/[pcre]/code/trunk/ChangeLog
ViewVC logotype

Contents of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log


Revision 383 - (hide annotations) (download)
Sun Mar 8 15:26:59 2009 UTC (5 years, 5 months ago) by ph10
File size: 162116 byte(s)
Fix PCRE_DOLLAR_ENDONLY bug in pcre_dfa_exec().

1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 ph10 376 Version 7.9 xx-xxx-09
5     ---------------------
6    
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.
13    
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.
18    
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.
21    
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.
26 ph10 377
27 ph10 378 5. In pcregrep, when --colour was used with -o, the list of matching strings
28     was not coloured; this is different to GNU grep, so I have changed it to be
29     the same.
30    
31     6. When --colo(u)r was used in pcregrep, only the first matching substring in
32     each matching line was coloured. Now it goes on to look for further matches
33     of any of the test patterns, which is the same behaviour as GNU grep.
34 ph10 379
35     7. A pattern that could match an empty string could cause pcregrep to loop; it
36     doesn't make sense to accept an empty string match in pcregrep, so I have
37     locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
38     seems to be how GNU grep behaves.
39 ph10 380
40     8. The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
41     start or after a newline", because the conditional assertion was not being
42 ph10 381 correctly handled. The rule now is that both the assertion and what follows
43     in the first alternative must satisfy the test.
44    
45     9. If auto-callout was enabled in a pattern with a conditional group, PCRE
46     could crash during matching.
47 ph10 383
48     10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
49     used for matching.
50 ph10 376
51    
52 ph10 374 Version 7.8 05-Sep-08
53 ph10 349 ---------------------
54    
55     1. Replaced UCP searching code with optimized version as implemented for Ad
56     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
57 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
58     to 5 times on some simple patterns that I tested. Permission was given to
59     distribute the MultiStage2.py script that generates the tables (it's not in
60     the tarball, but is in the Subversion repository).
61 ph10 349
62 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
63     scripts.
64 ph10 358
65 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
66     a group with a zero qualifier. The result of the study could be incorrect,
67 ph10 358 or the function might crash, depending on the pattern.
68    
69     4. Caseless matching was not working for non-ASCII characters in back
70 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
71 ph10 358 It now works when Unicode Property Support is available.
72    
73 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
74     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
75     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
76 ph10 358 truncation.
77 ph10 349
78 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
79    
80 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
81     pointers, in case they are 64-bit values.
82 ph10 371
83     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
84     test 2 if it fails.
85    
86 ph10 359 9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
87 ph10 371 and a #define of that name to empty if it is not externally set. This is to
88     allow users of MSVC to set it if necessary.
89    
90     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
91 ph10 359 the convenience functions in the pcre_get.c source file.
92 ph10 371
93 ph10 360 11. An option change at the start of a pattern that had top-level alternatives
94     could cause overwriting and/or a crash. This command provoked a crash in
95 ph10 371 some environments:
96    
97     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
98    
99 ph10 360 This potential security problem was recorded as CVE-2008-2371.
100 ph10 371
101 ph10 361 12. For a pattern where the match had to start at the beginning or immediately
102     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
103 ph10 371 pcre_dfa_exec() could read past the end of the passed subject if there was
104 ph10 361 no match. To help with detecting such bugs (e.g. with valgrind), I modified
105     pcretest so that it places the subject at the end of its malloc-ed buffer.
106 ph10 371
107 ph10 364 13. The change to pcretest in 12 above threw up a couple more cases when pcre_
108 ph10 371 exec() might read past the end of the data buffer in UTF-8 mode.
109    
110 ph10 364 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
111 ph10 371 the data contained the byte 0x85 as part of a UTF-8 character within its
112     first line. This applied both to normal and DFA matching.
113    
114 ph10 366 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
115 ph10 371 /^[^d]*?$/8 failed to match "abc".
116 ph10 351
117 ph10 371 16. Added a missing copyright notice to pcrecpp_internal.h.
118    
119     17. Make it more clear in the documentation that values returned from
120 ph10 368 pcre_exec() in ovector are byte offsets, not character counts.
121 ph10 357
122 ph10 371 18. Tidied a few places to stop certain compilers from issuing warnings.
123 ph10 368
124 ph10 373 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
125     supplied by Stefan Weber. I made a further small update for 7.8 because
126 ph10 374 there is a change of source arrangements: the pcre_searchfuncs.c module is
127     replaced by pcre_ucd.c.
128 ph10 371
129 ph10 373
130 ph10 347 Version 7.7 07-May-08
131 ph10 321 ---------------------
132    
133     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
134 ph10 345 a string to a long long, pretend we don't even have a long long." This is
135 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
136 ph10 345
137 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
138     pre-7.6 versions, which defined a global no_arg variable instead of putting
139 ph10 332 it in the RE class. (See also #8 below.)
140 ph10 345
141     3. Remove a line of dead code, identified by coverity and reported by Nuno
142     Lopes.
143    
144 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
145 ph10 321
146 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
147 ph10 345 of files, instead of just to the final components.
148    
149 ph10 324 (2) If there was more than one level of directory, the subdirectories were
150     skipped unless they satisfied the include/exclude conditions. This is
151     inconsistent with GNU grep (and could even be seen as contrary to the
152     pcregrep specification - which I improved to make it absolutely clear).
153     The action now is always to scan all levels of directory, and just
154     apply the include/exclude patterns to regular files.
155 ph10 345
156 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
157 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
158    
159 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
160 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
161 ph10 326 doesn't support NULs in patterns.
162 ph10 345
163     7. Added some missing "const"s to declarations of static tables in
164     pcre_compile.c and pcre_dfa_exec.c.
165    
166 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
167 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
168 ph10 345 first patch. And a third patch - this was a messy problem.)
169 ph10 321
170 ph10 345 9. Applied Craig's patch to remove the use of push_back().
171    
172 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
173     matching function regexec().
174 ph10 345
175     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
176     which, however, unlike Perl's \g{...}, are subroutine calls, not back
177 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
178     Oniguruma does).
179 ph10 345
180     12. Previously, a group with a zero repeat such as (...){0} was completely
181 ph10 335 omitted from the compiled regex. However, this means that if the group
182     was called as a subroutine from elsewhere in the pattern, things went wrong
183 ph10 345 (an internal error was given). Such groups are now left in the compiled
184     pattern, with a new opcode that causes them to be skipped at execution
185 ph10 335 time.
186 ph10 345
187 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
188     to the way PCRE behaves:
189 ph10 345
190 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
191 ph10 345
192     (b) A back reference to an unmatched subpattern matches an empty string
193 ph10 336 (Perl fails the current match path).
194 ph10 345
195 ph10 341 (c) A data ] in a character class must be notated as \] because if the
196 ph10 345 first data character in a class is ], it defines an empty class. (In
197 ph10 341 Perl it is not possible to have an empty class.) The empty class []
198     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
199     The negative empty class [^] matches any one character, independently
200     of the DOTALL setting.
201 ph10 345
202     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
203 ph10 340 non-existent subpattern following a character class starting with ']' and
204     containing () gave an internal compiling error instead of "reference to
205     non-existent subpattern". Fortunately, when the pattern did exist, the
206 ph10 345 compiled code was correct. (When scanning forwards to check for the
207 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
208 ph10 345 the class, so got the count wrong. When actually compiling, the reference
209 ph10 340 was subsequently set up correctly.)
210 ph10 345
211 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
212 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
213     other assertions are supported. I have made pcre_dfa_exec() support
214     (*FAIL).
215    
216 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
217 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
218     cannot be changed at match time, I realized I could make a small
219     improvement to matching performance by compiling OP_ALLANY instead of
220     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
221     on the OP_ANY path.
222    
223     17. Compiling pcretest on Windows with readline support failed without the
224 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
225 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
226    
227 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
228 ph10 345 ncurses library to be included for pcretest when ReadLine support is
229     requested, but also to allow for it to be overridden. This patch came from
230     Daniel Bergström.
231 ph10 347
232 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
233 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
234     any errors with the current Unicode tables. Thanks to Peter Kankowski for
235     spotting this.
236 ph10 324
237 ph10 332
238 ph10 319 Version 7.6 28-Jan-08
239 ph10 300 ---------------------
240    
241 ph10 302 1. A character class containing a very large number of characters with
242     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
243     overflow.
244 ph10 309
245     2. Patch to cut out the "long long" test in pcrecpp_unittest when
246     HAVE_LONG_LONG is not defined.
247    
248 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
249 ph10 304 bring them up to date and include new features. This patch includes:
250 ph10 309
251 ph10 304 - Fixed PH's badly added libz and libbz2 support.
252     - Fixed a problem with static linking.
253 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
254 ph10 304 - Fixed dftables problem and added an option.
255     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
256     HAVE_LONG_LONG.
257     - Added readline support for pcretest.
258 ph10 309 - Added an listing of the option settings after cmake has run.
259    
260 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
261     "pcre.dll" under mingw when using Configure/Make. I added stuff to
262     Makefile.am that cause it to include this special target, without
263     affecting anything else. Note that the same mingw target plus all
264     the other distribution libraries and programs are now supported
265     when configuring with CMake (see 6 below) instead of with
266     Configure/Make.
267 ph10 309
268 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
269     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
270 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
271     solves the problem, but it does no harm.
272 ph10 313
273 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
274 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
275 ph10 314 with CMake, and also correct the comment about stack recursion.
276 ph10 313
277 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
278 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
279     of a program that users should build themselves after PCRE is installed, so
280     building it automatically is not really right. What is more, it gave
281 ph10 312 trouble in some build environments.
282 ph10 300
283 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
284 ph10 308
285 ph10 319
286 ph10 298 Version 7.5 10-Jan-08
287 ph10 263 ---------------------
288    
289     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
290     values in parens when parsing an RE using the C++ wrapper."
291 ph10 286
292 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
293     Characters greater than 255 were excluded from the class instead of being
294     included.
295 ph10 286
296     3. The same bug as (2) above applied to negated POSIX classes such as
297 ph10 265 [:^space:].
298 ph10 286
299 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
300     defined or documented. It seems to have been a typo for PCRE_STATIC, so
301 ph10 286 I have changed it.
302    
303 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
304 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
305     first named subpattern whose name started with "a" (in other words, the
306 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
307     expected" is now given for (?&) (a zero-length name), and this patch also
308     makes it give the same error for \k'' (previously it complained that that
309     was a reference to a non-existent subpattern).
310 ph10 286
311 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
312 ph10 286 this is right because (?- can be followed by option settings as well as by
313 ph10 269 digits. I have, however, made the messages clearer.
314 ph10 286
315 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
316     than the number used in the conditional) now cause a compile-time error.
317     This is actually not compatible with Perl, which accepts such patterns, but
318     treats the conditional as always being FALSE (as PCRE used to), but it
319     seems to me that giving a diagnostic is better.
320 ph10 286
321 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
322 ph10 275 and messages.
323 ph10 286
324     9. Fix two occurrences of "backslash" in comments that should have been
325     "backspace".
326    
327     10. Remove two redundant lines of code that can never be obeyed (their function
328     was moved elsewhere).
329    
330     11. The program that makes PCRE's Unicode character property table had a bug
331     which caused it to generate incorrect table entries for sequences of
332 ph10 277 characters that have the same character type, but are in different scripts.
333 ph10 286 It amalgamated them into a single range, with the script of the first of
334 ph10 277 them. In other words, some characters were in the wrong script. There were
335     thirteen such cases, affecting characters in the following ranges:
336 ph10 286
337 ph10 277 U+002b0 - U+002c1
338     U+0060c - U+0060d
339 ph10 286 U+0061e - U+00612
340 ph10 277 U+0064b - U+0065e
341     U+0074d - U+0076d
342     U+01800 - U+01805
343     U+01d00 - U+01d77
344     U+01d9b - U+01dbf
345     U+0200b - U+0200f
346     U+030fc - U+030fe
347     U+03260 - U+0327f
348     U+0fb46 - U+0fbb1
349     U+10450 - U+1049d
350 ph10 286
351 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
352     compatible with GNU grep in that, if there was more than one match in a
353     line, it showed only the first of them. It now behaves in the same way as
354     GNU grep.
355 ph10 286
356     13. If the -o and -v options were combined for pcregrep, it printed a blank
357     line for every non-matching line. GNU grep prints nothing, and pcregrep now
358     does the same. The return code can be used to tell if there were any
359     non-matching lines.
360    
361 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
362    
363     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
364 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
365 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
366     and both kinds of lookbehind were skipped).
367    
368 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
369 ph10 284 inclusion of <windows.h> to before rather than after the definition of
370     INVALID_FILE_ATTRIBUTES (patch from David Byron).
371 ph10 263
372 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
373 ph10 286 character property caused pcre_compile() to compile bad code, which led at
374     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
375     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
376     caused the error; without that there was no problem.
377 ph10 263
378 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
379 ph10 286
380 ph10 289 19. Added --enable-pcretest-libreadline.
381 ph10 286
382 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
383 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
384 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
385     later patch that removed the other one (the right fix) and added unit tests
386     that check the return values (which was not done before).
387 ph10 292
388 ph10 291 21. Several CMake things:
389 ph10 287
390 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
391 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
392 ph10 288
393 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
394     linked with the newly-built libraries, not previously installed ones.
395 ph10 291
396 ph10 292 (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
397 ph10 298
398     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
399     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
400     UTF-8 newline character). The key issue is that the pattern starts .*;
401     this means that the match must be either at the beginning, or after a
402     newline. The bug was in the code for advancing after a failed match and
403     checking that the new position followed a newline. It was not taking
404 ph10 294 account of UTF-8 characters correctly.
405 ph10 298
406     23. PCRE was behaving differently from Perl in the way it recognized POSIX
407     character classes. PCRE was not treating the sequence [:...:] as a
408     character class unless the ... were all letters. Perl, however, seems to
409     allow any characters between [: and :], though of course it rejects as
410     unknown any "names" that contain non-letters, because all the known class
411     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
412     for example, whereas PCRE did not - it did not recognize a POSIX character
413     class. This seemed a bit dangerous, so the code has been changed to be
414     closer to Perl. The behaviour is not identical to Perl, because PCRE will
415     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
416     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
417     Perl does, and where it didn't before.
418    
419 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
420     Windows environments %n is disabled by default.
421 ph10 292
422    
423 ph10 260 Version 7.4 21-Sep-07
424 ph10 230 ---------------------
425    
426     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
427 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
428     LF". That isn't really right - the whole point of the change was to try to
429     help when there was an actual mention of one of the two characters. So now
430     the change happens only if \r or \n (or a literal CR or LF) character is
431 ph10 230 encountered.
432 ph10 231
433     2. The 32-bit options word was also used for 6 internal flags, but the numbers
434     of both had grown to the point where there were only 3 bits left.
435     Fortunately, there was spare space in the data structure, and so I have
436     moved the internal flags into a new 16-bit field to free up more option
437 ph10 230 bits.
