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Revision 556 - (hide annotations) (download)
Tue Oct 26 11:06:44 2010 UTC (4 years, 5 months ago) by ph10
File size: 192559 byte(s)
Fix #-comment bugs in UTF-8 mode with PCRE_NEWLINE_ANY.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 550 Version 8.11 10-Oct-2010
5     ------------------------
7     1. (*THEN) was not working properly if there were untried alternatives prior
8     to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
9     backtracked to try for "b" instead of moving to the next alternative branch
10     at the same level (in this case, to look for "c"). The Perl documentation
11     is clear that when (*THEN) is backtracked onto, it goes to the "next
12     alternative in the innermost enclosing group".
13 ph10 551
14     2. (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
15     such as (A(*COMMIT)B(*THEN)C|D) any failure after matching A should
16     result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
17     (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
18     (*THEN).
19 ph10 552
20     3. If \s appeared in a character class, it removed the VT character from
21     the class, even if it had been included by some previous item, for example
22     in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
23     of \s, but is part of the POSIX "space" class.)
24 ph10 553
25     4. A partial match never returns an empty string (because you can always
26     match an empty string at the end of the subject); however the checking for
27     an empty string was starting at the "start of match" point. This has been
28     changed to the "earliest inspected character" point, because the returned
29     data for a partial match starts at this character. This means that, for
30     example, /(?<=abc)def/ gives a partial match for the subject "abc"
31     (previously it gave "no match").
32 ph10 550
33 ph10 553 5. Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
34     of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
35     previously a full match would be given. However, setting PCRE_PARTIAL_HARD
36     has an implication that the given string is incomplete (because a partial
37     match is preferred over a full match). For this reason, these items now
38     give a partial match in this situation. [Aside: previously, the one case
39     /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
40     match rather than a full match, which was wrong by the old rules, but is
41     now correct.]
42 ph10 556
43     6. There was a bug in the handling of #-introduced comments, recognized when
44     PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
45     If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
46     UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
47     scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
48     but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
49     places in pcre_compile().
51     7. Related to (6) above, when pcre_compile() was skipping #-introduced
52     comments when looking ahead for named forward references to subpatterns,
53     the only newline sequence it recognized was NL. It now handles newlines
54     according to the set newline convention.
55 ph10 550
56 ph10 553
57 ph10 548 Version 8.10 25-Jun-2010
58 ph10 510 ------------------------
60 ph10 512 1. Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
61 ph10 510 THEN.
63 ph10 512 2. (*ACCEPT) was not working when inside an atomic group.
64 ph10 510
65 ph10 535 3. Inside a character class, \B is treated as a literal by default, but
66     faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
67 ph10 513 causes the error). The code is unchanged, but I tidied the documentation.
68 ph10 535
69     4. Inside a character class, PCRE always treated \R and \X as literals,
70 ph10 513 whereas Perl faults them if its -w option is set. I have changed PCRE so
71     that it faults them when PCRE_EXTRA is set.
72 ph10 535
73 ph10 514 5. Added support for \N, which always matches any character other than
74     newline. (It is the same as "." when PCRE_DOTALL is not set.)
75 ph10 535
76 ph10 515 6. When compiling pcregrep with newer versions of gcc which may have
77 ph10 535 FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
78 ph10 515 declared with attribute warn_unused_result" were given. Just casting the
79 ph10 535 result to (void) does not stop the warnings; a more elaborate fudge is
80     needed. I've used a macro to implement this.
81 ph10 512
82 ph10 535 7. Minor change to pcretest.c to avoid a compiler warning.
84 ph10 517 8. Added four artifical Unicode properties to help with an option to make
85 ph10 518 \s etc use properties (see next item). The new properties are: Xan
86     (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
87 ph10 535
88 ph10 518 9. Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
89 ph10 535 use Unicode properties. (*UCP) at the start of a pattern can be used to set
90 ph10 518 this option. Modified pcretest to add /W to test this facility. Added
91     REG_UCP to make it available via the POSIX interface.
92 ph10 513
93 ph10 535 10. Added --line-buffered to pcregrep.
95     11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
96     studied, and the match started with a letter with a code point greater than
97 ph10 520 127 whose first byte was different to the first byte of the other case of
98 ph10 545 the letter, the other case of this starting letter was not recognized
99 ph10 536 (#976).
100 ph10 535
101 ph10 536 12. If a pattern that was studied started with a repeated Unicode property
102 ph10 523 test, for example, \p{Nd}+, there was the theoretical possibility of
103 ph10 535 setting up an incorrect bitmap of starting bytes, but fortunately it could
104     not have actually happened in practice until change 8 above was made (it
105 ph10 523 added property types that matched character-matching opcodes).
106 ph10 535
107 ph10 536 13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
108 ph10 535 possible starting bytes for non-anchored patterns.
110 ph10 536 14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
111 ph10 535 \R, and also a number of cases that involve Unicode properties, both
112 ph10 532 explicit and implicit when PCRE_UCP is set.
113 ph10 529
114 ph10 536 15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
115 ph10 535 input, it could crash or give wrong results if characters with values
116     greater than 0xc0 were present in the subject string. (Detail: it assumed
117 ph10 529 UTF-8 input when processing these items.)
118 ph10 535
119 ph10 536 16. Added a lot of (int) casts to avoid compiler warnings in systems where
120     size_t is 64-bit (#991).
121 ph10 535
122 ph10 536 17. Added a check for running out of memory when PCRE is compiled with
123     --disable-stack-for-recursion (#990).
124 ph10 545
125 ph10 537 18. If the last data line in a file for pcretest does not have a newline on
126 ph10 545 the end, a newline was missing in the output.
128     19. The default pcre_chartables.c file recognizes only ASCII characters (values
129     less than 128) in its various bitmaps. However, there is a facility for
130     generating tables according to the current locale when PCRE is compiled. It
131     turns out that in some environments, 0x85 and 0xa0, which are Unicode space
132     characters, are recognized by isspace() and therefore were getting set in
133 ph10 541 these tables, and indeed these tables seem to approximate to ISO 8859. This
134     caused a problem in UTF-8 mode when pcre_study() was used to create a list
135     of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
136     which of course cannot start UTF-8 characters. I have changed the code so
137     that only real ASCII characters (less than 128) and the correct starting
138 ph10 545 bytes for UTF-8 encodings are set for characters greater than 127 when in
139 ph10 541 UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
140     altogether.)
141 ph10 545
142 ph10 541 20. Added the /T option to pcretest so as to be able to run tests with non-
143     standard character tables, thus making it possible to include the tests
144 ph10 545 used for 19 above in the standard set of tests.
146     21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
147     reference to a subpattern the other side of a comment that contains an
148     opening parenthesis caused either an internal compiling error, or a
149 ph10 544 reference to the wrong subpattern.
150 ph10 517
151 ph10 520
152 ph10 508 Version 8.02 19-Mar-2010
153 ph10 491 ------------------------
155     1. The Unicode data tables have been updated to Unicode 5.2.0.
157 ph10 492 2. Added the option --libs-cpp to pcre-config, but only when C++ support is
158     configured.
159 ph10 507
160 ph10 493 3. Updated the licensing terms in the pcregexp.pas file, as agreed with the
161 ph10 507 original author of that file, following a query about its status.
