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Revision 409 - (hide annotations) (download)
Sat Mar 28 17:10:56 2009 UTC (6 years ago) by ph10
File size: 165262 byte(s)
Further USPTR additions.

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


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