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Revision 520 - (hide annotations) (download)
Sat May 22 18:54:05 2010 UTC (4 years, 10 months ago) by ph10
File size: 186798 byte(s)
Fix caseless bug with pcre_study() for starting letter greater than 127.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 513 Version 8.10 03 May-2010
5 ph10 510 ------------------------
7 ph10 512 1. Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8 ph10 510 THEN.
10 ph10 512 2. (*ACCEPT) was not working when inside an atomic group.
11 ph10 510
12 ph10 513 3. Inside a character class, \B is treated as a literal by default, but
13     faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
14     causes the error). The code is unchanged, but I tidied the documentation.
16     4. Inside a character class, PCRE always treated \R and \X as literals,
17     whereas Perl faults them if its -w option is set. I have changed PCRE so
18     that it faults them when PCRE_EXTRA is set.
19 ph10 514
20     5. Added support for \N, which always matches any character other than
21     newline. (It is the same as "." when PCRE_DOTALL is not set.)
22 ph10 515
23     6. When compiling pcregrep with newer versions of gcc which may have
24     FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
25     declared with attribute warn_unused_result" were given. Just casting the
26     result to (void) does not stop the warnings; a more elaborate fudge is
27     needed. I've used a macro to implement this.
28 ph10 516
29     7. Minor change to pcretest.c to avoid a compiler warning.
30 ph10 512
31 ph10 517 8. Added four artifical Unicode properties to help with an option to make
32 ph10 518 \s etc use properties (see next item). The new properties are: Xan
33     (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
35     9. Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
36     use Unicode properties. (*UCP) at the start of a pattern can be used to set
37     this option. Modified pcretest to add /W to test this facility. Added
38     REG_UCP to make it available via the POSIX interface.
39 ph10 519
40     10. Added --line-buffered to pcregrep.
41 ph10 513
42 ph10 520 11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
43     studied, and the match started with a letter with a code point greater than
44     127 whose first byte was different to the first byte of the other case of
45     the letter, the other case of this starting letter was not recognized.
46 ph10 517
47 ph10 520
48 ph10 508 Version 8.02 19-Mar-2010
49 ph10 491 ------------------------
51     1. The Unicode data tables have been updated to Unicode 5.2.0.
53 ph10 492 2. Added the option --libs-cpp to pcre-config, but only when C++ support is
54     configured.
55 ph10 507
56 ph10 493 3. Updated the licensing terms in the pcregexp.pas file, as agreed with the
57 ph10 507 original author of that file, following a query about its status.
59     4. On systems that do not have stdint.h (e.g. Solaris), check for and include
60 ph10 494 inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
61 ph10 507
62 ph10 496 5. A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
63     quantifier applied to a forward-referencing subroutine call, could compile
64     incorrect code or give the error "internal error: previously-checked
65     referenced subpattern not found".
66 ph10 507
67     6. Both MS Visual Studio and Symbian OS have problems with initializing
68 ph10 497 variables to point to external functions. For these systems, therefore,
69     pcre_malloc etc. are now initialized to local functions that call the
70     relevant global functions.
71 ph10 507
72 ph10 498 7. There were two entries missing in the vectors called coptable and poptable
73     in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
74 ph10 507 I've fixed the data, and added a kludgy way of testing at compile time that
75     the lengths are correct (equal to the number of opcodes).
77     8. Following on from 7, I added a similar kludge to check the length of the
78     eint vector in pcreposix.c.
80     9. Error texts for pcre_compile() are held as one long string to avoid too
81     much relocation at load time. To find a text, the string is searched,
82 ph10 499 counting zeros. There was no check for running off the end of the string,
83     which could happen if a new error number was added without updating the
84 ph10 507 string.
86     10. \K gave a compile-time error if it appeared in a lookbehind assersion.
88 ph10 500 11. \K was not working if it appeared in an atomic group or in a group that
89 ph10 507 was called as a "subroutine", or in an assertion. Perl 5.11 documents that
90     \K is "not well defined" if used in an assertion. PCRE now accepts it if
91     the assertion is positive, but not if it is negative.
93 ph10 501 12. Change 11 fortuitously reduced the size of the stack frame used in the
94 ph10 507 "match()" function of pcre_exec.c by one pointer. Forthcoming
95     implementation of support for (*MARK) will need an extra pointer on the
96 ph10 501 stack; I have reserved it now, so that the stack frame size does not
97     decrease.
98 ph10 507
99     13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
100     item in branch that calls a recursion is a subroutine call - as in the
101 ph10 503 second branch in the above example - was incorrectly given the compile-
102     time error "recursive call could loop indefinitely" because pcre_compile()
103 ph10 507 was not correctly checking the subroutine for matching a non-empty string.
105 ph10 505 14. The checks for overrunning compiling workspace could trigger after an
106 ph10 507 overrun had occurred. This is a "should never occur" error, but it can be
107 ph10 505 triggered by pathological patterns such as hundreds of nested parentheses.
108 ph10 507 The checks now trigger 100 bytes before the end of the workspace.
109 ph10 491
110 ph10 507 15. Fix typo in configure.ac: "srtoq" should be "strtoq".
111 ph10 492
112 ph10 507
113 ph10 489 Version 8.01 19-Jan-2010
114     ------------------------
115 ph10 471
116     1. If a pattern contained a conditional subpattern with only one branch (in
117 ph10 489 particular, this includes all (*DEFINE) patterns), a call to pcre_study()
118 ph10 473 computed the wrong minimum data length (which is of course zero for such
119 ph10 489 subpatterns). This could cause incorrect "no match" results.
120 ph10 473
121     2. For patterns such as (?i)a(?-i)b|c where an option setting at the start of
122 ph10 472 the pattern is reset in the first branch, pcre_compile() failed with
123     "internal error: code overflow at offset...". This happened only when
124 ph10 473 the reset was to the original external option setting. (An optimization
125     abstracts leading options settings into an external setting, which was the
126 ph10 472 cause of this.)
127 ph10 471
128 ph10 473 3. A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
129     of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
130     assertion pattern did not match (meaning that the assertion was true), it
131     was incorrectly treated as false if the SKIP had been reached during the
132     matching. This also applied to assertions used as conditions.
133 ph10 471
134 ph10 473 4. If an item that is not supported by pcre_dfa_exec() was encountered in an
135     assertion subpattern, including such a pattern used as a condition,
136     unpredictable results occurred, instead of the error return
138 ph10 478
139 ph10 474 5. The C++ GlobalReplace function was not working like Perl for the special
140     situation when an empty string is matched. It now does the fancy magic
141 ph10 478 stuff that is necessary.
143     6. In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
144 ph10 475 removed. (These were left over from very, very early versions of PCRE.)
145 ph10 478
146 ph10 475 7. Some cosmetic changes to the code to make life easier when compiling it
147     as part of something else:
148 ph10 478
149     (a) Change DEBUG to PCRE_DEBUG.
151     (b) In pcre_compile(), rename the member of the "branch_chain" structure
152     called "current" as "current_branch", to prevent a collision with the
153 ph10 475 Linux macro when compiled as a kernel module.
154 ph10 478
155     (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
156     prevent a collision with the Linux macro when compiled as a kernel
157 ph10 475 module.
158 ph10 478
159 ph10 475 8. In pcre_compile() there are some checks for integer overflows that used to
160     cast potentially large values to (double). This has been changed to that
161 ph10 478 when building, a check for int64_t is made, and if it is found, it is used
162     instead, thus avoiding the use of floating point arithmetic. (There is no
163     other use of FP in PCRE.) If int64_t is not found, the fallback is to
164     double.
166     9. Added two casts to avoid signed/unsigned warnings from VS Studio Express
167 ph10 476 2005 (difference between two addresses compared to an unsigned value).
168 ph10 473
169 ph10 478 10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
170     custom one, because of the following reported problem in Windows:
171 ph10 473
172 ph10 478 - libbz2 uses the Pascal calling convention (WINAPI) for the functions
173 ph10 489 under Win32.
174 ph10 478 - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
175 ph10 489 therefore missing the function definition.
176 ph10 478 - The compiler thus generates a "C" signature for the test function.
177     - The linker fails to find the "C" function.
178     - PCRE fails to configure if asked to do so against libbz2.
179 ph10 486
180 ph10 479 11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
181     messages were output:
182 ph10 478
183 ph10 479 Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
184     rerunning libtoolize, to keep the correct libtool macros in-tree.
185     Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
186 ph10 486
187 ph10 479 I have done both of these things.
188 ph10 486
189 ph10 480 12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
190 ph10 486 most of the time, it *can* run out if it is given a pattern that contains a
191     runaway infinite recursion. I updated the discussion in the pcrestack man
192     page.
194     13. Now that we have gone to the x.xx style of version numbers, the minor
195     version may start with zero. Using 08 or 09 is a bad idea because users
196     might check the value of PCRE_MINOR in their code, and 08 or 09 may be
197     interpreted as invalid octal numbers. I've updated the previous comment in
198     configure.ac, and also added a check that gives an error if 08 or 09 are
199 ph10 481 used.
200 ph10 486
201 ph10 482 14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
202 ph10 483 causing partial matching to fail when the end of the subject matched \W
203     in a UTF-8 pattern where \W was quantified with a minimum of 3.
204 ph10 486
205 ph10 483 15. There were some discrepancies between the declarations in pcre_internal.h
206 ph10 486 of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
207 ph10 483 their definitions. The declarations used "const uschar *" and the
208     definitions used USPTR. Even though USPTR is normally defined as "const
209     unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
210     reported that: "This difference in casting confuses some C++ compilers, for
211     example, SunCC recognizes above declarations as different functions and
212 ph10 486 generates broken code for hbpcre." I have changed the declarations to use
213 ph10 483 USPTR.
214 ph10 486
215     16. GNU libtool is named differently on some systems. The autogen.sh script now
216 ph10 484 tries several variants such as glibtoolize (MacOSX) and libtoolize1x
217     (FreeBSD).
218 ph10 478
219 ph10 486 17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
220     (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
221     comment: "Figure out how to create a longlong from a string: strtoll and
222     equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
223     instance, but it only takes 2 args instead of 3!"
224 ph10 479
225 ph10 488 18. A subtle bug concerned with back references has been fixed by a change of
226     specification, with a corresponding code fix. A pattern such as
227     ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
228     refers, was giving matches when it shouldn't. For example, xa=xaaa would
229     match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
230     same bug. Such groups have to be quantified to be useful, or contained
231     inside another quantified group. (If there's no repetition, the reference
232     can never match.) The problem arises because, having left the group and
233     moved on to the rest of the pattern, a later failure that backtracks into
234     the group uses the captured value from the final iteration of the group
235     rather than the correct earlier one. I have fixed this in PCRE by forcing
236     any group that contains a reference to itself to be an atomic group; that
237     is, there cannot be any backtracking into it once it has completed. This is
238     similar to recursive and subroutine calls.
239 ph10 486
240 ph10 488
241 ph10 469 Version 8.00 19-Oct-09
242 ph10 418 ----------------------
244     1. The table for translating pcre_compile() error codes into POSIX error codes
245 ph10 461 was out-of-date, and there was no check on the pcre_compile() error code
246     being within the table. This could lead to an OK return being given in
247 ph10 418 error.
248 ph10 461
249     2. Changed the call to open a subject file in pcregrep from fopen(pathname,
250     "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
251     in a Windows environment.
253 ph10 420 3. The pcregrep --count option prints the count for each file even when it is
254     zero, as does GNU grep. However, pcregrep was also printing all files when
255     --files-with-matches was added. Now, when both options are given, it prints
256     counts only for those files that have at least one match. (GNU grep just
257 ph10 461 prints the file name in this circumstance, but including the count seems
258     more useful - otherwise, why use --count?) Also ensured that the
259 ph10 420 combination -clh just lists non-zero counts, with no names.
260 ph10 461
261     4. The long form of the pcregrep -F option was incorrectly implemented as
262     --fixed_strings instead of --fixed-strings. This is an incompatible change,
263     but it seems right to fix it, and I didn't think it was worth preserving
264     the old behaviour.
266     5. The command line items --regex=pattern and --regexp=pattern were not
267 ph10 422 recognized by pcregrep, which required --regex pattern or --regexp pattern
268 ph10 461 (with a space rather than an '='). The man page documented the '=' forms,
269 ph10 422 which are compatible with GNU grep; these now work.
270 ph10 461
271     6. No libpcreposix.pc file was created for pkg-config; there was just
272 ph10 423 libpcre.pc and libpcrecpp.pc. The omission has been rectified.
273 ph10 461
274 ph10 425 7. Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
275 ph10 461 when UCP support is not needed, by modifying the Python script that
276 ph10 425 generates it from Unicode data files. This should not matter if the module
277     is correctly used as a library, but I received one complaint about 50K of
278     unwanted data. My guess is that the person linked everything into his
279     program rather than using a library. Anyway, it does no harm.
280 ph10 461
281 ph10 426 8. A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
282 ph10 461 was a minimum greater than 1 for a wide character in a possessive
283 ph10 431 repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
284     which had an unlimited repeat of a nested, fixed maximum repeat of a wide
285     character. Chaos in the form of incorrect output or a compiling loop could
286     result.
287 ph10 461
288 ph10 426 9. The restrictions on what a pattern can contain when partial matching is
289 ph10 461 requested for pcre_exec() have been removed. All patterns can now be
290 ph10 426 partially matched by this function. In addition, if there are at least two
291 ph10 435 slots in the offset vector, the offset of the earliest inspected character
292     for the match and the offset of the end of the subject are set in them when
293 ph10 461 PCRE_ERROR_PARTIAL is returned.
295 ph10 428 10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
296     synonymous with PCRE_PARTIAL, for backwards compatibility, and
297     PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
298 ph10 462 and may be more useful for multi-segment matching.
299 ph10 461
300     11. Partial matching with pcre_exec() is now more intuitive. A partial match
301     used to be given if ever the end of the subject was reached; now it is
302     given only if matching could not proceed because another character was
303     needed. This makes a difference in some odd cases such as Z(*FAIL) with the
304     string "Z", which now yields "no match" instead of "partial match". In the
305     case of pcre_dfa_exec(), "no match" is given if every matching path for the
306     final character ended with (*FAIL).
308 ph10 428 12. Restarting a match using pcre_dfa_exec() after a partial match did not work
309 ph10 461 if the pattern had a "must contain" character that was already found in the
310 ph10 428 earlier partial match, unless partial matching was again requested. For
311     example, with the pattern /dog.(body)?/, the "must contain" character is
312     "g". If the first part-match was for the string "dog", restarting with
313 ph10 435 "sbody" failed. This bug has been fixed.
314 ph10 461
315     13. The string returned by pcre_dfa_exec() after a partial match has been
316     changed so that it starts at the first inspected character rather than the
317     first character of the match. This makes a difference only if the pattern
318     starts with a lookbehind assertion or \b or \B (\K is not supported by
319     pcre_dfa_exec()). It's an incompatible change, but it makes the two
320 ph10 435 matching functions compatible, and I think it's the right thing to do.
321 ph10 461
322 ph10 435 14. Added a pcredemo man page, created automatically from the pcredemo.c file,
323 ph10 461 so that the demonstration program is easily available in environments where
324     PCRE has not been installed from source.
326 ph10 435 15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
327 ph10 430 libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
328     library.
329 ph10 461
330 ph10 435 16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
331 ph10 432 It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
332 ph10 461 is not the first non-POSIX option to be added. Clearly some people find
333 ph10 433 these options useful.
334 ph10 461
335     17. If a caller to the POSIX matching function regexec() passes a non-zero
336 ph10 438 value for nmatch with a NULL value for pmatch, the value of
337 ph10 461 nmatch is forced to zero.
339 ph10 437 18. RunGrepTest did not have a test for the availability of the -u option of
340 ph10 461 the diff command, as RunTest does. It now checks in the same way as
341 ph10 437 RunTest, and also checks for the -b option.
342 ph10 461
343 ph10 438 19. If an odd number of negated classes containing just a single character
344     interposed, within parentheses, between a forward reference to a named
345 ph10 461 subpattern and the definition of the subpattern, compilation crashed with
346     an internal error, complaining that it could not find the referenced
347 ph10 438 subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
348 ph10 461 [The bug was that it was starting one character too far in when skipping
349     over the character class, thus treating the ] as data rather than
350     terminating the class. This meant it could skip too much.]
352 ph10 442 20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
353 ph10 461 /g option in pcretest when the pattern contains \K, which makes it possible
354 ph10 442 to have an empty string match not at the start, even when the pattern is
355 ph10 461 anchored. Updated pcretest and pcredemo to use this option.
357 ph10 446 21. If the maximum number of capturing subpatterns in a recursion was greater
358 ph10 461 than the maximum at the outer level, the higher number was returned, but
359     with unset values at the outer level. The correct (outer level) value is
360 ph10 446 now given.