438 ph10 231
439     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
440     but did not set the internal JCHANGED flag - either of these is enough to
441     control the way the "get" function works - but the PCRE_INFO_JCHANGED
442     facility is supposed to tell if (?J) was ever used, so now (?J) at the
443 ph10 230 start sets both bits.
444    
445 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
446     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
447 ph10 230
448 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
449    
450     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
451 ph10 233 compatibility, even though it is no longer used.
452 ph10 243
453     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
454 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
455 ph10 259 windows.h file is present (where different names are used). [This was
456 ph10 257 reversed later after testing - see 16 below.]
457 ph10 243
458     8. Changed all #include <config.h> to #include "config.h". There were also
459 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
460 ph10 243
461 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
462 ph10 243 sequence off the lines that it output.
463    
464     10. It was pointed out to me that arrays of string pointers cause lots of
465     relocations when a shared library is dynamically loaded. A technique of
466     using a single long string with a table of offsets can drastically reduce
467     these. I have refactored PCRE in four places to do this. The result is
468 ph10 240 dramatic:
469 ph10 243
470 ph10 240 Originally: 290
471     After changing UCP table: 187
472 ph10 243 After changing error message table: 43
473 ph10 240 After changing table of "verbs" 36
474     After changing table of Posix names 22
475 ph10 243
476 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
477 ph10 247
478 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
479 ph10 247 unicode-properties was also set.
480    
481 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
482 ph10 231
483 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
484     checked only for CRLF.
485 ph10 233
486 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
487    
488 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
489 ph10 253
490 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
491 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
492     entirely. This removes changes made in 7 above.
493 ph10 256
494 ph10 261 17. The CMake files have been updated, and there is now more information about
495     building with CMake in the NON-UNIX-USE document.
496 ph10 257
497 ph10 261
498 ph10 228 Version 7.3 28-Aug-07
499 ph10 157 ---------------------
500    
501 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
502     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
503     brackets there is not right, since it causes compilers to look for an
504     installed pcre.h, not the version that is in the source that is being
505     compiled (which of course may be different). I have changed it back to:
506 ph10 197
507 ph10 189 #include "pcre.h"
508 ph10 197
509     I have a vague recollection that the change was concerned with compiling in
510     different directories, but in the new build system, that is taken care of
511     by the VPATH setting the Makefile.
512    
513 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
514     when the subject happened to end in the byte 0x85 (e.g. if the last
515     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
516     characters but of course it shouldn't be taken as a newline when it is part
517     of another character. The bug was that, for an unlimited repeat of . in
518     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
519     characters when looking for a newline.
520 ph10 197
521     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
522    
523     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
524     in debug output.
525    
526 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
527     long printing in the pcrecpp unittest when running under MinGW.
528 ph10 189
529 ph10 197 6. ESC_K was left out of the EBCDIC table.
530 ph10 189
531 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
532     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
533     limit also applies to "virtual nesting" when a pattern is recursive, and in
534     this case 1000 isn't so big. I have been able to remove this limit at the
535     expense of backing off one optimization in certain circumstances. Normally,
536     when pcre_exec() would call its internal match() function recursively and
537     immediately return the result unconditionally, it uses a "tail recursion"
538     feature to save stack. However, when a subpattern that can match an empty
539     string has an unlimited repetition quantifier, it no longer makes this
540     optimization. That gives it a stack frame in which to save the data for
541     checking that an empty string has been matched. Previously this was taken
542     from the 1000-entry workspace that had been reserved. So now there is no
543     explicit limit, but more stack is used.
544 ph10 189
545 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
546     syntax that is required for Windows, and which was going wrong for the
547     pcreposix and pcrecpp parts of the library. These were overlooked when this
548     problem was solved for the main library.
549 ph10 197
550 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
551     the size of patterns that contain repeated groups with explicit upper
552     limits. As the maximum quantifier is 65535, the maximum group length was
553     set at 30,000 so that the product of these two numbers did not overflow a
554     32-bit integer. However, it turns out that people want to use groups that
555     are longer than 30,000 bytes (though not repeat them that many times).
556     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
557     made it possible to implement the integer overflow checks in a much more
558     dynamic way, which I have now done. The artificial limitation on group
559     length has been removed - we now have only the limit on the total length of
560     the compiled pattern, which depends on the LINK_SIZE setting.
561 ph10 208
562     10. Fixed a bug in the documentation for get/copy named substring when
563     duplicate names are permitted. If none of the named substrings are set, the
564     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
565     empty string.
566    
567     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
568     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
569     because the ] is interpreted as the first data character and the
570     terminating ] is not found. PCRE has been made compatible with Perl in this
571     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
572     cause memory overwriting.
573    
574 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
575     string has been matched (to stop an infinite loop). It was not recognizing
576 ph10 208 a conditional subpattern that could match an empty string if that
577 ph10 206 subpattern was within another subpattern. For example, it looped when
578 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
579 ph10 206 condition was not nested. This bug has been fixed.
580 ph10 208
581 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
582     past the start of the subject in the presence of bytes with the top bit
583     set, for example "\x8aBCD".
584 ph10 211
585 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
586     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
587 ph10 200
588 ph10 211 14. Optimized (?!) to (*FAIL).
589 ph10 202
590 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
591     This restricts code points to be within the range 0 to 0x10FFFF, excluding
592     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
593     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
594     does: it's just the validity check that is more restrictive.
595 ph10 220
596     16. Inserted checks for integer overflows during escape sequence (backslash)
597     processing, and also fixed erroneous offset values for syntax errors during
598     backslash processing.
599    
600 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
601 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
602    
603 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
604     caused an overrun.
605 ph10 220
606     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
607     something other than just ASCII characters) inside a group that had an
608     unlimited repeat caused a loop at compile time (while checking to see
609     whether the group could match an empty string).
610    
611 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
612     [\P{Any}] did so. (Error in the code for printing property names.)
613 ph10 210
614 ph10 220 21. An orphan \E inside a character class could cause a crash.
615    
616     22. A repeated capturing bracket such as (A)? could cause a wild memory
617 ph10 218 reference during compilation.
618 ph10 220
619     23. There are several functions in pcre_compile() that scan along a compiled
620     expression for various reasons (e.g. to see if it's fixed length for look
621 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
622 ph10 220 present in the pattern. These operators have additional parameters compared
623     with \d, etc, and these were not being taken into account when moving along
624 ph10 218 the compiled data. Specifically:
625 ph10 220
626     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
627     length.
628    
629     (b) An item such as \pL+ within a repeated group could cause crashes or
630 ph10 218 loops.
631 ph10 220
632 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
633 ph10 220 "reference to non-existent subpattern" error.
634    
635 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
636    
637 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
638 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
639 ph10 211
640 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
641 ph10 218
642 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
643 ph10 223 character were causing crashes (broken optimization).
644 ph10 227
645 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
646 ph10 227 \p or \P) caused a compile-time loop.
647    
648 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
649     break. For example, the unstudied pattern [\r\n]A does not match the string
650     "\r\nA" because change 7.0/46 below moves the current point on by two
651     characters after failing to match at the start. However, the pattern \nA
652 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
653     the same is true. There doesn't seem any very clean way out of this, but
654     what I have chosen to do makes the common cases work: PCRE now takes note
655     of whether there can be an explicit match for \r or \n anywhere in the
656     pattern, and if so, 7.0/46 no longer applies. As part of this change,
657     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
658     pattern has explicit CR or LF references.
659 ph10 222
660 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
661 ph10 223
662 ph10 227
663 ph10 189 Version 7.2 19-Jun-07
664     ---------------------
665    
666 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
667     which is apparently normally available under Windows.
668 ph10 159
669     2. Re-jig the pcregrep tests with different newline settings in an attempt
670     to make them independent of the local environment's newline setting.
671 ph10 157
672 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
673 ph10 165
674 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
675     was not 2, because the output contained actual offsets. The recent new
676 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
677     usable with all link sizes.
678    
679 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
680     stack recursion. This gives a massive performance boost under BSD, but just
681 ph10 165 a small improvement under Linux. However, it saves one field in the frame
682 ph10 164 in all cases.
683 ph10 172
684 ph10 166 6. Added more features from the forthcoming Perl 5.10:
685 ph10 172
686 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
687     recursion call. It refers to the nth most recently opened parentheses.
688 ph10 172
689 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
690 ph10 172 to be opened parentheses.
691    
692     (c) Conditions that refer to capturing parentheses can be specified
693 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
694 ph10 172
695 ph10 168 (d) \K resets the start of the current match so that everything before
696 ph10 172 is not part of it.
697    
698 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
699 ph10 172
700 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
701 ph10 172 reference syntax.
702 ph10 182
703 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
704 ph10 182 alternative starts with the same number.
705 ph10 172
706 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
707    
708 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
709     PCRE_INFO_JCHANGED.
710    
711     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
712     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
713 ph10 170 for detecting groups that can match an empty string.
714 ph10 159
715 ph10 172 9. A pattern with a very large number of alternatives (more than several
716     hundred) was running out of internal workspace during the pre-compile
717     phase, where pcre_compile() figures out how much memory will be needed. A
718     bit of new cunning has reduced the workspace needed for groups with
719     alternatives. The 1000-alternative test pattern now uses 12 bytes of
720     workspace instead of running out of the 4096 that are available.
721 ph10 182
722 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
723 ph10 172
724 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
725     The report of the bug said:
726 ph10 182
727 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
728     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
729 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
730 ph10 185
731 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
732 ph10 185 it matched the wrong number of bytes.
733 ph10 172
734 ph10 179
735 ph10 155 Version 7.1 24-Apr-07
736 ph10 98 ---------------------
737    
738 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
739 ph10 122 that is more "standard", making use of automake and other Autotools. There
740 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
741     on this.
742 ph10 111
743     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
744     for recursive directory scanning broke on some systems because the files
745     are not scanned in any specific order and on different systems the order
746     was different. A call to "sort" has been inserted into RunGrepTest for the
747     approprate test as a short-term fix. In the longer term there may be an
748 ph10 100 alternative.
749 ph10 111
750 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
751 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
752     people do their own conversions for various reasons). The problems
753     concerned the use of low-level troff macros .br and .in. I have therefore
754     removed all such uses from the man pages (some were redundant, some could
755 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
756     HTML has been updated to handle .nf/.fi and to complain if it encounters
757     .br or .in.
758 ph10 111
759 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
760 ph10 123 arranged for config.h to be included in the distribution, with the name
761 ph10 111 config.h.generic, for the benefit of those who have to compile without
762     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
763    
764     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
765     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
766 ph10 127 makevp.bat for the current PCRE, using the additional files
767 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
768 ph10 111
769     6. A Windows user reported a minor discrepancy with test 2, which turned out
770     to be caused by a trailing space on an input line that had got lost in his
771 ph10 102 copy. The trailing space was an accident, so I've just removed it.
772 ph10 111
773 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
774 ph10 111 that is needed.
775    
776 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
777     as "const" (a) because they are and (b) because it helps the PHP
778     maintainers who have recently made a script to detect big data structures
779 ph10 111 in the php code that should be moved to the .rodata section. I remembered
780     to update Builducptable as well, so it won't revert if ucptable.h is ever
781 ph10 105 re-created.
782 ph10 111
783     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
784 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
785 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
786     support is not required. This saves 1.5-2K of code, which is important in
787 ph10 107 some applications.
788 ph10 111
789 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
790 ph10 111 so as not to refer to the tables, even though these functions will never be
791     called when UTF-8 support is disabled. Otherwise there are problems with a
792     shared library.
793    
794 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
795    
796     (a) It was defining its arguments as char * instead of void *.
797    
798 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
799     a long time ago when I wrote it, but is no longer the case.
800    
801 ph10 118 The emulated memove() is provided for those environments that have neither
802 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
803 ph10 118 is clearly not the case, as these two bugs were recently reported.
804 ph10 123
805 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
806 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
807     pages, and it removes trailing spaces from listed files. It also creates
808     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
809     case, it wraps all the #defines with #ifndefs. This script should be run
810 ph10 111 before "make dist".
811 ph10 123
812 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
813     with Unicode property support.
814 ph10 123
815     (a) For a maximizing quantifier, if the two different cases of the
816     character were of different lengths in their UTF-8 codings (there are
817     some cases like this - I found 11), and the matching function had to
818 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
819     were both the same length.
820 ph10 123
821     (b) When PCRE was configured to use the heap rather than the stack for
822     recursion during matching, it was not correctly preserving the data for
823     the other case of a UTF-8 character when checking ahead for a match
824     while processing a minimizing repeat. If the check also involved
825 ph10 115 matching a wide character, but failed, corruption could cause an
826     erroneous result when trying to check for a repeat of the original
827     character.
828 ph10 123
829 ph10 116 13. Some tidying changes to the testing mechanism:
830 ph10 98
831 ph10 116 (a) The RunTest script now detects the internal link size and whether there
832     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
833 ph10 123 values substituted by "configure". (The RunGrepTest script already did
834     this for UTF-8.) The configure.ac script no longer substitutes the
835     relevant variables.
836    
837 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
838     with length and offset values. This means that the output is different
839     for different internal link sizes. Test 2 is skipped for link sizes
840     other than 2 because of this, bypassing the problem. Unfortunately,
841     there was also a test in test 3 (the locale tests) that used /B and
842 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
843     I have added a new /Z option to pcretest that replaces the length and
844     offset values with spaces. This is now used to make test 3 independent
845 ph10 122 of link size. (Test 2 will be tidied up later.)
846 ph10 123
847     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
848 ph10 122 segmentation fault instead of returning the appropriate error message.
849 ph10 134
850 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
851 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
852     This doesn't seem right; it now treats the CRLF combination as the line
853     ending, and so does not match in that case. It's only a pattern such as ^$
854     that would hit this one: something like ^ABC$ would have failed after \r
855     and then tried again after \r\n.
856    
857 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
858 ph10 134 in an attempt to make files that differ only in their line terminators
859     compare equal. This works on Linux.
860 ph10 142
861 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
862     as it exited. This is now fixed, thanks to valgrind.
863 ph10 142
864 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
865 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
866     was because its rules for how to advance for /g after matching an empty
867 ph10 143 string at the end of a line did not allow for this case. They now check for
868     it specially.
869 ph10 150
870     20. pcretest is supposed to handle patterns and data of any length, by
871     extending its buffers when necessary. It was getting this wrong when the
872 ph10 147 buffer for a data line had to be extended.
873 ph10 150
874 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
875 ph10 150 CRLF as a newline sequence.
876 ph10 152
877 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
878 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
879     I have nevertheless tidied it up.
880 ph10 111
881 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
882 ph10 123
883 ph10 153 24. Added a man page for pcre-config.
884 ph10 152
885 ph10 153
886 nigel 93 Version 7.0 19-Dec-06
887     ---------------------
888    
889     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
890     moving to gcc 4.1.1.
891    
892     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
893     sys/time.h, which is documented as needed for this function. It doesn't
894     seem to matter on Linux, but it showed up on some releases of OS X.
