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Revision 454 - (hide annotations) (download)
Tue Sep 22 09:42:11 2009 UTC (4 years, 7 months ago) by ph10
File size: 173098 byte(s)
Allow fixed-length subroutine calls in lookbehinds.

1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 ph10 418 Version 8.00 ??-???-??
5     ----------------------
6    
7     1. The table for translating pcre_compile() error codes into POSIX error codes
8     was out-of-date, and there was no check on the pcre_compile() error code
9     being within the table. This could lead to an OK return being given in
10     error.
11 ph10 419
12     2. Changed the call to open a subject file in pcregrep from fopen(pathname,
13     "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
14     in a Windows environment.
15 ph10 420
16     3. The pcregrep --count option prints the count for each file even when it is
17     zero, as does GNU grep. However, pcregrep was also printing all files when
18     --files-with-matches was added. Now, when both options are given, it prints
19     counts only for those files that have at least one match. (GNU grep just
20     prints the file name in this circumstance, but including the count seems
21     more useful - otherwise, why use --count?) Also ensured that the
22     combination -clh just lists non-zero counts, with no names.
23    
24 ph10 421 4. The long form of the pcregrep -F option was incorrectly implemented as
25     --fixed_strings instead of --fixed-strings. This is an incompatible change,
26     but it seems right to fix it, and I didn't think it was worth preserving
27     the old behaviour.
28    
29 ph10 422 5. The command line items --regex=pattern and --regexp=pattern were not
30     recognized by pcregrep, which required --regex pattern or --regexp pattern
31     (with a space rather than an '='). The man page documented the '=' forms,
32     which are compatible with GNU grep; these now work.
33    
34 ph10 423 6. No libpcreposix.pc file was created for pkg-config; there was just
35     libpcre.pc and libpcrecpp.pc. The omission has been rectified.
36    
37 ph10 425 7. Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
38     when UCP support is not needed, by modifying the Python script that
39     generates it from Unicode data files. This should not matter if the module
40     is correctly used as a library, but I received one complaint about 50K of
41     unwanted data. My guess is that the person linked everything into his
42     program rather than using a library. Anyway, it does no harm.
43    
44 ph10 426 8. A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
45     was a minimum greater than 1 for a wide character in a possessive
46 ph10 431 repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
47     which had an unlimited repeat of a nested, fixed maximum repeat of a wide
48     character. Chaos in the form of incorrect output or a compiling loop could
49     result.
50 ph10 426
51     9. The restrictions on what a pattern can contain when partial matching is
52     requested for pcre_exec() have been removed. All patterns can now be
53     partially matched by this function. In addition, if there are at least two
54 ph10 435 slots in the offset vector, the offset of the earliest inspected character
55     for the match and the offset of the end of the subject are set in them when
56     PCRE_ERROR_PARTIAL is returned.
57 ph10 426
58 ph10 428 10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
59     synonymous with PCRE_PARTIAL, for backwards compatibility, and
60     PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
61     and may be more useful for multi-segment matching, especially with
62     pcre_exec().
63 ph10 427
64 ph10 428 11. Partial matching with pcre_exec() is now more intuitive. A partial match
65     used to be given if ever the end of the subject was reached; now it is
66     given only if matching could not proceed because another character was
67     needed. This makes a difference in some odd cases such as Z(*FAIL) with the
68     string "Z", which now yields "no match" instead of "partial match". In the
69     case of pcre_dfa_exec(), "no match" is given if every matching path for the
70     final character ended with (*FAIL).
71    
72     12. Restarting a match using pcre_dfa_exec() after a partial match did not work
73     if the pattern had a "must contain" character that was already found in the
74     earlier partial match, unless partial matching was again requested. For
75     example, with the pattern /dog.(body)?/, the "must contain" character is
76     "g". If the first part-match was for the string "dog", restarting with
77 ph10 435 "sbody" failed. This bug has been fixed.
78 ph10 428
79 ph10 435 13. The string returned by pcre_dfa_exec() after a partial match has been
80     changed so that it starts at the first inspected character rather than the
81     first character of the match. This makes a difference only if the pattern
82     starts with a lookbehind assertion or \b or \B (\K is not supported by
83     pcre_dfa_exec()). It's an incompatible change, but it makes the two
84     matching functions compatible, and I think it's the right thing to do.
85    
86     14. Added a pcredemo man page, created automatically from the pcredemo.c file,
87 ph10 429 so that the demonstration program is easily available in environments where
88     PCRE has not been installed from source.
89    
90 ph10 435 15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
91 ph10 430 libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
92     library.
93    
94 ph10 435 16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
95 ph10 432 It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
96     is not the first non-POSIX option to be added. Clearly some people find
97 ph10 433 these options useful.
98 ph10 432
99 ph10 435 17. If a caller to the POSIX matching function regexec() passes a non-zero
100 ph10 438 value for nmatch with a NULL value for pmatch, the value of
101     nmatch is forced to zero.
102 ph10 433
103 ph10 437 18. RunGrepTest did not have a test for the availability of the -u option of
104     the diff command, as RunTest does. It now checks in the same way as
105     RunTest, and also checks for the -b option.
106    
107 ph10 438 19. If an odd number of negated classes containing just a single character
108     interposed, within parentheses, between a forward reference to a named
109     subpattern and the definition of the subpattern, compilation crashed with
110     an internal error, complaining that it could not find the referenced
111     subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
112     [The bug was that it was starting one character too far in when skipping
113     over the character class, thus treating the ] as data rather than
114     terminating the class. This meant it could skip too much.]
115    
116 ph10 442 20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
117     /g option in pcretest when the pattern contains \K, which makes it possible
118     to have an empty string match not at the start, even when the pattern is
119     anchored. Updated pcretest and pcredemo to use this option.
120    
121 ph10 446 21. If the maximum number of capturing subpatterns in a recursion was greater
122     than the maximum at the outer level, the higher number was returned, but
123     with unset values at the outer level. The correct (outer level) value is
124     now given.
125    
126 ph10 447 22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
127     PCRE did not set those parentheses (unlike Perl). I have now found a way to
128     make it do so. The string so far is captured, making this feature
129     compatible with Perl.
130    
131 ph10 448 23. The tests have been re-organized, adding tests 11 and 12, to make it
132     possible to check the Perl 5.10 features against Perl 5.10.
133    
134 ph10 454 24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
135     pattern matches a fixed length string. PCRE did not allow this; now it
136     does. Neither allows recursion.
137    
138 ph10 418
139 ph10 412 Version 7.9 11-Apr-09
140 ph10 376 ---------------------
141    
142 ph10 392 1. When building with support for bzlib/zlib (pcregrep) and/or readline
143 ph10 376 (pcretest), all targets were linked against these libraries. This included
144     libpcre, libpcreposix, and libpcrecpp, even though they do not use these
145     libraries. This caused unwanted dependencies to be created. This problem
146 ph10 392 has been fixed, and now only pcregrep is linked with bzlib/zlib and only
147 ph10 376 pcretest is linked with readline.
148 ph10 392
149 ph10 376 2. The "typedef int BOOL" in pcre_internal.h that was included inside the
150     "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
151     moved outside it again, because FALSE and TRUE are already defined in AIX,
152     but BOOL is not.
153 ph10 392
154     3. The pcre_config() function was treating the PCRE_MATCH_LIMIT and
155 ph10 409 PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
156 ph10 392
157 ph10 376 4. The pcregrep documentation said spaces were inserted as well as colons (or
158     hyphens) following file names and line numbers when outputting matching
159 ph10 392 lines. This is not true; no spaces are inserted. I have also clarified the
160 ph10 376 wording for the --colour (or --color) option.
161 ph10 392
162 ph10 378 5. In pcregrep, when --colour was used with -o, the list of matching strings
163     was not coloured; this is different to GNU grep, so I have changed it to be
164     the same.
165 ph10 392
166 ph10 378 6. When --colo(u)r was used in pcregrep, only the first matching substring in
167 ph10 392 each matching line was coloured. Now it goes on to look for further matches
168     of any of the test patterns, which is the same behaviour as GNU grep.
169    
170     7. A pattern that could match an empty string could cause pcregrep to loop; it
171     doesn't make sense to accept an empty string match in pcregrep, so I have
172 ph10 379 locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
173     seems to be how GNU grep behaves.
174 ph10 392
175 ph10 380 8. The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
176 ph10 392 start or after a newline", because the conditional assertion was not being
177     correctly handled. The rule now is that both the assertion and what follows
178     in the first alternative must satisfy the test.
179    
180 ph10 405 9. If auto-callout was enabled in a pattern with a conditional group whose
181 ph10 399 condition was an assertion, PCRE could crash during matching, both with
182     pcre_exec() and pcre_dfa_exec().
183 ph10 392
184     10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
185     used for matching.
186    
187     11. Unicode property support in character classes was not working for
188 ph10 385 characters (bytes) greater than 127 when not in UTF-8 mode.
189 ph10 388
190 ph10 392 12. Added the -M command line option to pcretest.
191    
192 ph10 388 14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
193 ph10 389
194     15. Added the PCRE_NO_START_OPTIMIZE match-time option.
195 ph10 390
196 ph10 392 16. Added comments and documentation about mis-use of no_arg in the C++
197 ph10 390 wrapper.
198 ph10 392
199 ph10 391 17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
200 ph10 392 from Martin Jerabek that uses macro names for all relevant character and
201 ph10 391 string constants.
202 ph10 405
203 ph10 393 18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
204     SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
205 ph10 405 SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
206     these, but not everybody uses configure.
207    
208     19. A conditional group that had only one branch was not being correctly
209     recognized as an item that could match an empty string. This meant that an
210     enclosing group might also not be so recognized, causing infinite looping
211     (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
212     with the subject "ab", where knowledge that the repeated group can match
213 ph10 396 nothing is needed in order to break the loop.
214 ph10 405
215 ph10 397 20. If a pattern that was compiled with callouts was matched using pcre_dfa_
216 ph10 405 exec(), but without supplying a callout function, matching went wrong.
217    
218     21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
219     leak if the size of the offset vector was greater than 30. When the vector
220     is smaller, the saved offsets during recursion go onto a local stack
221     vector, but for larger vectors malloc() is used. It was failing to free
222     when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
223 ph10 400 error, in fact).
224 ph10 405
225 ph10 402 22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
226 ph10 405 heapframe that is used only when UTF-8 support is enabled. This caused no
227     problem, but was untidy.
228 ph10 376
229 ph10 405 23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
230     CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
231     included within another project.
232 ph10 411
233 ph10 407 24. Steven Van Ingelgem's patches to add more options to the CMake support,
234     slightly modified by me:
235 ph10 411
236     (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
237     not building pcregrep.
238    
239 ph10 407 (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
240 ph10 411 if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
241    
242 ph10 408 25. Forward references, both numeric and by name, in patterns that made use of
243     duplicate group numbers, could behave incorrectly or give incorrect errors,
244     because when scanning forward to find the reference group, PCRE was not
245     taking into account the duplicate group numbers. A pattern such as
246     ^X(?3)(a)(?|(b)|(q))(Y) is an example.
247 ph10 411
248     26. Changed a few more instances of "const unsigned char *" to USPTR, making
249     the feature of a custom pointer more persuasive (as requested by a user).
250 ph10 416
251 ph10 411 27. Wrapped the definitions of fileno and isatty for Windows, which appear in
252 ph10 416 pcretest.c, inside #ifndefs, because it seems they are sometimes already
253     pre-defined.
254 ph10 392
255 ph10 416 28. Added support for (*UTF8) at the start of a pattern.
256    
257 ph10 413 29. Arrange for flags added by the "release type" setting in CMake to be shown
258     in the configuration summary.
259 ph10 405
260 ph10 411
261 ph10 374 Version 7.8 05-Sep-08
262 ph10 349 ---------------------
263    
264     1. Replaced UCP searching code with optimized version as implemented for Ad
265     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
266 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
267     to 5 times on some simple patterns that I tested. Permission was given to
268     distribute the MultiStage2.py script that generates the tables (it's not in
269     the tarball, but is in the Subversion repository).
270 ph10 349
271 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
272     scripts.
273 ph10 358
274 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
275     a group with a zero qualifier. The result of the study could be incorrect,
276 ph10 358 or the function might crash, depending on the pattern.
277    
278     4. Caseless matching was not working for non-ASCII characters in back
279 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
280 ph10 358 It now works when Unicode Property Support is available.
281    
282 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
283     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
284     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
285 ph10 358 truncation.
286 ph10 349
287 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
288    
289 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
290     pointers, in case they are 64-bit values.
291 ph10 371
292     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
293     test 2 if it fails.
294    
295 ph10 359 9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
296 ph10 371 and a #define of that name to empty if it is not externally set. This is to
297     allow users of MSVC to set it if necessary.
298    
299     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
300 ph10 359 the convenience functions in the pcre_get.c source file.
301 ph10 371
302 ph10 360 11. An option change at the start of a pattern that had top-level alternatives
303     could cause overwriting and/or a crash. This command provoked a crash in
304 ph10 371 some environments:
305    
306     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
307    
308 ph10 360 This potential security problem was recorded as CVE-2008-2371.
309 ph10 371
310 ph10 361 12. For a pattern where the match had to start at the beginning or immediately
311     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
312 ph10 371 pcre_dfa_exec() could read past the end of the passed subject if there was
313 ph10 361 no match. To help with detecting such bugs (e.g. with valgrind), I modified
314     pcretest so that it places the subject at the end of its malloc-ed buffer.
315 ph10 371
316 ph10 364 13. The change to pcretest in 12 above threw up a couple more cases when pcre_
317 ph10 371 exec() might read past the end of the data buffer in UTF-8 mode.
318    
319 ph10 364 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
320 ph10 371 the data contained the byte 0x85 as part of a UTF-8 character within its
321     first line. This applied both to normal and DFA matching.
322    
323 ph10 366 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
324 ph10 371 /^[^d]*?$/8 failed to match "abc".
325 ph10 351
326 ph10 371 16. Added a missing copyright notice to pcrecpp_internal.h.
327    
328     17. Make it more clear in the documentation that values returned from
329 ph10 368 pcre_exec() in ovector are byte offsets, not character counts.
330 ph10 357
331 ph10 371 18. Tidied a few places to stop certain compilers from issuing warnings.
332 ph10 368
333 ph10 373 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
334     supplied by Stefan Weber. I made a further small update for 7.8 because
335 ph10 374 there is a change of source arrangements: the pcre_searchfuncs.c module is
336     replaced by pcre_ucd.c.
337 ph10 371
338 ph10 373
339 ph10 347 Version 7.7 07-May-08
340 ph10 321 ---------------------
341    
342     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
343 ph10 345 a string to a long long, pretend we don't even have a long long." This is
344 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
345 ph10 345
346 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
347     pre-7.6 versions, which defined a global no_arg variable instead of putting
348 ph10 332 it in the RE class. (See also #8 below.)
349 ph10 345
350     3. Remove a line of dead code, identified by coverity and reported by Nuno
351     Lopes.
352    
353 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
354 ph10 321
355 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
356 ph10 345 of files, instead of just to the final components.
357    
358 ph10 324 (2) If there was more than one level of directory, the subdirectories were
359     skipped unless they satisfied the include/exclude conditions. This is
360     inconsistent with GNU grep (and could even be seen as contrary to the
361     pcregrep specification - which I improved to make it absolutely clear).
362     The action now is always to scan all levels of directory, and just
363     apply the include/exclude patterns to regular files.
364 ph10 345
365 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
366 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
367    
368 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
369 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
370 ph10 326 doesn't support NULs in patterns.
371 ph10 345
372     7. Added some missing "const"s to declarations of static tables in
373     pcre_compile.c and pcre_dfa_exec.c.
374    
375 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
376 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
377 ph10 345 first patch. And a third patch - this was a messy problem.)
378 ph10 321
379 ph10 345 9. Applied Craig's patch to remove the use of push_back().
380    
381 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
382     matching function regexec().
383 ph10 345
384     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
385     which, however, unlike Perl's \g{...}, are subroutine calls, not back
386 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
387     Oniguruma does).
388 ph10 345
389     12. Previously, a group with a zero repeat such as (...){0} was completely
390 ph10 335 omitted from the compiled regex. However, this means that if the group
391     was called as a subroutine from elsewhere in the pattern, things went wrong
392 ph10 345 (an internal error was given). Such groups are now left in the compiled
393     pattern, with a new opcode that causes them to be skipped at execution
394 ph10 335 time.