361 ph10 461
362 ph10 447 22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
363     PCRE did not set those parentheses (unlike Perl). I have now found a way to
364     make it do so. The string so far is captured, making this feature
365     compatible with Perl.
366 ph10 461
367     23. The tests have been re-organized, adding tests 11 and 12, to make it
368 ph10 448 possible to check the Perl 5.10 features against Perl 5.10.
369 ph10 461
370 ph10 454 24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
371 ph10 461 pattern matches a fixed length string. PCRE did not allow this; now it
372     does. Neither allows recursion.
374     25. I finally figured out how to implement a request to provide the minimum
375     length of subject string that was needed in order to match a given pattern.
376     (It was back references and recursion that I had previously got hung up
377     on.) This code has now been added to pcre_study(); it finds a lower bound
378 ph10 455 to the length of subject needed. It is not necessarily the greatest lower
379     bound, but using it to avoid searching strings that are too short does give
380     some useful speed-ups. The value is available to calling programs via
381     pcre_fullinfo().
382 ph10 461
383 ph10 455 26. While implementing 25, I discovered to my embarrassment that pcretest had
384     not been passing the result of pcre_study() to pcre_dfa_exec(), so the
385     study optimizations had never been tested with that matching function.
386     Oops. What is worse, even when it was passed study data, there was a bug in
387     pcre_dfa_exec() that meant it never actually used it. Double oops. There
388     were also very few tests of studied patterns with pcre_dfa_exec().
389 ph10 461
390 ph10 457 27. If (?| is used to create subpatterns with duplicate numbers, they are now
391     allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
392     on the other side of the coin, they are no longer allowed to have different
393     names, because these cannot be distinguished in PCRE, and this has caused
394     confusion. (This is a difference from Perl.)
395 ph10 461
396     28. When duplicate subpattern names are present (necessarily with different
397     numbers, as required by 27 above), and a test is made by name in a
398     conditional pattern, either for a subpattern having been matched, or for
399     recursion in such a pattern, all the associated numbered subpatterns are
400 ph10 459 tested, and the overall condition is true if the condition is true for any
401     one of them. This is the way Perl works, and is also more like the way
402     testing by number works.
403 ph10 418
404 ph10 461
405 ph10 412 Version 7.9 11-Apr-09
406 ph10 376 ---------------------
408 ph10 392 1. When building with support for bzlib/zlib (pcregrep) and/or readline
409 ph10 376 (pcretest), all targets were linked against these libraries. This included
410     libpcre, libpcreposix, and libpcrecpp, even though they do not use these
411     libraries. This caused unwanted dependencies to be created. This problem
412 ph10 392 has been fixed, and now only pcregrep is linked with bzlib/zlib and only
413 ph10 376 pcretest is linked with readline.
414 ph10 392
415 ph10 376 2. The "typedef int BOOL" in pcre_internal.h that was included inside the
416     "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
417     moved outside it again, because FALSE and TRUE are already defined in AIX,
418     but BOOL is not.
419 ph10 392
420     3. The pcre_config() function was treating the PCRE_MATCH_LIMIT and
421 ph10 409 PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
422 ph10 392
423 ph10 376 4. The pcregrep documentation said spaces were inserted as well as colons (or
424     hyphens) following file names and line numbers when outputting matching
425 ph10 392 lines. This is not true; no spaces are inserted. I have also clarified the
426 ph10 376 wording for the --colour (or --color) option.
427 ph10 392
428 ph10 378 5. In pcregrep, when --colour was used with -o, the list of matching strings
429     was not coloured; this is different to GNU grep, so I have changed it to be
430     the same.
431 ph10 392
432 ph10 378 6. When --colo(u)r was used in pcregrep, only the first matching substring in
433 ph10 392 each matching line was coloured. Now it goes on to look for further matches
434     of any of the test patterns, which is the same behaviour as GNU grep.
436     7. A pattern that could match an empty string could cause pcregrep to loop; it
437     doesn't make sense to accept an empty string match in pcregrep, so I have
438 ph10 379 locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
439     seems to be how GNU grep behaves.
440 ph10 392
441 ph10 380 8. The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
442 ph10 392 start or after a newline", because the conditional assertion was not being
443     correctly handled. The rule now is that both the assertion and what follows
444     in the first alternative must satisfy the test.
446 ph10 405 9. If auto-callout was enabled in a pattern with a conditional group whose
447 ph10 399 condition was an assertion, PCRE could crash during matching, both with
448     pcre_exec() and pcre_dfa_exec().
449 ph10 392
450     10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
451     used for matching.
453     11. Unicode property support in character classes was not working for
454 ph10 385 characters (bytes) greater than 127 when not in UTF-8 mode.
455 ph10 388
456 ph10 392 12. Added the -M command line option to pcretest.
458 ph10 388 14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
459 ph10 389
460     15. Added the PCRE_NO_START_OPTIMIZE match-time option.
461 ph10 390
462 ph10 392 16. Added comments and documentation about mis-use of no_arg in the C++
463 ph10 390 wrapper.
464 ph10 392
465 ph10 391 17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
466 ph10 392 from Martin Jerabek that uses macro names for all relevant character and
467 ph10 391 string constants.
468 ph10 405
469 ph10 393 18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
470     SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
471 ph10 405 SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
472     these, but not everybody uses configure.
474     19. A conditional group that had only one branch was not being correctly
475     recognized as an item that could match an empty string. This meant that an
476     enclosing group might also not be so recognized, causing infinite looping
477     (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
478     with the subject "ab", where knowledge that the repeated group can match
479 ph10 396 nothing is needed in order to break the loop.
480 ph10 405
481 ph10 397 20. If a pattern that was compiled with callouts was matched using pcre_dfa_
482 ph10 405 exec(), but without supplying a callout function, matching went wrong.
484     21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
485     leak if the size of the offset vector was greater than 30. When the vector
486     is smaller, the saved offsets during recursion go onto a local stack
487     vector, but for larger vectors malloc() is used. It was failing to free
488     when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
489 ph10 400 error, in fact).
490 ph10 405
491 ph10 402 22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
492 ph10 405 heapframe that is used only when UTF-8 support is enabled. This caused no
493     problem, but was untidy.
494 ph10 376
495 ph10 405 23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
496     CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
497     included within another project.
498 ph10 411
499 ph10 407 24. Steven Van Ingelgem's patches to add more options to the CMake support,
500     slightly modified by me:
501 ph10 411
502     (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
503     not building pcregrep.
505 ph10 407 (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
506 ph10 411 if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
508 ph10 408 25. Forward references, both numeric and by name, in patterns that made use of
509     duplicate group numbers, could behave incorrectly or give incorrect errors,
510     because when scanning forward to find the reference group, PCRE was not
511     taking into account the duplicate group numbers. A pattern such as
512     ^X(?3)(a)(?|(b)|(q))(Y) is an example.
513 ph10 411
514     26. Changed a few more instances of "const unsigned char *" to USPTR, making
515     the feature of a custom pointer more persuasive (as requested by a user).
516 ph10 416
517 ph10 411 27. Wrapped the definitions of fileno and isatty for Windows, which appear in
518 ph10 416 pcretest.c, inside #ifndefs, because it seems they are sometimes already
519     pre-defined.
520 ph10 392
521 ph10 416 28. Added support for (*UTF8) at the start of a pattern.
523 ph10 413 29. Arrange for flags added by the "release type" setting in CMake to be shown
524     in the configuration summary.
525 ph10 405
526 ph10 411
527 ph10 374 Version 7.8 05-Sep-08
528 ph10 349 ---------------------
530     1. Replaced UCP searching code with optimized version as implemented for Ad
531     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
532 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
533     to 5 times on some simple patterns that I tested. Permission was given to
534     distribute the MultiStage2.py script that generates the tables (it's not in
535     the tarball, but is in the Subversion repository).
536 ph10 349
537 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
538     scripts.
539 ph10 358
540 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
541     a group with a zero qualifier. The result of the study could be incorrect,
542 ph10 358 or the function might crash, depending on the pattern.
544     4. Caseless matching was not working for non-ASCII characters in back
545 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
546 ph10 358 It now works when Unicode Property Support is available.
548 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
549     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
550     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
551 ph10 358 truncation.
552 ph10 349
553 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
555 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
556     pointers, in case they are 64-bit values.
557 ph10 371
558     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
559     test 2 if it fails.
561 ph10 359 9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
562 ph10 371 and a #define of that name to empty if it is not externally set. This is to
563     allow users of MSVC to set it if necessary.
565     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
566 ph10 359 the convenience functions in the pcre_get.c source file.
567 ph10 371
568 ph10 360 11. An option change at the start of a pattern that had top-level alternatives
569     could cause overwriting and/or a crash. This command provoked a crash in
570 ph10 371 some environments:
572     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
574 ph10 360 This potential security problem was recorded as CVE-2008-2371.
575 ph10 371
576 ph10 361 12. For a pattern where the match had to start at the beginning or immediately
577     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
578 ph10 371 pcre_dfa_exec() could read past the end of the passed subject if there was
579 ph10 361 no match. To help with detecting such bugs (e.g. with valgrind), I modified
580     pcretest so that it places the subject at the end of its malloc-ed buffer.
581 ph10 371
582 ph10 364 13. The change to pcretest in 12 above threw up a couple more cases when pcre_
583 ph10 371 exec() might read past the end of the data buffer in UTF-8 mode.
585 ph10 364 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
586 ph10 371 the data contained the byte 0x85 as part of a UTF-8 character within its
587     first line. This applied both to normal and DFA matching.
589 ph10 366 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
590 ph10 371 /^[^d]*?$/8 failed to match "abc".
591 ph10 351
592 ph10 371 16. Added a missing copyright notice to pcrecpp_internal.h.
594     17. Make it more clear in the documentation that values returned from
595 ph10 368 pcre_exec() in ovector are byte offsets, not character counts.
596 ph10 357
597 ph10 371 18. Tidied a few places to stop certain compilers from issuing warnings.
598 ph10 368
599 ph10 373 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
600     supplied by Stefan Weber. I made a further small update for 7.8 because
601 ph10 374 there is a change of source arrangements: the pcre_searchfuncs.c module is
602     replaced by pcre_ucd.c.
603 ph10 371
604 ph10 373
605 ph10 347 Version 7.7 07-May-08
606 ph10 321 ---------------------
608     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
609 ph10 345 a string to a long long, pretend we don't even have a long long." This is
610 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
611 ph10 345
612 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
613     pre-7.6 versions, which defined a global no_arg variable instead of putting
614 ph10 332 it in the RE class. (See also #8 below.)
615 ph10 345
616     3. Remove a line of dead code, identified by coverity and reported by Nuno
617     Lopes.
619 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
620 ph10 321
621 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
622 ph10 345 of files, instead of just to the final components.
624 ph10 324 (2) If there was more than one level of directory, the subdirectories were
625     skipped unless they satisfied the include/exclude conditions. This is
626     inconsistent with GNU grep (and could even be seen as contrary to the
627     pcregrep specification - which I improved to make it absolutely clear).
628     The action now is always to scan all levels of directory, and just
629     apply the include/exclude patterns to regular files.
630 ph10 345
631 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
632 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
634 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
635 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
636 ph10 326 doesn't support NULs in patterns.
637 ph10 345
638     7. Added some missing "const"s to declarations of static tables in
639     pcre_compile.c and pcre_dfa_exec.c.
641 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
642 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
643 ph10 345 first patch. And a third patch - this was a messy problem.)
644 ph10 321
645 ph10 345 9. Applied Craig's patch to remove the use of push_back().
647 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
648     matching function regexec().
649 ph10 345
650     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
651     which, however, unlike Perl's \g{...}, are subroutine calls, not back
652 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
653     Oniguruma does).
654 ph10 345
655     12. Previously, a group with a zero repeat such as (...){0} was completely
656 ph10 335 omitted from the compiled regex. However, this means that if the group
657     was called as a subroutine from elsewhere in the pattern, things went wrong
658 ph10 345 (an internal error was given). Such groups are now left in the compiled
659     pattern, with a new opcode that causes them to be skipped at execution
660 ph10 335 time.
661 ph10 345
662 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
663     to the way PCRE behaves:
664 ph10 345
665 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
666 ph10 345
667     (b) A back reference to an unmatched subpattern matches an empty string
668 ph10 336 (Perl fails the current match path).
669 ph10 345
670 ph10 341 (c) A data ] in a character class must be notated as \] because if the
671 ph10 345 first data character in a class is ], it defines an empty class. (In
672 ph10 341 Perl it is not possible to have an empty class.) The empty class []
673     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
674     The negative empty class [^] matches any one character, independently
675     of the DOTALL setting.
676 ph10 345
677     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
678 ph10 340 non-existent subpattern following a character class starting with ']' and
679     containing () gave an internal compiling error instead of "reference to
680     non-existent subpattern". Fortunately, when the pattern did exist, the
681 ph10 345 compiled code was correct. (When scanning forwards to check for the
682 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
683 ph10 345 the class, so got the count wrong. When actually compiling, the reference
684 ph10 340 was subsequently set up correctly.)
685 ph10 345
686 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
687 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
688     other assertions are supported. I have made pcre_dfa_exec() support
689     (*FAIL).
691 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
692 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
693     cannot be changed at match time, I realized I could make a small
694     improvement to matching performance by compiling OP_ALLANY instead of
695     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
696     on the OP_ANY path.
698     17. Compiling pcretest on Windows with readline support failed without the
699 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
700 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
702 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
703 ph10 345 ncurses library to be included for pcretest when ReadLine support is
704     requested, but also to allow for it to be overridden. This patch came from
705     Daniel Bergström.
706 ph10 347
707 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
708 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
709     any errors with the current Unicode tables. Thanks to Peter Kankowski for
710     spotting this.
711 ph10 324
712 ph10 332
713 ph10 319 Version 7.6 28-Jan-08
714 ph10 300 ---------------------
716 ph10 302 1. A character class containing a very large number of characters with
717     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
718     overflow.
719 ph10 309
720     2. Patch to cut out the "long long" test in pcrecpp_unittest when
721     HAVE_LONG_LONG is not defined.
723 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
724 ph10 304 bring them up to date and include new features. This patch includes:
725 ph10 309
726 ph10 304 - Fixed PH's badly added libz and libbz2 support.
727     - Fixed a problem with static linking.
728 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
729 ph10 304 - Fixed dftables problem and added an option.
730     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
732     - Added readline support for pcretest.
733 ph10 309 - Added an listing of the option settings after cmake has run.
735 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
736     "pcre.dll" under mingw when using Configure/Make. I added stuff to
737     Makefile.am that cause it to include this special target, without
738     affecting anything else. Note that the same mingw target plus all
739     the other distribution libraries and programs are now supported
740     when configuring with CMake (see 6 below) instead of with
741     Configure/Make.
742 ph10 309
743 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
744     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
745 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
746     solves the problem, but it does no harm.
747 ph10 313
748 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
749 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
750 ph10 314 with CMake, and also correct the comment about stack recursion.
751 ph10 313
752 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
753 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
754     of a program that users should build themselves after PCRE is installed, so
755     building it automatically is not really right. What is more, it gave
756 ph10 312 trouble in some build environments.
757 ph10 300
758 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
759 ph10 308
760 ph10 319
761 ph10 298 Version 7.5 10-Jan-08
762 ph10 263 ---------------------
764     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
765     values in parens when parsing an RE using the C++ wrapper."
766 ph10 286
767 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
768     Characters greater than 255 were excluded from the class instead of being
769     included.
770 ph10 286
771     3. The same bug as (2) above applied to negated POSIX classes such as
772 ph10 265 [:^space:].
773 ph10 286
774 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
775     defined or documented. It seems to have been a typo for PCRE_STATIC, so
776 ph10 286 I have changed it.
778 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
779 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
780     first named subpattern whose name started with "a" (in other words, the
781 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
782     expected" is now given for (?&) (a zero-length name), and this patch also
783     makes it give the same error for \k'' (previously it complained that that
784     was a reference to a non-existent subpattern).
785 ph10 286
786 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
787 ph10 286 this is right because (?- can be followed by option settings as well as by
788 ph10 269 digits. I have, however, made the messages clearer.
789 ph10 286
790 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
791     than the number used in the conditional) now cause a compile-time error.
792     This is actually not compatible with Perl, which accepts such patterns, but
793     treats the conditional as always being FALSE (as PCRE used to), but it
794     seems to me that giving a diagnostic is better.
795 ph10 286
796 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
797 ph10 275 and messages.
798 ph10 286
799     9. Fix two occurrences of "backslash" in comments that should have been
800     "backspace".
802     10. Remove two redundant lines of code that can never be obeyed (their function
803     was moved elsewhere).
