be
2396     Electric Fenced for debugging.
2398     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2399     to read one or more bytes before the start of the subject string. Often this
2400     had no effect on PCRE's behaviour, but in some circumstances it could
2401     provoke a segmentation fault.
2403     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2404     to try to read one or more bytes before the start of the subject string.
2406     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2407     UTF-8 support could misbehave in various ways if the subject string
2408     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2409     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2410     back over UTF-8 characters.)
2413 nigel 67 Version 4.2 14-Apr-03
2414     ---------------------
2416     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2418     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2419     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2420     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2421     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2422     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2423     and BUILD_EXEEXT
2424     Note: automatic setting of the BUILD variables is not yet working
2425     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2426     compile-time but not at link-time
2427     [LINK]: use for linking executables only
2428     make different versions for Windows and non-Windows
2429     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2430     libraries
2431     [LINK_FOR_BUILD]: new variable
2432     [OBJEXT]: use throughout
2433     [EXEEXT]: use throughout
2434     <winshared>: new target
2435     <wininstall>: new target
2436     <dftables.o>: use native compiler
2437     <dftables>: use native linker
2438     <install>: handle Windows platform correctly
2439     <clean>: ditto
2440     <check>: ditto
2441     copy DLL to top builddir before testing
2443     As part of these changes, -no-undefined was removed again. This was reported
2444     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2445     in any case.
2447     3. Some tidies to get rid of compiler warnings:
2449     . In the match_data structure, match_limit was an unsigned long int, whereas
2450     match_call_count was an int. I've made them both unsigned long ints.
2452     . In pcretest the fact that a const uschar * doesn't automatically cast to
2453     a void * provoked a warning.
2455     . Turning on some more compiler warnings threw up some "shadow" variables
2456     and a few more missing casts.
2458     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2459     option, a class that contained a single character with a value between 128
2460     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2462     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2463     option, a class that contained several characters, but with at least one
2464     whose value was between 128 and 255 caused PCRE to crash.
2467 nigel 65 Version 4.1 12-Mar-03
2468     ---------------------
2469 nigel 63
2470 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2471     needed, and a string in dftables.c that was longer than standard compilers are
2472     required to support.
2474     2. Compiling with Sun's compiler found a few more places where the code could
2475     be tidied up in order to avoid warnings.
2477     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2478     first of these names is deprecated in the latest Autoconf in favour of the name
2479     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2480     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2481     analogy I have changed it to CFLAGS_FOR_BUILD.
2483     4. Added -no-undefined to the linking command in the Makefile, because this is
2484     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2485     linking step for the pcreposix library.
2487     5. PCRE was failing to diagnose the case of two named groups with the same
2488     name.
2490     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2491     literal character that is needed in the subject for a match, and scans along to
2492     ensure that it is present before embarking on the full matching process. This
2493     saves time in cases of nested unlimited repeats that are never going to match.
2494     Problem: the scan can take a lot of time if the subject is very long (e.g.
2495     megabytes), thus penalizing straightforward matches. It is now done only if the
2496     amount of subject to be scanned is less than 1000 bytes.
2498     7. A lesser problem with the same optimization is that it was recording the
2499     first character of an anchored pattern as "needed", thus provoking a search
2500     right along the subject, even when the first match of the pattern was going to
2501     fail. The "needed" character is now not set for anchored patterns, unless it
2502     follows something in the pattern that is of non-fixed length. Thus, it still
2503     fulfils its original purpose of finding quick non-matches in cases of nested
2504     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2507     Version 4.0 17-Feb-03
2508     ---------------------
2510 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2511     extended to the end of string, PCRE compiled incorrect data. This could lead to
2512     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2514     2. Moved to autoconf 2.53 and libtool 1.4.2.
2516     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2517     the special perltest8 script is no longer needed - all the tests can be run
2518     from a single perltest script.
2520     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2521     by \s. It has now been removed in PCRE. This means it isn't recognized as
2522     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2523     class [:space:] *does* include VT, thereby creating a mess.
2525     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2526     space and tab.
2528     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2529     its new features into the main test script, reducing the number of scripts.
2531     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2532     were backward compatible, and made the (?i) apply to the whole pattern, as if
2533     /i were given. Now it behaves more logically, and applies the option setting
2534     only to what follows. PCRE has been changed to follow suit. However, if it
2535     finds options settings right at the start of the pattern, it extracts them into
2536     the global options, as before. Thus, they show up in the info data.
2538     8. Added support for the \Q...\E escape sequence. Characters in between are
2539     treated as literals. This is slightly different from Perl in that $ and @ are
2540     also handled as literals inside the quotes. In Perl, they will cause variable
2541     interpolation. Note the following examples:
2543     Pattern PCRE matches Perl matches
2545     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2546     \Qabc\$xyz\E abc\$xyz abc\$xyz
2547     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2549     For compatibility with Perl, \Q...\E sequences are recognized inside character
2550     classes as well as outside them.