395 ph10 345
396 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
397     to the way PCRE behaves:
398 ph10 345
399 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
400 ph10 345
401     (b) A back reference to an unmatched subpattern matches an empty string
402 ph10 336 (Perl fails the current match path).
403 ph10 345
404 ph10 341 (c) A data ] in a character class must be notated as \] because if the
405 ph10 345 first data character in a class is ], it defines an empty class. (In
406 ph10 341 Perl it is not possible to have an empty class.) The empty class []
407     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
408     The negative empty class [^] matches any one character, independently
409     of the DOTALL setting.
410 ph10 345
411     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
412 ph10 340 non-existent subpattern following a character class starting with ']' and
413     containing () gave an internal compiling error instead of "reference to
414     non-existent subpattern". Fortunately, when the pattern did exist, the
415 ph10 345 compiled code was correct. (When scanning forwards to check for the
416 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
417 ph10 345 the class, so got the count wrong. When actually compiling, the reference
418 ph10 340 was subsequently set up correctly.)
419 ph10 345
420 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
421 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
422     other assertions are supported. I have made pcre_dfa_exec() support
423     (*FAIL).
424    
425 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
426 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
427     cannot be changed at match time, I realized I could make a small
428     improvement to matching performance by compiling OP_ALLANY instead of
429     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
430     on the OP_ANY path.
431    
432     17. Compiling pcretest on Windows with readline support failed without the
433 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
434 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
435    
436 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
437 ph10 345 ncurses library to be included for pcretest when ReadLine support is
438     requested, but also to allow for it to be overridden. This patch came from
439     Daniel Bergström.
440 ph10 347
441 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
442 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
443     any errors with the current Unicode tables. Thanks to Peter Kankowski for
444     spotting this.
445 ph10 324
446 ph10 332
447 ph10 319 Version 7.6 28-Jan-08
448 ph10 300 ---------------------
449    
450 ph10 302 1. A character class containing a very large number of characters with
451     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
452     overflow.
453 ph10 309
454     2. Patch to cut out the "long long" test in pcrecpp_unittest when
455     HAVE_LONG_LONG is not defined.
456    
457 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
458 ph10 304 bring them up to date and include new features. This patch includes:
459 ph10 309
460 ph10 304 - Fixed PH's badly added libz and libbz2 support.
461     - Fixed a problem with static linking.
462 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
463 ph10 304 - Fixed dftables problem and added an option.
464     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
465     HAVE_LONG_LONG.
466     - Added readline support for pcretest.
467 ph10 309 - Added an listing of the option settings after cmake has run.
468    
469 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
470     "pcre.dll" under mingw when using Configure/Make. I added stuff to
471     Makefile.am that cause it to include this special target, without
472     affecting anything else. Note that the same mingw target plus all
473     the other distribution libraries and programs are now supported
474     when configuring with CMake (see 6 below) instead of with
475     Configure/Make.
476 ph10 309
477 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
478     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
479 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
480     solves the problem, but it does no harm.
481 ph10 313
482 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
483 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
484 ph10 314 with CMake, and also correct the comment about stack recursion.
485 ph10 313
486 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
487 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
488     of a program that users should build themselves after PCRE is installed, so
489     building it automatically is not really right. What is more, it gave
490 ph10 312 trouble in some build environments.
491 ph10 300
492 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
493 ph10 308
494 ph10 319
495 ph10 298 Version 7.5 10-Jan-08
496 ph10 263 ---------------------
497    
498     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
499     values in parens when parsing an RE using the C++ wrapper."
500 ph10 286
501 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
502     Characters greater than 255 were excluded from the class instead of being
503     included.
504 ph10 286
505     3. The same bug as (2) above applied to negated POSIX classes such as
506 ph10 265 [:^space:].
507 ph10 286
508 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
509     defined or documented. It seems to have been a typo for PCRE_STATIC, so
510 ph10 286 I have changed it.
511    
512 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
513 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
514     first named subpattern whose name started with "a" (in other words, the
515 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
516     expected" is now given for (?&) (a zero-length name), and this patch also
517     makes it give the same error for \k'' (previously it complained that that
518     was a reference to a non-existent subpattern).
519 ph10 286
520 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
521 ph10 286 this is right because (?- can be followed by option settings as well as by
522 ph10 269 digits. I have, however, made the messages clearer.
523 ph10 286
524 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
525     than the number used in the conditional) now cause a compile-time error.
526     This is actually not compatible with Perl, which accepts such patterns, but
527     treats the conditional as always being FALSE (as PCRE used to), but it
528     seems to me that giving a diagnostic is better.
529 ph10 286
530 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
531 ph10 275 and messages.
532 ph10 286
533     9. Fix two occurrences of "backslash" in comments that should have been
534     "backspace".
535    
536     10. Remove two redundant lines of code that can never be obeyed (their function
537     was moved elsewhere).
538    
539     11. The program that makes PCRE's Unicode character property table had a bug
540     which caused it to generate incorrect table entries for sequences of
541 ph10 277 characters that have the same character type, but are in different scripts.
542 ph10 286 It amalgamated them into a single range, with the script of the first of
543 ph10 277 them. In other words, some characters were in the wrong script. There were
544     thirteen such cases, affecting characters in the following ranges:
545 ph10 286
546 ph10 277 U+002b0 - U+002c1
547     U+0060c - U+0060d
548 ph10 286 U+0061e - U+00612
549 ph10 277 U+0064b - U+0065e
550     U+0074d - U+0076d
551     U+01800 - U+01805
552     U+01d00 - U+01d77
553     U+01d9b - U+01dbf
554     U+0200b - U+0200f
555     U+030fc - U+030fe
556     U+03260 - U+0327f
557     U+0fb46 - U+0fbb1
558     U+10450 - U+1049d
559 ph10 286
560 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
561     compatible with GNU grep in that, if there was more than one match in a
562     line, it showed only the first of them. It now behaves in the same way as
563     GNU grep.
564 ph10 286
565     13. If the -o and -v options were combined for pcregrep, it printed a blank
566     line for every non-matching line. GNU grep prints nothing, and pcregrep now
567     does the same. The return code can be used to tell if there were any
568     non-matching lines.
569    
570 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
571    
572     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
573 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
574 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
575     and both kinds of lookbehind were skipped).
576    
577 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
578 ph10 284 inclusion of <windows.h> to before rather than after the definition of
579     INVALID_FILE_ATTRIBUTES (patch from David Byron).
580 ph10 263
581 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
582 ph10 286 character property caused pcre_compile() to compile bad code, which led at
583     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
584     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
585     caused the error; without that there was no problem.
586 ph10 263
587 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
588 ph10 286
589 ph10 289 19. Added --enable-pcretest-libreadline.
590 ph10 286
591 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
592 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
593 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
594     later patch that removed the other one (the right fix) and added unit tests
595     that check the return values (which was not done before).
596 ph10 292
597 ph10 291 21. Several CMake things:
598 ph10 287
599 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
600 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
601 ph10 288
602 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
603     linked with the newly-built libraries, not previously installed ones.
604 ph10 291
605 ph10 292 (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
606 ph10 298
607     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
608     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
609     UTF-8 newline character). The key issue is that the pattern starts .*;
610     this means that the match must be either at the beginning, or after a
611     newline. The bug was in the code for advancing after a failed match and
612     checking that the new position followed a newline. It was not taking
613 ph10 294 account of UTF-8 characters correctly.
614 ph10 298
615     23. PCRE was behaving differently from Perl in the way it recognized POSIX
616     character classes. PCRE was not treating the sequence [:...:] as a
617     character class unless the ... were all letters. Perl, however, seems to
618     allow any characters between [: and :], though of course it rejects as
619     unknown any "names" that contain non-letters, because all the known class
620     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
621     for example, whereas PCRE did not - it did not recognize a POSIX character
622     class. This seemed a bit dangerous, so the code has been changed to be
623     closer to Perl. The behaviour is not identical to Perl, because PCRE will
624     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
625     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
626     Perl does, and where it didn't before.
627    
628 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
629     Windows environments %n is disabled by default.
630 ph10 292
631    
632 ph10 260 Version 7.4 21-Sep-07
633 ph10 230 ---------------------
634    
635     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
636 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
637     LF". That isn't really right - the whole point of the change was to try to
638     help when there was an actual mention of one of the two characters. So now
639     the change happens only if \r or \n (or a literal CR or LF) character is
640 ph10 230 encountered.
641 ph10 231
642     2. The 32-bit options word was also used for 6 internal flags, but the numbers
643     of both had grown to the point where there were only 3 bits left.
644     Fortunately, there was spare space in the data structure, and so I have
645     moved the internal flags into a new 16-bit field to free up more option
646 ph10 230 bits.
647 ph10 231
648     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
649     but did not set the internal JCHANGED flag - either of these is enough to
650     control the way the "get" function works - but the PCRE_INFO_JCHANGED
651     facility is supposed to tell if (?J) was ever used, so now (?J) at the
652 ph10 230 start sets both bits.
653    
654 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
655     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
656 ph10 230
657 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
658    
659     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
660 ph10 233 compatibility, even though it is no longer used.
661 ph10 243
662     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
663 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
664 ph10 259 windows.h file is present (where different names are used). [This was
665 ph10 257 reversed later after testing - see 16 below.]
666 ph10 243
667     8. Changed all #include <config.h> to #include "config.h". There were also
668 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
669 ph10 243
670 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
671 ph10 243 sequence off the lines that it output.
672    
673     10. It was pointed out to me that arrays of string pointers cause lots of
674     relocations when a shared library is dynamically loaded. A technique of
675     using a single long string with a table of offsets can drastically reduce
676     these. I have refactored PCRE in four places to do this. The result is
677 ph10 240 dramatic:
678 ph10 243
679 ph10 240 Originally: 290
680     After changing UCP table: 187
681 ph10 243 After changing error message table: 43
682 ph10 240 After changing table of "verbs" 36
683     After changing table of Posix names 22
684 ph10 243
685 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
686 ph10 247
687 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
688 ph10 247 unicode-properties was also set.
689    
690 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
691 ph10 231
692 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
693     checked only for CRLF.
694 ph10 233
695 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
696    
697 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
698 ph10 253
699 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
700 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
701     entirely. This removes changes made in 7 above.
702 ph10 256
703 ph10 261 17. The CMake files have been updated, and there is now more information about
704     building with CMake in the NON-UNIX-USE document.
705 ph10 257
706 ph10 261
707 ph10 228 Version 7.3 28-Aug-07
708 ph10 157 ---------------------
709    
710 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
711     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
712     brackets there is not right, since it causes compilers to look for an
713     installed pcre.h, not the version that is in the source that is being
714     compiled (which of course may be different). I have changed it back to:
715 ph10 197
716 ph10 189 #include "pcre.h"
717 ph10 197
718     I have a vague recollection that the change was concerned with compiling in
719     different directories, but in the new build system, that is taken care of
720     by the VPATH setting the Makefile.
721    
722 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
723     when the subject happened to end in the byte 0x85 (e.g. if the last
724     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
725     characters but of course it shouldn't be taken as a newline when it is part
726     of another character. The bug was that, for an unlimited repeat of . in
727     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
728     characters when looking for a newline.
729 ph10 197
730     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
731    
732     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
733     in debug output.
734    
735 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
736     long printing in the pcrecpp unittest when running under MinGW.
737 ph10 189
738 ph10 197 6. ESC_K was left out of the EBCDIC table.
739 ph10 189
740 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
741     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
742     limit also applies to "virtual nesting" when a pattern is recursive, and in
743     this case 1000 isn't so big. I have been able to remove this limit at the
744     expense of backing off one optimization in certain circumstances. Normally,
745     when pcre_exec() would call its internal match() function recursively and
746     immediately return the result unconditionally, it uses a "tail recursion"
747     feature to save stack. However, when a subpattern that can match an empty
748     string has an unlimited repetition quantifier, it no longer makes this
749     optimization. That gives it a stack frame in which to save the data for
750     checking that an empty string has been matched. Previously this was taken
751     from the 1000-entry workspace that had been reserved. So now there is no
752     explicit limit, but more stack is used.
753 ph10 189
754 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
755     syntax that is required for Windows, and which was going wrong for the
756     pcreposix and pcrecpp parts of the library. These were overlooked when this
757     problem was solved for the main library.
758 ph10 197
759 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
760     the size of patterns that contain repeated groups with explicit upper
761     limits. As the maximum quantifier is 65535, the maximum group length was
762     set at 30,000 so that the product of these two numbers did not overflow a
763     32-bit integer. However, it turns out that people want to use groups that
764     are longer than 30,000 bytes (though not repeat them that many times).
765     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
766     made it possible to implement the integer overflow checks in a much more
767     dynamic way, which I have now done. The artificial limitation on group
768     length has been removed - we now have only the limit on the total length of
769     the compiled pattern, which depends on the LINK_SIZE setting.
770 ph10 208
771     10. Fixed a bug in the documentation for get/copy named substring when
772     duplicate names are permitted. If none of the named substrings are set, the
773     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
774     empty string.
775    
776     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
777     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
778     because the ] is interpreted as the first data character and the
779     terminating ] is not found. PCRE has been made compatible with Perl in this
780     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
781     cause memory overwriting.
782    
783 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
784     string has been matched (to stop an infinite loop). It was not recognizing
785 ph10 208 a conditional subpattern that could match an empty string if that
786 ph10 206 subpattern was within another subpattern. For example, it looped when
787 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
788 ph10 206 condition was not nested. This bug has been fixed.
789 ph10 208
790 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
791     past the start of the subject in the presence of bytes with the top bit
792     set, for example "\x8aBCD".
793 ph10 211
794 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
795     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
796 ph10 200
797 ph10 211 14. Optimized (?!) to (*FAIL).
798 ph10 202
799 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
800     This restricts code points to be within the range 0 to 0x10FFFF, excluding
801     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
802     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
803     does: it's just the validity check that is more restrictive.
804 ph10 220
805     16. Inserted checks for integer overflows during escape sequence (backslash)
806     processing, and also fixed erroneous offset values for syntax errors during
807     backslash processing.
808    
809 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
810 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
811    
812 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
813     caused an overrun.
814 ph10 220
815     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
816     something other than just ASCII characters) inside a group that had an
817     unlimited repeat caused a loop at compile time (while checking to see
818     whether the group could match an empty string).
819    
820 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
821     [\P{Any}] did so. (Error in the code for printing property names.)
822 ph10 210
823 ph10 220 21. An orphan \E inside a character class could cause a crash.
824    
825     22. A repeated capturing bracket such as (A)? could cause a wild memory
826 ph10 218 reference during compilation.
827 ph10 220
828     23. There are several functions in pcre_compile() that scan along a compiled
829     expression for various reasons (e.g. to see if it's fixed length for look
830 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
831 ph10 220 present in the pattern. These operators have additional parameters compared
832     with \d, etc, and these were not being taken into account when moving along
833 ph10 218 the compiled data. Specifically:
834 ph10 220
835     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
836     length.
837    
838     (b) An item such as \pL+ within a repeated group could cause crashes or
839 ph10 218 loops.
840 ph10 220
841 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
842 ph10 220 "reference to non-existent subpattern" error.
843    
844 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
845    
846 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
847 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
848 ph10 211
849 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
850 ph10 218
851 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
852 ph10 223 character were causing crashes (broken optimization).
853 ph10 227
854 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
855 ph10 227 \p or \P) caused a compile-time loop.
856    
857 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
858     break. For example, the unstudied pattern [\r\n]A does not match the string
859     "\r\nA" because change 7.0/46 below moves the current point on by two
860     characters after failing to match at the start. However, the pattern \nA
861 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
862     the same is true. There doesn't seem any very clean way out of this, but
863     what I have chosen to do makes the common cases work: PCRE now takes note
864     of whether there can be an explicit match for \r or \n anywhere in the
865     pattern, and if so, 7.0/46 no longer applies. As part of this change,
866     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
867     pattern has explicit CR or LF references.
868 ph10 222
869 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
870 ph10 223
871 ph10 227
872 ph10 189 Version 7.2 19-Jun-07
873     ---------------------
874    
875 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
876     which is apparently normally available under Windows.
877 ph10 159
878     2. Re-jig the pcregrep tests with different newline settings in an attempt
879     to make them independent of the local environment's newline setting.
880 ph10 157
881 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
882 ph10 165
883 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
884     was not 2, because the output contained actual offsets. The recent new
885 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
886     usable with all link sizes.