805     11. The program that makes PCRE's Unicode character property table had a bug
806     which caused it to generate incorrect table entries for sequences of
807 ph10 277 characters that have the same character type, but are in different scripts.
808 ph10 286 It amalgamated them into a single range, with the script of the first of
809 ph10 277 them. In other words, some characters were in the wrong script. There were
810     thirteen such cases, affecting characters in the following ranges:
811 ph10 286
812 ph10 277 U+002b0 - U+002c1
813     U+0060c - U+0060d
814 ph10 286 U+0061e - U+00612
815 ph10 277 U+0064b - U+0065e
816     U+0074d - U+0076d
817     U+01800 - U+01805
818     U+01d00 - U+01d77
819     U+01d9b - U+01dbf
820     U+0200b - U+0200f
821     U+030fc - U+030fe
822     U+03260 - U+0327f
823     U+0fb46 - U+0fbb1
824     U+10450 - U+1049d
825 ph10 286
826 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
827     compatible with GNU grep in that, if there was more than one match in a
828     line, it showed only the first of them. It now behaves in the same way as
829     GNU grep.
830 ph10 286
831     13. If the -o and -v options were combined for pcregrep, it printed a blank
832     line for every non-matching line. GNU grep prints nothing, and pcregrep now
833     does the same. The return code can be used to tell if there were any
834     non-matching lines.
836 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
838     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
839 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
840 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
841     and both kinds of lookbehind were skipped).
843 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
844 ph10 284 inclusion of <windows.h> to before rather than after the definition of
845     INVALID_FILE_ATTRIBUTES (patch from David Byron).
846 ph10 263
847 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
848 ph10 286 character property caused pcre_compile() to compile bad code, which led at
849     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
850     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
851     caused the error; without that there was no problem.
852 ph10 263
853 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
854 ph10 286
855 ph10 289 19. Added --enable-pcretest-libreadline.
856 ph10 286
857 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
858 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
859 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
860     later patch that removed the other one (the right fix) and added unit tests
861     that check the return values (which was not done before).
862 ph10 292
863 ph10 291 21. Several CMake things:
864 ph10 287
865 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
866 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
867 ph10 288
868 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
869     linked with the newly-built libraries, not previously installed ones.
870 ph10 291
872 ph10 298
873     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
874     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
875     UTF-8 newline character). The key issue is that the pattern starts .*;
876     this means that the match must be either at the beginning, or after a
877     newline. The bug was in the code for advancing after a failed match and
878     checking that the new position followed a newline. It was not taking
879 ph10 294 account of UTF-8 characters correctly.
880 ph10 298
881     23. PCRE was behaving differently from Perl in the way it recognized POSIX
882     character classes. PCRE was not treating the sequence [:...:] as a
883     character class unless the ... were all letters. Perl, however, seems to
884     allow any characters between [: and :], though of course it rejects as
885     unknown any "names" that contain non-letters, because all the known class
886     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
887     for example, whereas PCRE did not - it did not recognize a POSIX character
888     class. This seemed a bit dangerous, so the code has been changed to be
889     closer to Perl. The behaviour is not identical to Perl, because PCRE will
890     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
891     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
892     Perl does, and where it didn't before.
894 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
895     Windows environments %n is disabled by default.
896 ph10 292
898 ph10 260 Version 7.4 21-Sep-07
899 ph10 230 ---------------------
901     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
902 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
903     LF". That isn't really right - the whole point of the change was to try to
904     help when there was an actual mention of one of the two characters. So now
905     the change happens only if \r or \n (or a literal CR or LF) character is
906 ph10 230 encountered.
907 ph10 231
908     2. The 32-bit options word was also used for 6 internal flags, but the numbers
909     of both had grown to the point where there were only 3 bits left.
910     Fortunately, there was spare space in the data structure, and so I have
911     moved the internal flags into a new 16-bit field to free up more option
912 ph10 230 bits.
913 ph10 231
914     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
915     but did not set the internal JCHANGED flag - either of these is enough to
916     control the way the "get" function works - but the PCRE_INFO_JCHANGED
917     facility is supposed to tell if (?J) was ever used, so now (?J) at the
918 ph10 230 start sets both bits.
920 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
921     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
922 ph10 230
923 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
925     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
926 ph10 233 compatibility, even though it is no longer used.
927 ph10 243
928     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
929 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
930 ph10 259 windows.h file is present (where different names are used). [This was
931 ph10 257 reversed later after testing - see 16 below.]
932 ph10 243
933     8. Changed all #include <config.h> to #include "config.h". There were also
934 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
935 ph10 243
936 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
937 ph10 243 sequence off the lines that it output.
939     10. It was pointed out to me that arrays of string pointers cause lots of
940     relocations when a shared library is dynamically loaded. A technique of
941     using a single long string with a table of offsets can drastically reduce
942     these. I have refactored PCRE in four places to do this. The result is
943 ph10 240 dramatic:
944 ph10 243
945 ph10 240 Originally: 290
946     After changing UCP table: 187
947 ph10 243 After changing error message table: 43
948 ph10 240 After changing table of "verbs" 36
949     After changing table of Posix names 22
950 ph10 243
951 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
952 ph10 247
953 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
954 ph10 247 unicode-properties was also set.
956 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
957 ph10 231
958 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
959     checked only for CRLF.
960 ph10 233
961 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
963 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
964 ph10 253
965 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
966 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
967     entirely. This removes changes made in 7 above.
968 ph10 256
969 ph10 261 17. The CMake files have been updated, and there is now more information about
970     building with CMake in the NON-UNIX-USE document.
971 ph10 257
972 ph10 261
973 ph10 228 Version 7.3 28-Aug-07
974 ph10 157 ---------------------
976 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
977     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
978     brackets there is not right, since it causes compilers to look for an
979     installed pcre.h, not the version that is in the source that is being
980     compiled (which of course may be different). I have changed it back to:
981 ph10 197
982 ph10 189 #include "pcre.h"
983 ph10 197
984     I have a vague recollection that the change was concerned with compiling in
985     different directories, but in the new build system, that is taken care of
986     by the VPATH setting the Makefile.
988 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
989     when the subject happened to end in the byte 0x85 (e.g. if the last
990     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
991     characters but of course it shouldn't be taken as a newline when it is part
992     of another character. The bug was that, for an unlimited repeat of . in
993     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
994     characters when looking for a newline.
995 ph10 197
996     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
998     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
999     in debug output.
1001 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1002     long printing in the pcrecpp unittest when running under MinGW.
1003 ph10 189
1004 ph10 197 6. ESC_K was left out of the EBCDIC table.
1005 ph10 189
1006 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1007     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1008     limit also applies to "virtual nesting" when a pattern is recursive, and in
1009     this case 1000 isn't so big. I have been able to remove this limit at the
1010     expense of backing off one optimization in certain circumstances. Normally,
1011     when pcre_exec() would call its internal match() function recursively and
1012     immediately return the result unconditionally, it uses a "tail recursion"
1013     feature to save stack. However, when a subpattern that can match an empty
1014     string has an unlimited repetition quantifier, it no longer makes this
1015     optimization. That gives it a stack frame in which to save the data for
1016     checking that an empty string has been matched. Previously this was taken
1017     from the 1000-entry workspace that had been reserved. So now there is no
1018     explicit limit, but more stack is used.
1019 ph10 189
1020 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
1021     syntax that is required for Windows, and which was going wrong for the
1022     pcreposix and pcrecpp parts of the library. These were overlooked when this
1023     problem was solved for the main library.
1024 ph10 197
1025 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
1026     the size of patterns that contain repeated groups with explicit upper
1027     limits. As the maximum quantifier is 65535, the maximum group length was
1028     set at 30,000 so that the product of these two numbers did not overflow a
1029     32-bit integer. However, it turns out that people want to use groups that
1030     are longer than 30,000 bytes (though not repeat them that many times).
1031     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1032     made it possible to implement the integer overflow checks in a much more
1033     dynamic way, which I have now done. The artificial limitation on group
1034     length has been removed - we now have only the limit on the total length of
1035     the compiled pattern, which depends on the LINK_SIZE setting.
1036 ph10 208
1037     10. Fixed a bug in the documentation for get/copy named substring when
1038     duplicate names are permitted. If none of the named substrings are set, the
1039     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1040     empty string.
1042     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1043     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1044     because the ] is interpreted as the first data character and the
1045     terminating ] is not found. PCRE has been made compatible with Perl in this
1046     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1047     cause memory overwriting.
1049 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1050     string has been matched (to stop an infinite loop). It was not recognizing
1051 ph10 208 a conditional subpattern that could match an empty string if that
1052 ph10 206 subpattern was within another subpattern. For example, it looped when
1053 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
1054 ph10 206 condition was not nested. This bug has been fixed.
1055 ph10 208
1056 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1057     past the start of the subject in the presence of bytes with the top bit
1058     set, for example "\x8aBCD".
1059 ph10 211
1060 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1061     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1062 ph10 200
1063 ph10 211 14. Optimized (?!) to (*FAIL).
1064 ph10 202
1065 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1066     This restricts code points to be within the range 0 to 0x10FFFF, excluding
1067     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1068     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1069     does: it's just the validity check that is more restrictive.
1070 ph10 220
1071     16. Inserted checks for integer overflows during escape sequence (backslash)
1072     processing, and also fixed erroneous offset values for syntax errors during
1073     backslash processing.
1075 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1076 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1078 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1079     caused an overrun.
1080 ph10 220
1081     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1082     something other than just ASCII characters) inside a group that had an
1083     unlimited repeat caused a loop at compile time (while checking to see
1084     whether the group could match an empty string).
1086 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
1087     [\P{Any}] did so. (Error in the code for printing property names.)
1088 ph10 210
1089 ph10 220 21. An orphan \E inside a character class could cause a crash.
1091     22. A repeated capturing bracket such as (A)? could cause a wild memory
1092 ph10 218 reference during compilation.
1093 ph10 220
1094     23. There are several functions in pcre_compile() that scan along a compiled
1095     expression for various reasons (e.g. to see if it's fixed length for look
1096 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
1097 ph10 220 present in the pattern. These operators have additional parameters compared
1098     with \d, etc, and these were not being taken into account when moving along
1099 ph10 218 the compiled data. Specifically:
1100 ph10 220
1101     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1102     length.
1104     (b) An item such as \pL+ within a repeated group could cause crashes or
1105 ph10 218 loops.
1106 ph10 220
1107 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1108 ph10 220 "reference to non-existent subpattern" error.
1110 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1112 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1113 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1114 ph10 211
1115 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1116 ph10 218
1117 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1118 ph10 223 character were causing crashes (broken optimization).
1119 ph10 227
1120 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1121 ph10 227 \p or \P) caused a compile-time loop.
1123 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
1124     break. For example, the unstudied pattern [\r\n]A does not match the string
1125     "\r\nA" because change 7.0/46 below moves the current point on by two
1126     characters after failing to match at the start. However, the pattern \nA
1127 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1128     the same is true. There doesn't seem any very clean way out of this, but
1129     what I have chosen to do makes the common cases work: PCRE now takes note
1130     of whether there can be an explicit match for \r or \n anywhere in the
1131     pattern, and if so, 7.0/46 no longer applies. As part of this change,
1132     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1133     pattern has explicit CR or LF references.
1134 ph10 222
1135 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
1136 ph10 223
1137 ph10 227
1138 ph10 189 Version 7.2 19-Jun-07
1139     ---------------------
1141 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1142     which is apparently normally available under Windows.
1143 ph10 159
1144     2. Re-jig the pcregrep tests with different newline settings in an attempt
1145     to make them independent of the local environment's newline setting.
1146 ph10 157
1147 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1148 ph10 165
1149 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
1150     was not 2, because the output contained actual offsets. The recent new
1151 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
1152     usable with all link sizes.
1154 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1155     stack recursion. This gives a massive performance boost under BSD, but just
1156 ph10 165 a small improvement under Linux. However, it saves one field in the frame
1157 ph10 164 in all cases.
1158 ph10 172
1159 ph10 166 6. Added more features from the forthcoming Perl 5.10:
1160 ph10 172
1161 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
1162     recursion call. It refers to the nth most recently opened parentheses.
1163 ph10 172
1164 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
1165 ph10 172 to be opened parentheses.
1167     (c) Conditions that refer to capturing parentheses can be specified
1168 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
1169 ph10 172
1170 ph10 168 (d) \K resets the start of the current match so that everything before
1171 ph10 172 is not part of it.
1173 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1174 ph10 172
1175 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
1176 ph10 172 reference syntax.
1177 ph10 182
1178 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
1179 ph10 182 alternative starts with the same number.
1180 ph10 172
1181 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1183 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1186     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
1187     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1188 ph10 170 for detecting groups that can match an empty string.
1189 ph10 159
1190 ph10 172 9. A pattern with a very large number of alternatives (more than several
1191     hundred) was running out of internal workspace during the pre-compile
1192     phase, where pcre_compile() figures out how much memory will be needed. A
1193     bit of new cunning has reduced the workspace needed for groups with
1194     alternatives. The 1000-alternative test pattern now uses 12 bytes of
1195     workspace instead of running out of the 4096 that are available.
1196 ph10 182
1197 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1198 ph10 172
1199 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
1200     The report of the bug said:
1201 ph10 182
1202 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
1203     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1204 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1205 ph10 185
1206 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1207 ph10 185 it matched the wrong number of bytes.
1208 ph10 172
1209 ph10 179
1210 ph10 155 Version 7.1 24-Apr-07
1211 ph10 98 ---------------------
1213 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1214 ph10 122 that is more "standard", making use of automake and other Autotools. There
1215 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
1216     on this.
1217 ph10 111
1218     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1219     for recursive directory scanning broke on some systems because the files
1220     are not scanned in any specific order and on different systems the order
1221     was different. A call to "sort" has been inserted into RunGrepTest for the
1222     approprate test as a short-term fix. In the longer term there may be an
1223 ph10 100 alternative.
1224 ph10 111
1225 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
1226 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
1227     people do their own conversions for various reasons). The problems
1228     concerned the use of low-level troff macros .br and .in. I have therefore
1229     removed all such uses from the man pages (some were redundant, some could
1230 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
1231     HTML has been updated to handle .nf/.fi and to complain if it encounters
1232     .br or .in.
1233 ph10 111
1234 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
1235 ph10 123 arranged for config.h to be included in the distribution, with the name
1236 ph10 111 config.h.generic, for the benefit of those who have to compile without
1237     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1239     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1240     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1241 ph10 127 makevp.bat for the current PCRE, using the additional files
1242 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1243 ph10 111
1244     6. A Windows user reported a minor discrepancy with test 2, which turned out
1245     to be caused by a trailing space on an input line that had got lost in his
1246 ph10 102 copy. The trailing space was an accident, so I've just removed it.
1247 ph10 111
1248 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1249 ph10 111 that is needed.
1251 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1252     as "const" (a) because they are and (b) because it helps the PHP
1253     maintainers who have recently made a script to detect big data structures
1254 ph10 111 in the php code that should be moved to the .rodata section. I remembered
1255     to update Builducptable as well, so it won't revert if ucptable.h is ever
1256 ph10 105 re-created.
1257 ph10 111
1258     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1259 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1260 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
1261     support is not required. This saves 1.5-2K of code, which is important in
1262 ph10 107 some applications.
1263 ph10 111
1264 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1265 ph10 111 so as not to refer to the tables, even though these functions will never be
1266     called when UTF-8 support is disabled. Otherwise there are problems with a
1267     shared library.
1269 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1271     (a) It was defining its arguments as char * instead of void *.
1273 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
1274     a long time ago when I wrote it, but is no longer the case.
1276 ph10 118 The emulated memove() is provided for those environments that have neither
1277 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
1278 ph10 118 is clearly not the case, as these two bugs were recently reported.
1279 ph10 123
1280 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1281 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
1282     pages, and it removes trailing spaces from listed files. It also creates
1283     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1284     case, it wraps all the #defines with #ifndefs. This script should be run
1285 ph10 111 before "make dist".
1286 ph10 123
1287 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1288     with Unicode property support.
1289 ph10 123
1290     (a) For a maximizing quantifier, if the two different cases of the
1291     character were of different lengths in their UTF-8 codings (there are
1292     some cases like this - I found 11), and the matching function had to
1293 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
1294     were both the same length.
1295 ph10 123
1296     (b) When PCRE was configured to use the heap rather than the stack for
1297     recursion during matching, it was not correctly preserving the data for
1298     the other case of a UTF-8 character when checking ahead for a match
1299     while processing a minimizing repeat. If the check also involved
1300 ph10 115 matching a wide character, but failed, corruption could cause an
1301     erroneous result when trying to check for a repeat of the original
1302     character.
