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Revision 408 - (hide annotations) (download)
Fri Mar 27 17:52:03 2009 UTC (6 years, 1 month ago) by ph10
File size: 165101 byte(s)
Fix forward references when duplicate group numbers are involved.

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


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