887    
888 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
889     stack recursion. This gives a massive performance boost under BSD, but just
890 ph10 165 a small improvement under Linux. However, it saves one field in the frame
891 ph10 164 in all cases.
892 ph10 172
893 ph10 166 6. Added more features from the forthcoming Perl 5.10:
894 ph10 172
895 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
896     recursion call. It refers to the nth most recently opened parentheses.
897 ph10 172
898 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
899 ph10 172 to be opened parentheses.
900    
901     (c) Conditions that refer to capturing parentheses can be specified
902 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
903 ph10 172
904 ph10 168 (d) \K resets the start of the current match so that everything before
905 ph10 172 is not part of it.
906    
907 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
908 ph10 172
909 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
910 ph10 172 reference syntax.
911 ph10 182
912 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
913 ph10 182 alternative starts with the same number.
914 ph10 172
915 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
916    
917 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
918     PCRE_INFO_JCHANGED.
919    
920     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
921     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
922 ph10 170 for detecting groups that can match an empty string.
923 ph10 159
924 ph10 172 9. A pattern with a very large number of alternatives (more than several
925     hundred) was running out of internal workspace during the pre-compile
926     phase, where pcre_compile() figures out how much memory will be needed. A
927     bit of new cunning has reduced the workspace needed for groups with
928     alternatives. The 1000-alternative test pattern now uses 12 bytes of
929     workspace instead of running out of the 4096 that are available.
930 ph10 182
931 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
932 ph10 172
933 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
934     The report of the bug said:
935 ph10 182
936 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
937     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
938 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
939 ph10 185
940 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
941 ph10 185 it matched the wrong number of bytes.
942 ph10 172
943 ph10 179
944 ph10 155 Version 7.1 24-Apr-07
945 ph10 98 ---------------------
946    
947 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
948 ph10 122 that is more "standard", making use of automake and other Autotools. There
949 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
950     on this.
951 ph10 111
952     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
953     for recursive directory scanning broke on some systems because the files
954     are not scanned in any specific order and on different systems the order
955     was different. A call to "sort" has been inserted into RunGrepTest for the
956     approprate test as a short-term fix. In the longer term there may be an
957 ph10 100 alternative.
958 ph10 111
959 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
960 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
961     people do their own conversions for various reasons). The problems
962     concerned the use of low-level troff macros .br and .in. I have therefore
963     removed all such uses from the man pages (some were redundant, some could
964 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
965     HTML has been updated to handle .nf/.fi and to complain if it encounters
966     .br or .in.
967 ph10 111
968 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
969 ph10 123 arranged for config.h to be included in the distribution, with the name
970 ph10 111 config.h.generic, for the benefit of those who have to compile without
971     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
972    
973     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
974     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
975 ph10 127 makevp.bat for the current PCRE, using the additional files
976 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
977 ph10 111
978     6. A Windows user reported a minor discrepancy with test 2, which turned out
979     to be caused by a trailing space on an input line that had got lost in his
980 ph10 102 copy. The trailing space was an accident, so I've just removed it.
981 ph10 111
982 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
983 ph10 111 that is needed.
984    
985 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
986     as "const" (a) because they are and (b) because it helps the PHP
987     maintainers who have recently made a script to detect big data structures
988 ph10 111 in the php code that should be moved to the .rodata section. I remembered
989     to update Builducptable as well, so it won't revert if ucptable.h is ever
990 ph10 105 re-created.
991 ph10 111
992     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
993 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
994 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
995     support is not required. This saves 1.5-2K of code, which is important in
996 ph10 107 some applications.
997 ph10 111
998 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
999 ph10 111 so as not to refer to the tables, even though these functions will never be
1000     called when UTF-8 support is disabled. Otherwise there are problems with a
1001     shared library.
1002    
1003 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1004    
1005     (a) It was defining its arguments as char * instead of void *.
1006    
1007 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
1008     a long time ago when I wrote it, but is no longer the case.
1009    
1010 ph10 118 The emulated memove() is provided for those environments that have neither
1011 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
1012 ph10 118 is clearly not the case, as these two bugs were recently reported.
1013 ph10 123
1014 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1015 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
1016     pages, and it removes trailing spaces from listed files. It also creates
1017     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1018     case, it wraps all the #defines with #ifndefs. This script should be run
1019 ph10 111 before "make dist".
1020 ph10 123
1021 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1022     with Unicode property support.
1023 ph10 123
1024     (a) For a maximizing quantifier, if the two different cases of the
1025     character were of different lengths in their UTF-8 codings (there are
1026     some cases like this - I found 11), and the matching function had to
1027 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
1028     were both the same length.
1029 ph10 123
1030     (b) When PCRE was configured to use the heap rather than the stack for
1031     recursion during matching, it was not correctly preserving the data for
1032     the other case of a UTF-8 character when checking ahead for a match
1033     while processing a minimizing repeat. If the check also involved
1034 ph10 115 matching a wide character, but failed, corruption could cause an
1035     erroneous result when trying to check for a repeat of the original
1036     character.
1037 ph10 123
1038 ph10 116 13. Some tidying changes to the testing mechanism:
1039 ph10 98
1040 ph10 116 (a) The RunTest script now detects the internal link size and whether there
1041     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1042 ph10 123 values substituted by "configure". (The RunGrepTest script already did
1043     this for UTF-8.) The configure.ac script no longer substitutes the
1044     relevant variables.
1045    
1046 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
1047     with length and offset values. This means that the output is different
1048     for different internal link sizes. Test 2 is skipped for link sizes
1049     other than 2 because of this, bypassing the problem. Unfortunately,
1050     there was also a test in test 3 (the locale tests) that used /B and
1051 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
1052     I have added a new /Z option to pcretest that replaces the length and
1053     offset values with spaces. This is now used to make test 3 independent
1054 ph10 122 of link size. (Test 2 will be tidied up later.)
1055 ph10 123
1056     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1057 ph10 122 segmentation fault instead of returning the appropriate error message.
1058 ph10 134
1059 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
1060 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1061     This doesn't seem right; it now treats the CRLF combination as the line
1062     ending, and so does not match in that case. It's only a pattern such as ^$
1063     that would hit this one: something like ^ABC$ would have failed after \r
1064     and then tried again after \r\n.
1065    
1066 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1067 ph10 134 in an attempt to make files that differ only in their line terminators
1068     compare equal. This works on Linux.
1069 ph10 142
1070 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
1071     as it exited. This is now fixed, thanks to valgrind.
1072 ph10 142
1073 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1074 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1075     was because its rules for how to advance for /g after matching an empty
1076 ph10 143 string at the end of a line did not allow for this case. They now check for
1077     it specially.
1078 ph10 150
1079     20. pcretest is supposed to handle patterns and data of any length, by
1080     extending its buffers when necessary. It was getting this wrong when the
1081 ph10 147 buffer for a data line had to be extended.
1082 ph10 150
1083 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1084 ph10 150 CRLF as a newline sequence.
1085 ph10 152
1086 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1087 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1088     I have nevertheless tidied it up.
1089 ph10 111
1090 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
1091 ph10 123
1092 ph10 153 24. Added a man page for pcre-config.
1093 ph10 152
1094 ph10 153
1095 nigel 93 Version 7.0 19-Dec-06
1096     ---------------------
1097    
1098     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1099     moving to gcc 4.1.1.
1100    
1101     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1102     sys/time.h, which is documented as needed for this function. It doesn't
1103     seem to matter on Linux, but it showed up on some releases of OS X.
1104    
1105     3. It seems that there are systems where bytes whose values are greater than
1106     127 match isprint() in the "C" locale. The "C" locale should be the
1107     default when a C program starts up. In most systems, only ASCII printing
1108     characters match isprint(). This difference caused the output from pcretest
1109     to vary, making some of the tests fail. I have changed pcretest so that:
1110    
1111     (a) When it is outputting text in the compiled version of a pattern, bytes
1112     other than 32-126 are always shown as hex escapes.
1113    
1114     (b) When it is outputting text that is a matched part of a subject string,
1115     it does the same, unless a different locale has been set for the match
1116     (using the /L modifier). In this case, it uses isprint() to decide.
1117    
1118     4. Fixed a major bug that caused incorrect computation of the amount of memory
1119     required for a compiled pattern when options that changed within the
1120     pattern affected the logic of the preliminary scan that determines the
1121     length. The relevant options are -x, and -i in UTF-8 mode. The result was
1122     that the computed length was too small. The symptoms of this bug were
1123     either the PCRE error "internal error: code overflow" from pcre_compile(),
1124     or a glibc crash with a message such as "pcretest: free(): invalid next
1125     size (fast)". Examples of patterns that provoked this bug (shown in
1126     pcretest format) are:
1127    
1128     /(?-x: )/x
1129     /(?x)(?-x: \s*#\s*)/
1130     /((?i)[\x{c0}])/8
1131     /(?i:[\x{c0}])/8
1132    
1133     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1134     is now done differently.
1135    
1136     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1137     wrapper classes; (b) implement a new function in the C++ scanner that is
1138     more efficient than the old way of doing things because it avoids levels of
1139     recursion in the regex matching; (c) add a paragraph to the documentation
1140     for the FullMatch() function.
1141    
1142     6. The escape sequence \n was being treated as whatever was defined as
1143     "newline". Not only was this contrary to the documentation, which states
1144     that \n is character 10 (hex 0A), but it also went horribly wrong when
1145     "newline" was defined as CRLF. This has been fixed.
1146    
1147     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1148     was being set to -1 for the "end of line" case (supposedly a value that no
1149     character can have). Though this value is never used (the check for end of
1150     line is "zero bytes in current character"), it caused compiler complaints.
1151     I've changed it to 0xffffffff.
1152    
1153     8. In pcre_version.c, the version string was being built by a sequence of
1154     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1155     string (as it is for production releases) called a macro with an empty
1156     argument. The C standard says the result of this is undefined. The gcc
1157     compiler treats it as an empty string (which was what was wanted) but it is
1158     reported that Visual C gives an error. The source has been hacked around to
1159     avoid this problem.
1160    
1161     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1162     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1163     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1164     of them did).
1165    
1166     10. Originally, pcretest opened its input and output without "b"; then I was
1167     told that "b" was needed in some environments, so it was added for release
1168     5.0 to both the input and output. (It makes no difference on Unix-like
1169     systems.) Later I was told that it is wrong for the input on Windows. I've
1170     now abstracted the modes into two macros, to make it easier to fiddle with
1171     them, and removed "b" from the input mode under Windows.
1172    
1173     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1174    
1175     12. Added -help and --help to pcretest as an official way of being reminded
1176     of the options.
1177    
1178     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1179     and pcrecpp.cc because they annoy compilers at high warning levels.
1180    
1181     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1182    
1183     15. Fixed an occurrence of == in configure.ac that should have been = (shell
1184     scripts are not C programs :-) and which was not noticed because it works
1185     on Linux.
1186    
1187     16. pcretest is supposed to handle any length of pattern and data line (as one
1188     line or as a continued sequence of lines) by extending its input buffer if
1189     necessary. This feature was broken for very long pattern lines, leading to
1190     a string of junk being passed to pcre_compile() if the pattern was longer
1191     than about 50K.
1192    
1193     17. I have done a major re-factoring of the way pcre_compile() computes the
1194     amount of memory needed for a compiled pattern. Previously, there was code
1195     that made a preliminary scan of the pattern in order to do this. That was
1196     OK when PCRE was new, but as the facilities have expanded, it has become
1197     harder and harder to keep it in step with the real compile phase, and there
1198     have been a number of bugs (see for example, 4 above). I have now found a
1199     cunning way of running the real compile function in a "fake" mode that
1200     enables it to compute how much memory it would need, while actually only
1201     ever using a few hundred bytes of working memory and without too many
1202     tests of the mode. This should make future maintenance and development
1203     easier. A side effect of this work is that the limit of 200 on the nesting
1204     depth of parentheses has been removed (though this was never a serious
1205     limitation, I suspect). However, there is a downside: pcre_compile() now
1206     runs more slowly than before (30% or more, depending on the pattern). I
1207     hope this isn't a big issue. There is no effect on runtime performance.
1208    
1209     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1210     newline (only possible for the last line of a file) and it was a
1211     pattern that set a locale (followed by /Lsomething), pcretest crashed.
1212    
1213     19. Added additional timing features to pcretest. (1) The -tm option now times
1214     matching only, not compiling. (2) Both -t and -tm can be followed, as a
1215     separate command line item, by a number that specifies the number of
1216     repeats to use when timing. The default is 50000; this gives better
1217     precision, but takes uncomfortably long for very large patterns.
1218    
1219     20. Extended pcre_study() to be more clever in cases where a branch of a
1220     subpattern has no definite first character. For example, (a*|b*)[cd] would
1221     previously give no result from pcre_study(). Now it recognizes that the
1222     first character must be a, b, c, or d.
1223    
1224     21. There was an incorrect error "recursive call could loop indefinitely" if
1225     a subpattern (or the entire pattern) that was being tested for matching an
1226     empty string contained only one non-empty item after a nested subpattern.
1227     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1228     incorrectly, because the \d was being skipped in the check.
1229    
1230     22. The pcretest program now has a new pattern option /B and a command line
1231     option -b, which is equivalent to adding /B to every pattern. This causes
1232     it to show the compiled bytecode, without the additional information that
1233     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1234     is the same as /B/I).
1235    
1236     23. A new optimization is now able automatically to treat some sequences such
1237     as a*b as a*+b. More specifically, if something simple (such as a character
1238     or a simple class like \d) has an unlimited quantifier, and is followed by
1239     something that cannot possibly match the quantified thing, the quantifier
1240     is automatically "possessified".
1241    
1242     24. A recursive reference to a subpattern whose number was greater than 39
1243     went wrong under certain circumstances in UTF-8 mode. This bug could also
1244     have affected the operation of pcre_study().
1245    
1246     25. Realized that a little bit of performance could be had by replacing
1247     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1248    
1249     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1250    
1251     27. Possessive quantifiers such as a++ were previously implemented by turning
1252     them into atomic groups such as ($>a+). Now they have their own opcodes,
1253     which improves performance. This includes the automatically created ones
1254     from 23 above.
1255    
1256     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1257     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1258     the first matched character to be a colon. This applied both to named and
1259     numbered groups.
1260    
1261     29. The ucpinternal.h header file was missing its idempotency #ifdef.
1262    
1263     30. I was sent a "project" file called libpcre.a.dev which I understand makes
1264     building PCRE on Windows easier, so I have included it in the distribution.
1265    
1266     31. There is now a check in pcretest against a ridiculously large number being
1267     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1268     loop, the loop is abandoned.
1269    
1270     32. Forward references to subpatterns in conditions such as (?(2)...) where
1271     subpattern 2 is defined later cause pcre_compile() to search forwards in
1272     the pattern for the relevant set of parentheses. This search went wrong
1273     when there were unescaped parentheses in a character class, parentheses
1274     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1275    
1276     33. "Subroutine" calls and backreferences were previously restricted to
1277     referencing subpatterns earlier in the regex. This restriction has now
1278     been removed.
1279    
1280     34. Added a number of extra features that are going to be in Perl 5.10. On the
1281     whole, these are just syntactic alternatives for features that PCRE had
1282     previously implemented using the Python syntax or my own invention. The
1283     other formats are all retained for compatibility.
1284    
1285     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1286     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1287     also .NET compatible.
1288    
1289     (b) A recursion or subroutine call to a named group can now be defined as
1290     (?&name) as well as (?P>name).
1291    
1292     (c) A backreference to a named group can now be defined as \k<name> or
1293     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1294     5.10, are also .NET compatible.
1295    
1296     (d) A conditional reference to a named group can now use the syntax
1297     (?(<name>) or (?('name') as well as (?(name).
1298    
1299     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1300     groups (named and numbered) that are never evaluated inline, but can be
1301     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1302     is always false. There may be only one alternative in such a group.
1303    
1304     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1305     as the simple (?(R). The condition is true only if the most recent
1306     recursion is that of the given number or name. It does not search out
1307     through the entire recursion stack.
1308    
1309     (g) The escape \gN or \g{N} has been added, where N is a positive or
1310     negative number, specifying an absolute or relative reference.
1311    
1312     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1313     some "unreachable code" warnings.
1314    
1315     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1316     things, this adds five new scripts.