163     4. On systems that do not have stdint.h (e.g. Solaris), check for and include
164 ph10 494 inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
165 ph10 507
166 ph10 496 5. A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
167     quantifier applied to a forward-referencing subroutine call, could compile
168     incorrect code or give the error "internal error: previously-checked
169     referenced subpattern not found".
170 ph10 507
171     6. Both MS Visual Studio and Symbian OS have problems with initializing
172 ph10 497 variables to point to external functions. For these systems, therefore,
173     pcre_malloc etc. are now initialized to local functions that call the
174     relevant global functions.
175 ph10 507
176 ph10 498 7. There were two entries missing in the vectors called coptable and poptable
177     in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
178 ph10 507 I've fixed the data, and added a kludgy way of testing at compile time that
179     the lengths are correct (equal to the number of opcodes).
181     8. Following on from 7, I added a similar kludge to check the length of the
182     eint vector in pcreposix.c.
184     9. Error texts for pcre_compile() are held as one long string to avoid too
185     much relocation at load time. To find a text, the string is searched,
186 ph10 499 counting zeros. There was no check for running off the end of the string,
187     which could happen if a new error number was added without updating the
188 ph10 507 string.
190     10. \K gave a compile-time error if it appeared in a lookbehind assersion.
192 ph10 500 11. \K was not working if it appeared in an atomic group or in a group that
193 ph10 507 was called as a "subroutine", or in an assertion. Perl 5.11 documents that
194     \K is "not well defined" if used in an assertion. PCRE now accepts it if
195     the assertion is positive, but not if it is negative.
197 ph10 501 12. Change 11 fortuitously reduced the size of the stack frame used in the
198 ph10 507 "match()" function of pcre_exec.c by one pointer. Forthcoming
199     implementation of support for (*MARK) will need an extra pointer on the
200 ph10 501 stack; I have reserved it now, so that the stack frame size does not
201     decrease.
202 ph10 507
203     13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
204     item in branch that calls a recursion is a subroutine call - as in the
205 ph10 503 second branch in the above example - was incorrectly given the compile-
206     time error "recursive call could loop indefinitely" because pcre_compile()
207 ph10 507 was not correctly checking the subroutine for matching a non-empty string.
209 ph10 505 14. The checks for overrunning compiling workspace could trigger after an
210 ph10 507 overrun had occurred. This is a "should never occur" error, but it can be
211 ph10 505 triggered by pathological patterns such as hundreds of nested parentheses.
212 ph10 507 The checks now trigger 100 bytes before the end of the workspace.
213 ph10 491
214 ph10 507 15. Fix typo in configure.ac: "srtoq" should be "strtoq".
215 ph10 492
216 ph10 507
217 ph10 489 Version 8.01 19-Jan-2010
218     ------------------------
219 ph10 471
220     1. If a pattern contained a conditional subpattern with only one branch (in
221 ph10 489 particular, this includes all (*DEFINE) patterns), a call to pcre_study()
222 ph10 473 computed the wrong minimum data length (which is of course zero for such
223 ph10 489 subpatterns). This could cause incorrect "no match" results.
224 ph10 473
225     2. For patterns such as (?i)a(?-i)b|c where an option setting at the start of
226 ph10 472 the pattern is reset in the first branch, pcre_compile() failed with
227     "internal error: code overflow at offset...". This happened only when
228 ph10 473 the reset was to the original external option setting. (An optimization
229     abstracts leading options settings into an external setting, which was the
230 ph10 472 cause of this.)
231 ph10 471
232 ph10 473 3. A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
233     of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
234     assertion pattern did not match (meaning that the assertion was true), it
235     was incorrectly treated as false if the SKIP had been reached during the
236     matching. This also applied to assertions used as conditions.
237 ph10 471
238 ph10 473 4. If an item that is not supported by pcre_dfa_exec() was encountered in an
239     assertion subpattern, including such a pattern used as a condition,
240     unpredictable results occurred, instead of the error return
242 ph10 478
243 ph10 474 5. The C++ GlobalReplace function was not working like Perl for the special
244     situation when an empty string is matched. It now does the fancy magic
245 ph10 478 stuff that is necessary.
247     6. In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
248 ph10 475 removed. (These were left over from very, very early versions of PCRE.)
249 ph10 478
250 ph10 475 7. Some cosmetic changes to the code to make life easier when compiling it
251     as part of something else:
252 ph10 478
253     (a) Change DEBUG to PCRE_DEBUG.
255     (b) In pcre_compile(), rename the member of the "branch_chain" structure
256     called "current" as "current_branch", to prevent a collision with the
257 ph10 475 Linux macro when compiled as a kernel module.
258 ph10 478
259     (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
260     prevent a collision with the Linux macro when compiled as a kernel
261 ph10 475 module.
262 ph10 478
263 ph10 475 8. In pcre_compile() there are some checks for integer overflows that used to
264     cast potentially large values to (double). This has been changed to that
265 ph10 478 when building, a check for int64_t is made, and if it is found, it is used
266     instead, thus avoiding the use of floating point arithmetic. (There is no
267     other use of FP in PCRE.) If int64_t is not found, the fallback is to
268     double.
270     9. Added two casts to avoid signed/unsigned warnings from VS Studio Express
271 ph10 476 2005 (difference between two addresses compared to an unsigned value).
272 ph10 473
273 ph10 478 10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
274     custom one, because of the following reported problem in Windows:
275 ph10 473
276 ph10 478 - libbz2 uses the Pascal calling convention (WINAPI) for the functions
277 ph10 489 under Win32.
278 ph10 478 - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
279 ph10 489 therefore missing the function definition.
280 ph10 478 - The compiler thus generates a "C" signature for the test function.
281     - The linker fails to find the "C" function.
282     - PCRE fails to configure if asked to do so against libbz2.
283 ph10 486
284 ph10 479 11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
285     messages were output:
286 ph10 478
287 ph10 479 Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
288     rerunning libtoolize, to keep the correct libtool macros in-tree.
289     Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
290 ph10 486
291 ph10 479 I have done both of these things.
292 ph10 486
293 ph10 480 12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
294 ph10 486 most of the time, it *can* run out if it is given a pattern that contains a
295     runaway infinite recursion. I updated the discussion in the pcrestack man
296     page.
298     13. Now that we have gone to the x.xx style of version numbers, the minor
299     version may start with zero. Using 08 or 09 is a bad idea because users
300     might check the value of PCRE_MINOR in their code, and 08 or 09 may be
301     interpreted as invalid octal numbers. I've updated the previous comment in
302     configure.ac, and also added a check that gives an error if 08 or 09 are
303 ph10 481 used.
304 ph10 486
305 ph10 482 14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
306 ph10 483 causing partial matching to fail when the end of the subject matched \W
307     in a UTF-8 pattern where \W was quantified with a minimum of 3.
308 ph10 486
309 ph10 483 15. There were some discrepancies between the declarations in pcre_internal.h
310 ph10 486 of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
311 ph10 483 their definitions. The declarations used "const uschar *" and the
312     definitions used USPTR. Even though USPTR is normally defined as "const
313     unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
314     reported that: "This difference in casting confuses some C++ compilers, for
315     example, SunCC recognizes above declarations as different functions and
316 ph10 486 generates broken code for hbpcre." I have changed the declarations to use
317 ph10 483 USPTR.
318 ph10 486
319     16. GNU libtool is named differently on some systems. The autogen.sh script now
320 ph10 484 tries several variants such as glibtoolize (MacOSX) and libtoolize1x
321     (FreeBSD).