2552     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2553     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2554     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2555     signed/unsigned warnings.
2557     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2558     option for pcretest, so I've replaced it by a simple function that does just
2559     that job.
2561     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2562     "pcregrep -".
2564     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2565     Java package. This provides some syntactic sugar for simple cases of what my
2566     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2567     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2568     item, you can use this simplified notation. Note that only makes sense with
2569     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2570     greediness, whatever the setting of the PCRE_UNGREEDY option.
2572     13. A change of greediness default within a pattern was not taking effect at
2573     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2574     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2575     was abstracted outside.
2577     14. PCRE now supports the \G assertion. It is true when the current matching
2578     position is at the start point of the match. This differs from \A when the
2579     starting offset is non-zero. Used with the /g option of pcretest (or similar
2580     code), it works in the same way as it does for Perl's /g option. If all
2581     alternatives of a regex begin with \G, the expression is anchored to the start
2582     match position, and the "anchored" flag is set in the compiled expression.
2584     15. Some bugs concerning the handling of certain option changes within patterns
2585     have been fixed. These applied to options other than (?ims). For example,
2586     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2587     been the other way round. Some of this was related to change 7 above.
2589     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2590     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2591     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2592     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2594     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2595     mode. Unlike ".", it always matches newline, whatever the setting of
2596     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2597     assertions. Perl allows it, but it doesn't (in general) work because it can't
2598     calculate the length of the lookbehind. At least, that's the case for Perl
2599     5.8.0 - I've been told they are going to document that it doesn't work in
2600     future.
2602     18. Added an error diagnosis for escapes that PCRE does not support: these are
2603     \L, \l, \N, \P, \p, \U, \u, and \X.
2605     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2606     reading past the end of the pattern in cases such as /[abcd/.
2608     20. PCRE was getting more memory than necessary for patterns with classes that
2609     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2611     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2612     compiling PCRE for use with Virtual Pascal.
2614     22. Small fix to the Makefile to make it work properly if the build is done
2615     outside the source tree.
2617     23. Added a new extension: a condition to go with recursion. If a conditional
2618     subpattern starts with (?(R) the "true" branch is used if recursion has
2619     happened, whereas the "false" branch is used only at the top level.
2621     24. When there was a very long string of literal characters (over 255 bytes
2622     without UTF support, over 250 bytes with UTF support), the computation of how
2623     much memory was required could be incorrect, leading to segfaults or other
2624     strange effects.
2626     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2627     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2628     there was a subsequent back reference to those brackets. This meant that, for
2629     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2630     possible to check for precisely this case. All we can do is abandon the
2631     optimization if .* occurs inside capturing brackets when there are any back
2632     references whatsoever. (See below for a better fix that came later.)
2634     26. The handling of the optimization for finding the first character of a
2635     non-anchored pattern, and for finding a character that is required later in the
2636     match were failing in some cases. This didn't break the matching; it just
2637     failed to optimize when it could. The way this is done has been re-implemented.
2639     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2641     28. Added a new feature that provides some of the functionality that Perl
2642     provides with (?{...}). The facility is termed a "callout". The way it is done
2643     in PCRE is for the caller to provide an optional function, by setting
2644     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2645     global variable. By default it is unset, which disables all calling out. To get
2646     the function called, the regex must include (?C) at appropriate points. This
2647     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2648     This provides a means of identifying different callout points. When PCRE
2649     reaches such a point in the regex, if pcre_callout has been set, the external
2650     function is called. It is provided with data in a structure called
2651     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2652     matching continues; if it returns a non-zero value, the match at the current
2653     point fails. However, backtracking will occur if possible. [This was changed
2654     later and other features added - see item 49 below.]
2656     29. pcretest is upgraded to test the callout functionality. It provides a
2657     callout function that displays information. By default, it shows the start of
2658     the match and the current position in the text. There are some new data escapes
2659     to vary what happens:
2661     \C+ in addition, show current contents of captured substrings
2662     \C- do not supply a callout function
2663     \C!n return 1 when callout number n is reached
2664     \C!n!m return 1 when callout number n is reached for the mth time
2666     30. If pcregrep was called with the -l option and just a single file name, it
2667     output "<stdin>" if a match was found, instead of the file name.
2669     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2670     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2671     pcre_exec(). This saves a malloc/free per call. The default value of
2672     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2673     when configuring.
2675     32. The default maximum size of a compiled pattern is 64K. There have been a
2676     few cases of people hitting this limit. The code now uses macros to handle the
2677     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2678     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2679     configuring. Tests 2 and 5 work only with 2-byte links because they output
2680     debugging information about compiled patterns.
2682     33. Internal code re-arrangements:
2684     (a) Moved the debugging function for printing out a compiled regex into
2685     its own source file (printint.c) and used #include to pull it into
2686     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2687     separate copies.
2689     (b) Defined the list of op-code names for debugging as a macro in
2690     internal.h so that it is next to the definition of the opcodes.