1303 ph10 123
1304 ph10 116 13. Some tidying changes to the testing mechanism:
1305 ph10 98
1306 ph10 116 (a) The RunTest script now detects the internal link size and whether there
1307     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1308 ph10 123 values substituted by "configure". (The RunGrepTest script already did
1309     this for UTF-8.) The configure.ac script no longer substitutes the
1310     relevant variables.
1312 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
1313     with length and offset values. This means that the output is different
1314     for different internal link sizes. Test 2 is skipped for link sizes
1315     other than 2 because of this, bypassing the problem. Unfortunately,
1316     there was also a test in test 3 (the locale tests) that used /B and
1317 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
1318     I have added a new /Z option to pcretest that replaces the length and
1319     offset values with spaces. This is now used to make test 3 independent
1320 ph10 122 of link size. (Test 2 will be tidied up later.)
1321 ph10 123
1322     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1323 ph10 122 segmentation fault instead of returning the appropriate error message.
1324 ph10 134
1325 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
1326 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1327     This doesn't seem right; it now treats the CRLF combination as the line
1328     ending, and so does not match in that case. It's only a pattern such as ^$
1329     that would hit this one: something like ^ABC$ would have failed after \r
1330     and then tried again after \r\n.
1332 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1333 ph10 134 in an attempt to make files that differ only in their line terminators
1334     compare equal. This works on Linux.
1335 ph10 142
1336 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
1337     as it exited. This is now fixed, thanks to valgrind.
1338 ph10 142
1339 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1340 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1341     was because its rules for how to advance for /g after matching an empty
1342 ph10 143 string at the end of a line did not allow for this case. They now check for
1343     it specially.
1344 ph10 150
1345     20. pcretest is supposed to handle patterns and data of any length, by
1346     extending its buffers when necessary. It was getting this wrong when the
1347 ph10 147 buffer for a data line had to be extended.
1348 ph10 150
1349 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1350 ph10 150 CRLF as a newline sequence.
1351 ph10 152
1352 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1353 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1354     I have nevertheless tidied it up.
1355 ph10 111
1356 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
1357 ph10 123
1358 ph10 153 24. Added a man page for pcre-config.
1359 ph10 152
1360 ph10 153
1361 nigel 93 Version 7.0 19-Dec-06
1362     ---------------------
1364     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1365     moving to gcc 4.1.1.
1367     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1368     sys/time.h, which is documented as needed for this function. It doesn't
1369     seem to matter on Linux, but it showed up on some releases of OS X.
1371     3. It seems that there are systems where bytes whose values are greater than
1372     127 match isprint() in the "C" locale. The "C" locale should be the
1373     default when a C program starts up. In most systems, only ASCII printing
1374     characters match isprint(). This difference caused the output from pcretest
1375     to vary, making some of the tests fail. I have changed pcretest so that:
1377     (a) When it is outputting text in the compiled version of a pattern, bytes
1378     other than 32-126 are always shown as hex escapes.
1380     (b) When it is outputting text that is a matched part of a subject string,
1381     it does the same, unless a different locale has been set for the match
1382     (using the /L modifier). In this case, it uses isprint() to decide.
1384     4. Fixed a major bug that caused incorrect computation of the amount of memory
1385     required for a compiled pattern when options that changed within the
1386     pattern affected the logic of the preliminary scan that determines the
1387     length. The relevant options are -x, and -i in UTF-8 mode. The result was
1388     that the computed length was too small. The symptoms of this bug were
1389     either the PCRE error "internal error: code overflow" from pcre_compile(),
1390     or a glibc crash with a message such as "pcretest: free(): invalid next
1391     size (fast)". Examples of patterns that provoked this bug (shown in
1392     pcretest format) are:
1394     /(?-x: )/x
1395     /(?x)(?-x: \s*#\s*)/
1396     /((?i)[\x{c0}])/8
1397     /(?i:[\x{c0}])/8
1399     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1400     is now done differently.
1402     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1403     wrapper classes; (b) implement a new function in the C++ scanner that is
1404     more efficient than the old way of doing things because it avoids levels of
1405     recursion in the regex matching; (c) add a paragraph to the documentation
1406     for the FullMatch() function.
1408     6. The escape sequence \n was being treated as whatever was defined as
1409     "newline". Not only was this contrary to the documentation, which states
1410     that \n is character 10 (hex 0A), but it also went horribly wrong when
1411     "newline" was defined as CRLF. This has been fixed.
1413     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1414     was being set to -1 for the "end of line" case (supposedly a value that no
1415     character can have). Though this value is never used (the check for end of
1416     line is "zero bytes in current character"), it caused compiler complaints.
1417     I've changed it to 0xffffffff.
1419     8. In pcre_version.c, the version string was being built by a sequence of
1420     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1421     string (as it is for production releases) called a macro with an empty
1422     argument. The C standard says the result of this is undefined. The gcc
1423     compiler treats it as an empty string (which was what was wanted) but it is
1424     reported that Visual C gives an error. The source has been hacked around to
1425     avoid this problem.
1427     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1428     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1429     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1430     of them did).
1432     10. Originally, pcretest opened its input and output without "b"; then I was
1433     told that "b" was needed in some environments, so it was added for release
1434     5.0 to both the input and output. (It makes no difference on Unix-like
1435     systems.) Later I was told that it is wrong for the input on Windows. I've
1436     now abstracted the modes into two macros, to make it easier to fiddle with
1437     them, and removed "b" from the input mode under Windows.
1439     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1441     12. Added -help and --help to pcretest as an official way of being reminded
1442     of the options.
1444     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1445     and pcrecpp.cc because they annoy compilers at high warning levels.
1447     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1449     15. Fixed an occurrence of == in configure.ac that should have been = (shell
1450     scripts are not C programs :-) and which was not noticed because it works
1451     on Linux.
1453     16. pcretest is supposed to handle any length of pattern and data line (as one
1454     line or as a continued sequence of lines) by extending its input buffer if
1455     necessary. This feature was broken for very long pattern lines, leading to
1456     a string of junk being passed to pcre_compile() if the pattern was longer
1457     than about 50K.
1459     17. I have done a major re-factoring of the way pcre_compile() computes the
1460     amount of memory needed for a compiled pattern. Previously, there was code
1461     that made a preliminary scan of the pattern in order to do this. That was
1462     OK when PCRE was new, but as the facilities have expanded, it has become
1463     harder and harder to keep it in step with the real compile phase, and there
1464     have been a number of bugs (see for example, 4 above). I have now found a
1465     cunning way of running the real compile function in a "fake" mode that
1466     enables it to compute how much memory it would need, while actually only
1467     ever using a few hundred bytes of working memory and without too many
1468     tests of the mode. This should make future maintenance and development
1469     easier. A side effect of this work is that the limit of 200 on the nesting
1470     depth of parentheses has been removed (though this was never a serious
1471     limitation, I suspect). However, there is a downside: pcre_compile() now
1472     runs more slowly than before (30% or more, depending on the pattern). I
1473     hope this isn't a big issue. There is no effect on runtime performance.
1475     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1476     newline (only possible for the last line of a file) and it was a
1477     pattern that set a locale (followed by /Lsomething), pcretest crashed.
1479     19. Added additional timing features to pcretest. (1) The -tm option now times
1480     matching only, not compiling. (2) Both -t and -tm can be followed, as a
1481     separate command line item, by a number that specifies the number of
1482     repeats to use when timing. The default is 50000; this gives better
1483     precision, but takes uncomfortably long for very large patterns.
1485     20. Extended pcre_study() to be more clever in cases where a branch of a
1486     subpattern has no definite first character. For example, (a*|b*)[cd] would
1487     previously give no result from pcre_study(). Now it recognizes that the
1488     first character must be a, b, c, or d.
1490     21. There was an incorrect error "recursive call could loop indefinitely" if
1491     a subpattern (or the entire pattern) that was being tested for matching an
1492     empty string contained only one non-empty item after a nested subpattern.
1493     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1494     incorrectly, because the \d was being skipped in the check.
1496     22. The pcretest program now has a new pattern option /B and a command line
1497     option -b, which is equivalent to adding /B to every pattern. This causes
1498     it to show the compiled bytecode, without the additional information that
1499     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1500     is the same as /B/I).
1502     23. A new optimization is now able automatically to treat some sequences such
1503     as a*b as a*+b. More specifically, if something simple (such as a character
1504     or a simple class like \d) has an unlimited quantifier, and is followed by
1505     something that cannot possibly match the quantified thing, the quantifier
1506     is automatically "possessified".
1508     24. A recursive reference to a subpattern whose number was greater than 39
1509     went wrong under certain circumstances in UTF-8 mode. This bug could also
1510     have affected the operation of pcre_study().
1512     25. Realized that a little bit of performance could be had by replacing
1513     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1515     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1517     27. Possessive quantifiers such as a++ were previously implemented by turning
1518     them into atomic groups such as ($>a+). Now they have their own opcodes,
1519     which improves performance. This includes the automatically created ones
1520     from 23 above.
1522     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1523     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1524     the first matched character to be a colon. This applied both to named and
1525     numbered groups.
1527     29. The ucpinternal.h header file was missing its idempotency #ifdef.
1529     30. I was sent a "project" file called libpcre.a.dev which I understand makes
1530     building PCRE on Windows easier, so I have included it in the distribution.
1532     31. There is now a check in pcretest against a ridiculously large number being
1533     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1534     loop, the loop is abandoned.
1536     32. Forward references to subpatterns in conditions such as (?(2)...) where
1537     subpattern 2 is defined later cause pcre_compile() to search forwards in
1538     the pattern for the relevant set of parentheses. This search went wrong
1539     when there were unescaped parentheses in a character class, parentheses
1540     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1542     33. "Subroutine" calls and backreferences were previously restricted to
1543     referencing subpatterns earlier in the regex. This restriction has now
1544     been removed.
1546     34. Added a number of extra features that are going to be in Perl 5.10. On the
1547     whole, these are just syntactic alternatives for features that PCRE had
1548     previously implemented using the Python syntax or my own invention. The
1549     other formats are all retained for compatibility.
1551     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1552     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1553     also .NET compatible.
1555     (b) A recursion or subroutine call to a named group can now be defined as
1556     (?&name) as well as (?P>name).
1558     (c) A backreference to a named group can now be defined as \k<name> or
1559     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1560     5.10, are also .NET compatible.
1562     (d) A conditional reference to a named group can now use the syntax
1563     (?(<name>) or (?('name') as well as (?(name).
1565     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1566     groups (named and numbered) that are never evaluated inline, but can be
1567     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1568     is always false. There may be only one alternative in such a group.
1570     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1571     as the simple (?(R). The condition is true only if the most recent
1572     recursion is that of the given number or name. It does not search out
1573     through the entire recursion stack.
1575     (g) The escape \gN or \g{N} has been added, where N is a positive or
1576     negative number, specifying an absolute or relative reference.
1578     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1579     some "unreachable code" warnings.
1581     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1582     things, this adds five new scripts.
1584     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1585     There were also incompatibilities regarding the handling of \Q..\E inside
1586     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1587     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1589     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1590     matches an empty string, and forcibly breaks the loop. There were bugs in
1591     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1592     against aaaa the result was just "a" rather than "aaaa", for example. Two
1593     separate and independent bugs (that affected different cases) have been
1594     fixed.
1596     39. Refactored the code to abolish the use of different opcodes for small
1597     capturing bracket numbers. This is a tidy that I avoided doing when I
1598     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1599     The new approach is not only tidier, it makes it possible to reduce the
1600     memory needed to fix the previous bug (38).
1602     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1603     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1604     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1605     mode.
1607     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1608     report.
1610     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1611     copy construction and assignment in the C++ wrapper.
1613     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1614     couple of bugs that could have given wrong results in the "--newline=crlf"
1615     case.
1617     44. Added a number of casts and did some reorganization of signed/unsigned int
1618     variables following suggestions from Dair Grant. Also renamed the variable
1619     "this" as "item" because it is a C++ keyword.
1621     45. Arranged for dftables to add
1623     #include "pcre_internal.h"
1625     to pcre_chartables.c because without it, gcc 4.x may remove the array
1626     definition from the final binary if PCRE is built into a static library and
1627     dead code stripping is activated.
1629     46. For an unanchored pattern, if a match attempt fails at the start of a
1630     newline sequence, and the newline setting is CRLF or ANY, and the next two
1631     characters are CRLF, advance by two characters instead of one.
1634 nigel 91 Version 6.7 04-Jul-06
1635     ---------------------
1637     1. In order to handle tests when input lines are enormously long, pcretest has
1638     been re-factored so that it automatically extends its buffers when
1639     necessary. The code is crude, but this _is_ just a test program. The
1640     default size has been increased from 32K to 50K.
1642     2. The code in pcre_study() was using the value of the re argument before
1643     testing it for NULL. (Of course, in any sensible call of the function, it
1644     won't be NULL.)
1646     3. The memmove() emulation function in pcre_internal.h, which is used on
1647     systems that lack both memmove() and bcopy() - that is, hardly ever -
1648     was missing a "static" storage class specifier.
1650     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1651     containing an extended class (one that cannot be represented by a bitmap
1652     because it contains high-valued characters or Unicode property items, e.g.
1653     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1654     pattern, but PCRE should not loop if you do not (it no longer does).
1655     [Detail: two cases were found: (a) a repeated subpattern containing an
1656     extended class; (b) a recursive reference to a subpattern that followed a
1657     previous extended class. It wasn't skipping over the extended class
1658     correctly when UTF-8 mode was not set.]
1660     5. A negated single-character class was not being recognized as fixed-length
1661     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1662     compile error "lookbehind assertion is not fixed length".
1664     6. The RunPerlTest auxiliary script was showing an unexpected difference
1665     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1666     write a Perl script that can interpret lines of an input file either as
1667     byte characters or as UTF-8, which is what "perltest" was being required to
1668     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1669     can't do is switch easily at run time between having the "use utf8;" pragma
1670     or not. In the end, I fudged it by using the RunPerlTest script to insert
1671     "use utf8;" explicitly for the UTF-8 tests.
1673     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1674     the end of the subject string, contrary to the documentation and to what
1675     Perl does. This was true of both matching functions. Now it matches only at
1676     the start of the subject and immediately after *internal* newlines.
1678     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1679     a pointer to an int instead of a pointer to an unsigned long int. This
1680     caused problems on 64-bit systems.
1682     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1683     instance of the 'standard' template library not being so standard".
1685     10. There was no check on the number of named subpatterns nor the maximum
1686     length of a subpattern name. The product of these values is used to compute
1687     the size of the memory block for a compiled pattern. By supplying a very
1688     long subpattern name and a large number of named subpatterns, the size
1689     computation could be caused to overflow. This is now prevented by limiting
1690     the length of names to 32 characters, and the number of named subpatterns
1691     to 10,000.
1693     11. Subpatterns that are repeated with specific counts have to be replicated in
1694     the compiled pattern. The size of memory for this was computed from the
1695     length of the subpattern and the repeat count. The latter is limited to
1696     65535, but there was no limit on the former, meaning that integer overflow
1697     could in principle occur. The compiled length of a repeated subpattern is
1698     now limited to 30,000 bytes in order to prevent this.
1700     12. Added the optional facility to have named substrings with the same name.
1702     13. Added the ability to use a named substring as a condition, using the
1703     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1704     are numbers (not recommended). Forward references are permitted.
1706     14. Added forward references in named backreferences (if you see what I mean).
1708     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1709     pattern could run off the end of the subject. For example, the pattern
1710     "(?s)(.{1,5})"8 did this with the subject "ab".
1712     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1713     PCRE_CASELESS was set when matching characters that were quantified with ?
1714     or *.
1716     17. A character class other than a single negated character that had a minimum
1717     but no maximum quantifier - for example [ab]{6,} - was not handled
1718     correctly by pce_dfa_exec(). It would match only one character.
1720     18. A valid (though odd) pattern that looked like a POSIX character
1721     class but used an invalid character after [ (for example [[,abc,]]) caused
1722     pcre_compile() to give the error "Failed: internal error: code overflow" or
1723     in some cases to crash with a glibc free() error. This could even happen if
1724     the pattern terminated after [[ but there just happened to be a sequence of
1725     letters, a binary zero, and a closing ] in the memory that followed.
1727     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1728     over the years. Originally (before any Unicode support), just the bottom 8
1729     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1730     output from "man perlunicode" includes this:
1732     The regular expression compiler produces polymorphic opcodes. That
1733     is, the pattern adapts to the data and automatically switches to
1734     the Unicode character scheme when presented with Unicode data--or
1735     instead uses a traditional byte scheme when presented with byte
1736     data.
1738     Sadly, a wide octal escape does not cause a switch, and in a string with
1739     no other multibyte characters, these octal escapes are treated as before.
1740     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1741     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1742     Unicode string.