1317    
1318     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1319     There were also incompatibilities regarding the handling of \Q..\E inside
1320     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1321     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1322    
1323     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1324     matches an empty string, and forcibly breaks the loop. There were bugs in
1325     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1326     against aaaa the result was just "a" rather than "aaaa", for example. Two
1327     separate and independent bugs (that affected different cases) have been
1328     fixed.
1329    
1330     39. Refactored the code to abolish the use of different opcodes for small
1331     capturing bracket numbers. This is a tidy that I avoided doing when I
1332     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1333     The new approach is not only tidier, it makes it possible to reduce the
1334     memory needed to fix the previous bug (38).
1335    
1336     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1337     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1338     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1339     mode.
1340    
1341     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1342     report.
1343    
1344     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1345     copy construction and assignment in the C++ wrapper.
1346    
1347     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1348     couple of bugs that could have given wrong results in the "--newline=crlf"
1349     case.
1350    
1351     44. Added a number of casts and did some reorganization of signed/unsigned int
1352     variables following suggestions from Dair Grant. Also renamed the variable
1353     "this" as "item" because it is a C++ keyword.
1354    
1355     45. Arranged for dftables to add
1356    
1357     #include "pcre_internal.h"
1358    
1359     to pcre_chartables.c because without it, gcc 4.x may remove the array
1360     definition from the final binary if PCRE is built into a static library and
1361     dead code stripping is activated.
1362    
1363     46. For an unanchored pattern, if a match attempt fails at the start of a
1364     newline sequence, and the newline setting is CRLF or ANY, and the next two
1365     characters are CRLF, advance by two characters instead of one.
1366    
1367    
1368 nigel 91 Version 6.7 04-Jul-06
1369     ---------------------
1370    
1371     1. In order to handle tests when input lines are enormously long, pcretest has
1372     been re-factored so that it automatically extends its buffers when
1373     necessary. The code is crude, but this _is_ just a test program. The
1374     default size has been increased from 32K to 50K.
1375    
1376     2. The code in pcre_study() was using the value of the re argument before
1377     testing it for NULL. (Of course, in any sensible call of the function, it
1378     won't be NULL.)
1379    
1380     3. The memmove() emulation function in pcre_internal.h, which is used on
1381     systems that lack both memmove() and bcopy() - that is, hardly ever -
1382     was missing a "static" storage class specifier.
1383    
1384     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1385     containing an extended class (one that cannot be represented by a bitmap
1386     because it contains high-valued characters or Unicode property items, e.g.
1387     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1388     pattern, but PCRE should not loop if you do not (it no longer does).
1389     [Detail: two cases were found: (a) a repeated subpattern containing an
1390     extended class; (b) a recursive reference to a subpattern that followed a
1391     previous extended class. It wasn't skipping over the extended class
1392     correctly when UTF-8 mode was not set.]
1393    
1394     5. A negated single-character class was not being recognized as fixed-length
1395     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1396     compile error "lookbehind assertion is not fixed length".
1397    
1398     6. The RunPerlTest auxiliary script was showing an unexpected difference
1399     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1400     write a Perl script that can interpret lines of an input file either as
1401     byte characters or as UTF-8, which is what "perltest" was being required to
1402     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1403     can't do is switch easily at run time between having the "use utf8;" pragma
1404     or not. In the end, I fudged it by using the RunPerlTest script to insert
1405     "use utf8;" explicitly for the UTF-8 tests.
1406    
1407     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1408     the end of the subject string, contrary to the documentation and to what
1409     Perl does. This was true of both matching functions. Now it matches only at
1410     the start of the subject and immediately after *internal* newlines.
1411    
1412     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1413     a pointer to an int instead of a pointer to an unsigned long int. This
1414     caused problems on 64-bit systems.
1415    
1416     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1417     instance of the 'standard' template library not being so standard".
1418    
1419     10. There was no check on the number of named subpatterns nor the maximum
1420     length of a subpattern name. The product of these values is used to compute
1421     the size of the memory block for a compiled pattern. By supplying a very
1422     long subpattern name and a large number of named subpatterns, the size
1423     computation could be caused to overflow. This is now prevented by limiting
1424     the length of names to 32 characters, and the number of named subpatterns
1425     to 10,000.
1426    
1427     11. Subpatterns that are repeated with specific counts have to be replicated in
1428     the compiled pattern. The size of memory for this was computed from the
1429     length of the subpattern and the repeat count. The latter is limited to
1430     65535, but there was no limit on the former, meaning that integer overflow
1431     could in principle occur. The compiled length of a repeated subpattern is
1432     now limited to 30,000 bytes in order to prevent this.
1433    
1434     12. Added the optional facility to have named substrings with the same name.
1435    
1436     13. Added the ability to use a named substring as a condition, using the
1437     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1438     are numbers (not recommended). Forward references are permitted.
1439    
1440     14. Added forward references in named backreferences (if you see what I mean).
1441    
1442     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1443     pattern could run off the end of the subject. For example, the pattern
1444     "(?s)(.{1,5})"8 did this with the subject "ab".
1445    
1446     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1447     PCRE_CASELESS was set when matching characters that were quantified with ?
1448     or *.
1449    
1450     17. A character class other than a single negated character that had a minimum
1451     but no maximum quantifier - for example [ab]{6,} - was not handled
1452     correctly by pce_dfa_exec(). It would match only one character.
1453    
1454     18. A valid (though odd) pattern that looked like a POSIX character
1455     class but used an invalid character after [ (for example [[,abc,]]) caused
1456     pcre_compile() to give the error "Failed: internal error: code overflow" or
1457     in some cases to crash with a glibc free() error. This could even happen if
1458     the pattern terminated after [[ but there just happened to be a sequence of
1459     letters, a binary zero, and a closing ] in the memory that followed.
1460    
1461     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1462     over the years. Originally (before any Unicode support), just the bottom 8
1463     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1464     output from "man perlunicode" includes this:
1465    
1466     The regular expression compiler produces polymorphic opcodes. That
1467     is, the pattern adapts to the data and automatically switches to
1468     the Unicode character scheme when presented with Unicode data--or
1469     instead uses a traditional byte scheme when presented with byte
1470     data.
1471    
1472     Sadly, a wide octal escape does not cause a switch, and in a string with
1473     no other multibyte characters, these octal escapes are treated as before.
1474     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1475     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1476     Unicode string.
1477    
1478     I have not perpetrated such confusion in PCRE. Up till now, it took just
1479     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1480     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1481     translate to the appropriate multibyte character.
1482    
1483     29. Applied some refactoring to reduce the number of warnings from Microsoft
1484     and Borland compilers. This has included removing the fudge introduced
1485     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1486     a warning about an unused variable.
1487    
1488     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1489     characters since release 4.0, because Perl (from release 5.004) does not.
1490     [Or at least, is documented not to: some releases seem to be in conflict
1491     with the documentation.] However, when a pattern was studied with
1492     pcre_study() and all its branches started with \s, PCRE still included VT
1493     as a possible starting character. Of course, this did no harm; it just
1494     caused an unnecessary match attempt.
1495    
1496     22. Removed a now-redundant internal flag bit that recorded the fact that case
1497     dependency changed within the pattern. This was once needed for "required
1498     byte" processing, but is no longer used. This recovers a now-scarce options
1499     bit. Also moved the least significant internal flag bit to the most-
1500     significant bit of the word, which was not previously used (hangover from
1501     the days when it was an int rather than a uint) to free up another bit for
1502     the future.
1503    
1504     23. Added support for CRLF line endings as well as CR and LF. As well as the
1505     default being selectable at build time, it can now be changed at runtime
1506     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1507     specify that it is scanning data with non-default line endings.
1508    
1509     24. Changed the definition of CXXLINK to make it agree with the definition of
1510     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1511    
1512     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1513     recursions. This makes a big different to stack usage for some patterns.
1514    
1515     26. If a subpattern containing a named recursion or subroutine reference such
1516     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1517     the space required for the compiled pattern went wrong and gave too small a
1518     value. Depending on the environment, this could lead to "Failed: internal
1519     error: code overflow at offset 49" or "glibc detected double free or
1520     corruption" errors.
1521    
1522     27. Applied patches from Google (a) to support the new newline modes and (b) to
1523     advance over multibyte UTF-8 characters in GlobalReplace.
1524    
1525     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1526     difference for some implementation of PCRE in some Windows version.
1527    
1528     29. Added some extra testing facilities to pcretest:
1529    
1530     \q<number> in a data line sets the "match limit" value
1531     \Q<number> in a data line sets the "match recursion limt" value
1532     -S <number> sets the stack size, where <number> is in megabytes
1533    
1534     The -S option isn't available for Windows.
1535    
1536    
1537 nigel 89 Version 6.6 06-Feb-06
1538     ---------------------
1539    
1540     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1541     in pcreposix.h. I have copied the definition from pcre.h.
1542    
1543     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1544     because pcre.h is no longer a built file.
1545    
1546     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1547     not normally included in the compiled code.
1548    
1549    
1550 nigel 87 Version 6.5 01-Feb-06
1551     ---------------------
1552    
1553     1. When using the partial match feature with pcre_dfa_exec(), it was not
1554     anchoring the second and subsequent partial matches at the new starting
1555     point. This could lead to incorrect results. For example, with the pattern
1556     /1234/, partially matching against "123" and then "a4" gave a match.
1557    
1558     2. Changes to pcregrep:
1559    
1560     (a) All non-match returns from pcre_exec() were being treated as failures
1561     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1562     error message is output. Some extra information is given for the
1563     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1564     probably the only errors that are likely to be caused by users (by
1565     specifying a regex that has nested indefinite repeats, for instance).
1566     If there are more than 20 of these errors, pcregrep is abandoned.
1567    
1568     (b) A binary zero was treated as data while matching, but terminated the
1569     output line if it was written out. This has been fixed: binary zeroes
1570     are now no different to any other data bytes.
1571    
1572     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1573     used to set a locale for matching. The --locale=xxxx long option has
1574     been added (no short equivalent) to specify a locale explicitly on the
1575     pcregrep command, overriding the environment variables.
1576    
1577     (d) When -B was used with -n, some line numbers in the output were one less
1578     than they should have been.
1579    
1580     (e) Added the -o (--only-matching) option.
1581    
1582     (f) If -A or -C was used with -c (count only), some lines of context were
1583     accidentally printed for the final match.
1584    
1585     (g) Added the -H (--with-filename) option.
1586    
1587     (h) The combination of options -rh failed to suppress file names for files
1588     that were found from directory arguments.
1589    
1590     (i) Added the -D (--devices) and -d (--directories) options.
1591    
1592     (j) Added the -F (--fixed-strings) option.
1593    
1594     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1595    
1596     (l) Added the --colo(u)r option.
1597    
1598     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1599     is not present by default.
1600    
1601     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1602     items such as (?R) or (?1), when the recursion could match a number of
1603     alternatives. If it matched one of the alternatives, but subsequently,
1604     outside the recursion, there was a failure, the code tried to back up into
1605     the recursion. However, because of the way PCRE is implemented, this is not
1606     possible, and the result was an incorrect result from the match.
1607    
1608     In order to prevent this happening, the specification of recursion has
1609     been changed so that all such subpatterns are automatically treated as
1610     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1611    
1612     4. I had overlooked the fact that, in some locales, there are characters for
1613     which isalpha() is true but neither isupper() nor islower() are true. In
1614     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1615     and ordfeminine) are like this. This affected the treatment of \w and \W
1616     when they appeared in character classes, but not when they appeared outside
1617     a character class. The bit map for "word" characters is now created
1618     separately from the results of isalnum() instead of just taking it from the
1619     upper, lower, and digit maps. (Plus the underscore character, of course.)
1620    
1621     5. The above bug also affected the handling of POSIX character classes such as
1622     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1623     permanent tables. Instead, the bit maps for such a class were previously
1624     created as the appropriate unions of the upper, lower, and digit bitmaps.
1625     Now they are created by subtraction from the [[:word:]] class, which has
1626     its own bitmap.
1627    
1628     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1629     It is created by subtracting the vertical space characters (\x09, \x0a,
1630     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1631     subtraction was done in the overall bitmap for a character class, meaning
1632     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1633     be recognized. This bug has been fixed.
1634    
1635     7. Patches from the folks at Google:
1636    
1637     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1638     real life, but is still worth protecting against".
1639    
1640     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1641     regular expressions".
1642    
1643     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1644     have it.
1645    
1646     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1647     "configure" and the latter not, in order to fix a problem somebody had
1648     with compiling the Arg class on HP-UX.
1649    
1650     (e) Improve the error-handling of the C++ wrapper a little bit.
1651    
1652     (f) New tests for checking recursion limiting.
1653    
1654     8. The pcre_memmove() function, which is used only if the environment does not
1655     have a standard memmove() function (and is therefore rarely compiled),
1656     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1657     returning a result (though PCRE never actually uses the result).
1658    
1659     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1660     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1661     returned instead of calling malloc() with an overflowing number that would
1662     most likely cause subsequent chaos.
1663    
1664     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1665    
1666     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1667     with this option is matched, the nmatch and pmatch options of regexec() are
1668     ignored.
1669    
1670     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1671     provided in case anyone wants to the the POSIX interface with UTF-8
1672     strings.
1673    
1674     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1675     C++ linking (needed for some HP-UX environments).
1676    
1677     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1678     (unused parameter) and in the pcre_printint() function (omitted "default"
1679     switch label when the default is to do nothing).
1680    
1681     15. Added some code to make it possible, when PCRE is compiled as a C++
1682     library, to replace subject pointers for pcre_exec() with a smart pointer
1683     class, thus making it possible to process discontinuous strings.
1684    
1685     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1686     much the same function. They were added by different people who were trying
1687     to make PCRE easy to compile on non-Unix systems. It has been suggested
1688     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1689     for compiling on Windows systems. I have therefore replaced it with
1690     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1691     defaults to "extern" for C or "extern C" for C++, which works fine on
1692     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1693     SCOPE with something explicit in config.h. In addition:
1694    
1695     (a) pcreposix.h still had just "extern" instead of either of these macros;
1696     I have replaced it with PCRE_DATA_SCOPE.
1697    
1698     (b) Functions such as _pcre_xclass(), which are internal to the library,
1699     but external in the C sense, all had PCRE_EXPORT in their definitions.
1700     This is apparently wrong for the Windows case, so I have removed it.
1701     (It makes no difference on Unix-like systems.)
1702    
1703     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1704     of recursive calls to match(). This is different to MATCH_LIMIT because
1705     that limits the total number of calls to match(), not all of which increase
1706     the depth of recursion. Limiting the recursion depth limits the amount of
1707     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1708     when PCRE is compiled, and changed at run time. A patch from Google adds
1709     this functionality to the C++ interface.
1710    
1711     18. Changes to the handling of Unicode character properties:
1712    
1713     (a) Updated the table to Unicode 4.1.0.
1714    
1715     (b) Recognize characters that are not in the table as "Cn" (undefined).
1716    
1717     (c) I revised the way the table is implemented to a much improved format
1718     which includes recognition of ranges. It now supports the ranges that
1719     are defined in UnicodeData.txt, and it also amalgamates other
1720     characters into ranges. This has reduced the number of entries in the
1721     table from around 16,000 to around 3,000, thus reducing its size
1722     considerably. I realized I did not need to use a tree structure after
1723     all - a binary chop search is just as efficient. Having reduced the
1724     number of entries, I extended their size from 6 bytes to 8 bytes to
1725     allow for more data.
1726    
1727     (d) Added support for Unicode script names via properties such as \p{Han}.
1728    
1729     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1730     matching that character.
1731    
1732     20. When matching a repeated Unicode property with a minimum greater than zero,
1733     (for example \pL{2,}), PCRE could look past the end of the subject if it
1734     reached it while seeking the minimum number of characters. This could
1735     happen only if some of the characters were more than one byte long, because
1736     there is a check for at least the minimum number of bytes.
1737    
1738     21. Refactored the implementation of \p and \P so as to be more general, to
1739     allow for more different types of property in future. This has changed the
1740     compiled form incompatibly. Anybody with saved compiled patterns that use
1741     \p or \P will have to recompile them.
1742    
1743     22. Added "Any" and "L&" to the supported property types.
1744    
1745     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1746     but give a compile time error if the value is greater than 0xff.
1747    
1748     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1749     accidentally not being installed or uninstalled.
