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Revision 435 - (hide annotations) (download)
Sat Sep 5 10:20:44 2009 UTC (5 years, 6 months ago) by ph10
File size: 171156 byte(s)
Further updates to partial matching.

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8     was out-of-date, and there was no check on the pcre_compile() error code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


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