1744     I have not perpetrated such confusion in PCRE. Up till now, it took just
1745     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1746     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1747     translate to the appropriate multibyte character.
1749     29. Applied some refactoring to reduce the number of warnings from Microsoft
1750     and Borland compilers. This has included removing the fudge introduced
1751     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1752     a warning about an unused variable.
1754     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1755     characters since release 4.0, because Perl (from release 5.004) does not.
1756     [Or at least, is documented not to: some releases seem to be in conflict
1757     with the documentation.] However, when a pattern was studied with
1758     pcre_study() and all its branches started with \s, PCRE still included VT
1759     as a possible starting character. Of course, this did no harm; it just
1760     caused an unnecessary match attempt.
1762     22. Removed a now-redundant internal flag bit that recorded the fact that case
1763     dependency changed within the pattern. This was once needed for "required
1764     byte" processing, but is no longer used. This recovers a now-scarce options
1765     bit. Also moved the least significant internal flag bit to the most-
1766     significant bit of the word, which was not previously used (hangover from
1767     the days when it was an int rather than a uint) to free up another bit for
1768     the future.
1770     23. Added support for CRLF line endings as well as CR and LF. As well as the
1771     default being selectable at build time, it can now be changed at runtime
1772     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1773     specify that it is scanning data with non-default line endings.
1775     24. Changed the definition of CXXLINK to make it agree with the definition of
1776     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1778     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1779     recursions. This makes a big different to stack usage for some patterns.
1781     26. If a subpattern containing a named recursion or subroutine reference such
1782     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1783     the space required for the compiled pattern went wrong and gave too small a
1784     value. Depending on the environment, this could lead to "Failed: internal
1785     error: code overflow at offset 49" or "glibc detected double free or
1786     corruption" errors.
1788     27. Applied patches from Google (a) to support the new newline modes and (b) to
1789     advance over multibyte UTF-8 characters in GlobalReplace.
1791     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1792     difference for some implementation of PCRE in some Windows version.
1794     29. Added some extra testing facilities to pcretest:
1796     \q<number> in a data line sets the "match limit" value
1797     \Q<number> in a data line sets the "match recursion limt" value
1798     -S <number> sets the stack size, where <number> is in megabytes
1800     The -S option isn't available for Windows.
1803 nigel 89 Version 6.6 06-Feb-06
1804     ---------------------
1806     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1807     in pcreposix.h. I have copied the definition from pcre.h.
1809     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1810     because pcre.h is no longer a built file.
1812     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1813     not normally included in the compiled code.
1816 nigel 87 Version 6.5 01-Feb-06
1817     ---------------------
1819     1. When using the partial match feature with pcre_dfa_exec(), it was not
1820     anchoring the second and subsequent partial matches at the new starting
1821     point. This could lead to incorrect results. For example, with the pattern
1822     /1234/, partially matching against "123" and then "a4" gave a match.
1824     2. Changes to pcregrep:
1826     (a) All non-match returns from pcre_exec() were being treated as failures
1827     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1828     error message is output. Some extra information is given for the
1830     probably the only errors that are likely to be caused by users (by
1831     specifying a regex that has nested indefinite repeats, for instance).
1832     If there are more than 20 of these errors, pcregrep is abandoned.
1834     (b) A binary zero was treated as data while matching, but terminated the
1835     output line if it was written out. This has been fixed: binary zeroes
1836     are now no different to any other data bytes.
1838     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1839     used to set a locale for matching. The --locale=xxxx long option has
1840     been added (no short equivalent) to specify a locale explicitly on the
1841     pcregrep command, overriding the environment variables.
1843     (d) When -B was used with -n, some line numbers in the output were one less
1844     than they should have been.
1846     (e) Added the -o (--only-matching) option.
1848     (f) If -A or -C was used with -c (count only), some lines of context were
1849     accidentally printed for the final match.
1851     (g) Added the -H (--with-filename) option.
1853     (h) The combination of options -rh failed to suppress file names for files
1854     that were found from directory arguments.
1856     (i) Added the -D (--devices) and -d (--directories) options.
1858     (j) Added the -F (--fixed-strings) option.
1860     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1862     (l) Added the --colo(u)r option.
1864     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1865     is not present by default.
1867     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1868     items such as (?R) or (?1), when the recursion could match a number of
1869     alternatives. If it matched one of the alternatives, but subsequently,
1870     outside the recursion, there was a failure, the code tried to back up into
1871     the recursion. However, because of the way PCRE is implemented, this is not
1872     possible, and the result was an incorrect result from the match.
1874     In order to prevent this happening, the specification of recursion has
1875     been changed so that all such subpatterns are automatically treated as
1876     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1878     4. I had overlooked the fact that, in some locales, there are characters for
1879     which isalpha() is true but neither isupper() nor islower() are true. In
1880     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1881     and ordfeminine) are like this. This affected the treatment of \w and \W
1882     when they appeared in character classes, but not when they appeared outside
1883     a character class. The bit map for "word" characters is now created
1884     separately from the results of isalnum() instead of just taking it from the
1885     upper, lower, and digit maps. (Plus the underscore character, of course.)
1887     5. The above bug also affected the handling of POSIX character classes such as
1888     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1889     permanent tables. Instead, the bit maps for such a class were previously
1890     created as the appropriate unions of the upper, lower, and digit bitmaps.
1891     Now they are created by subtraction from the [[:word:]] class, which has
1892     its own bitmap.
1894     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1895     It is created by subtracting the vertical space characters (\x09, \x0a,
1896     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1897     subtraction was done in the overall bitmap for a character class, meaning
1898     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1899     be recognized. This bug has been fixed.
1901     7. Patches from the folks at Google:
1903     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1904     real life, but is still worth protecting against".
1906     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1907     regular expressions".
1909     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1910     have it.
1912     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1913     "configure" and the latter not, in order to fix a problem somebody had
1914     with compiling the Arg class on HP-UX.
1916     (e) Improve the error-handling of the C++ wrapper a little bit.
1918     (f) New tests for checking recursion limiting.
1920     8. The pcre_memmove() function, which is used only if the environment does not
1921     have a standard memmove() function (and is therefore rarely compiled),
1922     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1923     returning a result (though PCRE never actually uses the result).
1925     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1926     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1927     returned instead of calling malloc() with an overflowing number that would
1928     most likely cause subsequent chaos.
1930     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1932     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1933     with this option is matched, the nmatch and pmatch options of regexec() are
1934     ignored.
1936     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1937     provided in case anyone wants to the the POSIX interface with UTF-8
1938     strings.
1940     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1941     C++ linking (needed for some HP-UX environments).
1943     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1944     (unused parameter) and in the pcre_printint() function (omitted "default"
1945     switch label when the default is to do nothing).
1947     15. Added some code to make it possible, when PCRE is compiled as a C++
1948     library, to replace subject pointers for pcre_exec() with a smart pointer
1949     class, thus making it possible to process discontinuous strings.
1951     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1952     much the same function. They were added by different people who were trying
1953     to make PCRE easy to compile on non-Unix systems. It has been suggested
1954     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1955     for compiling on Windows systems. I have therefore replaced it with
1956     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1957     defaults to "extern" for C or "extern C" for C++, which works fine on
1958     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1959     SCOPE with something explicit in config.h. In addition:
1961     (a) pcreposix.h still had just "extern" instead of either of these macros;
1962     I have replaced it with PCRE_DATA_SCOPE.
1964     (b) Functions such as _pcre_xclass(), which are internal to the library,
1965     but external in the C sense, all had PCRE_EXPORT in their definitions.
1966     This is apparently wrong for the Windows case, so I have removed it.
1967     (It makes no difference on Unix-like systems.)
1969     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1970     of recursive calls to match(). This is different to MATCH_LIMIT because
1971     that limits the total number of calls to match(), not all of which increase
1972     the depth of recursion. Limiting the recursion depth limits the amount of
1973     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1974     when PCRE is compiled, and changed at run time. A patch from Google adds
1975     this functionality to the C++ interface.
1977     18. Changes to the handling of Unicode character properties:
1979     (a) Updated the table to Unicode 4.1.0.
1981     (b) Recognize characters that are not in the table as "Cn" (undefined).
1983     (c) I revised the way the table is implemented to a much improved format
1984     which includes recognition of ranges. It now supports the ranges that
1985     are defined in UnicodeData.txt, and it also amalgamates other
1986     characters into ranges. This has reduced the number of entries in the
1987     table from around 16,000 to around 3,000, thus reducing its size
1988     considerably. I realized I did not need to use a tree structure after
1989     all - a binary chop search is just as efficient. Having reduced the
1990     number of entries, I extended their size from 6 bytes to 8 bytes to
1991     allow for more data.
1993     (d) Added support for Unicode script names via properties such as \p{Han}.
1995     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1996     matching that character.
1998     20. When matching a repeated Unicode property with a minimum greater than zero,
1999     (for example \pL{2,}), PCRE could look past the end of the subject if it
2000     reached it while seeking the minimum number of characters. This could
2001     happen only if some of the characters were more than one byte long, because
2002     there is a check for at least the minimum number of bytes.
2004     21. Refactored the implementation of \p and \P so as to be more general, to
2005     allow for more different types of property in future. This has changed the
2006     compiled form incompatibly. Anybody with saved compiled patterns that use
2007     \p or \P will have to recompile them.
2009     22. Added "Any" and "L&" to the supported property types.
2011     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2012     but give a compile time error if the value is greater than 0xff.
2014     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2015     accidentally not being installed or uninstalled.
2017     25. The pcre.h file was built from pcre.h.in, but the only changes that were
2018     made were to insert the current release number. This seemed silly, because
2019     it made things harder for people building PCRE on systems that don't run
2020     "configure". I have turned pcre.h into a distributed file, no longer built
2021     by "configure", with the version identification directly included. There is
2022     no longer a pcre.h.in file.
2024     However, this change necessitated a change to the pcre-config script as
2025     well. It is built from pcre-config.in, and one of the substitutions was the
2026     release number. I have updated configure.ac so that ./configure now finds
2027     the release number by grepping pcre.h.
2029     26. Added the ability to run the tests under valgrind.
2032 nigel 85 Version 6.4 05-Sep-05
2033     ---------------------
2035     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2036     "--" to be printed when multiple files were scanned, even when none of the
2037     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2038     consider it to be a bug, and have restored the previous behaviour.
2040     2. A couple of code tidies to get rid of compiler warnings.
2042     3. The pcretest program used to cheat by referring to symbols in the library
2043     whose names begin with _pcre_. These are internal symbols that are not
2044     really supposed to be visible externally, and in some environments it is
2045     possible to suppress them. The cheating is now confined to including
2046     certain files from the library's source, which is a bit cleaner.
2048     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2049     file's purpose clearer.
2051     5. Reorganized pcre_ucp_findchar().
2054 nigel 83 Version 6.3 15-Aug-05
2055     ---------------------
2057     1. The file libpcre.pc.in did not have general read permission in the tarball.
2059     2. There were some problems when building without C++ support:
2061     (a) If C++ support was not built, "make install" and "make test" still
2062     tried to test it.
2064     (b) There were problems when the value of CXX was explicitly set. Some
2065     changes have been made to try to fix these, and ...
2067     (c) --disable-cpp can now be used to explicitly disable C++ support.
2069     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2070     backslash in a target when C++ was disabled. This confuses some
2071     versions of "make", apparently. Using an intermediate variable solves
2072     this. (Same for CPP_LOBJ.)
2074     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2075     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2076     necessary on certain architectures.
2078     4. Added a setting of -export-symbols-regex to the link command to remove
2079     those symbols that are exported in the C sense, but actually are local
2080     within the library, and not documented. Their names all begin with
2081     "_pcre_". This is not a perfect job, because (a) we have to except some
2082     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2083     available (and never for static libraries). I have made a note to try to
2084     find a way round (a) in the future.
2087 nigel 81 Version 6.2 01-Aug-05
2088     ---------------------
2090     1. There was no test for integer overflow of quantifier values. A construction
2091     such as {1111111111111111} would give undefined results. What is worse, if
2092     a minimum quantifier for a parenthesized subpattern overflowed and became
2093     negative, the calculation of the memory size went wrong. This could have
2094     led to memory overwriting.
2096     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2098     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2099     operating environments where this matters.
2101     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2102     PCRE options from within the C++ wrapper.
2104     5. Named capturing subpatterns were not being correctly counted when a pattern
2105     was compiled. This caused two problems: (a) If there were more than 100
2106     such subpatterns, the calculation of the memory needed for the whole
2107     compiled pattern went wrong, leading to an overflow error. (b) Numerical
2108     back references of the form \12, where the number was greater than 9, were
2109     not recognized as back references, even though there were sufficient
2110     previous subpatterns.
2112     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2113     versions of gcc, e.g. 2.95.4.
2116 nigel 79 Version 6.1 21-Jun-05
2117     ---------------------
2119     1. There was one reference to the variable "posix" in pcretest.c that was not
2120     surrounded by "#if !defined NOPOSIX".
2122     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2123     the cross-check on the old pcre_info() function, for the benefit of the
2124     cut-down version of PCRE that is currently imported into Exim.
2126     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2127     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2128     patterns that start (?i) but I don't think that matters. The use of (?i) is
2129     just an example; this all applies to the other options as well.
2131     4. Since libtool seems to echo the compile commands it is issuing, the output
2132     from "make" can be reduced a bit by putting "@" in front of each libtool
2133     compile command.
2135     5. Patch from the folks at Google for configure.in to be a bit more thorough
2136     in checking for a suitable C++ installation before trying to compile the
2137     C++ stuff. This should fix a reported problem when a compiler was present,
2138     but no suitable headers.
2140     6. The man pages all had just "PCRE" as their title. I have changed them to
2141     be the relevant file name. I have also arranged that these names are
2142     retained in the file doc/pcre.txt, which is a concatenation in text format
2143     of all the man pages except the little individual ones for each function.
2145     7. The NON-UNIX-USE file had not been updated for the different set of source
2146     files that come with release 6. I also added a few comments about the C++
2147     wrapper.
2150 nigel 77 Version 6.0 07-Jun-05
2151     ---------------------
2153     1. Some minor internal re-organization to help with my DFA experiments.
2155     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2156     didn't matter for the library itself when fully configured, but did matter
2157     when compiling without UCP support, or within Exim, where the ucp files are
2158     not imported.
2160     3. Refactoring of the library code to split up the various functions into
2161     different source modules. The addition of the new DFA matching code (see
2162     below) to a single monolithic source would have made it really too
2163     unwieldy, quite apart from causing all the code to be include in a
2164     statically linked application, when only some functions are used. This is
2165     relevant even without the DFA addition now that patterns can be compiled in
2166     one application and matched in another.
2168     The downside of splitting up is that there have to be some external
2169     functions and data tables that are used internally in different modules of
2170     the library but which are not part of the API. These have all had their
2171     names changed to start with "_pcre_" so that they are unlikely to clash
2172     with other external names.
2174     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2175     a different (DFA) algorithm. Although it is slower than the original
2176     function, it does have some advantages for certain types of matching
2177     problem.
2179     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2180     including restarting after a partial match.
2182     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2183     defined when compiling for Windows was sent to me. I have put it into the
2184     code, though I have no means of testing or verifying it.
2186     7. Added the pcre_refcount() auxiliary function.
2188     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2189     match before or at the first newline in the subject string. In pcretest,
2190     the /f option on a pattern can be used to set this.
2192     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2193     would behave wrongly. This has been present in PCRE since release 4.0.
2195     10. A number of changes to the pcregrep command:
2197     (a) Refactored how -x works; insert ^(...)$ instead of setting
2198     PCRE_ANCHORED and checking the length, in preparation for adding
2199     something similar for -w.
2201     (b) Added the -w (match as a word) option.
2203     (c) Refactored the way lines are read and buffered so as to have more
2204     than one at a time available.
2206     (d) Implemented a pcregrep test script.
2208     (e) Added the -M (multiline match) option. This allows patterns to match
2209     over several lines of the subject. The buffering ensures that at least
2210     8K, or the rest of the document (whichever is the shorter) is available
2211     for matching (and similarly the previous 8K for lookbehind assertions).
2213     (f) Changed the --help output so that it now says
2215     -w, --word-regex(p)
2217     instead of two lines, one with "regex" and the other with "regexp"
2218     because that confused at least one person since the short forms are the
2219     same. (This required a bit of code, as the output is generated
2220     automatically from a table. It wasn't just a text change.)
2222     (g) -- can be used to terminate pcregrep options if the next thing isn't an
2223     option but starts with a hyphen. Could be a pattern or a path name
2224     starting with a hyphen, for instance.
2226     (h) "-" can be given as a file name to represent stdin.
2228     (i) When file names are being printed, "(standard input)" is used for
2229     the standard input, for compatibility with GNU grep. Previously
2230     "<stdin>" was used.
