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Revision 411 - (hide annotations) (download)
Fri Apr 10 15:40:21 2009 UTC (6 years ago) by ph10
File size: 165409 byte(s)
Wrap fileno/isatty defs for Windows in #ifndefs

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


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