895    
896     3. It seems that there are systems where bytes whose values are greater than
897     127 match isprint() in the "C" locale. The "C" locale should be the
898     default when a C program starts up. In most systems, only ASCII printing
899     characters match isprint(). This difference caused the output from pcretest
900     to vary, making some of the tests fail. I have changed pcretest so that:
901    
902     (a) When it is outputting text in the compiled version of a pattern, bytes
903     other than 32-126 are always shown as hex escapes.
904    
905     (b) When it is outputting text that is a matched part of a subject string,
906     it does the same, unless a different locale has been set for the match
907     (using the /L modifier). In this case, it uses isprint() to decide.
908    
909     4. Fixed a major bug that caused incorrect computation of the amount of memory
910     required for a compiled pattern when options that changed within the
911     pattern affected the logic of the preliminary scan that determines the
912     length. The relevant options are -x, and -i in UTF-8 mode. The result was
913     that the computed length was too small. The symptoms of this bug were
914     either the PCRE error "internal error: code overflow" from pcre_compile(),
915     or a glibc crash with a message such as "pcretest: free(): invalid next
916     size (fast)". Examples of patterns that provoked this bug (shown in
917     pcretest format) are:
918    
919     /(?-x: )/x
920     /(?x)(?-x: \s*#\s*)/
921     /((?i)[\x{c0}])/8
922     /(?i:[\x{c0}])/8
923    
924     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
925     is now done differently.
926    
927     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
928     wrapper classes; (b) implement a new function in the C++ scanner that is
929     more efficient than the old way of doing things because it avoids levels of
930     recursion in the regex matching; (c) add a paragraph to the documentation
931     for the FullMatch() function.
932    
933     6. The escape sequence \n was being treated as whatever was defined as
934     "newline". Not only was this contrary to the documentation, which states
935     that \n is character 10 (hex 0A), but it also went horribly wrong when
936     "newline" was defined as CRLF. This has been fixed.
937    
938     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
939     was being set to -1 for the "end of line" case (supposedly a value that no
940     character can have). Though this value is never used (the check for end of
941     line is "zero bytes in current character"), it caused compiler complaints.
942     I've changed it to 0xffffffff.
943    
944     8. In pcre_version.c, the version string was being built by a sequence of
945     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
946     string (as it is for production releases) called a macro with an empty
947     argument. The C standard says the result of this is undefined. The gcc
948     compiler treats it as an empty string (which was what was wanted) but it is
949     reported that Visual C gives an error. The source has been hacked around to
950     avoid this problem.
951    
952     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
953     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
954     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
955     of them did).
956    
957     10. Originally, pcretest opened its input and output without "b"; then I was
958     told that "b" was needed in some environments, so it was added for release
959     5.0 to both the input and output. (It makes no difference on Unix-like
960     systems.) Later I was told that it is wrong for the input on Windows. I've
961     now abstracted the modes into two macros, to make it easier to fiddle with
962     them, and removed "b" from the input mode under Windows.
963    
964     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
965    
966     12. Added -help and --help to pcretest as an official way of being reminded
967     of the options.
968    
969     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
970     and pcrecpp.cc because they annoy compilers at high warning levels.
971    
972     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
973    
974     15. Fixed an occurrence of == in configure.ac that should have been = (shell
975     scripts are not C programs :-) and which was not noticed because it works
976     on Linux.
977    
978     16. pcretest is supposed to handle any length of pattern and data line (as one
979     line or as a continued sequence of lines) by extending its input buffer if
980     necessary. This feature was broken for very long pattern lines, leading to
981     a string of junk being passed to pcre_compile() if the pattern was longer
982     than about 50K.
983    
984     17. I have done a major re-factoring of the way pcre_compile() computes the
985     amount of memory needed for a compiled pattern. Previously, there was code
986     that made a preliminary scan of the pattern in order to do this. That was
987     OK when PCRE was new, but as the facilities have expanded, it has become
988     harder and harder to keep it in step with the real compile phase, and there
989     have been a number of bugs (see for example, 4 above). I have now found a
990     cunning way of running the real compile function in a "fake" mode that
991     enables it to compute how much memory it would need, while actually only
992     ever using a few hundred bytes of working memory and without too many
993     tests of the mode. This should make future maintenance and development
994     easier. A side effect of this work is that the limit of 200 on the nesting
995     depth of parentheses has been removed (though this was never a serious
996     limitation, I suspect). However, there is a downside: pcre_compile() now
997     runs more slowly than before (30% or more, depending on the pattern). I
998     hope this isn't a big issue. There is no effect on runtime performance.
999    
1000     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1001     newline (only possible for the last line of a file) and it was a
1002     pattern that set a locale (followed by /Lsomething), pcretest crashed.
1003    
1004     19. Added additional timing features to pcretest. (1) The -tm option now times
1005     matching only, not compiling. (2) Both -t and -tm can be followed, as a
1006     separate command line item, by a number that specifies the number of
1007     repeats to use when timing. The default is 50000; this gives better
1008     precision, but takes uncomfortably long for very large patterns.
1009    
1010     20. Extended pcre_study() to be more clever in cases where a branch of a
1011     subpattern has no definite first character. For example, (a*|b*)[cd] would
1012     previously give no result from pcre_study(). Now it recognizes that the
1013     first character must be a, b, c, or d.
1014    
1015     21. There was an incorrect error "recursive call could loop indefinitely" if
1016     a subpattern (or the entire pattern) that was being tested for matching an
1017     empty string contained only one non-empty item after a nested subpattern.
1018     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1019     incorrectly, because the \d was being skipped in the check.
1020    
1021     22. The pcretest program now has a new pattern option /B and a command line
1022     option -b, which is equivalent to adding /B to every pattern. This causes
1023     it to show the compiled bytecode, without the additional information that
1024     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1025     is the same as /B/I).
1026    
1027     23. A new optimization is now able automatically to treat some sequences such
1028     as a*b as a*+b. More specifically, if something simple (such as a character
1029     or a simple class like \d) has an unlimited quantifier, and is followed by
1030     something that cannot possibly match the quantified thing, the quantifier
1031     is automatically "possessified".
1032    
1033     24. A recursive reference to a subpattern whose number was greater than 39
1034     went wrong under certain circumstances in UTF-8 mode. This bug could also
1035     have affected the operation of pcre_study().
1036    
1037     25. Realized that a little bit of performance could be had by replacing
1038     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1039    
1040     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1041    
1042     27. Possessive quantifiers such as a++ were previously implemented by turning
1043     them into atomic groups such as ($>a+). Now they have their own opcodes,
1044     which improves performance. This includes the automatically created ones
1045     from 23 above.
1046    
1047     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1048     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1049     the first matched character to be a colon. This applied both to named and
1050     numbered groups.
1051    
1052     29. The ucpinternal.h header file was missing its idempotency #ifdef.
1053    
1054     30. I was sent a "project" file called libpcre.a.dev which I understand makes
1055     building PCRE on Windows easier, so I have included it in the distribution.
1056    
1057     31. There is now a check in pcretest against a ridiculously large number being
1058     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1059     loop, the loop is abandoned.
1060    
1061     32. Forward references to subpatterns in conditions such as (?(2)...) where
1062     subpattern 2 is defined later cause pcre_compile() to search forwards in
1063     the pattern for the relevant set of parentheses. This search went wrong
1064     when there were unescaped parentheses in a character class, parentheses
1065     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1066    
1067     33. "Subroutine" calls and backreferences were previously restricted to
1068     referencing subpatterns earlier in the regex. This restriction has now
1069     been removed.
1070    
1071     34. Added a number of extra features that are going to be in Perl 5.10. On the
1072     whole, these are just syntactic alternatives for features that PCRE had
1073     previously implemented using the Python syntax or my own invention. The
1074     other formats are all retained for compatibility.
1075    
1076     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1077     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1078     also .NET compatible.
1079    
1080     (b) A recursion or subroutine call to a named group can now be defined as
1081     (?&name) as well as (?P>name).
1082    
1083     (c) A backreference to a named group can now be defined as \k<name> or
1084     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1085     5.10, are also .NET compatible.
1086    
1087     (d) A conditional reference to a named group can now use the syntax
1088     (?(<name>) or (?('name') as well as (?(name).
1089    
1090     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1091     groups (named and numbered) that are never evaluated inline, but can be
1092     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1093     is always false. There may be only one alternative in such a group.
1094    
1095     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1096     as the simple (?(R). The condition is true only if the most recent
1097     recursion is that of the given number or name. It does not search out
1098     through the entire recursion stack.
1099    
1100     (g) The escape \gN or \g{N} has been added, where N is a positive or
1101     negative number, specifying an absolute or relative reference.
1102    
1103     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1104     some "unreachable code" warnings.
1105    
1106     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1107     things, this adds five new scripts.
1108    
1109     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1110     There were also incompatibilities regarding the handling of \Q..\E inside
1111     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1112     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1113    
1114     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1115     matches an empty string, and forcibly breaks the loop. There were bugs in
1116     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1117     against aaaa the result was just "a" rather than "aaaa", for example. Two
1118     separate and independent bugs (that affected different cases) have been
1119     fixed.
1120    
1121     39. Refactored the code to abolish the use of different opcodes for small
1122     capturing bracket numbers. This is a tidy that I avoided doing when I
1123     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1124     The new approach is not only tidier, it makes it possible to reduce the
1125     memory needed to fix the previous bug (38).
1126    
1127     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1128     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1129     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1130     mode.
1131    
1132     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1133     report.
1134    
1135     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1136     copy construction and assignment in the C++ wrapper.
1137    
1138     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1139     couple of bugs that could have given wrong results in the "--newline=crlf"
1140     case.
1141    
1142     44. Added a number of casts and did some reorganization of signed/unsigned int
1143     variables following suggestions from Dair Grant. Also renamed the variable
1144     "this" as "item" because it is a C++ keyword.
1145    
1146     45. Arranged for dftables to add
1147    
1148     #include "pcre_internal.h"
1149    
1150     to pcre_chartables.c because without it, gcc 4.x may remove the array
1151     definition from the final binary if PCRE is built into a static library and
1152     dead code stripping is activated.
1153    
1154     46. For an unanchored pattern, if a match attempt fails at the start of a
1155     newline sequence, and the newline setting is CRLF or ANY, and the next two
1156     characters are CRLF, advance by two characters instead of one.
1157    
1158    
1159 nigel 91 Version 6.7 04-Jul-06
1160     ---------------------
1161    
1162     1. In order to handle tests when input lines are enormously long, pcretest has
1163     been re-factored so that it automatically extends its buffers when
1164     necessary. The code is crude, but this _is_ just a test program. The
1165     default size has been increased from 32K to 50K.
1166    
1167     2. The code in pcre_study() was using the value of the re argument before
1168     testing it for NULL. (Of course, in any sensible call of the function, it
1169     won't be NULL.)
1170    
1171     3. The memmove() emulation function in pcre_internal.h, which is used on
1172     systems that lack both memmove() and bcopy() - that is, hardly ever -
1173     was missing a "static" storage class specifier.
1174    
1175     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1176     containing an extended class (one that cannot be represented by a bitmap
1177     because it contains high-valued characters or Unicode property items, e.g.
1178     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1179     pattern, but PCRE should not loop if you do not (it no longer does).
1180     [Detail: two cases were found: (a) a repeated subpattern containing an
1181     extended class; (b) a recursive reference to a subpattern that followed a
1182     previous extended class. It wasn't skipping over the extended class
1183     correctly when UTF-8 mode was not set.]
1184    
1185     5. A negated single-character class was not being recognized as fixed-length
1186     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1187     compile error "lookbehind assertion is not fixed length".
1188    
1189     6. The RunPerlTest auxiliary script was showing an unexpected difference
1190     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1191     write a Perl script that can interpret lines of an input file either as
1192     byte characters or as UTF-8, which is what "perltest" was being required to
1193     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1194     can't do is switch easily at run time between having the "use utf8;" pragma
1195     or not. In the end, I fudged it by using the RunPerlTest script to insert
1196     "use utf8;" explicitly for the UTF-8 tests.
1197    
1198     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1199     the end of the subject string, contrary to the documentation and to what
1200     Perl does. This was true of both matching functions. Now it matches only at
1201     the start of the subject and immediately after *internal* newlines.
1202    
1203     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1204     a pointer to an int instead of a pointer to an unsigned long int. This
1205     caused problems on 64-bit systems.
1206    
1207     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1208     instance of the 'standard' template library not being so standard".
1209    
1210     10. There was no check on the number of named subpatterns nor the maximum
1211     length of a subpattern name. The product of these values is used to compute
1212     the size of the memory block for a compiled pattern. By supplying a very
1213     long subpattern name and a large number of named subpatterns, the size
1214     computation could be caused to overflow. This is now prevented by limiting
1215     the length of names to 32 characters, and the number of named subpatterns
1216     to 10,000.
1217    
1218     11. Subpatterns that are repeated with specific counts have to be replicated in
1219     the compiled pattern. The size of memory for this was computed from the
1220     length of the subpattern and the repeat count. The latter is limited to
1221     65535, but there was no limit on the former, meaning that integer overflow
1222     could in principle occur. The compiled length of a repeated subpattern is
1223     now limited to 30,000 bytes in order to prevent this.
1224    
1225     12. Added the optional facility to have named substrings with the same name.
1226    
1227     13. Added the ability to use a named substring as a condition, using the
1228     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1229     are numbers (not recommended). Forward references are permitted.
1230    
1231     14. Added forward references in named backreferences (if you see what I mean).
1232    
1233     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1234     pattern could run off the end of the subject. For example, the pattern
1235     "(?s)(.{1,5})"8 did this with the subject "ab".
1236    
1237     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1238     PCRE_CASELESS was set when matching characters that were quantified with ?
1239     or *.
1240    
1241     17. A character class other than a single negated character that had a minimum
1242     but no maximum quantifier - for example [ab]{6,} - was not handled
1243     correctly by pce_dfa_exec(). It would match only one character.
1244    
1245     18. A valid (though odd) pattern that looked like a POSIX character
1246     class but used an invalid character after [ (for example [[,abc,]]) caused
1247     pcre_compile() to give the error "Failed: internal error: code overflow" or
1248     in some cases to crash with a glibc free() error. This could even happen if
1249     the pattern terminated after [[ but there just happened to be a sequence of
1250     letters, a binary zero, and a closing ] in the memory that followed.
1251    
1252     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1253     over the years. Originally (before any Unicode support), just the bottom 8
1254     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1255     output from "man perlunicode" includes this:
1256    
1257     The regular expression compiler produces polymorphic opcodes. That
1258     is, the pattern adapts to the data and automatically switches to
1259     the Unicode character scheme when presented with Unicode data--or
1260     instead uses a traditional byte scheme when presented with byte
1261     data.
1262    
1263     Sadly, a wide octal escape does not cause a switch, and in a string with
1264     no other multibyte characters, these octal escapes are treated as before.
1265     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1266     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1267     Unicode string.
1268    
1269     I have not perpetrated such confusion in PCRE. Up till now, it took just
1270     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1271     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1272     translate to the appropriate multibyte character.
1273    
1274     29. Applied some refactoring to reduce the number of warnings from Microsoft
1275     and Borland compilers. This has included removing the fudge introduced
1276     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1277     a warning about an unused variable.