2232     (j) The option --label=xxx can be used to supply a name to be used for
2233     stdin when file names are being printed. There is no short form.
2235     (k) Re-factored the options decoding logic because we are going to add
2236     two more options that take data. Such options can now be given in four
2237     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2239     (l) Added the -A, -B, and -C options for requesting that lines of context
2240     around matches be printed.
2242     (m) Added the -L option to print the names of files that do not contain
2243     any matching lines, that is, the complement of -l.
2245     (n) The return code is 2 if any file cannot be opened, but pcregrep does
2246     continue to scan other files.
2248     (o) The -s option was incorrectly implemented. For compatibility with other
2249     greps, it now suppresses the error message for a non-existent or non-
2250     accessible file (but not the return code). There is a new option called
2251     -q that suppresses the output of matching lines, which was what -s was
2252     previously doing.
2254     (p) Added --include and --exclude options to specify files for inclusion
2255     and exclusion when recursing.
2257     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2258     Hopefully, it now does.
2260     12. Missing cast in pcre_study().
2262     13. Added an "uninstall" target to the makefile.
2264     14. Replaced "extern" in the function prototypes in Makefile.in with
2265     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2266     world, but is set differently for Windows.
2268     15. Added a second compiling function called pcre_compile2(). The only
2269     difference is that it has an extra argument, which is a pointer to an
2270     integer error code. When there is a compile-time failure, this is set
2271     non-zero, in addition to the error test pointer being set to point to an
2272     error message. The new argument may be NULL if no error number is required
2273     (but then you may as well call pcre_compile(), which is now just a
2274     wrapper). This facility is provided because some applications need a
2275     numeric error indication, but it has also enabled me to tidy up the way
2276     compile-time errors are handled in the POSIX wrapper.
2278     16. Added VPATH=.libs to the makefile; this should help when building with one
2279     prefix path and installing with another. (Or so I'm told by someone who
2280     knows more about this stuff than I do.)
2282     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2283     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2284     match everything, including newlines. This is not POSIX-compatible, but
2285     somebody wanted the feature. From pcretest it can be activated by using
2286     both the P and the s flags.
2288     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2290     19. libpcre.pc was being incorrectly installed as executable.
2292     20. A couple of places in pcretest check for end-of-line by looking for '\n';
2293     it now also looks for '\r' so that it will work unmodified on Windows.
2295     21. Added Google's contributed C++ wrapper to the distribution.
2297     22. Added some untidy missing memory free() calls in pcretest, to keep
2298     Electric Fence happy when testing.
2302 nigel 75 Version 5.0 13-Sep-04
2303     ---------------------
2305     1. Internal change: literal characters are no longer packed up into items
2306     containing multiple characters in a single byte-string. Each character
2307     is now matched using a separate opcode. However, there may be more than one
2308     byte in the character in UTF-8 mode.
2310     2. The pcre_callout_block structure has two new fields: pattern_position and
2311     next_item_length. These contain the offset in the pattern to the next match
2312     item, and its length, respectively.
2314     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2315     insertion of callouts before each pattern item. Added the /C option to
2316     pcretest to make use of this.
2318     4. On the advice of a Windows user, the lines
2320     #if defined(_WIN32) || defined(WIN32)
2321     _setmode( _fileno( stdout ), 0x8000 );
2322     #endif /* defined(_WIN32) || defined(WIN32) */
2324     have been added to the source of pcretest. This apparently does useful
2325     magic in relation to line terminators.
2327     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2328     for the benefit of those environments where the "b" makes a difference.
2330     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2331     to know about it. I have put a hack into configure.in that adds in code
2332     to set GCC=yes if CC=icc. This seems to end up at a point in the
2333     generated configure script that is early enough to affect the setting of
2334     compiler options, which is what is needed, but I have no means of testing
2335     whether it really works. (The user who reported this had patched the
2336     generated configure script, which of course I cannot do.)
2338     LATER: After change 22 below (new libtool files), the configure script
2339     seems to know about icc (and also ecc). Therefore, I have commented out
2340     this hack in configure.in.
2342     7. Added support for pkg-config (2 patches were sent in).
2344     8. Negated POSIX character classes that used a combination of internal tables
2345     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2346     [[:^ascii]]. Typically, they would match almost any characters. The other
2347     POSIX classes were not broken in this way.
2349     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2350     to find the match, as PCRE was deluded into thinking that the match had to
2351     start at the start point or following a newline. The same bug applied to
2352     patterns with negative forward assertions or any backward assertions
2353     preceding ".*" at the start, unless the pattern required a fixed first
2354     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2356     10. In UTF-8 mode, when moving forwards in the subject after a failed match
2357     starting at the last subject character, bytes beyond the end of the subject
2358     string were read.
2360     11. Renamed the variable "class" as "classbits" to make life easier for C++
2361     users. (Previously there was a macro definition, but it apparently wasn't
2362     enough.)
2364     12. Added the new field "tables" to the extra data so that tables can be passed
2365     in at exec time, or the internal tables can be re-selected. This allows
2366     a compiled regex to be saved and re-used at a later time by a different
2367     program that might have everything at different addresses.
2369     13. Modified the pcre-config script so that, when run on Solaris, it shows a
2370     -R library as well as a -L library.
2372     14. The debugging options of pcretest (-d on the command line or D on a
2373     pattern) showed incorrect output for anything following an extended class
2374     that contained multibyte characters and which was followed by a quantifier.
2376     15. Added optional support for general category Unicode character properties
2377     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2378     support. It adds about 90K to the size of the library. The meanings of the
2379     inbuilt class escapes such as \d and \s have NOT been changed.
2381     16. Updated pcredemo.c to include calls to free() to release the memory for the
2382     compiled pattern.
2384     17. The generated file chartables.c was being created in the source directory
2385     instead of in the building directory. This caused the build to fail if the
2386     source directory was different from the building directory, and was
2387     read-only.
2389     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2390     file. No doubt somebody will tell me if they don't make sense... Also added
2391     Dan Mooney's comments about building on OpenVMS.
2393     19. Added support for partial matching via the PCRE_PARTIAL option for
2394     pcre_exec() and the \P data escape in pcretest.
2396     20. Extended pcretest with 3 new pattern features:
2398     (i) A pattern option of the form ">rest-of-line" causes pcretest to
2399     write the compiled pattern to the file whose name is "rest-of-line".
2400     This is a straight binary dump of the data, with the saved pointer to
2401     the character tables forced to be NULL. The study data, if any, is
2402     written too. After writing, pcretest reads a new pattern.
2404     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2405     compiled pattern from the given file. There must not be any
2406     occurrences of "<" in the file name (pretty unlikely); if there are,
2407     pcretest will instead treat the initial "<" as a pattern delimiter.
2408     After reading in the pattern, pcretest goes on to read data lines as
2409     usual.
2411     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2412     and 16-bit fields in a compiled pattern, to simulate a pattern that
2413     was compiled on a host of opposite endianness.
2415     21. The pcre-exec() function can now cope with patterns that were compiled on
2416     hosts of opposite endianness, with this restriction:
2418     As for any compiled expression that is saved and used later, the tables
2419     pointer field cannot be preserved; the extra_data field in the arguments
2420     to pcre_exec() should be used to pass in a tables address if a value
2421     other than the default internal tables were used at compile time.
2423     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2424     now diagnosed as an error. Previously, most of the time, a negative number
2425     would have been treated as zero, but if in addition "ovector" was passed as
2426     NULL, a crash could occur.
2428     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2429     new versions from the libtool 1.5 distribution (the last one is a copy of
2430     a file called libtool.m4). This seems to have fixed the need to patch
2431     "configure" to support Darwin 1.3 (which I used to do). However, I still
2432     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2433     workstation).
2435     24. Changed the PCRE licence to be the more standard "BSD" licence.
2438 nigel 73 Version 4.5 01-Dec-03
2439     ---------------------
2441     1. There has been some re-arrangement of the code for the match() function so
2442     that it can be compiled in a version that does not call itself recursively.
2443     Instead, it keeps those local variables that need separate instances for
2444     each "recursion" in a frame on the heap, and gets/frees frames whenever it
2445     needs to "recurse". Keeping track of where control must go is done by means
2446     of setjmp/longjmp. The whole thing is implemented by a set of macros that
2447     hide most of the details from the main code, and operates only if
2448     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2449     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2450     operating.
2452     To make it easier for callers to provide specially tailored get/free
2453     functions for this usage, two new functions, pcre_stack_malloc, and
2454     pcre_stack_free, are used. They are always called in strict stacking order,
2455     and the size of block requested is always the same.
2457     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2458     PCRE has been compiled to use the stack or the heap for recursion. The
2459     -C option of pcretest uses this to show which version is compiled.
2461     A new data escape \S, is added to pcretest; it causes the amounts of store
2462     obtained and freed by both kinds of malloc/free at match time to be added
2463     to the output.
2465     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2466     what's available on my current Linux desktop machine.
2468     3. When matching a UTF-8 string, the test for a valid string at the start has
2469     been extended. If start_offset is not zero, PCRE now checks that it points
2470     to a byte that is the start of a UTF-8 character. If not, it returns
2471     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2472     this is necessary because there may be backward assertions in the pattern.
2473     When matching the same subject several times, it may save resources to use
2474     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2476     4. The code for checking the validity of UTF-8 strings has been tightened so
2477     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2478     containing "overlong sequences".
2480     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2481     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2482     should have been "&", but it just so happened that all the cases this let
2483     through by mistake were picked up later in the function.
2485     6. I had used a variable called "isblank" - this is a C99 function, causing
2486     some compilers to warn. To avoid this, I renamed it (as "blankclass").
2488     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2489     prompting; (b) run "./pcretest /dev/null" at the start of the test script
2490     so the version is shown; (c) stop "make test" echoing "./RunTest".
2492     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2494     9. The prototype for memmove() for systems that don't have it was using
2495     size_t, but the inclusion of the header that defines size_t was later. I've
2496     moved the #includes for the C headers earlier to avoid this.
2498     10. Added some adjustments to the code to make it easier to compiler on certain
2499     special systems:
2501     (a) Some "const" qualifiers were missing.
2502     (b) Added the macro EXPORT before all exported functions; by default this
2503     is defined to be empty.
2504     (c) Changed the dftables auxiliary program (that builds chartables.c) so
2505     that it reads its output file name as an argument instead of writing
2506     to the standard output and assuming this can be redirected.
2508     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2509     class containing characters with values greater than 255, PCRE compilation
2510     went into a loop.
2512     12. A recursive reference to a subpattern that was within another subpattern
2513     that had a minimum quantifier of zero caused PCRE to crash. For example,
2514     (x(y(?2))z)? provoked this bug with a subject that got as far as the
2515     recursion. If the recursively-called subpattern itself had a zero repeat,
2516     that was OK.
2518     13. In pcretest, the buffer for reading a data line was set at 30K, but the
2519     buffer into which it was copied (for escape processing) was still set at
2520     1024, so long lines caused crashes.
2522     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2523     "internal error: code overflow...". This applied to any character class
2524     that was followed by a possessive quantifier.
2526     15. Modified the Makefile to add libpcre.la as a prerequisite for
2527     libpcreposix.la because I was told this is needed for a parallel build to
2528     work.
2530     16. If a pattern that contained .* following optional items at the start was
2531     studied, the wrong optimizing data was generated, leading to matching
2532     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2533     matching string must start with a or b or c. The correct conclusion for
2534     this pattern is that a match can start with any character.
2537 nigel 71 Version 4.4 13-Aug-03
2538     ---------------------
2540     1. In UTF-8 mode, a character class containing characters with values between
2541     127 and 255 was not handled correctly if the compiled pattern was studied.
2542     In fixing this, I have also improved the studying algorithm for such
2543     classes (slightly).
2545     2. Three internal functions had redundant arguments passed to them. Removal
2546     might give a very teeny performance improvement.
2548     3. Documentation bug: the value of the capture_top field in a callout is *one
2549     more than* the number of the hightest numbered captured substring.
2551     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2552     in incorrectly linking with a previously installed version. They now link
2553     explicitly with libpcre.la.
2555     5. configure.in no longer needs to recognize Cygwin specially.
2557     6. A problem in pcre.in for Windows platforms is fixed.
2559     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2560     pcretest, it used to include the size of the study block as part of its
2561     output. Unfortunately, the structure contains a field that has a different
2562     size on different hardware architectures. This meant that the tests that
2563     showed this size failed. As the block is currently always of a fixed size,
2564     this information isn't actually particularly useful in pcretest output, so
2565     I have just removed it.
2567     8. Three pre-processor statements accidentally did not start in column 1.
2568     Sadly, there are *still* compilers around that complain, even though
2569     standard C has not required this for well over a decade. Sigh.
2571     9. In pcretest, the code for checking callouts passed small integers in the
2572     callout_data field, which is a void * field. However, some picky compilers
2573     complained about the casts involved for this on 64-bit systems. Now
2574     pcretest passes the address of the small integer instead, which should get
2575     rid of the warnings.
2577     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2578     both compile and run time, and gives an error if an invalid UTF-8 sequence
2579     is found. There is a option for disabling this check in cases where the
2580     string is known to be correct and/or the maximum performance is wanted.
2582     11. In response to a bug report, I changed one line in Makefile.in from
2584     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2585     to
2586     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2588     to look similar to other lines, but I have no way of telling whether this
2589     is the right thing to do, as I do not use Windows. No doubt I'll get told
2590     if it's wrong...
2593 nigel 69 Version 4.3 21-May-03
2594     ---------------------
2596     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2597     Makefile.
2599     2. Some refactoring to improve the quality of the code:
2601     (i) The utf8_table... variables are now declared "const".
2603     (ii) The code for \cx, which used the "case flipping" table to upper case
2604     lower case letters, now just substracts 32. This is ASCII-specific,
2605     but the whole concept of \cx is ASCII-specific, so it seems
2606     reasonable.
2608     (iii) PCRE was using its character types table to recognize decimal and
2609     hexadecimal digits in the pattern. This is silly, because it handles
2610     only 0-9, a-f, and A-F, but the character types table is locale-
2611     specific, which means strange things might happen. A private
2612     table is now used for this - though it costs 256 bytes, a table is
2613     much faster than multiple explicit tests. Of course, the standard
2614     character types table is still used for matching digits in subject
2615     strings against \d.
2617     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2618     ending in _t are). So I've renamed it as ESC_tee.
2620     3. The first argument for regexec() in the POSIX wrapper should have been
2621     defined as "const".
2623     4. Changed pcretest to use malloc() for its buffers so that they can be
2624     Electric Fenced for debugging.
2626     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2627     to read one or more bytes before the start of the subject string. Often this
2628     had no effect on PCRE's behaviour, but in some circumstances it could
2629     provoke a segmentation fault.
2631     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2632     to try to read one or more bytes before the start of the subject string.
2634     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2635     UTF-8 support could misbehave in various ways if the subject string
2636     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2637     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2638     back over UTF-8 characters.)
2641 nigel 67 Version 4.2 14-Apr-03
2642     ---------------------
2644     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2646     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2647     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2648     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2649     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2650     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2651     and BUILD_EXEEXT
2652     Note: automatic setting of the BUILD variables is not yet working
2653     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2654     compile-time but not at link-time
2655     [LINK]: use for linking executables only
2656     make different versions for Windows and non-Windows
2657     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2658     libraries
2659     [LINK_FOR_BUILD]: new variable
2660     [OBJEXT]: use throughout
2661     [EXEEXT]: use throughout
2662     <winshared>: new target
2663     <wininstall>: new target
2664     <dftables.o>: use native compiler
2665     <dftables>: use native linker
2666     <install>: handle Windows platform correctly
2667     <clean>: ditto
2668     <check>: ditto
2669     copy DLL to top builddir before testing
2671     As part of these changes, -no-undefined was removed again. This was reported
2672     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2673     in any case.
2675     3. Some tidies to get rid of compiler warnings:
2677     . In the match_data structure, match_limit was an unsigned long int, whereas
2678     match_call_count was an int. I've made them both unsigned long ints.
2680     . In pcretest the fact that a const uschar * doesn't automatically cast to
2681     a void * provoked a warning.
2683     . Turning on some more compiler warnings threw up some "shadow" variables
2684     and a few more missing casts.
2686     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2687     option, a class that contained a single character with a value between 128
2688     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2690     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2691     option, a class that contained several characters, but with at least one
2692     whose value was between 128 and 255 caused PCRE to crash.
2695 nigel 65 Version 4.1 12-Mar-03
2696     ---------------------
2697 nigel 63
2698 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2699     needed, and a string in dftables.c that was longer than standard compilers are
2700     required to support.
2702     2. Compiling with Sun's compiler found a few more places where the code could
2703     be tidied up in order to avoid warnings.