2692     (c) Defined a table of op-code lengths for simpler skipping along compiled
2693     code. This is again a macro in internal.h so that it is next to the
2694     definition of the opcodes.
2696     34. Added support for recursive calls to individual subpatterns, along the
2697     lines of Robin Houston's patch (but implemented somewhat differently).
2699     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2700     allow it to read and process whole directories in Win32. This code was
2701     contributed by Lionel Fourquaux; it has not been tested by me.
2703     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2704     used to name a group. Names consist of alphanumerics and underscores, and must
2705     be unique. Back references use the syntax (?P=name) and recursive calls use
2706     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2707     numbers. The function pcre_fullinfo() can be used after compilation to extract
2708     a name/number map. There are three relevant calls:
2710     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2711     PCRE_INFO_NAMECOUNT yields the number of entries
2712     PCRE_INFO_NAMETABLE yields a pointer to the map.
2714     The map is a vector of fixed-size entries. The size of each entry depends on
2715     the length of the longest name used. The first two bytes of each entry are the
2716     group number, most significant byte first. There follows the corresponding
2717     name, zero terminated. The names are in alphabetical order.
2719     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2720     case instead of 255. Making it the same both with and without UTF-8 support
2721     means that the same test output works with both.
2723     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2724     calling malloc() with a zero argument.
2726     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2727     optimization. I've improved things by keeping a bitmap of backreferences with
2728     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2729     fact referenced, the optimization can be applied. It is unlikely that a
2730     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2731     the match to follow \n) will appear inside brackets with a number greater than
2732     31, but if it does, any back reference > 31 suppresses the optimization.
2734     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2735     of disabling numbered capturing parentheses. Any opening parenthesis that is
2736     not followed by ? behaves as if it were followed by ?: but named parentheses
2737     can still be used for capturing (and they will acquire numbers in the usual
2738     way).
2740     41. Redesigned the return codes from the match() function into yes/no/error so
2741     that errors can be passed back from deep inside the nested calls. A malloc
2742     failure while inside a recursive subpattern call now causes the
2743     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2745     42. It is now possible to set a limit on the number of times the match()
2746     function is called in a call to pcre_exec(). This facility makes it possible to
2747     limit the amount of recursion and backtracking, though not in a directly
2748     obvious way, because the match() function is used in a number of different
2749     circumstances. The count starts from zero for each position in the subject
2750     string (for non-anchored patterns). The default limit is, for compatibility, a
2751     large number, namely 10 000 000. You can change this in two ways:
2753     (a) When configuring PCRE before making, you can use --with-match-limit=n
2754     to set a default value for the compiled library.
2756     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2757     a different value is set. See 45 below.
2759     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2761     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2762     of things that can be changed at compile time. The first argument specifies
2763     what is wanted and the second points to where the information is to be placed.
2764     The current list of available information is:
2768     The output is an integer that is set to one if UTF-8 support is available;
2769     otherwise it is set to zero.
2773     The output is an integer that it set to the value of the code that is used for
2774     newline. It is either LF (10) or CR (13).
2778     The output is an integer that contains the number of bytes used for internal
2779     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2783     The output is an integer that contains the threshold above which the POSIX
2784     interface uses malloc() for output vectors. See item 31 above.
2788     The output is an unsigned integer that contains the default limit of the number
2789     of match() calls in a pcre_exec() execution. See 42 above.
2791     44. pcretest has been upgraded by the addition of the -C option. This causes it
2792     to extract all the available output from the new pcre_config() function, and to
2793     output it. The program then exits immediately.
2795     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2796     order to support additional features. One way would have been to define
2797     pcre_exec2() (for example) with extra arguments, but this would not have been
2798     extensible, and would also have required all calls to the original function to
2799     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2800     is used for passing in "extra" data from pcre_study().
2802     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2803     contains the following fields:
2805     flags a bitmap indicating which of the following fields are set
2806     study_data opaque data from pcre_study()
2807     match_limit a way of specifying a limit on match() calls for a specific
2808     call to pcre_exec()
2809     callout_data data for callouts (see 49 below)
2811     The flag bits are also defined in pcre.h, and are
2817     The pcre_study() function now returns one of these new pcre_extra blocks, with
2818     the actual study data pointed to by the study_data field, and the
2819     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2820     before. That is, this change is entirely upwards-compatible and requires no
2821     change to existing code.
2823     If you want to pass in additional data to pcre_exec(), you can either place it
2824     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2825     block.
2827     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2828     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2829     times with different match limits, until it finds the minimum value needed for
2830     pcre_exec() to complete. The value is then output. This can be instructive; for
2831     most simple matches the number is quite small, but for pathological cases it
2832     gets very large very quickly.
2834     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2835     returns the size of the data block pointed to by the study_data field in a
2836     pcre_extra block, that is, the value that was passed as the argument to
2837     pcre_malloc() when PCRE was getting memory in which to place the information
2838     created by pcre_study(). The fourth argument should point to a size_t variable.