322 ph10 478
323 ph10 486 17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
324     (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
325     comment: "Figure out how to create a longlong from a string: strtoll and
326     equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
327     instance, but it only takes 2 args instead of 3!"
328 ph10 479
329 ph10 488 18. A subtle bug concerned with back references has been fixed by a change of
330     specification, with a corresponding code fix. A pattern such as
331     ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
332     refers, was giving matches when it shouldn't. For example, xa=xaaa would
333     match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
334     same bug. Such groups have to be quantified to be useful, or contained
335     inside another quantified group. (If there's no repetition, the reference
336     can never match.) The problem arises because, having left the group and
337     moved on to the rest of the pattern, a later failure that backtracks into
338     the group uses the captured value from the final iteration of the group
339     rather than the correct earlier one. I have fixed this in PCRE by forcing
340     any group that contains a reference to itself to be an atomic group; that
341     is, there cannot be any backtracking into it once it has completed. This is
342     similar to recursive and subroutine calls.
343 ph10 486
344 ph10 488
345 ph10 469 Version 8.00 19-Oct-09
346 ph10 418 ----------------------
348     1. The table for translating pcre_compile() error codes into POSIX error codes
349 ph10 461 was out-of-date, and there was no check on the pcre_compile() error code
350     being within the table. This could lead to an OK return being given in
351 ph10 418 error.
352 ph10 461
353     2. Changed the call to open a subject file in pcregrep from fopen(pathname,
354     "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
355     in a Windows environment.
357 ph10 420 3. The pcregrep --count option prints the count for each file even when it is
358     zero, as does GNU grep. However, pcregrep was also printing all files when
359     --files-with-matches was added. Now, when both options are given, it prints
360     counts only for those files that have at least one match. (GNU grep just
361 ph10 461 prints the file name in this circumstance, but including the count seems
362     more useful - otherwise, why use --count?) Also ensured that the
363 ph10 420 combination -clh just lists non-zero counts, with no names.
364 ph10 461
365     4. The long form of the pcregrep -F option was incorrectly implemented as
366     --fixed_strings instead of --fixed-strings. This is an incompatible change,
367     but it seems right to fix it, and I didn't think it was worth preserving
368     the old behaviour.
370     5. The command line items --regex=pattern and --regexp=pattern were not
371 ph10 422 recognized by pcregrep, which required --regex pattern or --regexp pattern
372 ph10 461 (with a space rather than an '='). The man page documented the '=' forms,
373 ph10 422 which are compatible with GNU grep; these now work.
374 ph10 461
375     6. No libpcreposix.pc file was created for pkg-config; there was just
376 ph10 423 libpcre.pc and libpcrecpp.pc. The omission has been rectified.
377 ph10 461
378 ph10 425 7. Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
379 ph10 461 when UCP support is not needed, by modifying the Python script that
380 ph10 425 generates it from Unicode data files. This should not matter if the module
381     is correctly used as a library, but I received one complaint about 50K of
382     unwanted data. My guess is that the person linked everything into his
383     program rather than using a library. Anyway, it does no harm.
384 ph10 461
385 ph10 426 8. A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
386 ph10 461 was a minimum greater than 1 for a wide character in a possessive
387 ph10 431 repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
388     which had an unlimited repeat of a nested, fixed maximum repeat of a wide
389     character. Chaos in the form of incorrect output or a compiling loop could
390     result.
391 ph10 461
392 ph10 426 9. The restrictions on what a pattern can contain when partial matching is
393 ph10 461 requested for pcre_exec() have been removed. All patterns can now be
394 ph10 426 partially matched by this function. In addition, if there are at least two
395 ph10 435 slots in the offset vector, the offset of the earliest inspected character
396     for the match and the offset of the end of the subject are set in them when
397 ph10 461 PCRE_ERROR_PARTIAL is returned.
399 ph10 428 10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
400     synonymous with PCRE_PARTIAL, for backwards compatibility, and
401     PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
402 ph10 462 and may be more useful for multi-segment matching.
403 ph10 461
404     11. Partial matching with pcre_exec() is now more intuitive. A partial match
405     used to be given if ever the end of the subject was reached; now it is
406     given only if matching could not proceed because another character was
407     needed. This makes a difference in some odd cases such as Z(*FAIL) with the
408     string "Z", which now yields "no match" instead of "partial match". In the
409     case of pcre_dfa_exec(), "no match" is given if every matching path for the
410     final character ended with (*FAIL).
412 ph10 428 12. Restarting a match using pcre_dfa_exec() after a partial match did not work
413 ph10 461 if the pattern had a "must contain" character that was already found in the
414 ph10 428 earlier partial match, unless partial matching was again requested. For
415     example, with the pattern /dog.(body)?/, the "must contain" character is
416     "g". If the first part-match was for the string "dog", restarting with
417 ph10 435 "sbody" failed. This bug has been fixed.
418 ph10 461
419     13. The string returned by pcre_dfa_exec() after a partial match has been
420     changed so that it starts at the first inspected character rather than the
421     first character of the match. This makes a difference only if the pattern
422     starts with a lookbehind assertion or \b or \B (\K is not supported by
423     pcre_dfa_exec()). It's an incompatible change, but it makes the two
424 ph10 435 matching functions compatible, and I think it's the right thing to do.
425 ph10 461
426 ph10 435 14. Added a pcredemo man page, created automatically from the pcredemo.c file,
427 ph10 461 so that the demonstration program is easily available in environments where
428     PCRE has not been installed from source.
430 ph10 435 15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
431 ph10 430 libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
432     library.
433 ph10 461
434 ph10 435 16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
435 ph10 432 It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
436 ph10 461 is not the first non-POSIX option to be added. Clearly some people find
437 ph10 433 these options useful.
438 ph10 461
439     17. If a caller to the POSIX matching function regexec() passes a non-zero
440 ph10 438 value for nmatch with a NULL value for pmatch, the value of
441 ph10 461 nmatch is forced to zero.
443 ph10 437 18. RunGrepTest did not have a test for the availability of the -u option of
444 ph10 461 the diff command, as RunTest does. It now checks in the same way as
445 ph10 437 RunTest, and also checks for the -b option.
446 ph10 461
447 ph10 438 19. If an odd number of negated classes containing just a single character
448     interposed, within parentheses, between a forward reference to a named
449 ph10 461 subpattern and the definition of the subpattern, compilation crashed with
450     an internal error, complaining that it could not find the referenced
451 ph10 438 subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
452 ph10 461 [The bug was that it was starting one character too far in when skipping
453     over the character class, thus treating the ] as data rather than
454     terminating the class. This meant it could skip too much.]
456 ph10 442 20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
457 ph10 461 /g option in pcretest when the pattern contains \K, which makes it possible
458 ph10 442 to have an empty string match not at the start, even when the pattern is
459 ph10 461 anchored. Updated pcretest and pcredemo to use this option.
461 ph10 446 21. If the maximum number of capturing subpatterns in a recursion was greater
462 ph10 461 than the maximum at the outer level, the higher number was returned, but
463     with unset values at the outer level. The correct (outer level) value is
464 ph10 446 now given.
465 ph10 461
466 ph10 447 22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
467     PCRE did not set those parentheses (unlike Perl). I have now found a way to
468     make it do so. The string so far is captured, making this feature
469     compatible with Perl.