2705     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2706     first of these names is deprecated in the latest Autoconf in favour of the name
2707     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2708     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2709     analogy I have changed it to CFLAGS_FOR_BUILD.
2711     4. Added -no-undefined to the linking command in the Makefile, because this is
2712     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2713     linking step for the pcreposix library.
2715     5. PCRE was failing to diagnose the case of two named groups with the same
2716     name.
2718     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2719     literal character that is needed in the subject for a match, and scans along to
2720     ensure that it is present before embarking on the full matching process. This
2721     saves time in cases of nested unlimited repeats that are never going to match.
2722     Problem: the scan can take a lot of time if the subject is very long (e.g.
2723     megabytes), thus penalizing straightforward matches. It is now done only if the
2724     amount of subject to be scanned is less than 1000 bytes.
2726     7. A lesser problem with the same optimization is that it was recording the
2727     first character of an anchored pattern as "needed", thus provoking a search
2728     right along the subject, even when the first match of the pattern was going to
2729     fail. The "needed" character is now not set for anchored patterns, unless it
2730     follows something in the pattern that is of non-fixed length. Thus, it still
2731     fulfils its original purpose of finding quick non-matches in cases of nested
2732     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2735     Version 4.0 17-Feb-03
2736     ---------------------
2738 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2739     extended to the end of string, PCRE compiled incorrect data. This could lead to
2740     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2742     2. Moved to autoconf 2.53 and libtool 1.4.2.
2744     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2745     the special perltest8 script is no longer needed - all the tests can be run
2746     from a single perltest script.
2748     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2749     by \s. It has now been removed in PCRE. This means it isn't recognized as
2750     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2751     class [:space:] *does* include VT, thereby creating a mess.
2753     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2754     space and tab.
2756     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2757     its new features into the main test script, reducing the number of scripts.
2759     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2760     were backward compatible, and made the (?i) apply to the whole pattern, as if
2761     /i were given. Now it behaves more logically, and applies the option setting
2762     only to what follows. PCRE has been changed to follow suit. However, if it
2763     finds options settings right at the start of the pattern, it extracts them into
2764     the global options, as before. Thus, they show up in the info data.
2766     8. Added support for the \Q...\E escape sequence. Characters in between are
2767     treated as literals. This is slightly different from Perl in that $ and @ are
2768     also handled as literals inside the quotes. In Perl, they will cause variable
2769     interpolation. Note the following examples:
2771     Pattern PCRE matches Perl matches
2773     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2774     \Qabc\$xyz\E abc\$xyz abc\$xyz
2775     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2777     For compatibility with Perl, \Q...\E sequences are recognized inside character
2778     classes as well as outside them.
2780     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2781     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2782     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2783     signed/unsigned warnings.
2785     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2786     option for pcretest, so I've replaced it by a simple function that does just
2787     that job.
2789     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2790     "pcregrep -".
2792     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2793     Java package. This provides some syntactic sugar for simple cases of what my
2794     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2795     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2796     item, you can use this simplified notation. Note that only makes sense with
2797     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2798     greediness, whatever the setting of the PCRE_UNGREEDY option.
2800     13. A change of greediness default within a pattern was not taking effect at
2801     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2802     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2803     was abstracted outside.
2805     14. PCRE now supports the \G assertion. It is true when the current matching
2806     position is at the start point of the match. This differs from \A when the
2807     starting offset is non-zero. Used with the /g option of pcretest (or similar
2808     code), it works in the same way as it does for Perl's /g option. If all
2809     alternatives of a regex begin with \G, the expression is anchored to the start
2810     match position, and the "anchored" flag is set in the compiled expression.
2812     15. Some bugs concerning the handling of certain option changes within patterns
2813     have been fixed. These applied to options other than (?ims). For example,
2814     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2815     been the other way round. Some of this was related to change 7 above.
2817     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2818     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2819     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2820     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2822     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2823     mode. Unlike ".", it always matches newline, whatever the setting of
2824     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2825     assertions. Perl allows it, but it doesn't (in general) work because it can't
2826     calculate the length of the lookbehind. At least, that's the case for Perl
2827     5.8.0 - I've been told they are going to document that it doesn't work in
2828     future.
2830     18. Added an error diagnosis for escapes that PCRE does not support: these are
2831     \L, \l, \N, \P, \p, \U, \u, and \X.
2833     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2834     reading past the end of the pattern in cases such as /[abcd/.
2836     20. PCRE was getting more memory than necessary for patterns with classes that
2837     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2839     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2840     compiling PCRE for use with Virtual Pascal.
2842     22. Small fix to the Makefile to make it work properly if the build is done
2843     outside the source tree.
2845     23. Added a new extension: a condition to go with recursion. If a conditional
2846     subpattern starts with (?(R) the "true" branch is used if recursion has
2847     happened, whereas the "false" branch is used only at the top level.
2849     24. When there was a very long string of literal characters (over 255 bytes
2850     without UTF support, over 250 bytes with UTF support), the computation of how
2851     much memory was required could be incorrect, leading to segfaults or other
2852     strange effects.
2854     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2855     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2856     there was a subsequent back reference to those brackets. This meant that, for
2857     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2858     possible to check for precisely this case. All we can do is abandon the
2859     optimization if .* occurs inside capturing brackets when there are any back
2860     references whatsoever. (See below for a better fix that came later.)
2862     26. The handling of the optimization for finding the first character of a
2863     non-anchored pattern, and for finding a character that is required later in the
2864     match were failing in some cases. This didn't break the matching; it just
2865     failed to optimize when it could. The way this is done has been re-implemented.
2867     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2869     28. Added a new feature that provides some of the functionality that Perl
2870     provides with (?{...}). The facility is termed a "callout". The way it is done
2871     in PCRE is for the caller to provide an optional function, by setting
2872     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2873     global variable. By default it is unset, which disables all calling out. To get
2874     the function called, the regex must include (?C) at appropriate points. This
2875     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2876     This provides a means of identifying different callout points. When PCRE
2877     reaches such a point in the regex, if pcre_callout has been set, the external
2878     function is called. It is provided with data in a structure called
2879     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2880     matching continues; if it returns a non-zero value, the match at the current
2881     point fails. However, backtracking will occur if possible. [This was changed
2882     later and other features added - see item 49 below.]
2884     29. pcretest is upgraded to test the callout functionality. It provides a
2885     callout function that displays information. By default, it shows the start of
2886     the match and the current position in the text. There are some new data escapes
2887     to vary what happens:
2889     \C+ in addition, show current contents of captured substrings
2890     \C- do not supply a callout function
2891     \C!n return 1 when callout number n is reached
2892     \C!n!m return 1 when callout number n is reached for the mth time
2894     30. If pcregrep was called with the -l option and just a single file name, it
2895     output "<stdin>" if a match was found, instead of the file name.
2897     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2898     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2899     pcre_exec(). This saves a malloc/free per call. The default value of
2900     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2901     when configuring.
2903     32. The default maximum size of a compiled pattern is 64K. There have been a
2904     few cases of people hitting this limit. The code now uses macros to handle the
2905     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2906     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2907     configuring. Tests 2 and 5 work only with 2-byte links because they output
2908     debugging information about compiled patterns.
2910     33. Internal code re-arrangements:
2912     (a) Moved the debugging function for printing out a compiled regex into
2913     its own source file (printint.c) and used #include to pull it into
2914     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2915     separate copies.
2917     (b) Defined the list of op-code names for debugging as a macro in
2918     internal.h so that it is next to the definition of the opcodes.
2920     (c) Defined a table of op-code lengths for simpler skipping along compiled
2921     code. This is again a macro in internal.h so that it is next to the
2922     definition of the opcodes.
2924     34. Added support for recursive calls to individual subpatterns, along the
2925     lines of Robin Houston's patch (but implemented somewhat differently).
2927     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2928     allow it to read and process whole directories in Win32. This code was
2929     contributed by Lionel Fourquaux; it has not been tested by me.
2931     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2932     used to name a group. Names consist of alphanumerics and underscores, and must
2933     be unique. Back references use the syntax (?P=name) and recursive calls use
2934     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2935     numbers. The function pcre_fullinfo() can be used after compilation to extract
2936     a name/number map. There are three relevant calls:
2938     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2939     PCRE_INFO_NAMECOUNT yields the number of entries
2940     PCRE_INFO_NAMETABLE yields a pointer to the map.
2942     The map is a vector of fixed-size entries. The size of each entry depends on
2943     the length of the longest name used. The first two bytes of each entry are the
2944     group number, most significant byte first. There follows the corresponding
2945     name, zero terminated. The names are in alphabetical order.
2947     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2948     case instead of 255. Making it the same both with and without UTF-8 support
2949     means that the same test output works with both.
2951     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2952     calling malloc() with a zero argument.
2954     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2955     optimization. I've improved things by keeping a bitmap of backreferences with
2956     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2957     fact referenced, the optimization can be applied. It is unlikely that a
2958     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2959     the match to follow \n) will appear inside brackets with a number greater than
2960     31, but if it does, any back reference > 31 suppresses the optimization.
2962     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2963     of disabling numbered capturing parentheses. Any opening parenthesis that is
2964     not followed by ? behaves as if it were followed by ?: but named parentheses
2965     can still be used for capturing (and they will acquire numbers in the usual
2966     way).
2968     41. Redesigned the return codes from the match() function into yes/no/error so
2969     that errors can be passed back from deep inside the nested calls. A malloc
2970     failure while inside a recursive subpattern call now causes the
2971     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2973     42. It is now possible to set a limit on the number of times the match()
2974     function is called in a call to pcre_exec(). This facility makes it possible to
2975     limit the amount of recursion and backtracking, though not in a directly
2976     obvious way, because the match() function is used in a number of different
2977     circumstances. The count starts from zero for each position in the subject
2978     string (for non-anchored patterns). The default limit is, for compatibility, a
2979     large number, namely 10 000 000. You can change this in two ways:
2981     (a) When configuring PCRE before making, you can use --with-match-limit=n
2982     to set a default value for the compiled library.
2984     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2985     a different value is set. See 45 below.
2987     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2989     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2990     of things that can be changed at compile time. The first argument specifies
2991     what is wanted and the second points to where the information is to be placed.
2992     The current list of available information is:
2996     The output is an integer that is set to one if UTF-8 support is available;
2997     otherwise it is set to zero.
3001     The output is an integer that it set to the value of the code that is used for
3002     newline. It is either LF (10) or CR (13).
3006     The output is an integer that contains the number of bytes used for internal
3007     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
3011     The output is an integer that contains the threshold above which the POSIX
3012     interface uses malloc() for output vectors. See item 31 above.
3016     The output is an unsigned integer that contains the default limit of the number
3017     of match() calls in a pcre_exec() execution. See 42 above.
3019     44. pcretest has been upgraded by the addition of the -C option. This causes it
3020     to extract all the available output from the new pcre_config() function, and to
3021     output it. The program then exits immediately.
3023     45. A need has arisen to pass over additional data with calls to pcre_exec() in
3024     order to support additional features. One way would have been to define
3025     pcre_exec2() (for example) with extra arguments, but this would not have been
3026     extensible, and would also have required all calls to the original function to
3027     be mapped to the new one. Instead, I have chosen to extend the mechanism that
3028     is used for passing in "extra" data from pcre_study().
3030     The pcre_extra structure is now exposed and defined in pcre.h. It currently
3031     contains the following fields:
3033     flags a bitmap indicating which of the following fields are set
3034     study_data opaque data from pcre_study()
3035     match_limit a way of specifying a limit on match() calls for a specific
3036     call to pcre_exec()
3037     callout_data data for callouts (see 49 below)
3039     The flag bits are also defined in pcre.h, and are
3045     The pcre_study() function now returns one of these new pcre_extra blocks, with
3046     the actual study data pointed to by the study_data field, and the
3047     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
3048     before. That is, this change is entirely upwards-compatible and requires no
3049     change to existing code.
3051     If you want to pass in additional data to pcre_exec(), you can either place it
3052     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
3053     block.
3055     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
3056     data string contains the escape sequence \M, pcretest calls pcre_exec() several
3057     times with different match limits, until it finds the minimum value needed for
3058     pcre_exec() to complete. The value is then output. This can be instructive; for
3059     most simple matches the number is quite small, but for pathological cases it
3060     gets very large very quickly.
3062     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
3063     returns the size of the data block pointed to by the study_data field in a
3064     pcre_extra block, that is, the value that was passed as the argument to
3065     pcre_malloc() when PCRE was getting memory in which to place the information
3066     created by pcre_study(). The fourth argument should point to a size_t variable.
3067     pcretest has been extended so that this information is shown after a successful
3068     pcre_study() call when information about the compiled regex is being displayed.
3070     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
3071     because what follows is always an absolute path. (Later: it turns out that this
3072     is more than cosmetic for MinGW, because it doesn't like empty path
3073     components.)
3075     49. Some changes have been made to the callout feature (see 28 above):
3077     (i) A callout function now has three choices for what it returns:
3079     0 => success, carry on matching
3080     > 0 => failure at this point, but backtrack if possible
3081     < 0 => serious error, return this value from pcre_exec()
3083     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
3084     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
3085     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
3086     use by callout functions. It will never be used by PCRE itself.
3088     (ii) The pcre_extra structure (see 45 above) has a void * field called
3089     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
3090     pcre_callout_block structure has a field of the same name. The contents of
3091     the field passed in the pcre_extra structure are passed to the callout
3092     function in the corresponding field in the callout block. This makes it
3093     easier to use the same callout-containing regex from multiple threads. For
3094     testing, the pcretest program has a new data escape
3096     \C*n pass the number n (may be negative) as callout_data
3098     If the callout function in pcretest receives a non-zero value as
3099     callout_data, it returns that value.
3101     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
3102     there were some redundant $(CFLAGS) in commands that are now specified as
3103     $(LINK), which already includes $(CFLAGS).
3105     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
3106     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
3107     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
3108     one-byte characters throughout. Note that case-insensitive matching applies
3109     only to characters whose values are less than 256. PCRE doesn't support the
3110     notion of cases for higher-valued characters.
3112     (i) A character class whose characters are all within 0-255 is handled as
3113     a bit map, and the map is inverted for negative classes. Previously, a
3114     character > 255 always failed to match such a class; however it should
3115     match if the class was a negative one (e.g. [^ab]). This has been fixed.
3117     (ii) A negated character class with a single character < 255 is coded as
3118     "not this character" (OP_NOT). This wasn't working properly when the test
3119     character was multibyte, either singly or repeated.
3121     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
3122     mode, for example: \x{100}{2,3}.
3124     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
3125     singly or repeated) now correctly test multibyte characters. However,
3126     PCRE doesn't recognize any characters with values greater than 255 as
3127     digits, spaces, or word characters. Such characters always match \D, \S,
3128     and \W, and never match \d, \s, or \w.
3130     (v) Classes may now contain characters and character ranges with values
3131     greater than 255. For example: [ab\x{100}-\x{400}].
3133     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
3134     PCRE in UTF-8 mode.
3136     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
3137     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
3138     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
3139     value.)
3141     53. The single man page has become too large. I have therefore split it up into
3142     a number of separate man pages. These also give rise to individual HTML pages;
3143     these are now put in a separate directory, and there is an index.html page that
3144     lists them all. Some hyperlinking between the pages has been installed.
3146     54. Added convenience functions for handling named capturing parentheses.
3148     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3149     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3150     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3151     are faulted.
3153     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3154     calling configure. These values are used when compiling the dftables.c program
3155     which is run to generate the source of the default character tables. They
3156     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3157     you will need to set these values.
3159     57. Updated the building process for Windows DLL, as provided by Fred Cox.
3162     Version 3.9 02-Jan-02
3163 nigel 61 ---------------------
3165     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3167     2. If --disable-static was given, the building process failed when trying to
3168     build pcretest and pcregrep. (For some reason it was using libtool to compile
3169     them, which is not right, as they aren't part of the library.)
3172 nigel 59 Version 3.8 18-Dec-01
3173     ---------------------
3175     1. The experimental UTF-8 code was completely screwed up. It was packing the
3176     bytes in the wrong order. How dumb can you get?
3179 nigel 57 Version 3.7 29-Oct-01
3180     ---------------------
3182     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
3183     This caused pcretest, when used on the test data, to segfault. Unfortunately,
3184     this didn't happen under Solaris 8, where I normally test things.
3186 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
3187     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
3188     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
3189     this fix an hour or so after the initial 3.7 release.)
3190 nigel 57
3191 nigel 59
3192 nigel 55 Version 3.6 23-Oct-01
3193     ---------------------
3195     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
3196     offsets passed as NULL with zero offset count.
3198     2. The config.guess and config.sub files had not been updated when I moved to
3199     the latest autoconf.
3202 nigel 53 Version 3.5 15-Aug-01
3203     ---------------------
3204 nigel 5
3205 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
3206     had been forgotten.