1278    
1279     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1280     characters since release 4.0, because Perl (from release 5.004) does not.
1281     [Or at least, is documented not to: some releases seem to be in conflict
1282     with the documentation.] However, when a pattern was studied with
1283     pcre_study() and all its branches started with \s, PCRE still included VT
1284     as a possible starting character. Of course, this did no harm; it just
1285     caused an unnecessary match attempt.
1286    
1287     22. Removed a now-redundant internal flag bit that recorded the fact that case
1288     dependency changed within the pattern. This was once needed for "required
1289     byte" processing, but is no longer used. This recovers a now-scarce options
1290     bit. Also moved the least significant internal flag bit to the most-
1291     significant bit of the word, which was not previously used (hangover from
1292     the days when it was an int rather than a uint) to free up another bit for
1293     the future.
1294    
1295     23. Added support for CRLF line endings as well as CR and LF. As well as the
1296     default being selectable at build time, it can now be changed at runtime
1297     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1298     specify that it is scanning data with non-default line endings.
1299    
1300     24. Changed the definition of CXXLINK to make it agree with the definition of
1301     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1302    
1303     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1304     recursions. This makes a big different to stack usage for some patterns.
1305    
1306     26. If a subpattern containing a named recursion or subroutine reference such
1307     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1308     the space required for the compiled pattern went wrong and gave too small a
1309     value. Depending on the environment, this could lead to "Failed: internal
1310     error: code overflow at offset 49" or "glibc detected double free or
1311     corruption" errors.
1312    
1313     27. Applied patches from Google (a) to support the new newline modes and (b) to
1314     advance over multibyte UTF-8 characters in GlobalReplace.
1315    
1316     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1317     difference for some implementation of PCRE in some Windows version.
1318    
1319     29. Added some extra testing facilities to pcretest:
1320    
1321     \q<number> in a data line sets the "match limit" value
1322     \Q<number> in a data line sets the "match recursion limt" value
1323     -S <number> sets the stack size, where <number> is in megabytes
1324    
1325     The -S option isn't available for Windows.
1326    
1327    
1328 nigel 89 Version 6.6 06-Feb-06
1329     ---------------------
1330    
1331     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1332     in pcreposix.h. I have copied the definition from pcre.h.
1333    
1334     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1335     because pcre.h is no longer a built file.
1336    
1337     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1338     not normally included in the compiled code.
1339    
1340    
1341 nigel 87 Version 6.5 01-Feb-06
1342     ---------------------
1343    
1344     1. When using the partial match feature with pcre_dfa_exec(), it was not
1345     anchoring the second and subsequent partial matches at the new starting
1346     point. This could lead to incorrect results. For example, with the pattern
1347     /1234/, partially matching against "123" and then "a4" gave a match.
1348    
1349     2. Changes to pcregrep:
1350    
1351     (a) All non-match returns from pcre_exec() were being treated as failures
1352     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1353     error message is output. Some extra information is given for the
1354     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1355     probably the only errors that are likely to be caused by users (by
1356     specifying a regex that has nested indefinite repeats, for instance).
1357     If there are more than 20 of these errors, pcregrep is abandoned.
1358    
1359     (b) A binary zero was treated as data while matching, but terminated the
1360     output line if it was written out. This has been fixed: binary zeroes
1361     are now no different to any other data bytes.
1362    
1363     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1364     used to set a locale for matching. The --locale=xxxx long option has
1365     been added (no short equivalent) to specify a locale explicitly on the
1366     pcregrep command, overriding the environment variables.
1367    
1368     (d) When -B was used with -n, some line numbers in the output were one less
1369     than they should have been.
1370    
1371     (e) Added the -o (--only-matching) option.
1372    
1373     (f) If -A or -C was used with -c (count only), some lines of context were
1374     accidentally printed for the final match.
1375    
1376     (g) Added the -H (--with-filename) option.
1377    
1378     (h) The combination of options -rh failed to suppress file names for files
1379     that were found from directory arguments.
1380    
1381     (i) Added the -D (--devices) and -d (--directories) options.
1382    
1383     (j) Added the -F (--fixed-strings) option.
1384    
1385     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1386    
1387     (l) Added the --colo(u)r option.
1388    
1389     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1390     is not present by default.
1391    
1392     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1393     items such as (?R) or (?1), when the recursion could match a number of
1394     alternatives. If it matched one of the alternatives, but subsequently,
1395     outside the recursion, there was a failure, the code tried to back up into
1396     the recursion. However, because of the way PCRE is implemented, this is not
1397     possible, and the result was an incorrect result from the match.
1398    
1399     In order to prevent this happening, the specification of recursion has
1400     been changed so that all such subpatterns are automatically treated as
1401     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1402    
1403     4. I had overlooked the fact that, in some locales, there are characters for
1404     which isalpha() is true but neither isupper() nor islower() are true. In
1405     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1406     and ordfeminine) are like this. This affected the treatment of \w and \W
1407     when they appeared in character classes, but not when they appeared outside
1408     a character class. The bit map for "word" characters is now created
1409     separately from the results of isalnum() instead of just taking it from the
1410     upper, lower, and digit maps. (Plus the underscore character, of course.)
1411    
1412     5. The above bug also affected the handling of POSIX character classes such as
1413     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1414     permanent tables. Instead, the bit maps for such a class were previously
1415     created as the appropriate unions of the upper, lower, and digit bitmaps.
1416     Now they are created by subtraction from the [[:word:]] class, which has
1417     its own bitmap.
1418    
1419     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1420     It is created by subtracting the vertical space characters (\x09, \x0a,
1421     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1422     subtraction was done in the overall bitmap for a character class, meaning
1423     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1424     be recognized. This bug has been fixed.
1425    
1426     7. Patches from the folks at Google:
1427    
1428     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1429     real life, but is still worth protecting against".
1430    
1431     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1432     regular expressions".
1433    
1434     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1435     have it.
1436    
1437     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1438     "configure" and the latter not, in order to fix a problem somebody had
1439     with compiling the Arg class on HP-UX.
1440    
1441     (e) Improve the error-handling of the C++ wrapper a little bit.
1442    
1443     (f) New tests for checking recursion limiting.
1444    
1445     8. The pcre_memmove() function, which is used only if the environment does not
1446     have a standard memmove() function (and is therefore rarely compiled),
1447     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1448     returning a result (though PCRE never actually uses the result).
1449    
1450     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1451     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1452     returned instead of calling malloc() with an overflowing number that would
1453     most likely cause subsequent chaos.
1454    
1455     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1456    
1457     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1458     with this option is matched, the nmatch and pmatch options of regexec() are
1459     ignored.
1460    
1461     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1462     provided in case anyone wants to the the POSIX interface with UTF-8
1463     strings.
1464    
1465     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1466     C++ linking (needed for some HP-UX environments).
1467    
1468     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1469     (unused parameter) and in the pcre_printint() function (omitted "default"
1470     switch label when the default is to do nothing).
1471    
1472     15. Added some code to make it possible, when PCRE is compiled as a C++
1473     library, to replace subject pointers for pcre_exec() with a smart pointer
1474     class, thus making it possible to process discontinuous strings.
1475    
1476     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1477     much the same function. They were added by different people who were trying
1478     to make PCRE easy to compile on non-Unix systems. It has been suggested
1479     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1480     for compiling on Windows systems. I have therefore replaced it with
1481     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1482     defaults to "extern" for C or "extern C" for C++, which works fine on
1483     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1484     SCOPE with something explicit in config.h. In addition:
1485    
1486     (a) pcreposix.h still had just "extern" instead of either of these macros;
1487     I have replaced it with PCRE_DATA_SCOPE.
1488    
1489     (b) Functions such as _pcre_xclass(), which are internal to the library,
1490     but external in the C sense, all had PCRE_EXPORT in their definitions.
1491     This is apparently wrong for the Windows case, so I have removed it.
1492     (It makes no difference on Unix-like systems.)
1493    
1494     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1495     of recursive calls to match(). This is different to MATCH_LIMIT because
1496     that limits the total number of calls to match(), not all of which increase
1497     the depth of recursion. Limiting the recursion depth limits the amount of
1498     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1499     when PCRE is compiled, and changed at run time. A patch from Google adds
1500     this functionality to the C++ interface.
1501    
1502     18. Changes to the handling of Unicode character properties:
1503    
1504     (a) Updated the table to Unicode 4.1.0.
1505    
1506     (b) Recognize characters that are not in the table as "Cn" (undefined).
1507    
1508     (c) I revised the way the table is implemented to a much improved format
1509     which includes recognition of ranges. It now supports the ranges that
1510     are defined in UnicodeData.txt, and it also amalgamates other
1511     characters into ranges. This has reduced the number of entries in the
1512     table from around 16,000 to around 3,000, thus reducing its size
1513     considerably. I realized I did not need to use a tree structure after
1514     all - a binary chop search is just as efficient. Having reduced the
1515     number of entries, I extended their size from 6 bytes to 8 bytes to
1516     allow for more data.
1517    
1518     (d) Added support for Unicode script names via properties such as \p{Han}.
1519    
1520     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1521     matching that character.
1522    
1523     20. When matching a repeated Unicode property with a minimum greater than zero,
1524     (for example \pL{2,}), PCRE could look past the end of the subject if it
1525     reached it while seeking the minimum number of characters. This could
1526     happen only if some of the characters were more than one byte long, because
1527     there is a check for at least the minimum number of bytes.
1528    
1529     21. Refactored the implementation of \p and \P so as to be more general, to
1530     allow for more different types of property in future. This has changed the
1531     compiled form incompatibly. Anybody with saved compiled patterns that use
1532     \p or \P will have to recompile them.
1533    
1534     22. Added "Any" and "L&" to the supported property types.
1535    
1536     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1537     but give a compile time error if the value is greater than 0xff.
1538    
1539     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1540     accidentally not being installed or uninstalled.
1541    
1542     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1543     made were to insert the current release number. This seemed silly, because
1544     it made things harder for people building PCRE on systems that don't run
1545     "configure". I have turned pcre.h into a distributed file, no longer built
1546     by "configure", with the version identification directly included. There is
1547     no longer a pcre.h.in file.
1548    
1549     However, this change necessitated a change to the pcre-config script as
1550     well. It is built from pcre-config.in, and one of the substitutions was the
1551     release number. I have updated configure.ac so that ./configure now finds
1552     the release number by grepping pcre.h.
1553    
1554     26. Added the ability to run the tests under valgrind.
1555    
1556    
1557 nigel 85 Version 6.4 05-Sep-05
1558     ---------------------
1559    
1560     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1561     "--" to be printed when multiple files were scanned, even when none of the
1562     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1563     consider it to be a bug, and have restored the previous behaviour.
1564    
1565     2. A couple of code tidies to get rid of compiler warnings.
1566    
1567     3. The pcretest program used to cheat by referring to symbols in the library
1568     whose names begin with _pcre_. These are internal symbols that are not
1569     really supposed to be visible externally, and in some environments it is
1570     possible to suppress them. The cheating is now confined to including
1571     certain files from the library's source, which is a bit cleaner.
1572    
1573     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1574     file's purpose clearer.
1575    
1576     5. Reorganized pcre_ucp_findchar().
1577    
1578    
1579 nigel 83 Version 6.3 15-Aug-05
1580     ---------------------
1581    
1582     1. The file libpcre.pc.in did not have general read permission in the tarball.
1583    
1584     2. There were some problems when building without C++ support:
1585    
1586     (a) If C++ support was not built, "make install" and "make test" still
1587     tried to test it.
1588    
1589     (b) There were problems when the value of CXX was explicitly set. Some
1590     changes have been made to try to fix these, and ...
1591    
1592     (c) --disable-cpp can now be used to explicitly disable C++ support.
1593    
1594     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1595     backslash in a target when C++ was disabled. This confuses some
1596     versions of "make", apparently. Using an intermediate variable solves
1597     this. (Same for CPP_LOBJ.)
1598    
1599     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1600     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1601     necessary on certain architectures.
1602    
1603     4. Added a setting of -export-symbols-regex to the link command to remove
1604     those symbols that are exported in the C sense, but actually are local
1605     within the library, and not documented. Their names all begin with
1606     "_pcre_". This is not a perfect job, because (a) we have to except some
1607     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1608     available (and never for static libraries). I have made a note to try to
1609     find a way round (a) in the future.
1610    
1611    
1612 nigel 81 Version 6.2 01-Aug-05
1613     ---------------------
1614    
1615     1. There was no test for integer overflow of quantifier values. A construction
1616     such as {1111111111111111} would give undefined results. What is worse, if
1617     a minimum quantifier for a parenthesized subpattern overflowed and became
1618     negative, the calculation of the memory size went wrong. This could have
1619     led to memory overwriting.
1620    
1621     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1622    
1623     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1624     operating environments where this matters.
1625    
1626     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1627     PCRE options from within the C++ wrapper.
1628    
1629     5. Named capturing subpatterns were not being correctly counted when a pattern
1630     was compiled. This caused two problems: (a) If there were more than 100
1631     such subpatterns, the calculation of the memory needed for the whole
1632     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1633     back references of the form \12, where the number was greater than 9, were
1634     not recognized as back references, even though there were sufficient
1635     previous subpatterns.
1636    
1637     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1638     versions of gcc, e.g. 2.95.4.
1639    
1640    
1641 nigel 79 Version 6.1 21-Jun-05
1642     ---------------------
1643    
1644     1. There was one reference to the variable "posix" in pcretest.c that was not
1645     surrounded by "#if !defined NOPOSIX".
1646    
1647     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1648     the cross-check on the old pcre_info() function, for the benefit of the
1649     cut-down version of PCRE that is currently imported into Exim.
1650    
1651     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1652     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1653     patterns that start (?i) but I don't think that matters. The use of (?i) is
1654     just an example; this all applies to the other options as well.
1655    
1656     4. Since libtool seems to echo the compile commands it is issuing, the output
1657     from "make" can be reduced a bit by putting "@" in front of each libtool
1658     compile command.
1659    
1660     5. Patch from the folks at Google for configure.in to be a bit more thorough
1661     in checking for a suitable C++ installation before trying to compile the
1662     C++ stuff. This should fix a reported problem when a compiler was present,
1663     but no suitable headers.
1664    
1665     6. The man pages all had just "PCRE" as their title. I have changed them to
1666     be the relevant file name. I have also arranged that these names are
1667     retained in the file doc/pcre.txt, which is a concatenation in text format
1668     of all the man pages except the little individual ones for each function.
1669    
1670     7. The NON-UNIX-USE file had not been updated for the different set of source
1671     files that come with release 6. I also added a few comments about the C++
1672     wrapper.
1673    
1674    
1675 nigel 77 Version 6.0 07-Jun-05
1676     ---------------------
1677    
1678     1. Some minor internal re-organization to help with my DFA experiments.
1679    
1680     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1681     didn't matter for the library itself when fully configured, but did matter
1682     when compiling without UCP support, or within Exim, where the ucp files are
1683     not imported.