470 ph10 461
471     23. The tests have been re-organized, adding tests 11 and 12, to make it
472 ph10 448 possible to check the Perl 5.10 features against Perl 5.10.
473 ph10 461
474 ph10 454 24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
475 ph10 461 pattern matches a fixed length string. PCRE did not allow this; now it
476     does. Neither allows recursion.
478     25. I finally figured out how to implement a request to provide the minimum
479     length of subject string that was needed in order to match a given pattern.
480     (It was back references and recursion that I had previously got hung up
481     on.) This code has now been added to pcre_study(); it finds a lower bound
482 ph10 455 to the length of subject needed. It is not necessarily the greatest lower
483     bound, but using it to avoid searching strings that are too short does give
484     some useful speed-ups. The value is available to calling programs via
485     pcre_fullinfo().
486 ph10 461
487 ph10 455 26. While implementing 25, I discovered to my embarrassment that pcretest had
488     not been passing the result of pcre_study() to pcre_dfa_exec(), so the
489     study optimizations had never been tested with that matching function.
490     Oops. What is worse, even when it was passed study data, there was a bug in
491     pcre_dfa_exec() that meant it never actually used it. Double oops. There
492     were also very few tests of studied patterns with pcre_dfa_exec().
493 ph10 461
494 ph10 457 27. If (?| is used to create subpatterns with duplicate numbers, they are now
495     allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
496     on the other side of the coin, they are no longer allowed to have different
497     names, because these cannot be distinguished in PCRE, and this has caused
498     confusion. (This is a difference from Perl.)
499 ph10 461
500     28. When duplicate subpattern names are present (necessarily with different
501     numbers, as required by 27 above), and a test is made by name in a
502     conditional pattern, either for a subpattern having been matched, or for
503     recursion in such a pattern, all the associated numbered subpatterns are
504 ph10 459 tested, and the overall condition is true if the condition is true for any
505     one of them. This is the way Perl works, and is also more like the way
506     testing by number works.
507 ph10 418
508 ph10 461
509 ph10 412 Version 7.9 11-Apr-09
510 ph10 376 ---------------------
512 ph10 392 1. When building with support for bzlib/zlib (pcregrep) and/or readline
513 ph10 376 (pcretest), all targets were linked against these libraries. This included
514     libpcre, libpcreposix, and libpcrecpp, even though they do not use these
515     libraries. This caused unwanted dependencies to be created. This problem
516 ph10 392 has been fixed, and now only pcregrep is linked with bzlib/zlib and only
517 ph10 376 pcretest is linked with readline.
518 ph10 392
519 ph10 376 2. The "typedef int BOOL" in pcre_internal.h that was included inside the
520     "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
521     moved outside it again, because FALSE and TRUE are already defined in AIX,
522     but BOOL is not.
523 ph10 392
524     3. The pcre_config() function was treating the PCRE_MATCH_LIMIT and
525 ph10 409 PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
526 ph10 392
527 ph10 376 4. The pcregrep documentation said spaces were inserted as well as colons (or
528     hyphens) following file names and line numbers when outputting matching
529 ph10 392 lines. This is not true; no spaces are inserted. I have also clarified the
530 ph10 376 wording for the --colour (or --color) option.
531 ph10 392
532 ph10 378 5. In pcregrep, when --colour was used with -o, the list of matching strings
533     was not coloured; this is different to GNU grep, so I have changed it to be
534     the same.
535 ph10 392
536 ph10 378 6. When --colo(u)r was used in pcregrep, only the first matching substring in
537 ph10 392 each matching line was coloured. Now it goes on to look for further matches
538     of any of the test patterns, which is the same behaviour as GNU grep.
540     7. A pattern that could match an empty string could cause pcregrep to loop; it
541     doesn't make sense to accept an empty string match in pcregrep, so I have
542 ph10 379 locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
543     seems to be how GNU grep behaves.
544 ph10 392
545 ph10 380 8. The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
546 ph10 392 start or after a newline", because the conditional assertion was not being
547     correctly handled. The rule now is that both the assertion and what follows
548     in the first alternative must satisfy the test.
550 ph10 405 9. If auto-callout was enabled in a pattern with a conditional group whose
551 ph10 399 condition was an assertion, PCRE could crash during matching, both with
552     pcre_exec() and pcre_dfa_exec().
553 ph10 392
554     10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
555     used for matching.
557     11. Unicode property support in character classes was not working for
558 ph10 385 characters (bytes) greater than 127 when not in UTF-8 mode.
559 ph10 388
560 ph10 392 12. Added the -M command line option to pcretest.
562 ph10 388 14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
563 ph10 389
564     15. Added the PCRE_NO_START_OPTIMIZE match-time option.
565 ph10 390
566 ph10 392 16. Added comments and documentation about mis-use of no_arg in the C++
567 ph10 390 wrapper.
568 ph10 392
569 ph10 391 17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
570 ph10 392 from Martin Jerabek that uses macro names for all relevant character and
571 ph10 391 string constants.
572 ph10 405
573 ph10 393 18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
574     SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
575 ph10 405 SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
576     these, but not everybody uses configure.
578     19. A conditional group that had only one branch was not being correctly
579     recognized as an item that could match an empty string. This meant that an
580     enclosing group might also not be so recognized, causing infinite looping
581     (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
582     with the subject "ab", where knowledge that the repeated group can match
583 ph10 396 nothing is needed in order to break the loop.
584 ph10 405
585 ph10 397 20. If a pattern that was compiled with callouts was matched using pcre_dfa_
586 ph10 405 exec(), but without supplying a callout function, matching went wrong.
588     21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
589     leak if the size of the offset vector was greater than 30. When the vector
590     is smaller, the saved offsets during recursion go onto a local stack
591     vector, but for larger vectors malloc() is used. It was failing to free
592     when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
593 ph10 400 error, in fact).
594 ph10 405
595 ph10 402 22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
596 ph10 405 heapframe that is used only when UTF-8 support is enabled. This caused no
597     problem, but was untidy.
598 ph10 376
599 ph10 405 23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
600     CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
601     included within another project.
602 ph10 411
603 ph10 407 24. Steven Van Ingelgem's patches to add more options to the CMake support,
604     slightly modified by me:
605 ph10 411
606     (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
607     not building pcregrep.
609 ph10 407 (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
610 ph10 411 if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
612 ph10 408 25. Forward references, both numeric and by name, in patterns that made use of
613     duplicate group numbers, could behave incorrectly or give incorrect errors,
614     because when scanning forward to find the reference group, PCRE was not
615     taking into account the duplicate group numbers. A pattern such as
616     ^X(?3)(a)(?|(b)|(q))(Y) is an example.
617 ph10 411
618     26. Changed a few more instances of "const unsigned char *" to USPTR, making
619     the feature of a custom pointer more persuasive (as requested by a user).
620 ph10 416
621 ph10 411 27. Wrapped the definitions of fileno and isatty for Windows, which appear in
622 ph10 416 pcretest.c, inside #ifndefs, because it seems they are sometimes already
623     pre-defined.
624 ph10 392
625 ph10 416 28. Added support for (*UTF8) at the start of a pattern.
627 ph10 413 29. Arrange for flags added by the "release type" setting in CMake to be shown
628     in the configuration summary.