3208     2. By using declared but undefined structures, we can avoid using "void"
3209     definitions in pcre.h while keeping the internal definitions of the structures
3210     private.
3212     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3213     user point of view, this means that both static and shared libraries are built
3214     by default, but this can be individually controlled. More of the work of
3215     handling this static/shared cases is now inside libtool instead of PCRE's make
3216     file.
3218     4. The pcretest utility is now installed along with pcregrep because it is
3219     useful for users (to test regexs) and by doing this, it automatically gets
3220     relinked by libtool. The documentation has been turned into a man page, so
3221     there are now .1, .txt, and .html versions in /doc.
3223     5. Upgrades to pcregrep:
3224     (i) Added long-form option names like gnu grep.
3225     (ii) Added --help to list all options with an explanatory phrase.
3226     (iii) Added -r, --recursive to recurse into sub-directories.
3227     (iv) Added -f, --file to read patterns from a file.
3229     6. pcre_exec() was referring to its "code" argument before testing that
3230     argument for NULL (and giving an error if it was NULL).
3232     7. Upgraded Makefile.in to allow for compiling in a different directory from
3233     the source directory.
3235     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3236     options bits, the pointer it was passed was to an int instead of to an unsigned
3237     long int. This mattered only on 64-bit systems.
3239     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3240     generated) instead of pcre.in, which it its source. Also made the same change
3241     in several of the .c files.
3243     10. A new release of gcc defines printf() as a macro, which broke pcretest
3244     because it had an ifdef in the middle of a string argument for printf(). Fixed
3245     by using separate calls to printf().
3247     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3248     script, to force use of CR or LF instead of \n in the source. On non-Unix
3249     systems, the value can be set in config.h.
3251     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3252     absolute limit. Changed the text of the error message to make this clear, and
3253     likewise updated the man page.
3255     13. The limit of 99 on the number of capturing subpatterns has been removed.
3256     The new limit is 65535, which I hope will not be a "real" limit.
3259 nigel 51 Version 3.4 22-Aug-00
3260     ---------------------
3262     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3264     2. Diagnose condition (?(0) as an error instead of crashing on matching.
3267 nigel 49 Version 3.3 01-Aug-00
3268     ---------------------
3270     1. If an octal character was given, but the value was greater than \377, it
3271     was not getting masked to the least significant bits, as documented. This could
3272     lead to crashes in some systems.
3274     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3275     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3277     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3278     These just pass their arguments on to (pcre_free)(), but they are provided
3279     because some uses of PCRE bind it to non-C systems that can call its functions,
3280     but cannot call free() or pcre_free() directly.
3282     4. Add "make test" as a synonym for "make check". Corrected some comments in
3283     the Makefile.
3285     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3286     Makefile.
3288     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3289     command called pgrep for grepping around the active processes.
3291     7. Added the beginnings of support for UTF-8 character strings.
3293     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3294     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3295     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3296     out for the ar command.)
3299 nigel 47 Version 3.2 12-May-00
3300     ---------------------
3302     This is purely a bug fixing release.
3304     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3305     of ZA. This was just one example of several cases that could provoke this bug,
3306     which was introduced by change 9 of version 2.00. The code for breaking
3307     infinite loops after an iteration that matches an empty string was't working
3308     correctly.
3310     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3311     when matched against abbab (for example). After matching an empty string, it
3312     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3313     caused it to match further down the string than it should.
3315     3. The code contained an inclusion of sys/types.h. It isn't clear why this
3316     was there because it doesn't seem to be needed, and it causes trouble on some
3317     systems, as it is not a Standard C header. It has been removed.
3319     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3320     were reported on the Macintosh. The changes were from
3322     while ((c = *(++ptr)) != 0 && c != '\n');
3323     to
3324     while ((c = *(++ptr)) != 0 && c != '\n') ;
3326     Totally extraordinary, but if that's what it takes...
3328     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3329     available. Added HAVE_BCOPY and an autoconf test for it; if neither
3330     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3331     assumes the way PCRE uses memmove() (always moving upwards).
3333     6. PCRE is being used in one environment where strchr() is not available. There
3334     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3335     faster code anyway.
3338 nigel 45 Version 3.1 09-Feb-00
3339     ---------------------
3341     The only change in this release is the fixing of some bugs in Makefile.in for
3342     the "install" target:
3344     (1) It was failing to install pcreposix.h.
3346     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3349 nigel 43 Version 3.0 01-Feb-00
3350     ---------------------
3351 nigel 41
3352     1. Add support for the /+ modifier to perltest (to output $` like it does in
3353     pcretest).
3355     2. Add support for the /g modifier to perltest.
3357     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3358     matches null strings.
3360     4. Fix perltest so that it doesn't do unwanted things when fed an empty
3361     pattern. Perl treats empty patterns specially - it reuses the most recent
3362     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3363     effect.
3365     5. The POSIX interface was broken in that it was just handing over the POSIX
3366     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3367     required a bigger vector, with some working space on the end. This means that
3368     the POSIX wrapper now has to get and free some memory, and copy the results.
3370 nigel 43 6. Added some simple autoconf support, placing the test data and the
3371     documentation in separate directories, re-organizing some of the
3372     information files, and making it build pcre-config (a GNU standard). Also added
3373     libtool support for building PCRE as a shared library, which is now the
3374     default.
3375 nigel 41
3376 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3377     09 are not valid octal constants. Single digits will be used for minor values
3378     less than 10.
3380     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3381     existing programs that set these in the POSIX interface can use PCRE without
3382     modification.
3384     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3385     return all that pcre_info() returns, plus additional data. The pcre_info()
3386     function is retained for compatibility, but is considered to be obsolete.
3388     10. Added experimental recursion feature (?R) to handle one common case that
3389     Perl 5.6 will be able to do with (?p{...}).
3391     11. Added support for POSIX character classes like [:alpha:], which Perl is
3392     adopting.
3395 nigel 39 Version 2.08 31-Aug-99
3396     ----------------------
3398     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3399     trying to match at the startoffset position, but instead was moving forward to
3400     the next newline as if a previous match had failed.
3402     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3403     and could get into a loop if a null string was matched other than at the start
3404     of the subject.
3406     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3407     be distinguished at compile time, and for completeness also added PCRE_DATE.
3409     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3410     in GnuWin32 environments.
3413 nigel 37 Version 2.07 29-Jul-99
3414     ----------------------
3416     1. The documentation is now supplied in plain text form and HTML as well as in
3417     the form of man page sources.
3419     2. C++ compilers don't like assigning (void *) values to other pointer types.
3420     In particular this affects malloc(). Although there is no problem in Standard
3421     C, I've put in casts to keep C++ compilers happy.
3423     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3424     should be (const char *).
3426     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3427     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3428     However, I haven't made this a standard facility. The documentation doesn't
3429     mention it, and the Makefile doesn't support it.
3431     5. The Makefile now contains an "install" target, with editable destinations at
3432     the top of the file. The pcretest program is not installed.
3434     6. pgrep -V now gives the PCRE version number and date.
3436     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3437     causing the entire string to be ignored, instead of just the last character.
3439     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3440     non-matching string, it can take a very, very long time, even for strings of
3441     quite modest length, because of the nested recursion. PCRE now does better in
3442     some of these cases. It does this by remembering the last required literal
3443     character in the pattern, and pre-searching the subject to ensure it is present
3444     before running the real match. In other words, it applies a heuristic to detect
3445     some types of certain failure quickly, and in the above example, if presented
3446     with a string that has no trailing " it gives "no match" very quickly.
3448     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3449     other alternatives are tried instead.
3452 nigel 35 Version 2.06 09-Jun-99
3453     ----------------------
3455     1. Change pcretest's output for amount of store used to show just the code
3456     space, because the remainder (the data block) varies in size between 32-bit and
3457     64-bit systems.
3459     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3460     start matching at. This allows lookbehinds to work when searching for multiple
3461     occurrences in a string.
3463     3. Added additional options to pcretest for testing multiple occurrences:
3465     /+ outputs the rest of the string that follows a match
3466     /g loops for multiple occurrences, using the new startoffset argument
3467     /G loops for multiple occurrences by passing an incremented pointer
3469     4. PCRE wasn't doing the "first character" optimization for patterns starting
3470     with \b or \B, though it was doing it for other lookbehind assertions. That is,
3471     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3472     the letter 'x'. On long subject strings, this gives a significant speed-up.
3475 nigel 33 Version 2.05 21-Apr-99
3476     ----------------------
3478     1. Changed the type of magic_number from int to long int so that it works
3479     properly on 16-bit systems.
3481     2. Fixed a bug which caused patterns starting with .* not to work correctly
3482     when the subject string contained newline characters. PCRE was assuming
3483     anchoring for such patterns in all cases, which is not correct because .* will
3484     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3485     DOTALL is set at top level; otherwise it knows that patterns starting with .*
3486     must be retried after every newline in the subject.
3489 nigel 31 Version 2.04 18-Feb-99
3490     ----------------------
3492     1. For parenthesized subpatterns with repeats whose minimum was zero, the
3493     computation of the store needed to hold the pattern was incorrect (too large).
3494     If such patterns were nested a few deep, this could multiply and become a real
3495     problem.
3497     2. Added /M option to pcretest to show the memory requirement of a specific
3498     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3500     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3501     compiled in such a way that the backtracking after subsequent failure was
3502     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3503     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3506 nigel 29 Version 2.03 02-Feb-99
3507     ----------------------
3509     1. Fixed typo and small mistake in man page.
3511 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
3512     LICENCE file containing the conditions.
3513 nigel 29
3514     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3515     Perl, that is the internal \ allows the delimiter to be included in the
3516     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3517     the final delimiter, add \ to the end of the pattern (to test the error).
3519     4. Added the convenience functions for extracting substrings after a successful
3520     match. Updated pcretest to make it able to test these functions.
3523 nigel 27 Version 2.02 14-Jan-99
3524     ----------------------
3526     1. Initialized the working variables associated with each extraction so that
3527     their saving and restoring doesn't refer to uninitialized store.
3529     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3530     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3531     fix the problem.
3533     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3534     calls, and wasn't printing the correct value for compiling calls. Increased the
3535     default value of LOOPREPEAT, and the number of significant figures in the
3536     times.
3538     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3540     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3541     a building problem on Windows NT with a FAT file system.
3544 nigel 25 Version 2.01 21-Oct-98
3545     ----------------------
3547     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3548     to character tables built by pcre_maketables() in the current locale. If NULL
3549     is passed, the default tables are used.
3552 nigel 23 Version 2.00 24-Sep-98
3553 nigel 21 ----------------------
3555 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3556     it any more.
3558     2. Allow quantification of (?>) groups, and make it work correctly.
3560     3. The first character computation wasn't working for (?>) groups.
3562     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3563     end of the subject) and add 5.005's \z, which really does match only at the
3564     very end of the subject.
3566     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3568     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3569     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3570     localized options. All options to pcre_study() were also removed.
3572     7. Add other new features from 5.005:
3574     $(?<= positive lookbehind
3575     $(?<! negative lookbehind
3576     (?imsx-imsx) added the unsetting capability
3577     such a setting is global if at outer level; local otherwise
3578     (?imsx-imsx:) non-capturing groups with option setting
3579     (?(cond)re|re) conditional pattern matching
3581     A backreference to itself in a repeated group matches the previous
3582     captured string.
3584     8. General tidying up of studying (both automatic and via "study")
3585     consequential on the addition of new assertions.
3587     9. As in 5.005, unlimited repeated groups that could match an empty substring
3588     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3589     runtime if any iteration does actually match an empty substring.
3591     10. Include the RunTest script in the distribution.
3593     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3594     discrepancies, some of which were old and were also with respect to 5.004. They
3595     have now been fixed.
3598     Version 1.09 28-Apr-98
3599     ----------------------
3601 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3602     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3603     program crashes, or just wrong answers. This did not apply to negated classes
3604     containing more than one character, or to minima other than one.
3607 nigel 19 Version 1.08 27-Mar-98
3608     ----------------------
3610     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3612     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3613     latter must appear before anything that relies on it in the pattern.
3616 nigel 17 Version 1.07 16-Feb-98
3617     ----------------------
3619     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3620     repeat of a potentially empty string).
3623 nigel 15 Version 1.06 23-Jan-98
3624     ----------------------
3626     1. Added Markus Oberhumer's little patches for C++.
3628     2. Literal strings longer than 255 characters were broken.
3631 nigel 13 Version 1.05 23-Dec-97
3632     ----------------------
3634     1. Negated character classes containing more than one character were failing if
3635     PCRE_CASELESS was set at run time.
3638 nigel 11 Version 1.04 19-Dec-97
3639     ----------------------
3641     1. Corrected the man page, where some "const" qualifiers had been omitted.
3643     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3644     input syntax.
3646     3. Fixed memory leak which occurred when a regex with back references was
3647     matched with an offsets vector that wasn't big enough. The temporary memory
3648     that is used in this case wasn't being freed if the match failed.
3650     4. Tidied pcretest to ensure it frees memory that it gets.
3652     5. Temporary memory was being obtained in the case where the passed offsets
3653     vector was exactly big enough.
3655     6. Corrected definition of offsetof() from change 5 below.
3657     7. I had screwed up change 6 below and broken the rules for the use of
3658     setjmp(). Now fixed.
3661 nigel 9 Version 1.03 18-Dec-97
3662     ----------------------
3664     1. A erroneous regex with a missing opening parenthesis was correctly
3665     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3666     on some systems.
3668     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3669     it was reported that one broken compiler failed on the former because "code" is
3670     also an independent variable.
3672     3. The erroneous regex a[]b caused an array overrun reference.
3674     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3675     fail on data ending with that character. (It was going on too far, and checking
3676     the next character, typically a binary zero.) This was specific to the
3677     optimized code for single-character negative classes.
3679     5. Added a contributed patch from the TIN world which does the following:
3681     + Add an undef for memmove, in case the the system defines a macro for it.
3683     + Add a definition of offsetof(), in case there isn't one. (I don't know
3684     the reason behind this - offsetof() is part of the ANSI standard - but
3685     it does no harm).
3687     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3688     most of the places where whitespace preceded '#'. I have given up and
3689     allowed the remaining 2 cases to be at the margin.
3691     + Rename some variables in pcre to eliminate shadowing. This seems very
3692     pedantic, but does no harm, of course.
3694     6. Moved the call to setjmp() into its own function, to get rid of warnings
3695     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3697     7. Constructs such as \d{8,} were compiling into the equivalent of
3698 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3699 nigel 9 outcome, but in this particular case used more store than had been allocated,
3700     which caused the bug to be discovered because it threw up an internal error.
3702     8. The debugging code in both pcre and pcretest for outputting the compiled
3703     form of a regex was going wrong in the case of back references followed by
3704     curly-bracketed repeats.
3707 nigel 7 Version 1.02 12-Dec-97
3708     ----------------------
3710     1. Typos in pcre.3 and comments in the source fixed.
3712     2. Applied a contributed patch to get rid of places where it used to remove
3713     'const' from variables, and fixed some signed/unsigned and uninitialized
3714     variable warnings.
3716     3. Added the "runtest" target to Makefile.
3718     4. Set default compiler flag to -O2 rather than just -O.
3721 nigel 5 Version 1.01 19-Nov-97
3722     ----------------------
3724     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3725     like /([ab]*)*/, that is, for classes with more than one character in them.
3727     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3728     as /((?>a*))*/ (a PCRE_EXTRA facility).
3731     Version 1.00 18-Nov-97
3732     ----------------------
3734     1. Added compile-time macros to support systems such as SunOS4 which don't have
3735     memmove() or strerror() but have other things that can be used instead.
3737     2. Arranged that "make clean" removes the executables.
3740 nigel 3 Version 0.99 27-Oct-97
3741     ----------------------
3743     1. Fixed bug in code for optimizing classes with only one character. It was
3744     initializing a 32-byte map regardless, which could cause it to run off the end
3745     of the memory it had got.
3747     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3750     Version 0.98 22-Oct-97
3751     ----------------------
3753     1. Fixed bug in code for handling temporary memory usage when there are more
3754     back references than supplied space in the ovector. This could cause segfaults.
3757     Version 0.97 21-Oct-97
3758     ----------------------
3760     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3762     2. Optimized negated single characters not to use a bit map.
3764     3. Brought error texts together as macro definitions; clarified some of them;
3765     fixed one that was wrong - it said "range out of order" when it meant "invalid
3766     escape sequence".
3768     4. Changed some char * arguments to const char *.
3770     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3772     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3773     pcretest.
3776     Version 0.96 16-Oct-97
3777     ----------------------
3779     1. Added a simple "pgrep" utility to the distribution.
3781     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3782     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3783     where "ddd" means "one or more decimal digits".