2839     pcretest has been extended so that this information is shown after a successful
2840     pcre_study() call when information about the compiled regex is being displayed.
2842     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2843     because what follows is always an absolute path. (Later: it turns out that this
2844     is more than cosmetic for MinGW, because it doesn't like empty path
2845     components.)
2847     49. Some changes have been made to the callout feature (see 28 above):
2849     (i) A callout function now has three choices for what it returns:
2851     0 => success, carry on matching
2852     > 0 => failure at this point, but backtrack if possible
2853     < 0 => serious error, return this value from pcre_exec()
2855     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2856     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2857     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2858     use by callout functions. It will never be used by PCRE itself.
2860     (ii) The pcre_extra structure (see 45 above) has a void * field called
2861     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2862     pcre_callout_block structure has a field of the same name. The contents of
2863     the field passed in the pcre_extra structure are passed to the callout
2864     function in the corresponding field in the callout block. This makes it
2865     easier to use the same callout-containing regex from multiple threads. For
2866     testing, the pcretest program has a new data escape
2868     \C*n pass the number n (may be negative) as callout_data
2870     If the callout function in pcretest receives a non-zero value as
2871     callout_data, it returns that value.
2873     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2874     there were some redundant $(CFLAGS) in commands that are now specified as
2875     $(LINK), which already includes $(CFLAGS).
2877     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2878     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2879     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2880     one-byte characters throughout. Note that case-insensitive matching applies
2881     only to characters whose values are less than 256. PCRE doesn't support the
2882     notion of cases for higher-valued characters.
2884     (i) A character class whose characters are all within 0-255 is handled as
2885     a bit map, and the map is inverted for negative classes. Previously, a
2886     character > 255 always failed to match such a class; however it should
2887     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2889     (ii) A negated character class with a single character < 255 is coded as
2890     "not this character" (OP_NOT). This wasn't working properly when the test
2891     character was multibyte, either singly or repeated.
2893     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2894     mode, for example: \x{100}{2,3}.
2896     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2897     singly or repeated) now correctly test multibyte characters. However,
2898     PCRE doesn't recognize any characters with values greater than 255 as
2899     digits, spaces, or word characters. Such characters always match \D, \S,
2900     and \W, and never match \d, \s, or \w.
2902     (v) Classes may now contain characters and character ranges with values
2903     greater than 255. For example: [ab\x{100}-\x{400}].
2905     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2906     PCRE in UTF-8 mode.
2908     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2909     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2910     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2911     value.)
2913     53. The single man page has become too large. I have therefore split it up into
2914     a number of separate man pages. These also give rise to individual HTML pages;
2915     these are now put in a separate directory, and there is an index.html page that
2916     lists them all. Some hyperlinking between the pages has been installed.
2918     54. Added convenience functions for handling named capturing parentheses.
2920     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2921     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2922     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2923     are faulted.
2925     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2926     calling configure. These values are used when compiling the dftables.c program
2927     which is run to generate the source of the default character tables. They
2928     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2929     you will need to set these values.
2931     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2934     Version 3.9 02-Jan-02
2935 nigel 61 ---------------------
2937     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2939     2. If --disable-static was given, the building process failed when trying to
2940     build pcretest and pcregrep. (For some reason it was using libtool to compile
2941     them, which is not right, as they aren't part of the library.)
2944 nigel 59 Version 3.8 18-Dec-01
2945     ---------------------
2947     1. The experimental UTF-8 code was completely screwed up. It was packing the
2948     bytes in the wrong order. How dumb can you get?
2951 nigel 57 Version 3.7 29-Oct-01
2952     ---------------------
2954     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2955     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2956     this didn't happen under Solaris 8, where I normally test things.
2958 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2959     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2960     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2961     this fix an hour or so after the initial 3.7 release.)
2962 nigel 57
2963 nigel 59
2964 nigel 55 Version 3.6 23-Oct-01
2965     ---------------------
2967     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2968     offsets passed as NULL with zero offset count.
2970     2. The config.guess and config.sub files had not been updated when I moved to
2971     the latest autoconf.
2974 nigel 53 Version 3.5 15-Aug-01
2975     ---------------------
2976 nigel 5
2977 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2978     had been forgotten.
2980     2. By using declared but undefined structures, we can avoid using "void"
2981     definitions in pcre.h while keeping the internal definitions of the structures
2982     private.
2984     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2985     user point of view, this means that both static and shared libraries are built
2986     by default, but this can be individually controlled. More of the work of
2987     handling this static/shared cases is now inside libtool instead of PCRE's make
2988     file.
2990     4. The pcretest utility is now installed along with pcregrep because it is
2991     useful for users (to test regexs) and by doing this, it automatically gets
2992     relinked by libtool. The documentation has been turned into a man page, so
2993     there are now .1, .txt, and .html versions in /doc.
2995     5. Upgrades to pcregrep:
2996     (i) Added long-form option names like gnu grep.
2997     (ii) Added --help to list all options with an explanatory phrase.
