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Revision 412 - (hide annotations) (download)
Sat Apr 11 10:34:37 2009 UTC (6 years ago) by ph10
File size: 165472 byte(s)
Add support for (*UTF8).

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


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