1750    
1751     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1752     made were to insert the current release number. This seemed silly, because
1753     it made things harder for people building PCRE on systems that don't run
1754     "configure". I have turned pcre.h into a distributed file, no longer built
1755     by "configure", with the version identification directly included. There is
1756     no longer a pcre.h.in file.
1757    
1758     However, this change necessitated a change to the pcre-config script as
1759     well. It is built from pcre-config.in, and one of the substitutions was the
1760     release number. I have updated configure.ac so that ./configure now finds
1761     the release number by grepping pcre.h.
1762    
1763     26. Added the ability to run the tests under valgrind.
1764    
1765    
1766 nigel 85 Version 6.4 05-Sep-05
1767     ---------------------
1768    
1769     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1770     "--" to be printed when multiple files were scanned, even when none of the
1771     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1772     consider it to be a bug, and have restored the previous behaviour.
1773    
1774     2. A couple of code tidies to get rid of compiler warnings.
1775    
1776     3. The pcretest program used to cheat by referring to symbols in the library
1777     whose names begin with _pcre_. These are internal symbols that are not
1778     really supposed to be visible externally, and in some environments it is
1779     possible to suppress them. The cheating is now confined to including
1780     certain files from the library's source, which is a bit cleaner.
1781    
1782     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1783     file's purpose clearer.
1784    
1785     5. Reorganized pcre_ucp_findchar().
1786    
1787    
1788 nigel 83 Version 6.3 15-Aug-05
1789     ---------------------
1790    
1791     1. The file libpcre.pc.in did not have general read permission in the tarball.
1792    
1793     2. There were some problems when building without C++ support:
1794    
1795     (a) If C++ support was not built, "make install" and "make test" still
1796     tried to test it.
1797    
1798     (b) There were problems when the value of CXX was explicitly set. Some
1799     changes have been made to try to fix these, and ...
1800    
1801     (c) --disable-cpp can now be used to explicitly disable C++ support.
1802    
1803     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1804     backslash in a target when C++ was disabled. This confuses some
1805     versions of "make", apparently. Using an intermediate variable solves
1806     this. (Same for CPP_LOBJ.)
1807    
1808     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1809     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1810     necessary on certain architectures.
1811    
1812     4. Added a setting of -export-symbols-regex to the link command to remove
1813     those symbols that are exported in the C sense, but actually are local
1814     within the library, and not documented. Their names all begin with
1815     "_pcre_". This is not a perfect job, because (a) we have to except some
1816     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1817     available (and never for static libraries). I have made a note to try to
1818     find a way round (a) in the future.
1819    
1820    
1821 nigel 81 Version 6.2 01-Aug-05
1822     ---------------------
1823    
1824     1. There was no test for integer overflow of quantifier values. A construction
1825     such as {1111111111111111} would give undefined results. What is worse, if
1826     a minimum quantifier for a parenthesized subpattern overflowed and became
1827     negative, the calculation of the memory size went wrong. This could have
1828     led to memory overwriting.
1829    
1830     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1831    
1832     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1833     operating environments where this matters.
1834    
1835     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1836     PCRE options from within the C++ wrapper.
1837    
1838     5. Named capturing subpatterns were not being correctly counted when a pattern
1839     was compiled. This caused two problems: (a) If there were more than 100
1840     such subpatterns, the calculation of the memory needed for the whole
1841     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1842     back references of the form \12, where the number was greater than 9, were
1843     not recognized as back references, even though there were sufficient
1844     previous subpatterns.
1845    
1846     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1847     versions of gcc, e.g. 2.95.4.
1848    
1849    
1850 nigel 79 Version 6.1 21-Jun-05
1851     ---------------------
1852    
1853     1. There was one reference to the variable "posix" in pcretest.c that was not
1854     surrounded by "#if !defined NOPOSIX".
1855    
1856     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1857     the cross-check on the old pcre_info() function, for the benefit of the
1858     cut-down version of PCRE that is currently imported into Exim.
1859    
1860     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1861     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1862     patterns that start (?i) but I don't think that matters. The use of (?i) is
1863     just an example; this all applies to the other options as well.
1864    
1865     4. Since libtool seems to echo the compile commands it is issuing, the output
1866     from "make" can be reduced a bit by putting "@" in front of each libtool
1867     compile command.
1868    
1869     5. Patch from the folks at Google for configure.in to be a bit more thorough
1870     in checking for a suitable C++ installation before trying to compile the
1871     C++ stuff. This should fix a reported problem when a compiler was present,
1872     but no suitable headers.
1873    
1874     6. The man pages all had just "PCRE" as their title. I have changed them to
1875     be the relevant file name. I have also arranged that these names are
1876     retained in the file doc/pcre.txt, which is a concatenation in text format
1877     of all the man pages except the little individual ones for each function.
1878    
1879     7. The NON-UNIX-USE file had not been updated for the different set of source
1880     files that come with release 6. I also added a few comments about the C++
1881     wrapper.
1882    
1883    
1884 nigel 77 Version 6.0 07-Jun-05
1885     ---------------------
1886    
1887     1. Some minor internal re-organization to help with my DFA experiments.
1888    
1889     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1890     didn't matter for the library itself when fully configured, but did matter
1891     when compiling without UCP support, or within Exim, where the ucp files are
1892     not imported.
1893    
1894     3. Refactoring of the library code to split up the various functions into
1895     different source modules. The addition of the new DFA matching code (see
1896     below) to a single monolithic source would have made it really too
1897     unwieldy, quite apart from causing all the code to be include in a
1898     statically linked application, when only some functions are used. This is
1899     relevant even without the DFA addition now that patterns can be compiled in
1900     one application and matched in another.
1901    
1902     The downside of splitting up is that there have to be some external
1903     functions and data tables that are used internally in different modules of
1904     the library but which are not part of the API. These have all had their
1905     names changed to start with "_pcre_" so that they are unlikely to clash
1906     with other external names.
1907    
1908     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1909     a different (DFA) algorithm. Although it is slower than the original
1910     function, it does have some advantages for certain types of matching
1911     problem.
1912    
1913     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1914     including restarting after a partial match.
1915    
1916     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1917     defined when compiling for Windows was sent to me. I have put it into the
1918     code, though I have no means of testing or verifying it.
1919    
1920     7. Added the pcre_refcount() auxiliary function.
1921    
1922     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1923     match before or at the first newline in the subject string. In pcretest,
1924     the /f option on a pattern can be used to set this.
1925    
1926     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1927     would behave wrongly. This has been present in PCRE since release 4.0.
1928    
1929     10. A number of changes to the pcregrep command:
1930    
1931     (a) Refactored how -x works; insert ^(...)$ instead of setting
1932     PCRE_ANCHORED and checking the length, in preparation for adding
1933     something similar for -w.
1934    
1935     (b) Added the -w (match as a word) option.
1936    
1937     (c) Refactored the way lines are read and buffered so as to have more
1938     than one at a time available.
1939    
1940     (d) Implemented a pcregrep test script.
1941    
1942     (e) Added the -M (multiline match) option. This allows patterns to match
1943     over several lines of the subject. The buffering ensures that at least
1944     8K, or the rest of the document (whichever is the shorter) is available
1945     for matching (and similarly the previous 8K for lookbehind assertions).
1946    
1947     (f) Changed the --help output so that it now says
1948    
1949     -w, --word-regex(p)
1950    
1951     instead of two lines, one with "regex" and the other with "regexp"
1952     because that confused at least one person since the short forms are the
1953     same. (This required a bit of code, as the output is generated
1954     automatically from a table. It wasn't just a text change.)
1955    
1956     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1957     option but starts with a hyphen. Could be a pattern or a path name
1958     starting with a hyphen, for instance.
1959    
1960     (h) "-" can be given as a file name to represent stdin.
1961    
1962     (i) When file names are being printed, "(standard input)" is used for
1963     the standard input, for compatibility with GNU grep. Previously
1964     "<stdin>" was used.
1965    
1966     (j) The option --label=xxx can be used to supply a name to be used for
1967     stdin when file names are being printed. There is no short form.
1968    
1969     (k) Re-factored the options decoding logic because we are going to add
1970     two more options that take data. Such options can now be given in four
1971     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1972    
1973     (l) Added the -A, -B, and -C options for requesting that lines of context
1974     around matches be printed.
1975    
1976     (m) Added the -L option to print the names of files that do not contain
1977     any matching lines, that is, the complement of -l.
1978    
1979     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1980     continue to scan other files.
1981    
1982     (o) The -s option was incorrectly implemented. For compatibility with other
1983     greps, it now suppresses the error message for a non-existent or non-
1984     accessible file (but not the return code). There is a new option called
1985     -q that suppresses the output of matching lines, which was what -s was
1986     previously doing.
1987    
1988     (p) Added --include and --exclude options to specify files for inclusion
1989     and exclusion when recursing.
1990    
1991     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1992     Hopefully, it now does.
1993    
1994     12. Missing cast in pcre_study().
1995    
1996     13. Added an "uninstall" target to the makefile.
1997    
1998     14. Replaced "extern" in the function prototypes in Makefile.in with
1999     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2000     world, but is set differently for Windows.
2001    
2002     15. Added a second compiling function called pcre_compile2(). The only
2003     difference is that it has an extra argument, which is a pointer to an
2004     integer error code. When there is a compile-time failure, this is set
2005     non-zero, in addition to the error test pointer being set to point to an
2006     error message. The new argument may be NULL if no error number is required
2007     (but then you may as well call pcre_compile(), which is now just a
2008     wrapper). This facility is provided because some applications need a
2009     numeric error indication, but it has also enabled me to tidy up the way
2010     compile-time errors are handled in the POSIX wrapper.
2011    
2012     16. Added VPATH=.libs to the makefile; this should help when building with one
2013     prefix path and installing with another. (Or so I'm told by someone who
2014     knows more about this stuff than I do.)
2015    
2016     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2017     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2018     match everything, including newlines. This is not POSIX-compatible, but
2019     somebody wanted the feature. From pcretest it can be activated by using
2020     both the P and the s flags.
2021    
2022     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2023    
2024     19. libpcre.pc was being incorrectly installed as executable.
2025    
2026     20. A couple of places in pcretest check for end-of-line by looking for '\n';
2027     it now also looks for '\r' so that it will work unmodified on Windows.
2028    
2029     21. Added Google's contributed C++ wrapper to the distribution.
2030    
2031     22. Added some untidy missing memory free() calls in pcretest, to keep
2032     Electric Fence happy when testing.
2033    
2034    
2035    
2036 nigel 75 Version 5.0 13-Sep-04
2037     ---------------------
2038    
2039     1. Internal change: literal characters are no longer packed up into items
2040     containing multiple characters in a single byte-string. Each character
2041     is now matched using a separate opcode. However, there may be more than one
2042     byte in the character in UTF-8 mode.
2043    
2044     2. The pcre_callout_block structure has two new fields: pattern_position and
2045     next_item_length. These contain the offset in the pattern to the next match
2046     item, and its length, respectively.
2047    
2048     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2049     insertion of callouts before each pattern item. Added the /C option to
2050     pcretest to make use of this.
2051    
2052     4. On the advice of a Windows user, the lines
2053    
2054     #if defined(_WIN32) || defined(WIN32)
2055     _setmode( _fileno( stdout ), 0x8000 );
2056     #endif /* defined(_WIN32) || defined(WIN32) */
2057    
2058     have been added to the source of pcretest. This apparently does useful
2059     magic in relation to line terminators.
2060    
2061     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2062     for the benefit of those environments where the "b" makes a difference.
2063    
2064     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2065     to know about it. I have put a hack into configure.in that adds in code
2066     to set GCC=yes if CC=icc. This seems to end up at a point in the
2067     generated configure script that is early enough to affect the setting of
2068     compiler options, which is what is needed, but I have no means of testing
2069     whether it really works. (The user who reported this had patched the
2070     generated configure script, which of course I cannot do.)
2071    
2072     LATER: After change 22 below (new libtool files), the configure script
2073     seems to know about icc (and also ecc). Therefore, I have commented out
2074     this hack in configure.in.
2075    
2076     7. Added support for pkg-config (2 patches were sent in).
2077    
2078     8. Negated POSIX character classes that used a combination of internal tables
2079     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2080     [[:^ascii]]. Typically, they would match almost any characters. The other
2081     POSIX classes were not broken in this way.
2082    
2083     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2084     to find the match, as PCRE was deluded into thinking that the match had to
2085     start at the start point or following a newline. The same bug applied to
2086     patterns with negative forward assertions or any backward assertions
2087     preceding ".*" at the start, unless the pattern required a fixed first
2088     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2089    
2090     10. In UTF-8 mode, when moving forwards in the subject after a failed match
2091     starting at the last subject character, bytes beyond the end of the subject
2092     string were read.
2093    
2094     11. Renamed the variable "class" as "classbits" to make life easier for C++
2095     users. (Previously there was a macro definition, but it apparently wasn't
2096     enough.)
2097    
2098     12. Added the new field "tables" to the extra data so that tables can be passed
2099     in at exec time, or the internal tables can be re-selected. This allows
2100     a compiled regex to be saved and re-used at a later time by a different
2101     program that might have everything at different addresses.
2102    
2103     13. Modified the pcre-config script so that, when run on Solaris, it shows a
2104     -R library as well as a -L library.
2105    
2106     14. The debugging options of pcretest (-d on the command line or D on a
2107     pattern) showed incorrect output for anything following an extended class
2108     that contained multibyte characters and which was followed by a quantifier.
2109    
2110     15. Added optional support for general category Unicode character properties
2111     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2112     support. It adds about 90K to the size of the library. The meanings of the
2113     inbuilt class escapes such as \d and \s have NOT been changed.
2114    
2115     16. Updated pcredemo.c to include calls to free() to release the memory for the
2116     compiled pattern.
2117    
2118     17. The generated file chartables.c was being created in the source directory
2119     instead of in the building directory. This caused the build to fail if the
2120     source directory was different from the building directory, and was
2121     read-only.
2122    
2123     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2124     file. No doubt somebody will tell me if they don't make sense... Also added
2125     Dan Mooney's comments about building on OpenVMS.
2126    
2127     19. Added support for partial matching via the PCRE_PARTIAL option for
2128     pcre_exec() and the \P data escape in pcretest.
2129    
2130     20. Extended pcretest with 3 new pattern features:
2131    
2132     (i) A pattern option of the form ">rest-of-line" causes pcretest to
2133     write the compiled pattern to the file whose name is "rest-of-line".
2134     This is a straight binary dump of the data, with the saved pointer to
2135     the character tables forced to be NULL. The study data, if any, is
2136     written too. After writing, pcretest reads a new pattern.
2137    
2138     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2139     compiled pattern from the given file. There must not be any
2140     occurrences of "<" in the file name (pretty unlikely); if there are,
2141     pcretest will instead treat the initial "<" as a pattern delimiter.
2142     After reading in the pattern, pcretest goes on to read data lines as
2143     usual.
2144    
2145     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2146     and 16-bit fields in a compiled pattern, to simulate a pattern that
2147     was compiled on a host of opposite endianness.
2148    
2149     21. The pcre-exec() function can now cope with patterns that were compiled on
2150     hosts of opposite endianness, with this restriction:
2151    
2152     As for any compiled expression that is saved and used later, the tables
2153     pointer field cannot be preserved; the extra_data field in the arguments
2154     to pcre_exec() should be used to pass in a tables address if a value
2155     other than the default internal tables were used at compile time.
2156    
2157     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2158     now diagnosed as an error. Previously, most of the time, a negative number
2159     would have been treated as zero, but if in addition "ovector" was passed as
2160     NULL, a crash could occur.
2161    
2162     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2163     new versions from the libtool 1.5 distribution (the last one is a copy of
2164     a file called libtool.m4). This seems to have fixed the need to patch
2165     "configure" to support Darwin 1.3 (which I used to do). However, I still
2166     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2167     workstation).
2168    
2169     24. Changed the PCRE licence to be the more standard "BSD" licence.
2170    
2171    
2172 nigel 73 Version 4.5 01-Dec-03
2173     ---------------------
2174    
2175     1. There has been some re-arrangement of the code for the match() function so
2176     that it can be compiled in a version that does not call itself recursively.
2177     Instead, it keeps those local variables that need separate instances for
2178     each "recursion" in a frame on the heap, and gets/frees frames whenever it
2179     needs to "recurse". Keeping track of where control must go is done by means
2180     of setjmp/longjmp. The whole thing is implemented by a set of macros that
2181     hide most of the details from the main code, and operates only if
2182     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2183     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2184     operating.