1684    
1685     3. Refactoring of the library code to split up the various functions into
1686     different source modules. The addition of the new DFA matching code (see
1687     below) to a single monolithic source would have made it really too
1688     unwieldy, quite apart from causing all the code to be include in a
1689     statically linked application, when only some functions are used. This is
1690     relevant even without the DFA addition now that patterns can be compiled in
1691     one application and matched in another.
1692    
1693     The downside of splitting up is that there have to be some external
1694     functions and data tables that are used internally in different modules of
1695     the library but which are not part of the API. These have all had their
1696     names changed to start with "_pcre_" so that they are unlikely to clash
1697     with other external names.
1698    
1699     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1700     a different (DFA) algorithm. Although it is slower than the original
1701     function, it does have some advantages for certain types of matching
1702     problem.
1703    
1704     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1705     including restarting after a partial match.
1706    
1707     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1708     defined when compiling for Windows was sent to me. I have put it into the
1709     code, though I have no means of testing or verifying it.
1710    
1711     7. Added the pcre_refcount() auxiliary function.
1712    
1713     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1714     match before or at the first newline in the subject string. In pcretest,
1715     the /f option on a pattern can be used to set this.
1716    
1717     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1718     would behave wrongly. This has been present in PCRE since release 4.0.
1719    
1720     10. A number of changes to the pcregrep command:
1721    
1722     (a) Refactored how -x works; insert ^(...)$ instead of setting
1723     PCRE_ANCHORED and checking the length, in preparation for adding
1724     something similar for -w.
1725    
1726     (b) Added the -w (match as a word) option.
1727    
1728     (c) Refactored the way lines are read and buffered so as to have more
1729     than one at a time available.
1730    
1731     (d) Implemented a pcregrep test script.
1732    
1733     (e) Added the -M (multiline match) option. This allows patterns to match
1734     over several lines of the subject. The buffering ensures that at least
1735     8K, or the rest of the document (whichever is the shorter) is available
1736     for matching (and similarly the previous 8K for lookbehind assertions).
1737    
1738     (f) Changed the --help output so that it now says
1739    
1740     -w, --word-regex(p)
1741    
1742     instead of two lines, one with "regex" and the other with "regexp"
1743     because that confused at least one person since the short forms are the
1744     same. (This required a bit of code, as the output is generated
1745     automatically from a table. It wasn't just a text change.)
1746    
1747     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1748     option but starts with a hyphen. Could be a pattern or a path name
1749     starting with a hyphen, for instance.
1750    
1751     (h) "-" can be given as a file name to represent stdin.
1752    
1753     (i) When file names are being printed, "(standard input)" is used for
1754     the standard input, for compatibility with GNU grep. Previously
1755     "<stdin>" was used.
1756    
1757     (j) The option --label=xxx can be used to supply a name to be used for
1758     stdin when file names are being printed. There is no short form.
1759    
1760     (k) Re-factored the options decoding logic because we are going to add
1761     two more options that take data. Such options can now be given in four
1762     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1763    
1764     (l) Added the -A, -B, and -C options for requesting that lines of context
1765     around matches be printed.
1766    
1767     (m) Added the -L option to print the names of files that do not contain
1768     any matching lines, that is, the complement of -l.
1769    
1770     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1771     continue to scan other files.
1772    
1773     (o) The -s option was incorrectly implemented. For compatibility with other
1774     greps, it now suppresses the error message for a non-existent or non-
1775     accessible file (but not the return code). There is a new option called
1776     -q that suppresses the output of matching lines, which was what -s was
1777     previously doing.
1778    
1779     (p) Added --include and --exclude options to specify files for inclusion
1780     and exclusion when recursing.
1781    
1782     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1783     Hopefully, it now does.
1784    
1785     12. Missing cast in pcre_study().
1786    
1787     13. Added an "uninstall" target to the makefile.
1788    
1789     14. Replaced "extern" in the function prototypes in Makefile.in with
1790     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1791     world, but is set differently for Windows.
1792    
1793     15. Added a second compiling function called pcre_compile2(). The only
1794     difference is that it has an extra argument, which is a pointer to an
1795     integer error code. When there is a compile-time failure, this is set
1796     non-zero, in addition to the error test pointer being set to point to an
1797     error message. The new argument may be NULL if no error number is required
1798     (but then you may as well call pcre_compile(), which is now just a
1799     wrapper). This facility is provided because some applications need a
1800     numeric error indication, but it has also enabled me to tidy up the way
1801     compile-time errors are handled in the POSIX wrapper.
1802    
1803     16. Added VPATH=.libs to the makefile; this should help when building with one
1804     prefix path and installing with another. (Or so I'm told by someone who
1805     knows more about this stuff than I do.)
1806    
1807     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1808     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1809     match everything, including newlines. This is not POSIX-compatible, but
1810     somebody wanted the feature. From pcretest it can be activated by using
1811     both the P and the s flags.
1812    
1813     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1814    
1815     19. libpcre.pc was being incorrectly installed as executable.
1816    
1817     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1818     it now also looks for '\r' so that it will work unmodified on Windows.
1819    
1820     21. Added Google's contributed C++ wrapper to the distribution.
1821    
1822     22. Added some untidy missing memory free() calls in pcretest, to keep
1823     Electric Fence happy when testing.
1824    
1825    
1826    
1827 nigel 75 Version 5.0 13-Sep-04
1828     ---------------------
1829    
1830     1. Internal change: literal characters are no longer packed up into items
1831     containing multiple characters in a single byte-string. Each character
1832     is now matched using a separate opcode. However, there may be more than one
1833     byte in the character in UTF-8 mode.
1834    
1835     2. The pcre_callout_block structure has two new fields: pattern_position and
1836     next_item_length. These contain the offset in the pattern to the next match
1837     item, and its length, respectively.
1838    
1839     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1840     insertion of callouts before each pattern item. Added the /C option to
1841     pcretest to make use of this.
1842    
1843     4. On the advice of a Windows user, the lines
1844    
1845     #if defined(_WIN32) || defined(WIN32)
1846     _setmode( _fileno( stdout ), 0x8000 );
1847     #endif /* defined(_WIN32) || defined(WIN32) */
1848    
1849     have been added to the source of pcretest. This apparently does useful
1850     magic in relation to line terminators.
1851    
1852     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1853     for the benefit of those environments where the "b" makes a difference.
1854    
1855     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1856     to know about it. I have put a hack into configure.in that adds in code
1857     to set GCC=yes if CC=icc. This seems to end up at a point in the
1858     generated configure script that is early enough to affect the setting of
1859     compiler options, which is what is needed, but I have no means of testing
1860     whether it really works. (The user who reported this had patched the
1861     generated configure script, which of course I cannot do.)
1862    
1863     LATER: After change 22 below (new libtool files), the configure script
1864     seems to know about icc (and also ecc). Therefore, I have commented out
1865     this hack in configure.in.
1866    
1867     7. Added support for pkg-config (2 patches were sent in).
1868    
1869     8. Negated POSIX character classes that used a combination of internal tables
1870     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1871     [[:^ascii]]. Typically, they would match almost any characters. The other
1872     POSIX classes were not broken in this way.
1873    
1874     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1875     to find the match, as PCRE was deluded into thinking that the match had to
1876     start at the start point or following a newline. The same bug applied to
1877     patterns with negative forward assertions or any backward assertions
1878     preceding ".*" at the start, unless the pattern required a fixed first
1879     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1880    
1881     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1882     starting at the last subject character, bytes beyond the end of the subject
1883     string were read.
1884    
1885     11. Renamed the variable "class" as "classbits" to make life easier for C++
1886     users. (Previously there was a macro definition, but it apparently wasn't
1887     enough.)
1888    
1889     12. Added the new field "tables" to the extra data so that tables can be passed
1890     in at exec time, or the internal tables can be re-selected. This allows
1891     a compiled regex to be saved and re-used at a later time by a different
1892     program that might have everything at different addresses.
1893    
1894     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1895     -R library as well as a -L library.
1896    
1897     14. The debugging options of pcretest (-d on the command line or D on a
1898     pattern) showed incorrect output for anything following an extended class
1899     that contained multibyte characters and which was followed by a quantifier.
1900    
1901     15. Added optional support for general category Unicode character properties
1902     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1903     support. It adds about 90K to the size of the library. The meanings of the
1904     inbuilt class escapes such as \d and \s have NOT been changed.
1905    
1906     16. Updated pcredemo.c to include calls to free() to release the memory for the
1907     compiled pattern.
1908    
1909     17. The generated file chartables.c was being created in the source directory
1910     instead of in the building directory. This caused the build to fail if the
1911     source directory was different from the building directory, and was
1912     read-only.
1913    
1914     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1915     file. No doubt somebody will tell me if they don't make sense... Also added
1916     Dan Mooney's comments about building on OpenVMS.
1917    
1918     19. Added support for partial matching via the PCRE_PARTIAL option for
1919     pcre_exec() and the \P data escape in pcretest.
1920    
1921     20. Extended pcretest with 3 new pattern features:
1922    
1923     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1924     write the compiled pattern to the file whose name is "rest-of-line".
1925     This is a straight binary dump of the data, with the saved pointer to
1926     the character tables forced to be NULL. The study data, if any, is
1927     written too. After writing, pcretest reads a new pattern.
1928    
1929     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1930     compiled pattern from the given file. There must not be any
1931     occurrences of "<" in the file name (pretty unlikely); if there are,
1932     pcretest will instead treat the initial "<" as a pattern delimiter.
1933     After reading in the pattern, pcretest goes on to read data lines as
1934     usual.
1935    
1936     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1937     and 16-bit fields in a compiled pattern, to simulate a pattern that
1938     was compiled on a host of opposite endianness.
1939    
1940     21. The pcre-exec() function can now cope with patterns that were compiled on
1941     hosts of opposite endianness, with this restriction:
1942    
1943     As for any compiled expression that is saved and used later, the tables
1944     pointer field cannot be preserved; the extra_data field in the arguments
1945     to pcre_exec() should be used to pass in a tables address if a value
1946     other than the default internal tables were used at compile time.
1947    
1948     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1949     now diagnosed as an error. Previously, most of the time, a negative number
1950     would have been treated as zero, but if in addition "ovector" was passed as
1951     NULL, a crash could occur.
1952    
1953     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1954     new versions from the libtool 1.5 distribution (the last one is a copy of
1955     a file called libtool.m4). This seems to have fixed the need to patch
1956     "configure" to support Darwin 1.3 (which I used to do). However, I still
1957     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1958     workstation).
1959    
1960     24. Changed the PCRE licence to be the more standard "BSD" licence.
1961    
1962    
1963 nigel 73 Version 4.5 01-Dec-03
1964     ---------------------
1965    
1966     1. There has been some re-arrangement of the code for the match() function so
1967     that it can be compiled in a version that does not call itself recursively.
1968     Instead, it keeps those local variables that need separate instances for
1969     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1970     needs to "recurse". Keeping track of where control must go is done by means
1971     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1972     hide most of the details from the main code, and operates only if
1973     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1974     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1975     operating.
1976    
1977     To make it easier for callers to provide specially tailored get/free
1978     functions for this usage, two new functions, pcre_stack_malloc, and
1979     pcre_stack_free, are used. They are always called in strict stacking order,
1980     and the size of block requested is always the same.
1981    
1982     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1983     PCRE has been compiled to use the stack or the heap for recursion. The
1984     -C option of pcretest uses this to show which version is compiled.
1985    
1986     A new data escape \S, is added to pcretest; it causes the amounts of store
1987     obtained and freed by both kinds of malloc/free at match time to be added
1988     to the output.
1989    
1990     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1991     what's available on my current Linux desktop machine.
1992    
1993     3. When matching a UTF-8 string, the test for a valid string at the start has
1994     been extended. If start_offset is not zero, PCRE now checks that it points
1995     to a byte that is the start of a UTF-8 character. If not, it returns
1996     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1997     this is necessary because there may be backward assertions in the pattern.
1998     When matching the same subject several times, it may save resources to use
1999     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2000    
2001     4. The code for checking the validity of UTF-8 strings has been tightened so
2002     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2003     containing "overlong sequences".
2004    
2005     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2006     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2007     should have been "&", but it just so happened that all the cases this let
2008     through by mistake were picked up later in the function.
2009    
2010     6. I had used a variable called "isblank" - this is a C99 function, causing
2011     some compilers to warn. To avoid this, I renamed it (as "blankclass").
2012    
2013     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2014     prompting; (b) run "./pcretest /dev/null" at the start of the test script
2015     so the version is shown; (c) stop "make test" echoing "./RunTest".
2016    
2017     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2018    
2019     9. The prototype for memmove() for systems that don't have it was using
2020     size_t, but the inclusion of the header that defines size_t was later. I've
2021     moved the #includes for the C headers earlier to avoid this.
2022    
2023     10. Added some adjustments to the code to make it easier to compiler on certain
2024     special systems:
2025    
2026     (a) Some "const" qualifiers were missing.
2027     (b) Added the macro EXPORT before all exported functions; by default this
2028     is defined to be empty.
2029     (c) Changed the dftables auxiliary program (that builds chartables.c) so
2030     that it reads its output file name as an argument instead of writing
2031     to the standard output and assuming this can be redirected.
2032    
2033     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2034     class containing characters with values greater than 255, PCRE compilation
2035     went into a loop.
2036    
2037     12. A recursive reference to a subpattern that was within another subpattern
2038     that had a minimum quantifier of zero caused PCRE to crash. For example,
2039     (x(y(?2))z)? provoked this bug with a subject that got as far as the
2040     recursion. If the recursively-called subpattern itself had a zero repeat,
2041     that was OK.
2042    
2043     13. In pcretest, the buffer for reading a data line was set at 30K, but the
2044     buffer into which it was copied (for escape processing) was still set at
2045     1024, so long lines caused crashes.
2046    
2047     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2048     "internal error: code overflow...". This applied to any character class
2049     that was followed by a possessive quantifier.
2050    
2051     15. Modified the Makefile to add libpcre.la as a prerequisite for
2052     libpcreposix.la because I was told this is needed for a parallel build to
2053     work.
2054    
2055     16. If a pattern that contained .* following optional items at the start was
2056     studied, the wrong optimizing data was generated, leading to matching
2057     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2058     matching string must start with a or b or c. The correct conclusion for
2059     this pattern is that a match can start with any character.
2060    
2061    
2062 nigel 71 Version 4.4 13-Aug-03
2063     ---------------------
2064    
2065     1. In UTF-8 mode, a character class containing characters with values between
2066     127 and 255 was not handled correctly if the compiled pattern was studied.
2067     In fixing this, I have also improved the studying algorithm for such
2068     classes (slightly).
2069    
2070     2. Three internal functions had redundant arguments passed to them. Removal
2071     might give a very teeny performance improvement.
2072    
2073     3. Documentation bug: the value of the capture_top field in a callout is *one
2074     more than* the number of the hightest numbered captured substring.
2075    
2076     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2077     in incorrectly linking with a previously installed version. They now link
2078     explicitly with libpcre.la.