629 ph10 405
630 ph10 411
631 ph10 374 Version 7.8 05-Sep-08
632 ph10 349 ---------------------
634     1. Replaced UCP searching code with optimized version as implemented for Ad
635     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
636 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
637     to 5 times on some simple patterns that I tested. Permission was given to
638     distribute the MultiStage2.py script that generates the tables (it's not in
639     the tarball, but is in the Subversion repository).
640 ph10 349
641 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
642     scripts.
643 ph10 358
644 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
645     a group with a zero qualifier. The result of the study could be incorrect,
646 ph10 358 or the function might crash, depending on the pattern.
648     4. Caseless matching was not working for non-ASCII characters in back
649 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
650 ph10 358 It now works when Unicode Property Support is available.
652 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
653     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
654     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
655 ph10 358 truncation.
656 ph10 349
657 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
659 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
660     pointers, in case they are 64-bit values.
661 ph10 371
662     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
663     test 2 if it fails.
665 ph10 359 9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
666 ph10 371 and a #define of that name to empty if it is not externally set. This is to
667     allow users of MSVC to set it if necessary.
669     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
670 ph10 359 the convenience functions in the pcre_get.c source file.
671 ph10 371
672 ph10 360 11. An option change at the start of a pattern that had top-level alternatives
673     could cause overwriting and/or a crash. This command provoked a crash in
674 ph10 371 some environments:
676     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
678 ph10 360 This potential security problem was recorded as CVE-2008-2371.
679 ph10 371
680 ph10 361 12. For a pattern where the match had to start at the beginning or immediately
681     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
682 ph10 371 pcre_dfa_exec() could read past the end of the passed subject if there was
683 ph10 361 no match. To help with detecting such bugs (e.g. with valgrind), I modified
684     pcretest so that it places the subject at the end of its malloc-ed buffer.
685 ph10 371
686 ph10 364 13. The change to pcretest in 12 above threw up a couple more cases when pcre_
687 ph10 371 exec() might read past the end of the data buffer in UTF-8 mode.
689 ph10 364 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
690 ph10 371 the data contained the byte 0x85 as part of a UTF-8 character within its
691     first line. This applied both to normal and DFA matching.
693 ph10 366 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
694 ph10 371 /^[^d]*?$/8 failed to match "abc".
695 ph10 351
696 ph10 371 16. Added a missing copyright notice to pcrecpp_internal.h.
698     17. Make it more clear in the documentation that values returned from
699 ph10 368 pcre_exec() in ovector are byte offsets, not character counts.
700 ph10 357
701 ph10 371 18. Tidied a few places to stop certain compilers from issuing warnings.
702 ph10 368
703 ph10 373 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
704     supplied by Stefan Weber. I made a further small update for 7.8 because
705 ph10 374 there is a change of source arrangements: the pcre_searchfuncs.c module is
706     replaced by pcre_ucd.c.
707 ph10 371
708 ph10 373
709 ph10 347 Version 7.7 07-May-08
710 ph10 321 ---------------------
712     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
713 ph10 345 a string to a long long, pretend we don't even have a long long." This is
714 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
715 ph10 345
716 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
717     pre-7.6 versions, which defined a global no_arg variable instead of putting
718 ph10 332 it in the RE class. (See also #8 below.)
719 ph10 345
720     3. Remove a line of dead code, identified by coverity and reported by Nuno
721     Lopes.
723 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
724 ph10 321
725 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
726 ph10 345 of files, instead of just to the final components.
728 ph10 324 (2) If there was more than one level of directory, the subdirectories were
729     skipped unless they satisfied the include/exclude conditions. This is
730     inconsistent with GNU grep (and could even be seen as contrary to the
731     pcregrep specification - which I improved to make it absolutely clear).
732     The action now is always to scan all levels of directory, and just
733     apply the include/exclude patterns to regular files.
734 ph10 345
735 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
736 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
738 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
739 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
740 ph10 326 doesn't support NULs in patterns.
741 ph10 345
742     7. Added some missing "const"s to declarations of static tables in
743     pcre_compile.c and pcre_dfa_exec.c.
745 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
746 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
747 ph10 345 first patch. And a third patch - this was a messy problem.)
748 ph10 321
749 ph10 345 9. Applied Craig's patch to remove the use of push_back().
751 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
752     matching function regexec().
753 ph10 345
754     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
755     which, however, unlike Perl's \g{...}, are subroutine calls, not back
756 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
757     Oniguruma does).
758 ph10 345
759     12. Previously, a group with a zero repeat such as (...){0} was completely
760 ph10 335 omitted from the compiled regex. However, this means that if the group
761     was called as a subroutine from elsewhere in the pattern, things went wrong
762 ph10 345 (an internal error was given). Such groups are now left in the compiled
763     pattern, with a new opcode that causes them to be skipped at execution
764 ph10 335 time.
765 ph10 345
766 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
767     to the way PCRE behaves:
768 ph10 345
769 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
770 ph10 345
771     (b) A back reference to an unmatched subpattern matches an empty string
772 ph10 336 (Perl fails the current match path).
773 ph10 345
774 ph10 341 (c) A data ] in a character class must be notated as \] because if the
775 ph10 345 first data character in a class is ], it defines an empty class. (In
776 ph10 341 Perl it is not possible to have an empty class.) The empty class []
777     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
778     The negative empty class [^] matches any one character, independently
779     of the DOTALL setting.
780 ph10 345
781     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
782 ph10 340 non-existent subpattern following a character class starting with ']' and
783     containing () gave an internal compiling error instead of "reference to
784     non-existent subpattern". Fortunately, when the pattern did exist, the
785 ph10 345 compiled code was correct. (When scanning forwards to check for the
786 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
787 ph10 345 the class, so got the count wrong. When actually compiling, the reference
788 ph10 340 was subsequently set up correctly.)
789 ph10 345
790 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
791 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
792     other assertions are supported. I have made pcre_dfa_exec() support
793     (*FAIL).
795 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
796 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
797     cannot be changed at match time, I realized I could make a small
798     improvement to matching performance by compiling OP_ALLANY instead of
799     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
800     on the OP_ANY path.
802     17. Compiling pcretest on Windows with readline support failed without the
803 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
804 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
806 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
807 ph10 345 ncurses library to be included for pcretest when ReadLine support is
808     requested, but also to allow for it to be overridden. This patch came from
809     Daniel Bergström.
810 ph10 347
811 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
812 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
813     any errors with the current Unicode tables. Thanks to Peter Kankowski for
814     spotting this.
815 ph10 324
816 ph10 332
817 ph10 319 Version 7.6 28-Jan-08
818 ph10 300 ---------------------
820 ph10 302 1. A character class containing a very large number of characters with
821     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
822     overflow.
823 ph10 309
824     2. Patch to cut out the "long long" test in pcrecpp_unittest when
825     HAVE_LONG_LONG is not defined.
827 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
828 ph10 304 bring them up to date and include new features. This patch includes:
829 ph10 309
830 ph10 304 - Fixed PH's badly added libz and libbz2 support.
831     - Fixed a problem with static linking.
832 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
833 ph10 304 - Fixed dftables problem and added an option.
834     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
836     - Added readline support for pcretest.
837 ph10 309 - Added an listing of the option settings after cmake has run.
839 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
840     "pcre.dll" under mingw when using Configure/Make. I added stuff to
841     Makefile.am that cause it to include this special target, without
842     affecting anything else. Note that the same mingw target plus all
843     the other distribution libraries and programs are now supported
844     when configuring with CMake (see 6 below) instead of with
845     Configure/Make.
846 ph10 309
847 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
848     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
849 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
850     solves the problem, but it does no harm.