2185    
2186     To make it easier for callers to provide specially tailored get/free
2187     functions for this usage, two new functions, pcre_stack_malloc, and
2188     pcre_stack_free, are used. They are always called in strict stacking order,
2189     and the size of block requested is always the same.
2190    
2191     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2192     PCRE has been compiled to use the stack or the heap for recursion. The
2193     -C option of pcretest uses this to show which version is compiled.
2194    
2195     A new data escape \S, is added to pcretest; it causes the amounts of store
2196     obtained and freed by both kinds of malloc/free at match time to be added
2197     to the output.
2198    
2199     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2200     what's available on my current Linux desktop machine.
2201    
2202     3. When matching a UTF-8 string, the test for a valid string at the start has
2203     been extended. If start_offset is not zero, PCRE now checks that it points
2204     to a byte that is the start of a UTF-8 character. If not, it returns
2205     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2206     this is necessary because there may be backward assertions in the pattern.
2207     When matching the same subject several times, it may save resources to use
2208     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2209    
2210     4. The code for checking the validity of UTF-8 strings has been tightened so
2211     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2212     containing "overlong sequences".
2213    
2214     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2215     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2216     should have been "&", but it just so happened that all the cases this let
2217     through by mistake were picked up later in the function.
2218    
2219     6. I had used a variable called "isblank" - this is a C99 function, causing
2220     some compilers to warn. To avoid this, I renamed it (as "blankclass").
2221    
2222     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2223     prompting; (b) run "./pcretest /dev/null" at the start of the test script
2224     so the version is shown; (c) stop "make test" echoing "./RunTest".
2225    
2226     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2227    
2228     9. The prototype for memmove() for systems that don't have it was using
2229     size_t, but the inclusion of the header that defines size_t was later. I've
2230     moved the #includes for the C headers earlier to avoid this.
2231    
2232     10. Added some adjustments to the code to make it easier to compiler on certain
2233     special systems:
2234    
2235     (a) Some "const" qualifiers were missing.
2236     (b) Added the macro EXPORT before all exported functions; by default this
2237     is defined to be empty.
2238     (c) Changed the dftables auxiliary program (that builds chartables.c) so
2239     that it reads its output file name as an argument instead of writing
2240     to the standard output and assuming this can be redirected.
2241    
2242     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2243     class containing characters with values greater than 255, PCRE compilation
2244     went into a loop.
2245    
2246     12. A recursive reference to a subpattern that was within another subpattern
2247     that had a minimum quantifier of zero caused PCRE to crash. For example,
2248     (x(y(?2))z)? provoked this bug with a subject that got as far as the
2249     recursion. If the recursively-called subpattern itself had a zero repeat,
2250     that was OK.
2251    
2252     13. In pcretest, the buffer for reading a data line was set at 30K, but the
2253     buffer into which it was copied (for escape processing) was still set at
2254     1024, so long lines caused crashes.
2255    
2256     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2257     "internal error: code overflow...". This applied to any character class
2258     that was followed by a possessive quantifier.
2259    
2260     15. Modified the Makefile to add libpcre.la as a prerequisite for
2261     libpcreposix.la because I was told this is needed for a parallel build to
2262     work.
2263    
2264     16. If a pattern that contained .* following optional items at the start was
2265     studied, the wrong optimizing data was generated, leading to matching
2266     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2267     matching string must start with a or b or c. The correct conclusion for
2268     this pattern is that a match can start with any character.
2269    
2270    
2271 nigel 71 Version 4.4 13-Aug-03
2272     ---------------------
2273    
2274     1. In UTF-8 mode, a character class containing characters with values between
2275     127 and 255 was not handled correctly if the compiled pattern was studied.
2276     In fixing this, I have also improved the studying algorithm for such
2277     classes (slightly).
2278    
2279     2. Three internal functions had redundant arguments passed to them. Removal
2280     might give a very teeny performance improvement.
2281    
2282     3. Documentation bug: the value of the capture_top field in a callout is *one
2283     more than* the number of the hightest numbered captured substring.
2284    
2285     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2286     in incorrectly linking with a previously installed version. They now link
2287     explicitly with libpcre.la.
2288    
2289     5. configure.in no longer needs to recognize Cygwin specially.
2290    
2291     6. A problem in pcre.in for Windows platforms is fixed.
2292    
2293     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2294     pcretest, it used to include the size of the study block as part of its
2295     output. Unfortunately, the structure contains a field that has a different
2296     size on different hardware architectures. This meant that the tests that
2297     showed this size failed. As the block is currently always of a fixed size,
2298     this information isn't actually particularly useful in pcretest output, so
2299     I have just removed it.
2300    
2301     8. Three pre-processor statements accidentally did not start in column 1.
2302     Sadly, there are *still* compilers around that complain, even though
2303     standard C has not required this for well over a decade. Sigh.
2304    
2305     9. In pcretest, the code for checking callouts passed small integers in the
2306     callout_data field, which is a void * field. However, some picky compilers
2307     complained about the casts involved for this on 64-bit systems. Now
2308     pcretest passes the address of the small integer instead, which should get
2309     rid of the warnings.
2310    
2311     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2312     both compile and run time, and gives an error if an invalid UTF-8 sequence
2313     is found. There is a option for disabling this check in cases where the
2314     string is known to be correct and/or the maximum performance is wanted.
2315    
2316     11. In response to a bug report, I changed one line in Makefile.in from
2317    
2318     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2319     to
2320     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2321    
2322     to look similar to other lines, but I have no way of telling whether this
2323     is the right thing to do, as I do not use Windows. No doubt I'll get told
2324     if it's wrong...
2325    
2326    
2327 nigel 69 Version 4.3 21-May-03
2328     ---------------------
2329    
2330     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2331     Makefile.
2332    
2333     2. Some refactoring to improve the quality of the code:
2334    
2335     (i) The utf8_table... variables are now declared "const".
2336    
2337     (ii) The code for \cx, which used the "case flipping" table to upper case
2338     lower case letters, now just substracts 32. This is ASCII-specific,
2339     but the whole concept of \cx is ASCII-specific, so it seems
2340     reasonable.
2341    
2342     (iii) PCRE was using its character types table to recognize decimal and
2343     hexadecimal digits in the pattern. This is silly, because it handles
2344     only 0-9, a-f, and A-F, but the character types table is locale-
2345     specific, which means strange things might happen. A private
2346     table is now used for this - though it costs 256 bytes, a table is
2347     much faster than multiple explicit tests. Of course, the standard
2348     character types table is still used for matching digits in subject
2349     strings against \d.
2350    
2351     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2352     ending in _t are). So I've renamed it as ESC_tee.
2353    
2354     3. The first argument for regexec() in the POSIX wrapper should have been
2355     defined as "const".
2356    
2357     4. Changed pcretest to use malloc() for its buffers so that they can be
2358     Electric Fenced for debugging.
2359    
2360     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2361     to read one or more bytes before the start of the subject string. Often this
2362     had no effect on PCRE's behaviour, but in some circumstances it could
2363     provoke a segmentation fault.
2364    
2365     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2366     to try to read one or more bytes before the start of the subject string.
2367    
2368     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2369     UTF-8 support could misbehave in various ways if the subject string
2370     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2371     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2372     back over UTF-8 characters.)
2373    
2374    
2375 nigel 67 Version 4.2 14-Apr-03
2376     ---------------------
2377    
2378     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2379    
2380     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2381     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2382     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2383     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2384     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2385     and BUILD_EXEEXT
2386     Note: automatic setting of the BUILD variables is not yet working
2387     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2388     compile-time but not at link-time
2389     [LINK]: use for linking executables only
2390     make different versions for Windows and non-Windows
2391     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2392     libraries
2393     [LINK_FOR_BUILD]: new variable
2394     [OBJEXT]: use throughout
2395     [EXEEXT]: use throughout
2396     <winshared>: new target
2397     <wininstall>: new target
2398     <dftables.o>: use native compiler
2399     <dftables>: use native linker
2400     <install>: handle Windows platform correctly
2401     <clean>: ditto
2402     <check>: ditto
2403     copy DLL to top builddir before testing
2404    
2405     As part of these changes, -no-undefined was removed again. This was reported
2406     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2407     in any case.
2408    
2409     3. Some tidies to get rid of compiler warnings:
2410    
2411     . In the match_data structure, match_limit was an unsigned long int, whereas
2412     match_call_count was an int. I've made them both unsigned long ints.
2413    
2414     . In pcretest the fact that a const uschar * doesn't automatically cast to
2415     a void * provoked a warning.
2416    
2417     . Turning on some more compiler warnings threw up some "shadow" variables
2418     and a few more missing casts.
2419    
2420     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2421     option, a class that contained a single character with a value between 128
2422     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2423    
2424     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2425     option, a class that contained several characters, but with at least one
2426     whose value was between 128 and 255 caused PCRE to crash.
2427    
2428    
2429 nigel 65 Version 4.1 12-Mar-03
2430     ---------------------
2431 nigel 63
2432 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2433     needed, and a string in dftables.c that was longer than standard compilers are
2434     required to support.
2435    
2436     2. Compiling with Sun's compiler found a few more places where the code could
2437     be tidied up in order to avoid warnings.
2438    
2439     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2440     first of these names is deprecated in the latest Autoconf in favour of the name
2441     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2442     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2443     analogy I have changed it to CFLAGS_FOR_BUILD.
2444    
2445     4. Added -no-undefined to the linking command in the Makefile, because this is
2446     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2447     linking step for the pcreposix library.
2448    
2449     5. PCRE was failing to diagnose the case of two named groups with the same
2450     name.
2451    
2452     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2453     literal character that is needed in the subject for a match, and scans along to
2454     ensure that it is present before embarking on the full matching process. This
2455     saves time in cases of nested unlimited repeats that are never going to match.
2456     Problem: the scan can take a lot of time if the subject is very long (e.g.
2457     megabytes), thus penalizing straightforward matches. It is now done only if the
2458     amount of subject to be scanned is less than 1000 bytes.
2459    
2460     7. A lesser problem with the same optimization is that it was recording the
2461     first character of an anchored pattern as "needed", thus provoking a search
2462     right along the subject, even when the first match of the pattern was going to
2463     fail. The "needed" character is now not set for anchored patterns, unless it
2464     follows something in the pattern that is of non-fixed length. Thus, it still
2465     fulfils its original purpose of finding quick non-matches in cases of nested
2466     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2467    
2468    
2469     Version 4.0 17-Feb-03
2470     ---------------------
2471    
2472 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2473     extended to the end of string, PCRE compiled incorrect data. This could lead to
2474     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2475    
2476     2. Moved to autoconf 2.53 and libtool 1.4.2.
2477    
2478     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2479     the special perltest8 script is no longer needed - all the tests can be run
2480     from a single perltest script.
2481    
2482     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2483     by \s. It has now been removed in PCRE. This means it isn't recognized as
2484     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2485     class [:space:] *does* include VT, thereby creating a mess.
2486    
2487     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2488     space and tab.
2489    
2490     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2491     its new features into the main test script, reducing the number of scripts.
2492    
2493     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2494     were backward compatible, and made the (?i) apply to the whole pattern, as if
2495     /i were given. Now it behaves more logically, and applies the option setting
2496     only to what follows. PCRE has been changed to follow suit. However, if it
2497     finds options settings right at the start of the pattern, it extracts them into
2498     the global options, as before. Thus, they show up in the info data.
2499    
2500     8. Added support for the \Q...\E escape sequence. Characters in between are
2501     treated as literals. This is slightly different from Perl in that $ and @ are
2502     also handled as literals inside the quotes. In Perl, they will cause variable
2503     interpolation. Note the following examples:
2504    
2505     Pattern PCRE matches Perl matches
2506    
2507     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2508     \Qabc\$xyz\E abc\$xyz abc\$xyz
2509     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2510    
2511     For compatibility with Perl, \Q...\E sequences are recognized inside character
2512     classes as well as outside them.
2513    
2514     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2515     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2516     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2517     signed/unsigned warnings.
2518    
2519     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2520     option for pcretest, so I've replaced it by a simple function that does just
2521     that job.
2522    
2523     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2524     "pcregrep -".
2525    
2526     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2527     Java package. This provides some syntactic sugar for simple cases of what my
2528     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2529     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2530     item, you can use this simplified notation. Note that only makes sense with
2531     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2532     greediness, whatever the setting of the PCRE_UNGREEDY option.
2533    
2534     13. A change of greediness default within a pattern was not taking effect at
2535     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2536     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2537     was abstracted outside.
2538    
2539     14. PCRE now supports the \G assertion. It is true when the current matching
2540     position is at the start point of the match. This differs from \A when the
2541     starting offset is non-zero. Used with the /g option of pcretest (or similar
2542     code), it works in the same way as it does for Perl's /g option. If all
2543     alternatives of a regex begin with \G, the expression is anchored to the start
2544     match position, and the "anchored" flag is set in the compiled expression.
2545    
2546     15. Some bugs concerning the handling of certain option changes within patterns
2547     have been fixed. These applied to options other than (?ims). For example,
2548     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2549     been the other way round. Some of this was related to change 7 above.
2550    
2551     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2552     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2553     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2554     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2555    
2556     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2557     mode. Unlike ".", it always matches newline, whatever the setting of
2558     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2559     assertions. Perl allows it, but it doesn't (in general) work because it can't
2560     calculate the length of the lookbehind. At least, that's the case for Perl
2561     5.8.0 - I've been told they are going to document that it doesn't work in
2562     future.
2563    
2564     18. Added an error diagnosis for escapes that PCRE does not support: these are
2565     \L, \l, \N, \P, \p, \U, \u, and \X.
2566    
2567     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2568     reading past the end of the pattern in cases such as /[abcd/.
2569    
2570     20. PCRE was getting more memory than necessary for patterns with classes that
2571     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2572    
2573     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2574     compiling PCRE for use with Virtual Pascal.
2575    
2576     22. Small fix to the Makefile to make it work properly if the build is done
2577     outside the source tree.
2578    
2579     23. Added a new extension: a condition to go with recursion. If a conditional
2580     subpattern starts with (?(R) the "true" branch is used if recursion has
2581     happened, whereas the "false" branch is used only at the top level.
2582    
2583     24. When there was a very long string of literal characters (over 255 bytes
2584     without UTF support, over 250 bytes with UTF support), the computation of how
2585     much memory was required could be incorrect, leading to segfaults or other
2586     strange effects.
2587    
2588     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2589     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2590     there was a subsequent back reference to those brackets. This meant that, for
2591     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2592     possible to check for precisely this case. All we can do is abandon the
2593     optimization if .* occurs inside capturing brackets when there are any back
2594     references whatsoever. (See below for a better fix that came later.)
2595    
2596     26. The handling of the optimization for finding the first character of a
2597     non-anchored pattern, and for finding a character that is required later in the
2598     match were failing in some cases. This didn't break the matching; it just
2599     failed to optimize when it could. The way this is done has been re-implemented.
2600    
2601     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2602    
2603     28. Added a new feature that provides some of the functionality that Perl
2604     provides with (?{...}). The facility is termed a "callout". The way it is done
2605     in PCRE is for the caller to provide an optional function, by setting
2606     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2607     global variable. By default it is unset, which disables all calling out. To get
2608     the function called, the regex must include (?C) at appropriate points. This
2609     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2610     This provides a means of identifying different callout points. When PCRE
2611     reaches such a point in the regex, if pcre_callout has been set, the external
2612     function is called. It is provided with data in a structure called
2613     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2614     matching continues; if it returns a non-zero value, the match at the current
2615     point fails. However, backtracking will occur if possible. [This was changed
2616     later and other features added - see item 49 below.]
2617    
2618     29. pcretest is upgraded to test the callout functionality. It provides a
2619     callout function that displays information. By default, it shows the start of
2620     the match and the current position in the text. There are some new data escapes
2621     to vary what happens:
2622    
2623     \C+ in addition, show current contents of captured substrings
2624     \C- do not supply a callout function
2625     \C!n return 1 when callout number n is reached
2626     \C!n!m return 1 when callout number n is reached for the mth time
2627    
2628     30. If pcregrep was called with the -l option and just a single file name, it
2629     output "<stdin>" if a match was found, instead of the file name.
2630    
2631     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2632     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2633     pcre_exec(). This saves a malloc/free per call. The default value of
2634     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2635     when configuring.