2079    
2080     5. configure.in no longer needs to recognize Cygwin specially.
2081    
2082     6. A problem in pcre.in for Windows platforms is fixed.
2083    
2084     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2085     pcretest, it used to include the size of the study block as part of its
2086     output. Unfortunately, the structure contains a field that has a different
2087     size on different hardware architectures. This meant that the tests that
2088     showed this size failed. As the block is currently always of a fixed size,
2089     this information isn't actually particularly useful in pcretest output, so
2090     I have just removed it.
2091    
2092     8. Three pre-processor statements accidentally did not start in column 1.
2093     Sadly, there are *still* compilers around that complain, even though
2094     standard C has not required this for well over a decade. Sigh.
2095    
2096     9. In pcretest, the code for checking callouts passed small integers in the
2097     callout_data field, which is a void * field. However, some picky compilers
2098     complained about the casts involved for this on 64-bit systems. Now
2099     pcretest passes the address of the small integer instead, which should get
2100     rid of the warnings.
2101    
2102     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2103     both compile and run time, and gives an error if an invalid UTF-8 sequence
2104     is found. There is a option for disabling this check in cases where the
2105     string is known to be correct and/or the maximum performance is wanted.
2106    
2107     11. In response to a bug report, I changed one line in Makefile.in from
2108    
2109     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2110     to
2111     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2112    
2113     to look similar to other lines, but I have no way of telling whether this
2114     is the right thing to do, as I do not use Windows. No doubt I'll get told
2115     if it's wrong...
2116    
2117    
2118 nigel 69 Version 4.3 21-May-03
2119     ---------------------
2120    
2121     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2122     Makefile.
2123    
2124     2. Some refactoring to improve the quality of the code:
2125    
2126     (i) The utf8_table... variables are now declared "const".
2127    
2128     (ii) The code for \cx, which used the "case flipping" table to upper case
2129     lower case letters, now just substracts 32. This is ASCII-specific,
2130     but the whole concept of \cx is ASCII-specific, so it seems
2131     reasonable.
2132    
2133     (iii) PCRE was using its character types table to recognize decimal and
2134     hexadecimal digits in the pattern. This is silly, because it handles
2135     only 0-9, a-f, and A-F, but the character types table is locale-
2136     specific, which means strange things might happen. A private
2137     table is now used for this - though it costs 256 bytes, a table is
2138     much faster than multiple explicit tests. Of course, the standard
2139     character types table is still used for matching digits in subject
2140     strings against \d.
2141    
2142     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2143     ending in _t are). So I've renamed it as ESC_tee.
2144    
2145     3. The first argument for regexec() in the POSIX wrapper should have been
2146     defined as "const".
2147    
2148     4. Changed pcretest to use malloc() for its buffers so that they can be
2149     Electric Fenced for debugging.
2150    
2151     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2152     to read one or more bytes before the start of the subject string. Often this
2153     had no effect on PCRE's behaviour, but in some circumstances it could
2154     provoke a segmentation fault.
2155    
2156     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2157     to try to read one or more bytes before the start of the subject string.
2158    
2159     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2160     UTF-8 support could misbehave in various ways if the subject string
2161     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2162     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2163     back over UTF-8 characters.)
2164    
2165    
2166 nigel 67 Version 4.2 14-Apr-03
2167     ---------------------
2168    
2169     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2170    
2171     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2172     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2173     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2174     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2175     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2176     and BUILD_EXEEXT
2177     Note: automatic setting of the BUILD variables is not yet working
2178     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2179     compile-time but not at link-time
2180     [LINK]: use for linking executables only
2181     make different versions for Windows and non-Windows
2182     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2183     libraries
2184     [LINK_FOR_BUILD]: new variable
2185     [OBJEXT]: use throughout
2186     [EXEEXT]: use throughout
2187     <winshared>: new target
2188     <wininstall>: new target
2189     <dftables.o>: use native compiler
2190     <dftables>: use native linker
2191     <install>: handle Windows platform correctly
2192     <clean>: ditto
2193     <check>: ditto
2194     copy DLL to top builddir before testing
2195    
2196     As part of these changes, -no-undefined was removed again. This was reported
2197     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2198     in any case.
2199    
2200     3. Some tidies to get rid of compiler warnings:
2201    
2202     . In the match_data structure, match_limit was an unsigned long int, whereas
2203     match_call_count was an int. I've made them both unsigned long ints.
2204    
2205     . In pcretest the fact that a const uschar * doesn't automatically cast to
2206     a void * provoked a warning.
2207    
2208     . Turning on some more compiler warnings threw up some "shadow" variables
2209     and a few more missing casts.
2210    
2211     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2212     option, a class that contained a single character with a value between 128
2213     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2214    
2215     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2216     option, a class that contained several characters, but with at least one
2217     whose value was between 128 and 255 caused PCRE to crash.
2218    
2219    
2220 nigel 65 Version 4.1 12-Mar-03
2221     ---------------------
2222 nigel 63
2223 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2224     needed, and a string in dftables.c that was longer than standard compilers are
2225     required to support.
2226    
2227     2. Compiling with Sun's compiler found a few more places where the code could
2228     be tidied up in order to avoid warnings.
2229    
2230     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2231     first of these names is deprecated in the latest Autoconf in favour of the name
2232     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2233     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2234     analogy I have changed it to CFLAGS_FOR_BUILD.
2235    
2236     4. Added -no-undefined to the linking command in the Makefile, because this is
2237     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2238     linking step for the pcreposix library.
2239    
2240     5. PCRE was failing to diagnose the case of two named groups with the same
2241     name.
2242    
2243     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2244     literal character that is needed in the subject for a match, and scans along to
2245     ensure that it is present before embarking on the full matching process. This
2246     saves time in cases of nested unlimited repeats that are never going to match.
2247     Problem: the scan can take a lot of time if the subject is very long (e.g.
2248     megabytes), thus penalizing straightforward matches. It is now done only if the
2249     amount of subject to be scanned is less than 1000 bytes.
2250    
2251     7. A lesser problem with the same optimization is that it was recording the
2252     first character of an anchored pattern as "needed", thus provoking a search
2253     right along the subject, even when the first match of the pattern was going to
2254     fail. The "needed" character is now not set for anchored patterns, unless it
2255     follows something in the pattern that is of non-fixed length. Thus, it still
2256     fulfils its original purpose of finding quick non-matches in cases of nested
2257     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2258    
2259    
2260     Version 4.0 17-Feb-03
2261     ---------------------
2262    
2263 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2264     extended to the end of string, PCRE compiled incorrect data. This could lead to
2265     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2266    
2267     2. Moved to autoconf 2.53 and libtool 1.4.2.
2268    
2269     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2270     the special perltest8 script is no longer needed - all the tests can be run
2271     from a single perltest script.
2272    
2273     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2274     by \s. It has now been removed in PCRE. This means it isn't recognized as
2275     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2276     class [:space:] *does* include VT, thereby creating a mess.
2277    
2278     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2279     space and tab.
2280    
2281     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2282     its new features into the main test script, reducing the number of scripts.
2283    
2284     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2285     were backward compatible, and made the (?i) apply to the whole pattern, as if
2286     /i were given. Now it behaves more logically, and applies the option setting
2287     only to what follows. PCRE has been changed to follow suit. However, if it
2288     finds options settings right at the start of the pattern, it extracts them into
2289     the global options, as before. Thus, they show up in the info data.
2290    
2291     8. Added support for the \Q...\E escape sequence. Characters in between are
2292     treated as literals. This is slightly different from Perl in that $ and @ are
2293     also handled as literals inside the quotes. In Perl, they will cause variable
2294     interpolation. Note the following examples:
2295    
2296     Pattern PCRE matches Perl matches
2297    
2298     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2299     \Qabc\$xyz\E abc\$xyz abc\$xyz
2300     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2301    
2302     For compatibility with Perl, \Q...\E sequences are recognized inside character
2303     classes as well as outside them.
2304    
2305     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2306     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2307     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2308     signed/unsigned warnings.
2309    
2310     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2311     option for pcretest, so I've replaced it by a simple function that does just
2312     that job.
2313    
2314     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2315     "pcregrep -".
2316    
2317     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2318     Java package. This provides some syntactic sugar for simple cases of what my
2319     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2320     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2321     item, you can use this simplified notation. Note that only makes sense with
2322     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2323     greediness, whatever the setting of the PCRE_UNGREEDY option.
2324    
2325     13. A change of greediness default within a pattern was not taking effect at
2326     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2327     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2328     was abstracted outside.
2329    
2330     14. PCRE now supports the \G assertion. It is true when the current matching
2331     position is at the start point of the match. This differs from \A when the
2332     starting offset is non-zero. Used with the /g option of pcretest (or similar
2333     code), it works in the same way as it does for Perl's /g option. If all
2334     alternatives of a regex begin with \G, the expression is anchored to the start
2335     match position, and the "anchored" flag is set in the compiled expression.
2336    
2337     15. Some bugs concerning the handling of certain option changes within patterns
2338     have been fixed. These applied to options other than (?ims). For example,
2339     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2340     been the other way round. Some of this was related to change 7 above.
2341    
2342     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2343     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2344     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2345     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2346    
2347     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2348     mode. Unlike ".", it always matches newline, whatever the setting of
2349     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2350     assertions. Perl allows it, but it doesn't (in general) work because it can't
2351     calculate the length of the lookbehind. At least, that's the case for Perl
2352     5.8.0 - I've been told they are going to document that it doesn't work in
2353     future.
2354    
2355     18. Added an error diagnosis for escapes that PCRE does not support: these are
2356     \L, \l, \N, \P, \p, \U, \u, and \X.
2357    
2358     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2359     reading past the end of the pattern in cases such as /[abcd/.
2360    
2361     20. PCRE was getting more memory than necessary for patterns with classes that
2362     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2363    
2364     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2365     compiling PCRE for use with Virtual Pascal.
2366    
2367     22. Small fix to the Makefile to make it work properly if the build is done
2368     outside the source tree.
2369    
2370     23. Added a new extension: a condition to go with recursion. If a conditional
2371     subpattern starts with (?(R) the "true" branch is used if recursion has
2372     happened, whereas the "false" branch is used only at the top level.
2373    
2374     24. When there was a very long string of literal characters (over 255 bytes
2375     without UTF support, over 250 bytes with UTF support), the computation of how
2376     much memory was required could be incorrect, leading to segfaults or other
2377     strange effects.
2378    
2379     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2380     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2381     there was a subsequent back reference to those brackets. This meant that, for
2382     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2383     possible to check for precisely this case. All we can do is abandon the
2384     optimization if .* occurs inside capturing brackets when there are any back
2385     references whatsoever. (See below for a better fix that came later.)
2386    
2387     26. The handling of the optimization for finding the first character of a
2388     non-anchored pattern, and for finding a character that is required later in the
2389     match were failing in some cases. This didn't break the matching; it just
2390     failed to optimize when it could. The way this is done has been re-implemented.
2391    
2392     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2393    
2394     28. Added a new feature that provides some of the functionality that Perl
2395     provides with (?{...}). The facility is termed a "callout". The way it is done
2396     in PCRE is for the caller to provide an optional function, by setting
2397     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2398     global variable. By default it is unset, which disables all calling out. To get
2399     the function called, the regex must include (?C) at appropriate points. This
2400     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2401     This provides a means of identifying different callout points. When PCRE
2402     reaches such a point in the regex, if pcre_callout has been set, the external
2403     function is called. It is provided with data in a structure called
2404     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2405     matching continues; if it returns a non-zero value, the match at the current
2406     point fails. However, backtracking will occur if possible. [This was changed
2407     later and other features added - see item 49 below.]
2408    
2409     29. pcretest is upgraded to test the callout functionality. It provides a
2410     callout function that displays information. By default, it shows the start of
2411     the match and the current position in the text. There are some new data escapes
2412     to vary what happens:
2413    
2414     \C+ in addition, show current contents of captured substrings
2415     \C- do not supply a callout function
2416     \C!n return 1 when callout number n is reached
2417     \C!n!m return 1 when callout number n is reached for the mth time
2418    
2419     30. If pcregrep was called with the -l option and just a single file name, it
2420     output "<stdin>" if a match was found, instead of the file name.
2421    
2422     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2423     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2424     pcre_exec(). This saves a malloc/free per call. The default value of
2425     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2426     when configuring.
2427    
2428     32. The default maximum size of a compiled pattern is 64K. There have been a
2429     few cases of people hitting this limit. The code now uses macros to handle the
2430     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2431     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2432     configuring. Tests 2 and 5 work only with 2-byte links because they output
2433     debugging information about compiled patterns.
2434    
2435     33. Internal code re-arrangements:
2436    
2437     (a) Moved the debugging function for printing out a compiled regex into
2438     its own source file (printint.c) and used #include to pull it into
2439     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2440     separate copies.
2441    
2442     (b) Defined the list of op-code names for debugging as a macro in
2443     internal.h so that it is next to the definition of the opcodes.
2444    
2445     (c) Defined a table of op-code lengths for simpler skipping along compiled
2446     code. This is again a macro in internal.h so that it is next to the
2447     definition of the opcodes.
2448    
2449     34. Added support for recursive calls to individual subpatterns, along the
2450     lines of Robin Houston's patch (but implemented somewhat differently).
2451    
2452     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2453     allow it to read and process whole directories in Win32. This code was
2454     contributed by Lionel Fourquaux; it has not been tested by me.
2455    
2456     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2457     used to name a group. Names consist of alphanumerics and underscores, and must
2458     be unique. Back references use the syntax (?P=name) and recursive calls use
2459     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2460     numbers. The function pcre_fullinfo() can be used after compilation to extract
2461     a name/number map. There are three relevant calls:
2462    
2463     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2464     PCRE_INFO_NAMECOUNT yields the number of entries
2465     PCRE_INFO_NAMETABLE yields a pointer to the map.
2466    
2467     The map is a vector of fixed-size entries. The size of each entry depends on
2468     the length of the longest name used. The first two bytes of each entry are the
2469     group number, most significant byte first. There follows the corresponding
2470     name, zero terminated. The names are in alphabetical order.
2471    
2472     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2473     case instead of 255. Making it the same both with and without UTF-8 support
2474     means that the same test output works with both.
2475    
2476     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2477     calling malloc() with a zero argument.
2478    
2479     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2480     optimization. I've improved things by keeping a bitmap of backreferences with
2481     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2482     fact referenced, the optimization can be applied. It is unlikely that a
2483     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2484     the match to follow \n) will appear inside brackets with a number greater than
2485     31, but if it does, any back reference > 31 suppresses the optimization.
2486    
2487     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2488     of disabling numbered capturing parentheses. Any opening parenthesis that is
2489     not followed by ? behaves as if it were followed by ?: but named parentheses
2490     can still be used for capturing (and they will acquire numbers in the usual
2491     way).
