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Revision 437 - (hide annotations) (download)
Sun Sep 6 16:34:42 2009 UTC (5 years, 7 months ago) by ph10
File size: 171359 byte(s)
Add test for diff -u to RunGrepTest.

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8     was out-of-date, and there was no check on the pcre_compile() error code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


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