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Revision 376 - (hide annotations) (download)
Sun Mar 1 12:00:59 2009 UTC (6 years, 1 month ago) by ph10
File size: 160904 byte(s)
Bug fixes: forgot to commit these individually.

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


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