2492    
2493     41. Redesigned the return codes from the match() function into yes/no/error so
2494     that errors can be passed back from deep inside the nested calls. A malloc
2495     failure while inside a recursive subpattern call now causes the
2496     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2497    
2498     42. It is now possible to set a limit on the number of times the match()
2499     function is called in a call to pcre_exec(). This facility makes it possible to
2500     limit the amount of recursion and backtracking, though not in a directly
2501     obvious way, because the match() function is used in a number of different
2502     circumstances. The count starts from zero for each position in the subject
2503     string (for non-anchored patterns). The default limit is, for compatibility, a
2504     large number, namely 10 000 000. You can change this in two ways:
2505    
2506     (a) When configuring PCRE before making, you can use --with-match-limit=n
2507     to set a default value for the compiled library.
2508    
2509     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2510     a different value is set. See 45 below.
2511    
2512     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2513    
2514     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2515     of things that can be changed at compile time. The first argument specifies
2516     what is wanted and the second points to where the information is to be placed.
2517     The current list of available information is:
2518    
2519     PCRE_CONFIG_UTF8
2520    
2521     The output is an integer that is set to one if UTF-8 support is available;
2522     otherwise it is set to zero.
2523    
2524     PCRE_CONFIG_NEWLINE
2525    
2526     The output is an integer that it set to the value of the code that is used for
2527     newline. It is either LF (10) or CR (13).
2528    
2529     PCRE_CONFIG_LINK_SIZE
2530    
2531     The output is an integer that contains the number of bytes used for internal
2532     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2533    
2534     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2535    
2536     The output is an integer that contains the threshold above which the POSIX
2537     interface uses malloc() for output vectors. See item 31 above.
2538    
2539     PCRE_CONFIG_MATCH_LIMIT
2540    
2541     The output is an unsigned integer that contains the default limit of the number
2542     of match() calls in a pcre_exec() execution. See 42 above.
2543    
2544     44. pcretest has been upgraded by the addition of the -C option. This causes it
2545     to extract all the available output from the new pcre_config() function, and to
2546     output it. The program then exits immediately.
2547    
2548     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2549     order to support additional features. One way would have been to define
2550     pcre_exec2() (for example) with extra arguments, but this would not have been
2551     extensible, and would also have required all calls to the original function to
2552     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2553     is used for passing in "extra" data from pcre_study().
2554    
2555     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2556     contains the following fields:
2557    
2558     flags a bitmap indicating which of the following fields are set
2559     study_data opaque data from pcre_study()
2560     match_limit a way of specifying a limit on match() calls for a specific
2561     call to pcre_exec()
2562     callout_data data for callouts (see 49 below)
2563    
2564     The flag bits are also defined in pcre.h, and are
2565    
2566     PCRE_EXTRA_STUDY_DATA
2567     PCRE_EXTRA_MATCH_LIMIT
2568     PCRE_EXTRA_CALLOUT_DATA
2569    
2570     The pcre_study() function now returns one of these new pcre_extra blocks, with
2571     the actual study data pointed to by the study_data field, and the
2572     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2573     before. That is, this change is entirely upwards-compatible and requires no
2574     change to existing code.
2575    
2576     If you want to pass in additional data to pcre_exec(), you can either place it
2577     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2578     block.
2579    
2580     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2581     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2582     times with different match limits, until it finds the minimum value needed for
2583     pcre_exec() to complete. The value is then output. This can be instructive; for
2584     most simple matches the number is quite small, but for pathological cases it
2585     gets very large very quickly.
2586    
2587     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2588     returns the size of the data block pointed to by the study_data field in a
2589     pcre_extra block, that is, the value that was passed as the argument to
2590     pcre_malloc() when PCRE was getting memory in which to place the information
2591     created by pcre_study(). The fourth argument should point to a size_t variable.
2592     pcretest has been extended so that this information is shown after a successful
2593     pcre_study() call when information about the compiled regex is being displayed.
2594    
2595     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2596     because what follows is always an absolute path. (Later: it turns out that this
2597     is more than cosmetic for MinGW, because it doesn't like empty path
2598     components.)
2599    
2600     49. Some changes have been made to the callout feature (see 28 above):
2601    
2602     (i) A callout function now has three choices for what it returns:
2603    
2604     0 => success, carry on matching
2605     > 0 => failure at this point, but backtrack if possible
2606     < 0 => serious error, return this value from pcre_exec()
2607    
2608     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2609     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2610     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2611     use by callout functions. It will never be used by PCRE itself.
2612    
2613     (ii) The pcre_extra structure (see 45 above) has a void * field called
2614     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2615     pcre_callout_block structure has a field of the same name. The contents of
2616     the field passed in the pcre_extra structure are passed to the callout
2617     function in the corresponding field in the callout block. This makes it
2618     easier to use the same callout-containing regex from multiple threads. For
2619     testing, the pcretest program has a new data escape
2620    
2621     \C*n pass the number n (may be negative) as callout_data
2622    
2623     If the callout function in pcretest receives a non-zero value as
2624     callout_data, it returns that value.
2625    
2626     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2627     there were some redundant $(CFLAGS) in commands that are now specified as
2628     $(LINK), which already includes $(CFLAGS).
2629    
2630     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2631     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2632     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2633     one-byte characters throughout. Note that case-insensitive matching applies
2634     only to characters whose values are less than 256. PCRE doesn't support the
2635     notion of cases for higher-valued characters.
2636    
2637     (i) A character class whose characters are all within 0-255 is handled as
2638     a bit map, and the map is inverted for negative classes. Previously, a
2639     character > 255 always failed to match such a class; however it should
2640     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2641    
2642     (ii) A negated character class with a single character < 255 is coded as
2643     "not this character" (OP_NOT). This wasn't working properly when the test
2644     character was multibyte, either singly or repeated.
2645    
2646     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2647     mode, for example: \x{100}{2,3}.
2648    
2649     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2650     singly or repeated) now correctly test multibyte characters. However,
2651     PCRE doesn't recognize any characters with values greater than 255 as
2652     digits, spaces, or word characters. Such characters always match \D, \S,
2653     and \W, and never match \d, \s, or \w.
2654    
2655     (v) Classes may now contain characters and character ranges with values
2656     greater than 255. For example: [ab\x{100}-\x{400}].
2657    
2658     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2659     PCRE in UTF-8 mode.
2660    
2661     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2662     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2663     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2664     value.)
2665    
2666     53. The single man page has become too large. I have therefore split it up into
2667     a number of separate man pages. These also give rise to individual HTML pages;
2668     these are now put in a separate directory, and there is an index.html page that
2669     lists them all. Some hyperlinking between the pages has been installed.
2670    
2671     54. Added convenience functions for handling named capturing parentheses.
2672    
2673     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2674     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2675     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2676     are faulted.
2677    
2678     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2679     calling configure. These values are used when compiling the dftables.c program
2680     which is run to generate the source of the default character tables. They
2681     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2682     you will need to set these values.
2683    
2684     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2685    
2686    
2687     Version 3.9 02-Jan-02
2688 nigel 61 ---------------------
2689    
2690     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2691    
2692     2. If --disable-static was given, the building process failed when trying to
2693     build pcretest and pcregrep. (For some reason it was using libtool to compile
2694     them, which is not right, as they aren't part of the library.)
2695    
2696    
2697 nigel 59 Version 3.8 18-Dec-01
2698     ---------------------
2699    
2700     1. The experimental UTF-8 code was completely screwed up. It was packing the
2701     bytes in the wrong order. How dumb can you get?
2702    
2703    
2704 nigel 57 Version 3.7 29-Oct-01
2705     ---------------------
2706    
2707     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2708     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2709     this didn't happen under Solaris 8, where I normally test things.
2710    
2711 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2712     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2713     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2714     this fix an hour or so after the initial 3.7 release.)
2715 nigel 57
2716 nigel 59
2717 nigel 55 Version 3.6 23-Oct-01
2718     ---------------------
2719    
2720     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2721     offsets passed as NULL with zero offset count.
2722    
2723     2. The config.guess and config.sub files had not been updated when I moved to
2724     the latest autoconf.
2725    
2726    
2727 nigel 53 Version 3.5 15-Aug-01
2728     ---------------------
2729 nigel 5
2730 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2731     had been forgotten.
2732    
2733     2. By using declared but undefined structures, we can avoid using "void"
2734     definitions in pcre.h while keeping the internal definitions of the structures
2735     private.
2736    
2737     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2738     user point of view, this means that both static and shared libraries are built
2739     by default, but this can be individually controlled. More of the work of
2740     handling this static/shared cases is now inside libtool instead of PCRE's make
2741     file.
2742    
2743     4. The pcretest utility is now installed along with pcregrep because it is
2744     useful for users (to test regexs) and by doing this, it automatically gets
2745     relinked by libtool. The documentation has been turned into a man page, so
2746     there are now .1, .txt, and .html versions in /doc.
2747    
2748     5. Upgrades to pcregrep:
2749     (i) Added long-form option names like gnu grep.
2750     (ii) Added --help to list all options with an explanatory phrase.
2751     (iii) Added -r, --recursive to recurse into sub-directories.
2752     (iv) Added -f, --file to read patterns from a file.
2753    
2754     6. pcre_exec() was referring to its "code" argument before testing that
2755     argument for NULL (and giving an error if it was NULL).
2756    
2757     7. Upgraded Makefile.in to allow for compiling in a different directory from
2758     the source directory.
2759    
2760     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2761     options bits, the pointer it was passed was to an int instead of to an unsigned
2762     long int. This mattered only on 64-bit systems.
2763    
2764     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2765     generated) instead of pcre.in, which it its source. Also made the same change
2766     in several of the .c files.
2767    
2768     10. A new release of gcc defines printf() as a macro, which broke pcretest
2769     because it had an ifdef in the middle of a string argument for printf(). Fixed
2770     by using separate calls to printf().
2771    
2772     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2773     script, to force use of CR or LF instead of \n in the source. On non-Unix
2774     systems, the value can be set in config.h.
2775    
2776     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2777     absolute limit. Changed the text of the error message to make this clear, and
2778     likewise updated the man page.
2779    
2780     13. The limit of 99 on the number of capturing subpatterns has been removed.
2781     The new limit is 65535, which I hope will not be a "real" limit.
2782    
2783    
2784 nigel 51 Version 3.4 22-Aug-00
2785     ---------------------
2786    
2787     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2788    
2789     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2790    
2791    
2792 nigel 49 Version 3.3 01-Aug-00
2793     ---------------------
2794    
2795     1. If an octal character was given, but the value was greater than \377, it
2796     was not getting masked to the least significant bits, as documented. This could
2797     lead to crashes in some systems.
2798    
2799     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2800     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2801    
2802     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2803     These just pass their arguments on to (pcre_free)(), but they are provided
2804     because some uses of PCRE bind it to non-C systems that can call its functions,
2805     but cannot call free() or pcre_free() directly.
2806    
2807     4. Add "make test" as a synonym for "make check". Corrected some comments in
2808     the Makefile.
2809    
2810     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2811     Makefile.
2812    
2813     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2814     command called pgrep for grepping around the active processes.
2815    
2816     7. Added the beginnings of support for UTF-8 character strings.
2817    
2818     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2819     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2820     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2821     out for the ar command.)
2822    
2823    
2824 nigel 47 Version 3.2 12-May-00
2825     ---------------------
2826    
2827     This is purely a bug fixing release.
2828    
2829     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2830     of ZA. This was just one example of several cases that could provoke this bug,
2831     which was introduced by change 9 of version 2.00. The code for breaking
2832     infinite loops after an iteration that matches an empty string was't working
2833     correctly.
2834    
2835     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2836     when matched against abbab (for example). After matching an empty string, it
2837     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2838     caused it to match further down the string than it should.
2839    
2840     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2841     was there because it doesn't seem to be needed, and it causes trouble on some
2842     systems, as it is not a Standard C header. It has been removed.
2843    
2844     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2845     were reported on the Macintosh. The changes were from
2846    
2847     while ((c = *(++ptr)) != 0 && c != '\n');
2848     to
2849     while ((c = *(++ptr)) != 0 && c != '\n') ;
2850    
2851     Totally extraordinary, but if that's what it takes...
2852    
2853     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2854     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2855     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2856     assumes the way PCRE uses memmove() (always moving upwards).
2857    
2858     6. PCRE is being used in one environment where strchr() is not available. There
2859     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2860     faster code anyway.
2861    
2862    
2863 nigel 45 Version 3.1 09-Feb-00
2864     ---------------------
2865    
2866     The only change in this release is the fixing of some bugs in Makefile.in for
2867     the "install" target:
2868    
2869     (1) It was failing to install pcreposix.h.
2870    
2871     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2872    
2873    
2874 nigel 43 Version 3.0 01-Feb-00
2875     ---------------------
2876 nigel 41
2877     1. Add support for the /+ modifier to perltest (to output $` like it does in
2878     pcretest).
2879    
2880     2. Add support for the /g modifier to perltest.
2881    
2882     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2883     matches null strings.
2884    
2885     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2886     pattern. Perl treats empty patterns specially - it reuses the most recent
2887     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2888     effect.
2889    
2890     5. The POSIX interface was broken in that it was just handing over the POSIX
2891     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2892     required a bigger vector, with some working space on the end. This means that
2893     the POSIX wrapper now has to get and free some memory, and copy the results.
2894    
2895 nigel 43 6. Added some simple autoconf support, placing the test data and the
2896     documentation in separate directories, re-organizing some of the
2897     information files, and making it build pcre-config (a GNU standard). Also added
2898     libtool support for building PCRE as a shared library, which is now the
2899     default.
2900 nigel 41
2901 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2902     09 are not valid octal constants. Single digits will be used for minor values
2903     less than 10.
2904    
2905     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2906     existing programs that set these in the POSIX interface can use PCRE without
2907     modification.
2908    
2909     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2910     return all that pcre_info() returns, plus additional data. The pcre_info()
2911     function is retained for compatibility, but is considered to be obsolete.
2912    
2913     10. Added experimental recursion feature (?R) to handle one common case that
2914     Perl 5.6 will be able to do with (?p{...}).
2915    
2916     11. Added support for POSIX character classes like [:alpha:], which Perl is
2917     adopting.
2918    
2919    
2920 nigel 39 Version 2.08 31-Aug-99
2921     ----------------------
2922    
2923     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2924     trying to match at the startoffset position, but instead was moving forward to
2925     the next newline as if a previous match had failed.
2926    
2927     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2928     and could get into a loop if a null string was matched other than at the start
2929     of the subject.
2930    
2931     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2932     be distinguished at compile time, and for completeness also added PCRE_DATE.
2933    
2934     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2935     in GnuWin32 environments.
2936    
2937    
2938 nigel 37 Version 2.07 29-Jul-99
2939     ----------------------
2940    
2941     1. The documentation is now supplied in plain text form and HTML as well as in
2942     the form of man page sources.
2943    
2944     2. C++ compilers don't like assigning (void *) values to other pointer types.
2945     In particular this affects malloc(). Although there is no problem in Standard
2946     C, I've put in casts to keep C++ compilers happy.
2947    
2948     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2949     should be (const char *).
2950    
2951     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2952     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2953     However, I haven't made this a standard facility. The documentation doesn't
2954     mention it, and the Makefile doesn't support it.