851 ph10 313
852 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
853 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
854 ph10 314 with CMake, and also correct the comment about stack recursion.
855 ph10 313
856 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
857 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
858     of a program that users should build themselves after PCRE is installed, so
859     building it automatically is not really right. What is more, it gave
860 ph10 312 trouble in some build environments.
861 ph10 300
862 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
863 ph10 308
864 ph10 319
865 ph10 298 Version 7.5 10-Jan-08
866 ph10 263 ---------------------
868     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
869     values in parens when parsing an RE using the C++ wrapper."
870 ph10 286
871 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
872     Characters greater than 255 were excluded from the class instead of being
873     included.
874 ph10 286
875     3. The same bug as (2) above applied to negated POSIX classes such as
876 ph10 265 [:^space:].
877 ph10 286
878 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
879     defined or documented. It seems to have been a typo for PCRE_STATIC, so
880 ph10 286 I have changed it.
882 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
883 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
884     first named subpattern whose name started with "a" (in other words, the
885 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
886     expected" is now given for (?&) (a zero-length name), and this patch also
887     makes it give the same error for \k'' (previously it complained that that
888     was a reference to a non-existent subpattern).
889 ph10 286
890 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
891 ph10 286 this is right because (?- can be followed by option settings as well as by
892 ph10 269 digits. I have, however, made the messages clearer.
893 ph10 286
894 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
895     than the number used in the conditional) now cause a compile-time error.
896     This is actually not compatible with Perl, which accepts such patterns, but
897     treats the conditional as always being FALSE (as PCRE used to), but it
898     seems to me that giving a diagnostic is better.
899 ph10 286
900 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
901 ph10 275 and messages.
902 ph10 286
903     9. Fix two occurrences of "backslash" in comments that should have been
904     "backspace".
906     10. Remove two redundant lines of code that can never be obeyed (their function
907     was moved elsewhere).
909     11. The program that makes PCRE's Unicode character property table had a bug
910     which caused it to generate incorrect table entries for sequences of
911 ph10 277 characters that have the same character type, but are in different scripts.
912 ph10 286 It amalgamated them into a single range, with the script of the first of
913 ph10 277 them. In other words, some characters were in the wrong script. There were
914     thirteen such cases, affecting characters in the following ranges:
915 ph10 286
916 ph10 277 U+002b0 - U+002c1
917     U+0060c - U+0060d
918 ph10 286 U+0061e - U+00612
919 ph10 277 U+0064b - U+0065e
920     U+0074d - U+0076d
921     U+01800 - U+01805
922     U+01d00 - U+01d77
923     U+01d9b - U+01dbf
924     U+0200b - U+0200f
925     U+030fc - U+030fe
926     U+03260 - U+0327f
927     U+0fb46 - U+0fbb1
928     U+10450 - U+1049d
929 ph10 286
930 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
931     compatible with GNU grep in that, if there was more than one match in a
932     line, it showed only the first of them. It now behaves in the same way as
933     GNU grep.
934 ph10 286
935     13. If the -o and -v options were combined for pcregrep, it printed a blank
936     line for every non-matching line. GNU grep prints nothing, and pcregrep now
937     does the same. The return code can be used to tell if there were any
938     non-matching lines.
940 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
942     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
943 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
944 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
945     and both kinds of lookbehind were skipped).
947 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
948 ph10 284 inclusion of <windows.h> to before rather than after the definition of
949     INVALID_FILE_ATTRIBUTES (patch from David Byron).
950 ph10 263
951 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
952 ph10 286 character property caused pcre_compile() to compile bad code, which led at
953     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
954     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
955     caused the error; without that there was no problem.
956 ph10 263
957 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
958 ph10 286
959 ph10 289 19. Added --enable-pcretest-libreadline.
960 ph10 286
961 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
962 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
963 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
964     later patch that removed the other one (the right fix) and added unit tests
965     that check the return values (which was not done before).
966 ph10 292
967 ph10 291 21. Several CMake things:
968 ph10 287
969 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
970 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
971 ph10 288
972 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
973     linked with the newly-built libraries, not previously installed ones.
974 ph10 291
976 ph10 298
977     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
978     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
979     UTF-8 newline character). The key issue is that the pattern starts .*;
980     this means that the match must be either at the beginning, or after a
981     newline. The bug was in the code for advancing after a failed match and
982     checking that the new position followed a newline. It was not taking
983 ph10 294 account of UTF-8 characters correctly.
984 ph10 298
985     23. PCRE was behaving differently from Perl in the way it recognized POSIX
986     character classes. PCRE was not treating the sequence [:...:] as a
987     character class unless the ... were all letters. Perl, however, seems to
988     allow any characters between [: and :], though of course it rejects as
989     unknown any "names" that contain non-letters, because all the known class
990     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
991     for example, whereas PCRE did not - it did not recognize a POSIX character
992     class. This seemed a bit dangerous, so the code has been changed to be
993     closer to Perl. The behaviour is not identical to Perl, because PCRE will
994     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
995     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
996     Perl does, and where it didn't before.
998 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
999     Windows environments %n is disabled by default.
1000 ph10 292
1002 ph10 260 Version 7.4 21-Sep-07
1003 ph10 230 ---------------------
1005     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
1006 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
1007     LF". That isn't really right - the whole point of the change was to try to
1008     help when there was an actual mention of one of the two characters. So now
1009     the change happens only if \r or \n (or a literal CR or LF) character is
1010 ph10 230 encountered.
1011 ph10 231
1012     2. The 32-bit options word was also used for 6 internal flags, but the numbers
1013     of both had grown to the point where there were only 3 bits left.
1014     Fortunately, there was spare space in the data structure, and so I have
1015     moved the internal flags into a new 16-bit field to free up more option
1016 ph10 230 bits.
1017 ph10 231
1018     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1019     but did not set the internal JCHANGED flag - either of these is enough to
1020     control the way the "get" function works - but the PCRE_INFO_JCHANGED
1021     facility is supposed to tell if (?J) was ever used, so now (?J) at the
1022 ph10 230 start sets both bits.
1024 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
1025     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1026 ph10 230
1027 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
1029     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1030 ph10 233 compatibility, even though it is no longer used.
1031 ph10 243
1032     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1033 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1034 ph10 259 windows.h file is present (where different names are used). [This was
1035 ph10 257 reversed later after testing - see 16 below.]
1036 ph10 243
1037     8. Changed all #include <config.h> to #include "config.h". There were also
1038 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
1039 ph10 243
1040 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
1041 ph10 243 sequence off the lines that it output.
1043     10. It was pointed out to me that arrays of string pointers cause lots of
1044     relocations when a shared library is dynamically loaded. A technique of
1045     using a single long string with a table of offsets can drastically reduce
1046     these. I have refactored PCRE in four places to do this. The result is
1047 ph10 240 dramatic:
1048 ph10 243
1049 ph10 240 Originally: 290
1050     After changing UCP table: 187
1051 ph10 243 After changing error message table: 43
1052 ph10 240 After changing table of "verbs" 36
1053     After changing table of Posix names 22
1054 ph10 243
1055 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
1056 ph10 247
1057 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1058 ph10 247 unicode-properties was also set.
1060 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1061 ph10 231
1062 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1063     checked only for CRLF.