2998     (iii) Added -r, --recursive to recurse into sub-directories.
2999     (iv) Added -f, --file to read patterns from a file.
3001     6. pcre_exec() was referring to its "code" argument before testing that
3002     argument for NULL (and giving an error if it was NULL).
3004     7. Upgraded Makefile.in to allow for compiling in a different directory from
3005     the source directory.
3007     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3008     options bits, the pointer it was passed was to an int instead of to an unsigned
3009     long int. This mattered only on 64-bit systems.
3011     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3012     generated) instead of pcre.in, which it its source. Also made the same change
3013     in several of the .c files.
3015     10. A new release of gcc defines printf() as a macro, which broke pcretest
3016     because it had an ifdef in the middle of a string argument for printf(). Fixed
3017     by using separate calls to printf().
3019     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3020     script, to force use of CR or LF instead of \n in the source. On non-Unix
3021     systems, the value can be set in config.h.
3023     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3024     absolute limit. Changed the text of the error message to make this clear, and
3025     likewise updated the man page.
3027     13. The limit of 99 on the number of capturing subpatterns has been removed.
3028     The new limit is 65535, which I hope will not be a "real" limit.
3031 nigel 51 Version 3.4 22-Aug-00
3032     ---------------------
3034     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3036     2. Diagnose condition (?(0) as an error instead of crashing on matching.
3039 nigel 49 Version 3.3 01-Aug-00
3040     ---------------------
3042     1. If an octal character was given, but the value was greater than \377, it
3043     was not getting masked to the least significant bits, as documented. This could
3044     lead to crashes in some systems.
3046     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3047     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3049     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3050     These just pass their arguments on to (pcre_free)(), but they are provided
3051     because some uses of PCRE bind it to non-C systems that can call its functions,
3052     but cannot call free() or pcre_free() directly.
3054     4. Add "make test" as a synonym for "make check". Corrected some comments in
3055     the Makefile.
3057     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3058     Makefile.
3060     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3061     command called pgrep for grepping around the active processes.
3063     7. Added the beginnings of support for UTF-8 character strings.
3065     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3066     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3067     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3068     out for the ar command.)
3071 nigel 47 Version 3.2 12-May-00
3072     ---------------------
3074     This is purely a bug fixing release.
3076     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3077     of ZA. This was just one example of several cases that could provoke this bug,
3078     which was introduced by change 9 of version 2.00. The code for breaking
3079     infinite loops after an iteration that matches an empty string was't working
3080     correctly.
3082     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3083     when matched against abbab (for example). After matching an empty string, it
3084     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3085     caused it to match further down the string than it should.
3087     3. The code contained an inclusion of sys/types.h. It isn't clear why this
3088     was there because it doesn't seem to be needed, and it causes trouble on some
3089     systems, as it is not a Standard C header. It has been removed.
3091     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3092     were reported on the Macintosh. The changes were from
3094     while ((c = *(++ptr)) != 0 && c != '\n');
3095     to
3096     while ((c = *(++ptr)) != 0 && c != '\n') ;
3098     Totally extraordinary, but if that's what it takes...
3100     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3101     available. Added HAVE_BCOPY and an autoconf test for it; if neither
3102     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3103     assumes the way PCRE uses memmove() (always moving upwards).
3105     6. PCRE is being used in one environment where strchr() is not available. There
3106     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3107     faster code anyway.
3110 nigel 45 Version 3.1 09-Feb-00
3111     ---------------------
3113     The only change in this release is the fixing of some bugs in Makefile.in for
3114     the "install" target:
3116     (1) It was failing to install pcreposix.h.
3118     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3121 nigel 43 Version 3.0 01-Feb-00
3122     ---------------------
3123 nigel 41
3124     1. Add support for the /+ modifier to perltest (to output $` like it does in
3125     pcretest).
3127     2. Add support for the /g modifier to perltest.
3129     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3130     matches null strings.
3132     4. Fix perltest so that it doesn't do unwanted things when fed an empty
3133     pattern. Perl treats empty patterns specially - it reuses the most recent
3134     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3135     effect.
3137     5. The POSIX interface was broken in that it was just handing over the POSIX
3138     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3139     required a bigger vector, with some working space on the end. This means that
3140     the POSIX wrapper now has to get and free some memory, and copy the results.
3142 nigel 43 6. Added some simple autoconf support, placing the test data and the
3143     documentation in separate directories, re-organizing some of the
3144     information files, and making it build pcre-config (a GNU standard). Also added
3145     libtool support for building PCRE as a shared library, which is now the
3146     default.
3147 nigel 41
3148 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3149     09 are not valid octal constants. Single digits will be used for minor values
3150     less than 10.
3152     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3153     existing programs that set these in the POSIX interface can use PCRE without
3154     modification.
3156     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3157     return all that pcre_info() returns, plus additional data. The pcre_info()
3158     function is retained for compatibility, but is considered to be obsolete.