2636    
2637     32. The default maximum size of a compiled pattern is 64K. There have been a
2638     few cases of people hitting this limit. The code now uses macros to handle the
2639     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2640     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2641     configuring. Tests 2 and 5 work only with 2-byte links because they output
2642     debugging information about compiled patterns.
2643    
2644     33. Internal code re-arrangements:
2645    
2646     (a) Moved the debugging function for printing out a compiled regex into
2647     its own source file (printint.c) and used #include to pull it into
2648     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2649     separate copies.
2650    
2651     (b) Defined the list of op-code names for debugging as a macro in
2652     internal.h so that it is next to the definition of the opcodes.
2653    
2654     (c) Defined a table of op-code lengths for simpler skipping along compiled
2655     code. This is again a macro in internal.h so that it is next to the
2656     definition of the opcodes.
2657    
2658     34. Added support for recursive calls to individual subpatterns, along the
2659     lines of Robin Houston's patch (but implemented somewhat differently).
2660    
2661     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2662     allow it to read and process whole directories in Win32. This code was
2663     contributed by Lionel Fourquaux; it has not been tested by me.
2664    
2665     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2666     used to name a group. Names consist of alphanumerics and underscores, and must
2667     be unique. Back references use the syntax (?P=name) and recursive calls use
2668     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2669     numbers. The function pcre_fullinfo() can be used after compilation to extract
2670     a name/number map. There are three relevant calls:
2671    
2672     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2673     PCRE_INFO_NAMECOUNT yields the number of entries
2674     PCRE_INFO_NAMETABLE yields a pointer to the map.
2675    
2676     The map is a vector of fixed-size entries. The size of each entry depends on
2677     the length of the longest name used. The first two bytes of each entry are the
2678     group number, most significant byte first. There follows the corresponding
2679     name, zero terminated. The names are in alphabetical order.
2680    
2681     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2682     case instead of 255. Making it the same both with and without UTF-8 support
2683     means that the same test output works with both.
2684    
2685     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2686     calling malloc() with a zero argument.
2687    
2688     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2689     optimization. I've improved things by keeping a bitmap of backreferences with
2690     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2691     fact referenced, the optimization can be applied. It is unlikely that a
2692     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2693     the match to follow \n) will appear inside brackets with a number greater than
2694     31, but if it does, any back reference > 31 suppresses the optimization.
2695    
2696     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2697     of disabling numbered capturing parentheses. Any opening parenthesis that is
2698     not followed by ? behaves as if it were followed by ?: but named parentheses
2699     can still be used for capturing (and they will acquire numbers in the usual
2700     way).
2701    
2702     41. Redesigned the return codes from the match() function into yes/no/error so
2703     that errors can be passed back from deep inside the nested calls. A malloc
2704     failure while inside a recursive subpattern call now causes the
2705     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2706    
2707     42. It is now possible to set a limit on the number of times the match()
2708     function is called in a call to pcre_exec(). This facility makes it possible to
2709     limit the amount of recursion and backtracking, though not in a directly
2710     obvious way, because the match() function is used in a number of different
2711     circumstances. The count starts from zero for each position in the subject
2712     string (for non-anchored patterns). The default limit is, for compatibility, a
2713     large number, namely 10 000 000. You can change this in two ways:
2714    
2715     (a) When configuring PCRE before making, you can use --with-match-limit=n
2716     to set a default value for the compiled library.
2717    
2718     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2719     a different value is set. See 45 below.
2720    
2721     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2722    
2723     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2724     of things that can be changed at compile time. The first argument specifies
2725     what is wanted and the second points to where the information is to be placed.
2726     The current list of available information is:
2727    
2728     PCRE_CONFIG_UTF8
2729    
2730     The output is an integer that is set to one if UTF-8 support is available;
2731     otherwise it is set to zero.
2732    
2733     PCRE_CONFIG_NEWLINE
2734    
2735     The output is an integer that it set to the value of the code that is used for
2736     newline. It is either LF (10) or CR (13).
2737    
2738     PCRE_CONFIG_LINK_SIZE
2739    
2740     The output is an integer that contains the number of bytes used for internal
2741     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2742    
2743     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2744    
2745     The output is an integer that contains the threshold above which the POSIX
2746     interface uses malloc() for output vectors. See item 31 above.
2747    
2748     PCRE_CONFIG_MATCH_LIMIT
2749    
2750     The output is an unsigned integer that contains the default limit of the number
2751     of match() calls in a pcre_exec() execution. See 42 above.
2752    
2753     44. pcretest has been upgraded by the addition of the -C option. This causes it
2754     to extract all the available output from the new pcre_config() function, and to
2755     output it. The program then exits immediately.
2756    
2757     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2758     order to support additional features. One way would have been to define
2759     pcre_exec2() (for example) with extra arguments, but this would not have been
2760     extensible, and would also have required all calls to the original function to
2761     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2762     is used for passing in "extra" data from pcre_study().
2763    
2764     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2765     contains the following fields:
2766    
2767     flags a bitmap indicating which of the following fields are set
2768     study_data opaque data from pcre_study()
2769     match_limit a way of specifying a limit on match() calls for a specific
2770     call to pcre_exec()
2771     callout_data data for callouts (see 49 below)
2772    
2773     The flag bits are also defined in pcre.h, and are
2774    
2775     PCRE_EXTRA_STUDY_DATA
2776     PCRE_EXTRA_MATCH_LIMIT
2777     PCRE_EXTRA_CALLOUT_DATA
2778    
2779     The pcre_study() function now returns one of these new pcre_extra blocks, with
2780     the actual study data pointed to by the study_data field, and the
2781     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2782     before. That is, this change is entirely upwards-compatible and requires no
2783     change to existing code.
2784    
2785     If you want to pass in additional data to pcre_exec(), you can either place it
2786     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2787     block.
2788    
2789     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2790     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2791     times with different match limits, until it finds the minimum value needed for
2792     pcre_exec() to complete. The value is then output. This can be instructive; for
2793     most simple matches the number is quite small, but for pathological cases it
2794     gets very large very quickly.
2795    
2796     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2797     returns the size of the data block pointed to by the study_data field in a
2798     pcre_extra block, that is, the value that was passed as the argument to
2799     pcre_malloc() when PCRE was getting memory in which to place the information
2800     created by pcre_study(). The fourth argument should point to a size_t variable.
2801     pcretest has been extended so that this information is shown after a successful
2802     pcre_study() call when information about the compiled regex is being displayed.
2803    
2804     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2805     because what follows is always an absolute path. (Later: it turns out that this
2806     is more than cosmetic for MinGW, because it doesn't like empty path
2807     components.)
2808    
2809     49. Some changes have been made to the callout feature (see 28 above):
2810    
2811     (i) A callout function now has three choices for what it returns:
2812    
2813     0 => success, carry on matching
2814     > 0 => failure at this point, but backtrack if possible
2815     < 0 => serious error, return this value from pcre_exec()
2816    
2817     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2818     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2819     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2820     use by callout functions. It will never be used by PCRE itself.
2821    
2822     (ii) The pcre_extra structure (see 45 above) has a void * field called
2823     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2824     pcre_callout_block structure has a field of the same name. The contents of
2825     the field passed in the pcre_extra structure are passed to the callout
2826     function in the corresponding field in the callout block. This makes it
2827     easier to use the same callout-containing regex from multiple threads. For
2828     testing, the pcretest program has a new data escape
2829    
2830     \C*n pass the number n (may be negative) as callout_data
2831    
2832     If the callout function in pcretest receives a non-zero value as
2833     callout_data, it returns that value.
2834    
2835     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2836     there were some redundant $(CFLAGS) in commands that are now specified as
2837     $(LINK), which already includes $(CFLAGS).
2838    
2839     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2840     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2841     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2842     one-byte characters throughout. Note that case-insensitive matching applies
2843     only to characters whose values are less than 256. PCRE doesn't support the
2844     notion of cases for higher-valued characters.
2845    
2846     (i) A character class whose characters are all within 0-255 is handled as
2847     a bit map, and the map is inverted for negative classes. Previously, a
2848     character > 255 always failed to match such a class; however it should
2849     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2850    
2851     (ii) A negated character class with a single character < 255 is coded as
2852     "not this character" (OP_NOT). This wasn't working properly when the test
2853     character was multibyte, either singly or repeated.
2854    
2855     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2856     mode, for example: \x{100}{2,3}.
2857    
2858     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2859     singly or repeated) now correctly test multibyte characters. However,
2860     PCRE doesn't recognize any characters with values greater than 255 as
2861     digits, spaces, or word characters. Such characters always match \D, \S,
2862     and \W, and never match \d, \s, or \w.
2863    
2864     (v) Classes may now contain characters and character ranges with values
2865     greater than 255. For example: [ab\x{100}-\x{400}].
2866    
2867     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2868     PCRE in UTF-8 mode.
2869    
2870     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2871     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2872     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2873     value.)
2874    
2875     53. The single man page has become too large. I have therefore split it up into
2876     a number of separate man pages. These also give rise to individual HTML pages;
2877     these are now put in a separate directory, and there is an index.html page that
2878     lists them all. Some hyperlinking between the pages has been installed.
2879    
2880     54. Added convenience functions for handling named capturing parentheses.
2881    
2882     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2883     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2884     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2885     are faulted.
2886    
2887     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2888     calling configure. These values are used when compiling the dftables.c program
2889     which is run to generate the source of the default character tables. They
2890     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2891     you will need to set these values.
2892    
2893     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2894    
2895    
2896     Version 3.9 02-Jan-02
2897 nigel 61 ---------------------
2898    
2899     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2900    
2901     2. If --disable-static was given, the building process failed when trying to
2902     build pcretest and pcregrep. (For some reason it was using libtool to compile
2903     them, which is not right, as they aren't part of the library.)
2904    
2905    
2906 nigel 59 Version 3.8 18-Dec-01
2907     ---------------------
2908    
2909     1. The experimental UTF-8 code was completely screwed up. It was packing the
2910     bytes in the wrong order. How dumb can you get?
2911    
2912    
2913 nigel 57 Version 3.7 29-Oct-01
2914     ---------------------
2915    
2916     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2917     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2918     this didn't happen under Solaris 8, where I normally test things.
2919    
2920 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2921     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2922     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2923     this fix an hour or so after the initial 3.7 release.)
2924 nigel 57
2925 nigel 59
2926 nigel 55 Version 3.6 23-Oct-01
2927     ---------------------
2928    
2929     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2930     offsets passed as NULL with zero offset count.
2931    
2932     2. The config.guess and config.sub files had not been updated when I moved to
2933     the latest autoconf.
2934    
2935    
2936 nigel 53 Version 3.5 15-Aug-01
2937     ---------------------
2938 nigel 5
2939 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2940     had been forgotten.
2941    
2942     2. By using declared but undefined structures, we can avoid using "void"
2943     definitions in pcre.h while keeping the internal definitions of the structures
2944     private.
2945    
2946     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2947     user point of view, this means that both static and shared libraries are built
2948     by default, but this can be individually controlled. More of the work of
2949     handling this static/shared cases is now inside libtool instead of PCRE's make
2950     file.
2951    
2952     4. The pcretest utility is now installed along with pcregrep because it is
2953     useful for users (to test regexs) and by doing this, it automatically gets
2954     relinked by libtool. The documentation has been turned into a man page, so
2955     there are now .1, .txt, and .html versions in /doc.
2956    
2957     5. Upgrades to pcregrep:
2958     (i) Added long-form option names like gnu grep.
2959     (ii) Added --help to list all options with an explanatory phrase.
2960     (iii) Added -r, --recursive to recurse into sub-directories.
2961     (iv) Added -f, --file to read patterns from a file.
2962    
2963     6. pcre_exec() was referring to its "code" argument before testing that
2964     argument for NULL (and giving an error if it was NULL).
2965    
2966     7. Upgraded Makefile.in to allow for compiling in a different directory from
2967     the source directory.
2968    
2969     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2970     options bits, the pointer it was passed was to an int instead of to an unsigned
2971     long int. This mattered only on 64-bit systems.
2972    
2973     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2974     generated) instead of pcre.in, which it its source. Also made the same change
2975     in several of the .c files.
2976    
2977     10. A new release of gcc defines printf() as a macro, which broke pcretest
2978     because it had an ifdef in the middle of a string argument for printf(). Fixed
2979     by using separate calls to printf().
2980    
2981     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2982     script, to force use of CR or LF instead of \n in the source. On non-Unix
2983     systems, the value can be set in config.h.
2984    
2985     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2986     absolute limit. Changed the text of the error message to make this clear, and
2987     likewise updated the man page.
2988    
2989     13. The limit of 99 on the number of capturing subpatterns has been removed.
2990     The new limit is 65535, which I hope will not be a "real" limit.
2991    
2992    
2993 nigel 51 Version 3.4 22-Aug-00
2994     ---------------------
2995    
2996     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2997    
2998     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2999    
3000    
3001 nigel 49 Version 3.3 01-Aug-00
3002     ---------------------
3003    
3004     1. If an octal character was given, but the value was greater than \377, it
3005     was not getting masked to the least significant bits, as documented. This could
3006     lead to crashes in some systems.
3007    
3008     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3009     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3010    
3011     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3012     These just pass their arguments on to (pcre_free)(), but they are provided
3013     because some uses of PCRE bind it to non-C systems that can call its functions,
3014     but cannot call free() or pcre_free() directly.
3015    
3016     4. Add "make test" as a synonym for "make check". Corrected some comments in
3017     the Makefile.
3018    
3019     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3020     Makefile.
3021    
3022     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3023     command called pgrep for grepping around the active processes.
3024    
3025     7. Added the beginnings of support for UTF-8 character strings.
3026    
3027     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3028     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3029     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3030     out for the ar command.)
3031    
3032    
3033 nigel 47 Version 3.2 12-May-00
3034     ---------------------
3035    
3036     This is purely a bug fixing release.
3037    
3038     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3039     of ZA. This was just one example of several cases that could provoke this bug,
3040     which was introduced by change 9 of version 2.00. The code for breaking
3041     infinite loops after an iteration that matches an empty string was't working
3042     correctly.
3043    
3044     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3045     when matched against abbab (for example). After matching an empty string, it
3046     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3047     caused it to match further down the string than it should.
3048    
3049     3. The code contained an inclusion of sys/types.h. It isn't clear why this
3050     was there because it doesn't seem to be needed, and it causes trouble on some
3051     systems, as it is not a Standard C header. It has been removed.
3052    
3053     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3054     were reported on the Macintosh. The changes were from
3055    
3056     while ((c = *(++ptr)) != 0 && c != '\n');
3057     to
3058     while ((c = *(++ptr)) != 0 && c != '\n') ;
3059    
3060     Totally extraordinary, but if that's what it takes...
3061    
3062     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3063     available. Added HAVE_BCOPY and an autoconf test for it; if neither
3064     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3065     assumes the way PCRE uses memmove() (always moving upwards).
3066    
3067     6. PCRE is being used in one environment where strchr() is not available. There
3068     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3069     faster code anyway.
3070    
3071    
3072 nigel 45 Version 3.1 09-Feb-00
3073     ---------------------
3074    
3075     The only change in this release is the fixing of some bugs in Makefile.in for
3076     the "install" target:
3077    
3078     (1) It was failing to install pcreposix.h.
3079    
3080     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3081    
3082    
3083 nigel 43 Version 3.0 01-Feb-00
3084     ---------------------
3085 nigel 41
3086     1. Add support for the /+ modifier to perltest (to output $` like it does in
3087     pcretest).
3088    
3089     2. Add support for the /g modifier to perltest.
3090    
3091     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3092     matches null strings.
3093    
3094     4. Fix perltest so that it doesn't do unwanted things when fed an empty
3095     pattern. Perl treats empty patterns specially - it reuses the most recent
3096     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3097     effect.
3098    
3099     5. The POSIX interface was broken in that it was just handing over the POSIX
3100     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3101     required a bigger vector, with some working space on the end. This means that
3102     the POSIX wrapper now has to get and free some memory, and copy the results.
3103    
3104 nigel 43 6. Added some simple autoconf support, placing the test data and the
3105     documentation in separate directories, re-organizing some of the
3106     information files, and making it build pcre-config (a GNU standard). Also added
3107     libtool support for building PCRE as a shared library, which is now the
3108     default.
3109 nigel 41
3110 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3111     09 are not valid octal constants. Single digits will be used for minor values
3112     less than 10.
3113    
3114     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3115     existing programs that set these in the POSIX interface can use PCRE without
3116     modification.