1064 ph10 233
1065 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
1067 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1068 ph10 253
1069 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1070 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1071     entirely. This removes changes made in 7 above.
1072 ph10 256
1073 ph10 261 17. The CMake files have been updated, and there is now more information about
1074     building with CMake in the NON-UNIX-USE document.
1075 ph10 257
1076 ph10 261
1077 ph10 228 Version 7.3 28-Aug-07
1078 ph10 157 ---------------------
1080 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
1081     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1082     brackets there is not right, since it causes compilers to look for an
1083     installed pcre.h, not the version that is in the source that is being
1084     compiled (which of course may be different). I have changed it back to:
1085 ph10 197
1086 ph10 189 #include "pcre.h"
1087 ph10 197
1088     I have a vague recollection that the change was concerned with compiling in
1089     different directories, but in the new build system, that is taken care of
1090     by the VPATH setting the Makefile.
1092 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1093     when the subject happened to end in the byte 0x85 (e.g. if the last
1094     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1095     characters but of course it shouldn't be taken as a newline when it is part
1096     of another character. The bug was that, for an unlimited repeat of . in
1097     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1098     characters when looking for a newline.
1099 ph10 197
1100     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1102     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1103     in debug output.
1105 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1106     long printing in the pcrecpp unittest when running under MinGW.
1107 ph10 189
1108 ph10 197 6. ESC_K was left out of the EBCDIC table.
1109 ph10 189
1110 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1111     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1112     limit also applies to "virtual nesting" when a pattern is recursive, and in
1113     this case 1000 isn't so big. I have been able to remove this limit at the
1114     expense of backing off one optimization in certain circumstances. Normally,
1115     when pcre_exec() would call its internal match() function recursively and
1116     immediately return the result unconditionally, it uses a "tail recursion"
1117     feature to save stack. However, when a subpattern that can match an empty
1118     string has an unlimited repetition quantifier, it no longer makes this
1119     optimization. That gives it a stack frame in which to save the data for
1120     checking that an empty string has been matched. Previously this was taken
1121     from the 1000-entry workspace that had been reserved. So now there is no
1122     explicit limit, but more stack is used.
1123 ph10 189
1124 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
1125     syntax that is required for Windows, and which was going wrong for the
1126     pcreposix and pcrecpp parts of the library. These were overlooked when this
1127     problem was solved for the main library.
1128 ph10 197
1129 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
1130     the size of patterns that contain repeated groups with explicit upper
1131     limits. As the maximum quantifier is 65535, the maximum group length was
1132     set at 30,000 so that the product of these two numbers did not overflow a
1133     32-bit integer. However, it turns out that people want to use groups that
1134     are longer than 30,000 bytes (though not repeat them that many times).
1135     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1136     made it possible to implement the integer overflow checks in a much more
1137     dynamic way, which I have now done. The artificial limitation on group
1138     length has been removed - we now have only the limit on the total length of
1139     the compiled pattern, which depends on the LINK_SIZE setting.
1140 ph10 208
1141     10. Fixed a bug in the documentation for get/copy named substring when
1142     duplicate names are permitted. If none of the named substrings are set, the
1143     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1144     empty string.
1146     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1147     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1148     because the ] is interpreted as the first data character and the
1149     terminating ] is not found. PCRE has been made compatible with Perl in this
1150     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1151     cause memory overwriting.
1153 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1154     string has been matched (to stop an infinite loop). It was not recognizing
1155 ph10 208 a conditional subpattern that could match an empty string if that
1156 ph10 206 subpattern was within another subpattern. For example, it looped when
1157 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
1158 ph10 206 condition was not nested. This bug has been fixed.
1159 ph10 208
1160 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1161     past the start of the subject in the presence of bytes with the top bit
1162     set, for example "\x8aBCD".
1163 ph10 211
1164 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1165     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1166 ph10 200
1167 ph10 211 14. Optimized (?!) to (*FAIL).
1168 ph10 202
1169 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1170     This restricts code points to be within the range 0 to 0x10FFFF, excluding
1171     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1172     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1173     does: it's just the validity check that is more restrictive.
1174 ph10 220
1175     16. Inserted checks for integer overflows during escape sequence (backslash)
1176     processing, and also fixed erroneous offset values for syntax errors during
1177     backslash processing.
1179 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1180 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1182 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1183     caused an overrun.
1184 ph10 220
1185     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1186     something other than just ASCII characters) inside a group that had an
1187     unlimited repeat caused a loop at compile time (while checking to see
1188     whether the group could match an empty string).
1190 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
1191     [\P{Any}] did so. (Error in the code for printing property names.)
1192 ph10 210
1193 ph10 220 21. An orphan \E inside a character class could cause a crash.
1195     22. A repeated capturing bracket such as (A)? could cause a wild memory
1196 ph10 218 reference during compilation.
1197 ph10 220
1198     23. There are several functions in pcre_compile() that scan along a compiled
1199     expression for various reasons (e.g. to see if it's fixed length for look
1200 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
1201 ph10 220 present in the pattern. These operators have additional parameters compared
1202     with \d, etc, and these were not being taken into account when moving along
1203 ph10 218 the compiled data. Specifically:
1204 ph10 220
1205     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1206     length.
1208     (b) An item such as \pL+ within a repeated group could cause crashes or
1209 ph10 218 loops.
1210 ph10 220
1211 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1212 ph10 220 "reference to non-existent subpattern" error.
1214 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1216 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1217 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1218 ph10 211
1219 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1220 ph10 218
1221 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1222 ph10 223 character were causing crashes (broken optimization).
1223 ph10 227
1224 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1225 ph10 227 \p or \P) caused a compile-time loop.
1227 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
1228     break. For example, the unstudied pattern [\r\n]A does not match the string
1229     "\r\nA" because change 7.0/46 below moves the current point on by two
1230     characters after failing to match at the start. However, the pattern \nA
1231 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1232     the same is true. There doesn't seem any very clean way out of this, but
1233     what I have chosen to do makes the common cases work: PCRE now takes note
1234     of whether there can be an explicit match for \r or \n anywhere in the
1235     pattern, and if so, 7.0/46 no longer applies. As part of this change,
1236     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1237     pattern has explicit CR or LF references.
1238 ph10 222
1239 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
1240 ph10 223
1241 ph10 227
1242 ph10 189 Version 7.2 19-Jun-07
1243     ---------------------
1245 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1246     which is apparently normally available under Windows.
1247 ph10 159
1248     2. Re-jig the pcregrep tests with different newline settings in an attempt
1249     to make them independent of the local environment's newline setting.
1250 ph10 157
1251 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1252 ph10 165
1253 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
1254     was not 2, because the output contained actual offsets. The recent new
1255 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
1256     usable with all link sizes.
1258 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1259     stack recursion. This gives a massive performance boost under BSD, but just
1260 ph10 165 a small improvement under Linux. However, it saves one field in the frame
1261 ph10 164 in all cases.
1262 ph10 172
1263 ph10 166 6. Added more features from the forthcoming Perl 5.10:
1264 ph10 172
1265 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
1266     recursion call. It refers to the nth most recently opened parentheses.
1267 ph10 172
1268 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
1269 ph10 172 to be opened parentheses.
1271     (c) Conditions that refer to capturing parentheses can be specified
1272 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
1273 ph10 172
1274 ph10 168 (d) \K resets the start of the current match so that everything before
1275 ph10 172 is not part of it.