3160     10. Added experimental recursion feature (?R) to handle one common case that
3161     Perl 5.6 will be able to do with (?p{...}).
3163     11. Added support for POSIX character classes like [:alpha:], which Perl is
3164     adopting.
3167 nigel 39 Version 2.08 31-Aug-99
3168     ----------------------
3170     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3171     trying to match at the startoffset position, but instead was moving forward to
3172     the next newline as if a previous match had failed.
3174     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3175     and could get into a loop if a null string was matched other than at the start
3176     of the subject.
3178     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3179     be distinguished at compile time, and for completeness also added PCRE_DATE.
3181     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3182     in GnuWin32 environments.
3185 nigel 37 Version 2.07 29-Jul-99
3186     ----------------------
3188     1. The documentation is now supplied in plain text form and HTML as well as in
3189     the form of man page sources.
3191     2. C++ compilers don't like assigning (void *) values to other pointer types.
3192     In particular this affects malloc(). Although there is no problem in Standard
3193     C, I've put in casts to keep C++ compilers happy.
3195     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3196     should be (const char *).
3198     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3199     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3200     However, I haven't made this a standard facility. The documentation doesn't
3201     mention it, and the Makefile doesn't support it.
3203     5. The Makefile now contains an "install" target, with editable destinations at
3204     the top of the file. The pcretest program is not installed.
3206     6. pgrep -V now gives the PCRE version number and date.
3208     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3209     causing the entire string to be ignored, instead of just the last character.
3211     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3212     non-matching string, it can take a very, very long time, even for strings of
3213     quite modest length, because of the nested recursion. PCRE now does better in
3214     some of these cases. It does this by remembering the last required literal
3215     character in the pattern, and pre-searching the subject to ensure it is present
3216     before running the real match. In other words, it applies a heuristic to detect
3217     some types of certain failure quickly, and in the above example, if presented
3218     with a string that has no trailing " it gives "no match" very quickly.
3220     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3221     other alternatives are tried instead.
3224 nigel 35 Version 2.06 09-Jun-99
3225     ----------------------
3227     1. Change pcretest's output for amount of store used to show just the code
3228     space, because the remainder (the data block) varies in size between 32-bit and
3229     64-bit systems.
3231     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3232     start matching at. This allows lookbehinds to work when searching for multiple
3233     occurrences in a string.
3235     3. Added additional options to pcretest for testing multiple occurrences:
3237     /+ outputs the rest of the string that follows a match
3238     /g loops for multiple occurrences, using the new startoffset argument
3239     /G loops for multiple occurrences by passing an incremented pointer
3241     4. PCRE wasn't doing the "first character" optimization for patterns starting
3242     with \b or \B, though it was doing it for other lookbehind assertions. That is,
3243     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3244     the letter 'x'. On long subject strings, this gives a significant speed-up.
3247 nigel 33 Version 2.05 21-Apr-99
3248     ----------------------
3250     1. Changed the type of magic_number from int to long int so that it works
3251     properly on 16-bit systems.
3253     2. Fixed a bug which caused patterns starting with .* not to work correctly
3254     when the subject string contained newline characters. PCRE was assuming
3255     anchoring for such patterns in all cases, which is not correct because .* will
3256     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3257     DOTALL is set at top level; otherwise it knows that patterns starting with .*
3258     must be retried after every newline in the subject.
3261 nigel 31 Version 2.04 18-Feb-99
3262     ----------------------
3264     1. For parenthesized subpatterns with repeats whose minimum was zero, the
3265     computation of the store needed to hold the pattern was incorrect (too large).
3266     If such patterns were nested a few deep, this could multiply and become a real
3267     problem.
3269     2. Added /M option to pcretest to show the memory requirement of a specific
3270     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3272     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3273     compiled in such a way that the backtracking after subsequent failure was
3274     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3275     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3278 nigel 29 Version 2.03 02-Feb-99
3279     ----------------------
3281     1. Fixed typo and small mistake in man page.
3283 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
3284     LICENCE file containing the conditions.
3285 nigel 29
3286     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3287     Perl, that is the internal \ allows the delimiter to be included in the
3288     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3289     the final delimiter, add \ to the end of the pattern (to test the error).
3291     4. Added the convenience functions for extracting substrings after a successful
3292     match. Updated pcretest to make it able to test these functions.
3295 nigel 27 Version 2.02 14-Jan-99
3296     ----------------------
3298     1. Initialized the working variables associated with each extraction so that
3299     their saving and restoring doesn't refer to uninitialized store.
3301     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3302     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3303     fix the problem.
3305     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3306     calls, and wasn't printing the correct value for compiling calls. Increased the
3307     default value of LOOPREPEAT, and the number of significant figures in the
3308     times.
3310     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3312     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3313     a building problem on Windows NT with a FAT file system.
3316 nigel 25 Version 2.01 21-Oct-98
3317     ----------------------
3319     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3320     to character tables built by pcre_maketables() in the current locale. If NULL
3321     is passed, the default tables are used.
