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Revision 426 - (hide annotations) (download)
Wed Aug 26 15:38:32 2009 UTC (4 years, 11 months ago) by ph10
File size: 168316 byte(s)
Remove restrictions on pcre_exec() partial matching.

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8     was out-of-date, and there was no check on the pcre_compile() error code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

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