3117    
3118     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3119     return all that pcre_info() returns, plus additional data. The pcre_info()
3120     function is retained for compatibility, but is considered to be obsolete.
3121    
3122     10. Added experimental recursion feature (?R) to handle one common case that
3123     Perl 5.6 will be able to do with (?p{...}).
3124    
3125     11. Added support for POSIX character classes like [:alpha:], which Perl is
3126     adopting.
3127    
3128    
3129 nigel 39 Version 2.08 31-Aug-99
3130     ----------------------
3131    
3132     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3133     trying to match at the startoffset position, but instead was moving forward to
3134     the next newline as if a previous match had failed.
3135    
3136     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3137     and could get into a loop if a null string was matched other than at the start
3138     of the subject.
3139    
3140     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3141     be distinguished at compile time, and for completeness also added PCRE_DATE.
3142    
3143     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3144     in GnuWin32 environments.
3145    
3146    
3147 nigel 37 Version 2.07 29-Jul-99
3148     ----------------------
3149    
3150     1. The documentation is now supplied in plain text form and HTML as well as in
3151     the form of man page sources.
3152    
3153     2. C++ compilers don't like assigning (void *) values to other pointer types.
3154     In particular this affects malloc(). Although there is no problem in Standard
3155     C, I've put in casts to keep C++ compilers happy.
3156    
3157     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3158     should be (const char *).
3159    
3160     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3161     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3162     However, I haven't made this a standard facility. The documentation doesn't
3163     mention it, and the Makefile doesn't support it.
3164    
3165     5. The Makefile now contains an "install" target, with editable destinations at
3166     the top of the file. The pcretest program is not installed.
3167    
3168     6. pgrep -V now gives the PCRE version number and date.
3169    
3170     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3171     causing the entire string to be ignored, instead of just the last character.
3172    
3173     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3174     non-matching string, it can take a very, very long time, even for strings of
3175     quite modest length, because of the nested recursion. PCRE now does better in
3176     some of these cases. It does this by remembering the last required literal
3177     character in the pattern, and pre-searching the subject to ensure it is present
3178     before running the real match. In other words, it applies a heuristic to detect
3179     some types of certain failure quickly, and in the above example, if presented
3180     with a string that has no trailing " it gives "no match" very quickly.
3181    
3182     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3183     other alternatives are tried instead.
3184    
3185    
3186 nigel 35 Version 2.06 09-Jun-99
3187     ----------------------
3188    
3189     1. Change pcretest's output for amount of store used to show just the code
3190     space, because the remainder (the data block) varies in size between 32-bit and
3191     64-bit systems.
3192    
3193     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3194     start matching at. This allows lookbehinds to work when searching for multiple
3195     occurrences in a string.
3196    
3197     3. Added additional options to pcretest for testing multiple occurrences:
3198    
3199     /+ outputs the rest of the string that follows a match
3200     /g loops for multiple occurrences, using the new startoffset argument
3201     /G loops for multiple occurrences by passing an incremented pointer
3202    
3203     4. PCRE wasn't doing the "first character" optimization for patterns starting
3204     with \b or \B, though it was doing it for other lookbehind assertions. That is,
3205     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3206     the letter 'x'. On long subject strings, this gives a significant speed-up.
3207    
3208    
3209 nigel 33 Version 2.05 21-Apr-99
3210     ----------------------
3211    
3212     1. Changed the type of magic_number from int to long int so that it works
3213     properly on 16-bit systems.
3214    
3215     2. Fixed a bug which caused patterns starting with .* not to work correctly
3216     when the subject string contained newline characters. PCRE was assuming
3217     anchoring for such patterns in all cases, which is not correct because .* will
3218     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3219     DOTALL is set at top level; otherwise it knows that patterns starting with .*
3220     must be retried after every newline in the subject.
3221    
3222    
3223 nigel 31 Version 2.04 18-Feb-99
3224     ----------------------
3225    
3226     1. For parenthesized subpatterns with repeats whose minimum was zero, the
3227     computation of the store needed to hold the pattern was incorrect (too large).
3228     If such patterns were nested a few deep, this could multiply and become a real
3229     problem.
3230    
3231     2. Added /M option to pcretest to show the memory requirement of a specific
3232     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3233    
3234     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3235     compiled in such a way that the backtracking after subsequent failure was
3236     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3237     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3238    
3239    
3240 nigel 29 Version 2.03 02-Feb-99
3241     ----------------------
3242    
3243     1. Fixed typo and small mistake in man page.
3244    
3245 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
3246     LICENCE file containing the conditions.
3247 nigel 29
3248     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3249     Perl, that is the internal \ allows the delimiter to be included in the
3250     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3251     the final delimiter, add \ to the end of the pattern (to test the error).
3252    
3253     4. Added the convenience functions for extracting substrings after a successful
3254     match. Updated pcretest to make it able to test these functions.
3255    
3256    
3257 nigel 27 Version 2.02 14-Jan-99
3258     ----------------------
3259    
3260     1. Initialized the working variables associated with each extraction so that
3261     their saving and restoring doesn't refer to uninitialized store.
3262    
3263     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3264     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3265     fix the problem.
3266    
3267     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3268     calls, and wasn't printing the correct value for compiling calls. Increased the
3269     default value of LOOPREPEAT, and the number of significant figures in the
3270     times.
3271    
3272     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3273    
3274     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3275     a building problem on Windows NT with a FAT file system.
3276    
3277    
3278 nigel 25 Version 2.01 21-Oct-98
3279     ----------------------
3280    
3281     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3282     to character tables built by pcre_maketables() in the current locale. If NULL
3283     is passed, the default tables are used.
3284    
3285    
3286 nigel 23 Version 2.00 24-Sep-98
3287 nigel 21 ----------------------
3288    
3289 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3290     it any more.
3291    
3292     2. Allow quantification of (?>) groups, and make it work correctly.
3293    
3294     3. The first character computation wasn't working for (?>) groups.
3295    
3296     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3297     end of the subject) and add 5.005's \z, which really does match only at the
3298     very end of the subject.
3299    
3300     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3301    
3302     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3303     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3304     localized options. All options to pcre_study() were also removed.
3305    
3306     7. Add other new features from 5.005:
3307    
3308     $(?<= positive lookbehind
3309     $(?<! negative lookbehind
3310     (?imsx-imsx) added the unsetting capability
3311     such a setting is global if at outer level; local otherwise
3312     (?imsx-imsx:) non-capturing groups with option setting
3313     (?(cond)re|re) conditional pattern matching
3314    
3315     A backreference to itself in a repeated group matches the previous
3316     captured string.
3317    
3318     8. General tidying up of studying (both automatic and via "study")
3319     consequential on the addition of new assertions.
3320    
3321     9. As in 5.005, unlimited repeated groups that could match an empty substring
3322     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3323     runtime if any iteration does actually match an empty substring.
3324    
3325     10. Include the RunTest script in the distribution.
3326    
3327     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3328     discrepancies, some of which were old and were also with respect to 5.004. They
3329     have now been fixed.
3330    
3331    
3332     Version 1.09 28-Apr-98
3333     ----------------------
3334    
3335 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3336     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3337     program crashes, or just wrong answers. This did not apply to negated classes
3338     containing more than one character, or to minima other than one.
3339    
3340    
3341 nigel 19 Version 1.08 27-Mar-98
3342     ----------------------
3343    
3344     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3345    
3346     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3347     latter must appear before anything that relies on it in the pattern.
3348    
3349    
3350 nigel 17 Version 1.07 16-Feb-98
3351     ----------------------
3352    
3353     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3354     repeat of a potentially empty string).
3355    
3356    
3357 nigel 15 Version 1.06 23-Jan-98
3358     ----------------------
3359    
3360     1. Added Markus Oberhumer's little patches for C++.
3361    
3362     2. Literal strings longer than 255 characters were broken.
3363    
3364    
3365 nigel 13 Version 1.05 23-Dec-97
3366     ----------------------
3367    
3368     1. Negated character classes containing more than one character were failing if
3369     PCRE_CASELESS was set at run time.
3370    
3371    
3372 nigel 11 Version 1.04 19-Dec-97
3373     ----------------------
3374    
3375     1. Corrected the man page, where some "const" qualifiers had been omitted.
3376    
3377     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3378     input syntax.
3379    
3380     3. Fixed memory leak which occurred when a regex with back references was
3381     matched with an offsets vector that wasn't big enough. The temporary memory
3382     that is used in this case wasn't being freed if the match failed.
3383    
3384     4. Tidied pcretest to ensure it frees memory that it gets.
3385    
3386     5. Temporary memory was being obtained in the case where the passed offsets
3387     vector was exactly big enough.
3388    
3389     6. Corrected definition of offsetof() from change 5 below.
3390    
3391     7. I had screwed up change 6 below and broken the rules for the use of
3392     setjmp(). Now fixed.
3393    
3394    
3395 nigel 9 Version 1.03 18-Dec-97
3396     ----------------------
3397    
3398     1. A erroneous regex with a missing opening parenthesis was correctly
3399     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3400     on some systems.
3401    
3402     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3403     it was reported that one broken compiler failed on the former because "code" is
3404     also an independent variable.
3405    
3406     3. The erroneous regex a[]b caused an array overrun reference.
3407    
3408     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3409     fail on data ending with that character. (It was going on too far, and checking
3410     the next character, typically a binary zero.) This was specific to the
3411     optimized code for single-character negative classes.
3412    
3413     5. Added a contributed patch from the TIN world which does the following:
3414    
3415     + Add an undef for memmove, in case the the system defines a macro for it.
3416    
3417     + Add a definition of offsetof(), in case there isn't one. (I don't know
3418     the reason behind this - offsetof() is part of the ANSI standard - but
3419     it does no harm).
3420    
3421     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3422     most of the places where whitespace preceded '#'. I have given up and
3423     allowed the remaining 2 cases to be at the margin.
3424    
3425     + Rename some variables in pcre to eliminate shadowing. This seems very
3426     pedantic, but does no harm, of course.
3427    
3428     6. Moved the call to setjmp() into its own function, to get rid of warnings
3429     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3430    
3431     7. Constructs such as \d{8,} were compiling into the equivalent of
3432 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3433 nigel 9 outcome, but in this particular case used more store than had been allocated,
3434     which caused the bug to be discovered because it threw up an internal error.
3435    
3436     8. The debugging code in both pcre and pcretest for outputting the compiled
3437     form of a regex was going wrong in the case of back references followed by
3438     curly-bracketed repeats.
3439    
3440    
3441 nigel 7 Version 1.02 12-Dec-97
3442     ----------------------
3443    
3444     1. Typos in pcre.3 and comments in the source fixed.
3445    
3446     2. Applied a contributed patch to get rid of places where it used to remove
3447     'const' from variables, and fixed some signed/unsigned and uninitialized
3448     variable warnings.
3449    
3450     3. Added the "runtest" target to Makefile.
3451    
3452     4. Set default compiler flag to -O2 rather than just -O.
3453    
3454    
3455 nigel 5 Version 1.01 19-Nov-97
3456     ----------------------
3457    
3458     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3459     like /([ab]*)*/, that is, for classes with more than one character in them.
3460    
3461     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3462     as /((?>a*))*/ (a PCRE_EXTRA facility).
3463    
3464    
3465     Version 1.00 18-Nov-97
3466     ----------------------
3467    
3468     1. Added compile-time macros to support systems such as SunOS4 which don't have
3469     memmove() or strerror() but have other things that can be used instead.
3470    
3471     2. Arranged that "make clean" removes the executables.
3472    
3473    
3474 nigel 3 Version 0.99 27-Oct-97
3475     ----------------------
3476    
3477     1. Fixed bug in code for optimizing classes with only one character. It was
3478     initializing a 32-byte map regardless, which could cause it to run off the end
3479     of the memory it had got.
3480    
3481     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3482    
3483    
3484     Version 0.98 22-Oct-97
3485     ----------------------
3486    
3487     1. Fixed bug in code for handling temporary memory usage when there are more
3488     back references than supplied space in the ovector. This could cause segfaults.
3489    
3490    
3491     Version 0.97 21-Oct-97
3492     ----------------------
3493    
3494     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3495    
3496     2. Optimized negated single characters not to use a bit map.
3497    
3498     3. Brought error texts together as macro definitions; clarified some of them;
3499     fixed one that was wrong - it said "range out of order" when it meant "invalid
3500     escape sequence".
3501    
3502     4. Changed some char * arguments to const char *.
3503    
3504     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3505    
3506     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3507     pcretest.
3508    
3509    
3510     Version 0.96 16-Oct-97
3511     ----------------------
3512    
3513     1. Added a simple "pgrep" utility to the distribution.
3514    
3515     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3516     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3517     where "ddd" means "one or more decimal digits".
3518    
3519     3. Fixed serious bug. If a pattern had a back reference, but the call to
3520     pcre_exec() didn't supply a large enough ovector to record the related
3521     identifying subpattern, the match always failed. PCRE now remembers the number
3522     of the largest back reference, and gets some temporary memory in which to save
3523     the offsets during matching if necessary, in order to ensure that
3524     backreferences always work.
3525    
3526     4. Increased the compatibility with Perl in a number of ways:
3527    
3528     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3529     to request this handling. The option can be set at compile or exec time.
3530    
3531     (b) $ matches before a terminating newline by default; an option
3532     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3533     mode). The option can be set at compile or exec time.
3534    
3535     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3536     the same as Perl's. If the decimal number it represents is less than 10
3537     or there aren't that many previous left capturing parentheses, an octal
3538     escape is read. Inside a character class, it's always an octal escape,
3539     even if it is a single digit.
3540    
3541     (d) An escaped but undefined alphabetic character is taken as a literal,
3542     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3543     escapes.
3544    
3545     (e) {0} is now permitted. (The previous item is removed from the compiled
3546     pattern).
3547    
3548     5. Changed all the names of code files so that the basic parts are no longer
3549     than 10 characters, and abolished the teeny "globals.c" file.
3550    
3551     6. Changed the handling of character classes; they are now done with a 32-byte
3552     bit map always.
3553    
3554     7. Added the -d and /D options to pcretest to make it possible to look at the
3555     internals of compilation without having to recompile pcre.
3556    
3557    
3558     Version 0.95 23-Sep-97
3559     ----------------------
3560    
3561     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3562     \x20 at the start of a run of normal characters. These were being treated as
3563     real characters, instead of the source characters being re-checked.
3564    
3565    
3566     Version 0.94 18-Sep-97
3567     ----------------------
3568    
3569     1. The functions are now thread-safe, with the caveat that the global variables
3570     containing pointers to malloc() and free() or alternative functions are the
3571     same for all threads.
3572    
3573     2. Get pcre_study() to generate a bitmap of initial characters for non-
3574     anchored patterns when this is possible, and use it if passed to pcre_exec().
3575    
3576    
3577     Version 0.93 15-Sep-97
3578     ----------------------
3579    
3580     1. /(b)|(:+)/ was computing an incorrect first character.
3581    
3582     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3583     but not actually doing anything yet.
3584    
3585     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3586     as Perl does (e.g. [-az] or [az-]).
3587    
3588     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3589     all possible positions.
3590    
3591     5. Split up into different modules to avoid including unneeded functions in a
3592     compiled binary. However, compile and exec are still in one module. The "study"
3593     function is split off.
3594    
3595     6. The character tables are now in a separate module whose source is generated
3596     by an auxiliary program - but can then be edited by hand if required. There are
3597     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3598     toupper() in the code.
3599    
3600     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3601     make them global. Abolish the function for setting them, as the caller can now
3602     set them directly.
3603    
3604    
3605     Version 0.92 11-Sep-97
3606     ----------------------
3607    
3608     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3609     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3610    
3611     2. Caseless matching was not working in character classes if the characters in
3612     the pattern were in upper case.
3613    
3614     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3615    
3616     4. Make PCRE_ANCHORED public and accept as a compile option.
3617    
3618     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3619     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3620     pass them.
3621    
3622     6. Give an error if bad option bits passed at compile or run time.
3623    
3624     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3625     pcretest to cause it to pass that flag.
3626    
3627     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3628     options, and the first character, if set.
3629    
3630     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3631    
3632    
3633     Version 0.91 10-Sep-97
3634     ----------------------
3635    
3636     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3637     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3638    
3639     2. PCRE was looping on encountering an indefinitely repeated back reference to
3640     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3641     Perl does - treats the match as successful.
3642    
3643     ****

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