3324 nigel 23 Version 2.00 24-Sep-98
3325 nigel 21 ----------------------
3327 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3328     it any more.
3330     2. Allow quantification of (?>) groups, and make it work correctly.
3332     3. The first character computation wasn't working for (?>) groups.
3334     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3335     end of the subject) and add 5.005's \z, which really does match only at the
3336     very end of the subject.
3338     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3340     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3341     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3342     localized options. All options to pcre_study() were also removed.
3344     7. Add other new features from 5.005:
3346     $(?<= positive lookbehind
3347     $(?<! negative lookbehind
3348     (?imsx-imsx) added the unsetting capability
3349     such a setting is global if at outer level; local otherwise
3350     (?imsx-imsx:) non-capturing groups with option setting
3351     (?(cond)re|re) conditional pattern matching
3353     A backreference to itself in a repeated group matches the previous
3354     captured string.
3356     8. General tidying up of studying (both automatic and via "study")
3357     consequential on the addition of new assertions.
3359     9. As in 5.005, unlimited repeated groups that could match an empty substring
3360     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3361     runtime if any iteration does actually match an empty substring.
3363     10. Include the RunTest script in the distribution.
3365     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3366     discrepancies, some of which were old and were also with respect to 5.004. They
3367     have now been fixed.
3370     Version 1.09 28-Apr-98
3371     ----------------------
3373 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3374     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3375     program crashes, or just wrong answers. This did not apply to negated classes
3376     containing more than one character, or to minima other than one.
3379 nigel 19 Version 1.08 27-Mar-98
3380     ----------------------
3382     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3384     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3385     latter must appear before anything that relies on it in the pattern.
3388 nigel 17 Version 1.07 16-Feb-98
3389     ----------------------
3391     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3392     repeat of a potentially empty string).
3395 nigel 15 Version 1.06 23-Jan-98
3396     ----------------------
3398     1. Added Markus Oberhumer's little patches for C++.
3400     2. Literal strings longer than 255 characters were broken.
3403 nigel 13 Version 1.05 23-Dec-97
3404     ----------------------
3406     1. Negated character classes containing more than one character were failing if
3407     PCRE_CASELESS was set at run time.
3410 nigel 11 Version 1.04 19-Dec-97
3411     ----------------------
3413     1. Corrected the man page, where some "const" qualifiers had been omitted.
3415     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3416     input syntax.
3418     3. Fixed memory leak which occurred when a regex with back references was
3419     matched with an offsets vector that wasn't big enough. The temporary memory
3420     that is used in this case wasn't being freed if the match failed.
3422     4. Tidied pcretest to ensure it frees memory that it gets.
3424     5. Temporary memory was being obtained in the case where the passed offsets
3425     vector was exactly big enough.
3427     6. Corrected definition of offsetof() from change 5 below.
3429     7. I had screwed up change 6 below and broken the rules for the use of
3430     setjmp(). Now fixed.
3433 nigel 9 Version 1.03 18-Dec-97
3434     ----------------------
3436     1. A erroneous regex with a missing opening parenthesis was correctly
3437     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3438     on some systems.
3440     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3441     it was reported that one broken compiler failed on the former because "code" is
3442     also an independent variable.
3444     3. The erroneous regex a[]b caused an array overrun reference.
3446     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3447     fail on data ending with that character. (It was going on too far, and checking
3448     the next character, typically a binary zero.) This was specific to the
3449     optimized code for single-character negative classes.
3451     5. Added a contributed patch from the TIN world which does the following:
3453     + Add an undef for memmove, in case the the system defines a macro for it.
3455     + Add a definition of offsetof(), in case there isn't one. (I don't know
3456     the reason behind this - offsetof() is part of the ANSI standard - but
3457     it does no harm).
3459     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3460     most of the places where whitespace preceded '#'. I have given up and
3461     allowed the remaining 2 cases to be at the margin.
3463     + Rename some variables in pcre to eliminate shadowing. This seems very
3464     pedantic, but does no harm, of course.
3466     6. Moved the call to setjmp() into its own function, to get rid of warnings
3467     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3469     7. Constructs such as \d{8,} were compiling into the equivalent of
3470 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3471 nigel 9 outcome, but in this particular case used more store than had been allocated,
3472     which caused the bug to be discovered because it threw up an internal error.
3474     8. The debugging code in both pcre and pcretest for outputting the compiled
3475     form of a regex was going wrong in the case of back references followed by
3476     curly-bracketed repeats.
3479 nigel 7 Version 1.02 12-Dec-97
3480     ----------------------
3482     1. Typos in pcre.3 and comments in the source fixed.
3484     2. Applied a contributed patch to get rid of places where it used to remove
3485     'const' from variables, and fixed some signed/unsigned and uninitialized
3486     variable warnings.
3488     3. Added the "runtest" target to Makefile.
3490     4. Set default compiler flag to -O2 rather than just -O.
