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Revision 427 - (hide annotations) (download)
Fri Aug 28 09:55:54 2009 UTC (4 years, 11 months ago) by ph10
File size: 168654 byte(s)
Add new PCRE_PARTIAL_HARD option.

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8     was out-of-date, and there was no check on the pcre_compile() error code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

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