2955    
2956     5. The Makefile now contains an "install" target, with editable destinations at
2957     the top of the file. The pcretest program is not installed.
2958    
2959     6. pgrep -V now gives the PCRE version number and date.
2960    
2961     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2962     causing the entire string to be ignored, instead of just the last character.
2963    
2964     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2965     non-matching string, it can take a very, very long time, even for strings of
2966     quite modest length, because of the nested recursion. PCRE now does better in
2967     some of these cases. It does this by remembering the last required literal
2968     character in the pattern, and pre-searching the subject to ensure it is present
2969     before running the real match. In other words, it applies a heuristic to detect
2970     some types of certain failure quickly, and in the above example, if presented
2971     with a string that has no trailing " it gives "no match" very quickly.
2972    
2973     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2974     other alternatives are tried instead.
2975    
2976    
2977 nigel 35 Version 2.06 09-Jun-99
2978     ----------------------
2979    
2980     1. Change pcretest's output for amount of store used to show just the code
2981     space, because the remainder (the data block) varies in size between 32-bit and
2982     64-bit systems.
2983    
2984     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2985     start matching at. This allows lookbehinds to work when searching for multiple
2986     occurrences in a string.
2987    
2988     3. Added additional options to pcretest for testing multiple occurrences:
2989    
2990     /+ outputs the rest of the string that follows a match
2991     /g loops for multiple occurrences, using the new startoffset argument
2992     /G loops for multiple occurrences by passing an incremented pointer
2993    
2994     4. PCRE wasn't doing the "first character" optimization for patterns starting
2995     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2996     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2997     the letter 'x'. On long subject strings, this gives a significant speed-up.
2998    
2999    
3000 nigel 33 Version 2.05 21-Apr-99
3001     ----------------------
3002    
3003     1. Changed the type of magic_number from int to long int so that it works
3004     properly on 16-bit systems.
3005    
3006     2. Fixed a bug which caused patterns starting with .* not to work correctly
3007     when the subject string contained newline characters. PCRE was assuming
3008     anchoring for such patterns in all cases, which is not correct because .* will
3009     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3010     DOTALL is set at top level; otherwise it knows that patterns starting with .*
3011     must be retried after every newline in the subject.
3012    
3013    
3014 nigel 31 Version 2.04 18-Feb-99
3015     ----------------------
3016    
3017     1. For parenthesized subpatterns with repeats whose minimum was zero, the
3018     computation of the store needed to hold the pattern was incorrect (too large).
3019     If such patterns were nested a few deep, this could multiply and become a real
3020     problem.
3021    
3022     2. Added /M option to pcretest to show the memory requirement of a specific
3023     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3024    
3025     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3026     compiled in such a way that the backtracking after subsequent failure was
3027     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3028     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3029    
3030    
3031 nigel 29 Version 2.03 02-Feb-99
3032     ----------------------
3033    
3034     1. Fixed typo and small mistake in man page.
3035    
3036 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
3037     LICENCE file containing the conditions.
3038 nigel 29
3039     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3040     Perl, that is the internal \ allows the delimiter to be included in the
3041     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3042     the final delimiter, add \ to the end of the pattern (to test the error).
3043    
3044     4. Added the convenience functions for extracting substrings after a successful
3045     match. Updated pcretest to make it able to test these functions.
3046    
3047    
3048 nigel 27 Version 2.02 14-Jan-99
3049     ----------------------
3050    
3051     1. Initialized the working variables associated with each extraction so that
3052     their saving and restoring doesn't refer to uninitialized store.
3053    
3054     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3055     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3056     fix the problem.
3057    
3058     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3059     calls, and wasn't printing the correct value for compiling calls. Increased the
3060     default value of LOOPREPEAT, and the number of significant figures in the
3061     times.
3062    
3063     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3064    
3065     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3066     a building problem on Windows NT with a FAT file system.
3067    
3068    
3069 nigel 25 Version 2.01 21-Oct-98
3070     ----------------------
3071    
3072     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3073     to character tables built by pcre_maketables() in the current locale. If NULL
3074     is passed, the default tables are used.
3075    
3076    
3077 nigel 23 Version 2.00 24-Sep-98
3078 nigel 21 ----------------------
3079    
3080 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3081     it any more.
3082    
3083     2. Allow quantification of (?>) groups, and make it work correctly.
3084    
3085     3. The first character computation wasn't working for (?>) groups.
3086    
3087     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3088     end of the subject) and add 5.005's \z, which really does match only at the
3089     very end of the subject.
3090    
3091     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3092    
3093     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3094     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3095     localized options. All options to pcre_study() were also removed.
3096    
3097     7. Add other new features from 5.005:
3098    
3099     $(?<= positive lookbehind
3100     $(?<! negative lookbehind
3101     (?imsx-imsx) added the unsetting capability
3102     such a setting is global if at outer level; local otherwise
3103     (?imsx-imsx:) non-capturing groups with option setting
3104     (?(cond)re|re) conditional pattern matching
3105    
3106     A backreference to itself in a repeated group matches the previous
3107     captured string.
3108    
3109     8. General tidying up of studying (both automatic and via "study")
3110     consequential on the addition of new assertions.
3111    
3112     9. As in 5.005, unlimited repeated groups that could match an empty substring
3113     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3114     runtime if any iteration does actually match an empty substring.
3115    
3116     10. Include the RunTest script in the distribution.
3117    
3118     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3119     discrepancies, some of which were old and were also with respect to 5.004. They
3120     have now been fixed.
3121    
3122    
3123     Version 1.09 28-Apr-98
3124     ----------------------
3125    
3126 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3127     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3128     program crashes, or just wrong answers. This did not apply to negated classes
3129     containing more than one character, or to minima other than one.
3130    
3131    
3132 nigel 19 Version 1.08 27-Mar-98
3133     ----------------------
3134    
3135     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3136    
3137     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3138     latter must appear before anything that relies on it in the pattern.
3139    
3140    
3141 nigel 17 Version 1.07 16-Feb-98
3142     ----------------------
3143    
3144     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3145     repeat of a potentially empty string).
3146    
3147    
3148 nigel 15 Version 1.06 23-Jan-98
3149     ----------------------
3150    
3151     1. Added Markus Oberhumer's little patches for C++.
3152    
3153     2. Literal strings longer than 255 characters were broken.
3154    
3155    
3156 nigel 13 Version 1.05 23-Dec-97
3157     ----------------------
3158    
3159     1. Negated character classes containing more than one character were failing if
3160     PCRE_CASELESS was set at run time.
3161    
3162    
3163 nigel 11 Version 1.04 19-Dec-97
3164     ----------------------
3165    
3166     1. Corrected the man page, where some "const" qualifiers had been omitted.
3167    
3168     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3169     input syntax.
3170    
3171     3. Fixed memory leak which occurred when a regex with back references was
3172     matched with an offsets vector that wasn't big enough. The temporary memory
3173     that is used in this case wasn't being freed if the match failed.
3174    
3175     4. Tidied pcretest to ensure it frees memory that it gets.
3176    
3177     5. Temporary memory was being obtained in the case where the passed offsets
3178     vector was exactly big enough.
3179    
3180     6. Corrected definition of offsetof() from change 5 below.
3181    
3182     7. I had screwed up change 6 below and broken the rules for the use of
3183     setjmp(). Now fixed.
3184    
3185    
3186 nigel 9 Version 1.03 18-Dec-97
3187     ----------------------
3188    
3189     1. A erroneous regex with a missing opening parenthesis was correctly
3190     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3191     on some systems.
3192    
3193     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3194     it was reported that one broken compiler failed on the former because "code" is
3195     also an independent variable.
3196    
3197     3. The erroneous regex a[]b caused an array overrun reference.
3198    
3199     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3200     fail on data ending with that character. (It was going on too far, and checking
3201     the next character, typically a binary zero.) This was specific to the
3202     optimized code for single-character negative classes.
3203    
3204     5. Added a contributed patch from the TIN world which does the following:
3205    
3206     + Add an undef for memmove, in case the the system defines a macro for it.
3207    
3208     + Add a definition of offsetof(), in case there isn't one. (I don't know
3209     the reason behind this - offsetof() is part of the ANSI standard - but
3210     it does no harm).
3211    
3212     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3213     most of the places where whitespace preceded '#'. I have given up and
3214     allowed the remaining 2 cases to be at the margin.
3215    
3216     + Rename some variables in pcre to eliminate shadowing. This seems very
3217     pedantic, but does no harm, of course.
3218    
3219     6. Moved the call to setjmp() into its own function, to get rid of warnings
3220     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3221    
3222     7. Constructs such as \d{8,} were compiling into the equivalent of
3223 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3224 nigel 9 outcome, but in this particular case used more store than had been allocated,
3225     which caused the bug to be discovered because it threw up an internal error.
3226    
3227     8. The debugging code in both pcre and pcretest for outputting the compiled
3228     form of a regex was going wrong in the case of back references followed by
3229     curly-bracketed repeats.
3230    
3231    
3232 nigel 7 Version 1.02 12-Dec-97
3233     ----------------------
3234    
3235     1. Typos in pcre.3 and comments in the source fixed.
3236    
3237     2. Applied a contributed patch to get rid of places where it used to remove
3238     'const' from variables, and fixed some signed/unsigned and uninitialized
3239     variable warnings.
3240    
3241     3. Added the "runtest" target to Makefile.
3242    
3243     4. Set default compiler flag to -O2 rather than just -O.
3244    
3245    
3246 nigel 5 Version 1.01 19-Nov-97
3247     ----------------------
3248    
3249     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3250     like /([ab]*)*/, that is, for classes with more than one character in them.
3251    
3252     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3253     as /((?>a*))*/ (a PCRE_EXTRA facility).
3254    
3255    
3256     Version 1.00 18-Nov-97
3257     ----------------------
3258    
3259     1. Added compile-time macros to support systems such as SunOS4 which don't have
3260     memmove() or strerror() but have other things that can be used instead.
3261    
3262     2. Arranged that "make clean" removes the executables.
3263    
3264    
3265 nigel 3 Version 0.99 27-Oct-97
3266     ----------------------
3267    
3268     1. Fixed bug in code for optimizing classes with only one character. It was
3269     initializing a 32-byte map regardless, which could cause it to run off the end
3270     of the memory it had got.
3271    
3272     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3273    
3274    
3275     Version 0.98 22-Oct-97
3276     ----------------------
3277    
3278     1. Fixed bug in code for handling temporary memory usage when there are more
3279     back references than supplied space in the ovector. This could cause segfaults.
3280    
3281    
3282     Version 0.97 21-Oct-97
3283     ----------------------
3284    
3285     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3286    
3287     2. Optimized negated single characters not to use a bit map.
3288    
3289     3. Brought error texts together as macro definitions; clarified some of them;
3290     fixed one that was wrong - it said "range out of order" when it meant "invalid
3291     escape sequence".
3292    
3293     4. Changed some char * arguments to const char *.
3294    
3295     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3296    
3297     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3298     pcretest.
3299    
3300    
3301     Version 0.96 16-Oct-97
3302     ----------------------
3303    
3304     1. Added a simple "pgrep" utility to the distribution.
3305    
3306     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3307     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3308     where "ddd" means "one or more decimal digits".
3309    
3310     3. Fixed serious bug. If a pattern had a back reference, but the call to
3311     pcre_exec() didn't supply a large enough ovector to record the related
3312     identifying subpattern, the match always failed. PCRE now remembers the number
3313     of the largest back reference, and gets some temporary memory in which to save
3314     the offsets during matching if necessary, in order to ensure that
3315     backreferences always work.
3316    
3317     4. Increased the compatibility with Perl in a number of ways:
3318    
3319     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3320     to request this handling. The option can be set at compile or exec time.
3321    
3322     (b) $ matches before a terminating newline by default; an option
3323     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3324     mode). The option can be set at compile or exec time.
3325    
3326     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3327     the same as Perl's. If the decimal number it represents is less than 10
3328     or there aren't that many previous left capturing parentheses, an octal
3329     escape is read. Inside a character class, it's always an octal escape,
3330     even if it is a single digit.
3331    
3332     (d) An escaped but undefined alphabetic character is taken as a literal,
3333     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3334     escapes.
3335    
3336     (e) {0} is now permitted. (The previous item is removed from the compiled
3337     pattern).
3338    
3339     5. Changed all the names of code files so that the basic parts are no longer
3340     than 10 characters, and abolished the teeny "globals.c" file.
3341    
3342     6. Changed the handling of character classes; they are now done with a 32-byte
3343     bit map always.
3344    
3345     7. Added the -d and /D options to pcretest to make it possible to look at the
3346     internals of compilation without having to recompile pcre.
3347    
3348    
3349     Version 0.95 23-Sep-97
3350     ----------------------
3351    
3352     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3353     \x20 at the start of a run of normal characters. These were being treated as
3354     real characters, instead of the source characters being re-checked.
3355    
3356    
3357     Version 0.94 18-Sep-97
3358     ----------------------
3359    
3360     1. The functions are now thread-safe, with the caveat that the global variables
3361     containing pointers to malloc() and free() or alternative functions are the
3362     same for all threads.
3363    
3364     2. Get pcre_study() to generate a bitmap of initial characters for non-
3365     anchored patterns when this is possible, and use it if passed to pcre_exec().
3366    
3367    
3368     Version 0.93 15-Sep-97
3369     ----------------------
3370    
3371     1. /(b)|(:+)/ was computing an incorrect first character.
3372    
3373     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3374     but not actually doing anything yet.
3375    
3376     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3377     as Perl does (e.g. [-az] or [az-]).
3378    
3379     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3380     all possible positions.
3381    
3382     5. Split up into different modules to avoid including unneeded functions in a
3383     compiled binary. However, compile and exec are still in one module. The "study"
3384     function is split off.
3385    
3386     6. The character tables are now in a separate module whose source is generated
3387     by an auxiliary program - but can then be edited by hand if required. There are
3388     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3389     toupper() in the code.
3390    
3391     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3392     make them global. Abolish the function for setting them, as the caller can now
3393     set them directly.
3394    
3395    
3396     Version 0.92 11-Sep-97
3397     ----------------------
3398    
3399     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3400     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3401    
3402     2. Caseless matching was not working in character classes if the characters in
3403     the pattern were in upper case.
3404    
3405     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3406    
3407     4. Make PCRE_ANCHORED public and accept as a compile option.
3408    
3409     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3410     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3411     pass them.
3412    
3413     6. Give an error if bad option bits passed at compile or run time.
3414    
3415     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3416     pcretest to cause it to pass that flag.
3417    
3418     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3419     options, and the first character, if set.
3420    
3421     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3422    
3423    
3424     Version 0.91 10-Sep-97
3425     ----------------------
3426    
3427     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3428     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3429    
3430     2. PCRE was looping on encountering an indefinitely repeated back reference to
3431     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3432     Perl does - treats the match as successful.
3433    
3434     ****

Properties

Name Value
svn:eol-style native
svn:keywords "Author Date Id Revision Url"

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12