3493 nigel 5 Version 1.01 19-Nov-97
3494     ----------------------
3496     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3497     like /([ab]*)*/, that is, for classes with more than one character in them.
3499     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3500     as /((?>a*))*/ (a PCRE_EXTRA facility).
3503     Version 1.00 18-Nov-97
3504     ----------------------
3506     1. Added compile-time macros to support systems such as SunOS4 which don't have
3507     memmove() or strerror() but have other things that can be used instead.
3509     2. Arranged that "make clean" removes the executables.
3512 nigel 3 Version 0.99 27-Oct-97
3513     ----------------------
3515     1. Fixed bug in code for optimizing classes with only one character. It was
3516     initializing a 32-byte map regardless, which could cause it to run off the end
3517     of the memory it had got.
3519     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3522     Version 0.98 22-Oct-97
3523     ----------------------
3525     1. Fixed bug in code for handling temporary memory usage when there are more
3526     back references than supplied space in the ovector. This could cause segfaults.
3529     Version 0.97 21-Oct-97
3530     ----------------------
3532     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3534     2. Optimized negated single characters not to use a bit map.
3536     3. Brought error texts together as macro definitions; clarified some of them;
3537     fixed one that was wrong - it said "range out of order" when it meant "invalid
3538     escape sequence".
3540     4. Changed some char * arguments to const char *.
3542     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3544     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3545     pcretest.
3548     Version 0.96 16-Oct-97
3549     ----------------------
3551     1. Added a simple "pgrep" utility to the distribution.
3553     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3554     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3555     where "ddd" means "one or more decimal digits".
3557     3. Fixed serious bug. If a pattern had a back reference, but the call to
3558     pcre_exec() didn't supply a large enough ovector to record the related
3559     identifying subpattern, the match always failed. PCRE now remembers the number
3560     of the largest back reference, and gets some temporary memory in which to save
3561     the offsets during matching if necessary, in order to ensure that
3562     backreferences always work.
3564     4. Increased the compatibility with Perl in a number of ways:
3566     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3567     to request this handling. The option can be set at compile or exec time.
3569     (b) $ matches before a terminating newline by default; an option
3570     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3571     mode). The option can be set at compile or exec time.
3573     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3574     the same as Perl's. If the decimal number it represents is less than 10
3575     or there aren't that many previous left capturing parentheses, an octal
3576     escape is read. Inside a character class, it's always an octal escape,
3577     even if it is a single digit.
3579     (d) An escaped but undefined alphabetic character is taken as a literal,
3580     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3581     escapes.
3583     (e) {0} is now permitted. (The previous item is removed from the compiled
3584     pattern).
3586     5. Changed all the names of code files so that the basic parts are no longer
3587     than 10 characters, and abolished the teeny "globals.c" file.
3589     6. Changed the handling of character classes; they are now done with a 32-byte
3590     bit map always.
3592     7. Added the -d and /D options to pcretest to make it possible to look at the
3593     internals of compilation without having to recompile pcre.
3596     Version 0.95 23-Sep-97
3597     ----------------------
3599     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3600     \x20 at the start of a run of normal characters. These were being treated as
3601     real characters, instead of the source characters being re-checked.
3604     Version 0.94 18-Sep-97
3605     ----------------------
3607     1. The functions are now thread-safe, with the caveat that the global variables
3608     containing pointers to malloc() and free() or alternative functions are the
3609     same for all threads.
3611     2. Get pcre_study() to generate a bitmap of initial characters for non-
3612     anchored patterns when this is possible, and use it if passed to pcre_exec().
3615     Version 0.93 15-Sep-97
3616     ----------------------
3618     1. /(b)|(:+)/ was computing an incorrect first character.
3620     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3621     but not actually doing anything yet.
3623     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3624     as Perl does (e.g. [-az] or [az-]).
3626     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3627     all possible positions.
3629     5. Split up into different modules to avoid including unneeded functions in a
3630     compiled binary. However, compile and exec are still in one module. The "study"
3631     function is split off.
3633     6. The character tables are now in a separate module whose source is generated
3634     by an auxiliary program - but can then be edited by hand if required. There are
3635     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3636     toupper() in the code.
3638     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3639     make them global. Abolish the function for setting them, as the caller can now
3640     set them directly.
3643     Version 0.92 11-Sep-97
3644     ----------------------
3646     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3647     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3649     2. Caseless matching was not working in character classes if the characters in
3650     the pattern were in upper case.
3652     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3654     4. Make PCRE_ANCHORED public and accept as a compile option.
3656     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3657     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3658     pass them.
3660     6. Give an error if bad option bits passed at compile or run time.
3662     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3663     pcretest to cause it to pass that flag.
3665     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3666     options, and the first character, if set.
3668     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3671     Version 0.91 10-Sep-97
3672     ----------------------
3674     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3675     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3677     2. PCRE was looping on encountering an indefinitely repeated back reference to
3678     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3679     Perl does - treats the match as successful.
3681     ****


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