1277 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1278 ph10 172
1279 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
1280 ph10 172 reference syntax.
1281 ph10 182
1282 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
1283 ph10 182 alternative starts with the same number.
1284 ph10 172
1285 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1287 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1290     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
1291     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1292 ph10 170 for detecting groups that can match an empty string.
1293 ph10 159
1294 ph10 172 9. A pattern with a very large number of alternatives (more than several
1295     hundred) was running out of internal workspace during the pre-compile
1296     phase, where pcre_compile() figures out how much memory will be needed. A
1297     bit of new cunning has reduced the workspace needed for groups with
1298     alternatives. The 1000-alternative test pattern now uses 12 bytes of
1299     workspace instead of running out of the 4096 that are available.
1300 ph10 182
1301 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1302 ph10 172
1303 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
1304     The report of the bug said:
1305 ph10 182
1306 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
1307     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1308 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1309 ph10 185
1310 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1311 ph10 185 it matched the wrong number of bytes.
1312 ph10 172
1313 ph10 179
1314 ph10 155 Version 7.1 24-Apr-07
1315 ph10 98 ---------------------
1317 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1318 ph10 122 that is more "standard", making use of automake and other Autotools. There
1319 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
1320     on this.
1321 ph10 111
1322     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1323     for recursive directory scanning broke on some systems because the files
1324     are not scanned in any specific order and on different systems the order
1325     was different. A call to "sort" has been inserted into RunGrepTest for the
1326     approprate test as a short-term fix. In the longer term there may be an
1327 ph10 100 alternative.
1328 ph10 111
1329 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
1330 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
1331     people do their own conversions for various reasons). The problems
1332     concerned the use of low-level troff macros .br and .in. I have therefore
1333     removed all such uses from the man pages (some were redundant, some could
1334 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
1335     HTML has been updated to handle .nf/.fi and to complain if it encounters
1336     .br or .in.
1337 ph10 111
1338 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
1339 ph10 123 arranged for config.h to be included in the distribution, with the name
1340 ph10 111 config.h.generic, for the benefit of those who have to compile without
1341     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1343     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1344     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1345 ph10 127 makevp.bat for the current PCRE, using the additional files
1346 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1347 ph10 111
1348     6. A Windows user reported a minor discrepancy with test 2, which turned out
1349     to be caused by a trailing space on an input line that had got lost in his
1350 ph10 102 copy. The trailing space was an accident, so I've just removed it.
1351 ph10 111
1352 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1353 ph10 111 that is needed.
1355 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1356     as "const" (a) because they are and (b) because it helps the PHP
1357     maintainers who have recently made a script to detect big data structures
1358 ph10 111 in the php code that should be moved to the .rodata section. I remembered
1359     to update Builducptable as well, so it won't revert if ucptable.h is ever
1360 ph10 105 re-created.
1361 ph10 111
1362     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1363 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1364 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
1365     support is not required. This saves 1.5-2K of code, which is important in
1366 ph10 107 some applications.
1367 ph10 111
1368 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1369 ph10 111 so as not to refer to the tables, even though these functions will never be
1370     called when UTF-8 support is disabled. Otherwise there are problems with a
1371     shared library.
1373 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1375     (a) It was defining its arguments as char * instead of void *.
1377 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
1378     a long time ago when I wrote it, but is no longer the case.
1380 ph10 118 The emulated memove() is provided for those environments that have neither
1381 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
1382 ph10 118 is clearly not the case, as these two bugs were recently reported.
1383 ph10 123
1384 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1385 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
1386     pages, and it removes trailing spaces from listed files. It also creates
1387     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1388     case, it wraps all the #defines with #ifndefs. This script should be run
1389 ph10 111 before "make dist".
1390 ph10 123
1391 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1392     with Unicode property support.
1393 ph10 123
1394     (a) For a maximizing quantifier, if the two different cases of the
1395     character were of different lengths in their UTF-8 codings (there are
1396     some cases like this - I found 11), and the matching function had to
1397 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
1398     were both the same length.
1399 ph10 123
1400     (b) When PCRE was configured to use the heap rather than the stack for
1401     recursion during matching, it was not correctly preserving the data for
1402     the other case of a UTF-8 character when checking ahead for a match
1403     while processing a minimizing repeat. If the check also involved
1404 ph10 115 matching a wide character, but failed, corruption could cause an
1405     erroneous result when trying to check for a repeat of the original
1406     character.
1407 ph10 123
1408 ph10 116 13. Some tidying changes to the testing mechanism:
1409 ph10 98
1410 ph10 116 (a) The RunTest script now detects the internal link size and whether there
1411     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1412 ph10 123 values substituted by "configure". (The RunGrepTest script already did
1413     this for UTF-8.) The configure.ac script no longer substitutes the
1414     relevant variables.
1416 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
1417     with length and offset values. This means that the output is different
1418     for different internal link sizes. Test 2 is skipped for link sizes
1419     other than 2 because of this, bypassing the problem. Unfortunately,
1420     there was also a test in test 3 (the locale tests) that used /B and
1421 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
1422     I have added a new /Z option to pcretest that replaces the length and
1423     offset values with spaces. This is now used to make test 3 independent
1424 ph10 122 of link size. (Test 2 will be tidied up later.)
1425 ph10 123
1426     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1427 ph10 122 segmentation fault instead of returning the appropriate error message.
1428 ph10 134
1429 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
1430 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1431     This doesn't seem right; it now treats the CRLF combination as the line
1432     ending, and so does not match in that case. It's only a pattern such as ^$
1433     that would hit this one: something like ^ABC$ would have failed after \r
1434     and then tried again after \r\n.
1436 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1437 ph10 134 in an attempt to make files that differ only in their line terminators
1438     compare equal. This works on Linux.
1439 ph10 142
1440 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
1441     as it exited. This is now fixed, thanks to valgrind.
1442 ph10 142
1443 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1444 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1445     was because its rules for how to advance for /g after matching an empty
1446 ph10 143 string at the end of a line did not allow for this case. They now check for
1447     it specially.
1448 ph10 150
1449     20. pcretest is supposed to handle patterns and data of any length, by
1450     extending its buffers when necessary. It was getting this wrong when the
1451 ph10 147 buffer for a data line had to be extended.
1452 ph10 150
1453 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1454 ph10 150 CRLF as a newline sequence.
1455 ph10 152
1456 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1457 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1458     I have nevertheless tidied it up.
1459 ph10 111
1460 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
1461 ph10 123
1462 ph10 153 24. Added a man page for pcre-config.
1463 ph10 152
1464 ph10 153
1465 nigel 93 Version 7.0 19-Dec-06
1466     ---------------------
1468     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1469     moving to gcc 4.1.1.
1471     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1472     sys/time.h, which is documented as needed for this function. It doesn't
1473     seem to matter on Linux, but it showed up on some releases of OS X.
1475     3. It seems that there are systems where bytes whose values are greater than
1476     127 match isprint() in the "C" locale. The "C" locale should be the
1477     default when a C program starts up. In most systems, only ASCII printing
1478     characters match isprint(). This difference caused the output from pcretest
1479     to vary, making some of the tests fail. I have changed pcretest so that:
1481     (a) When it is outputting text in the compiled version of a pattern, bytes
1482     other than 32-126 are always shown as hex escapes.
1484     (b) When it is outputting text that is a matched part of a subject string,
1485     it does the same, unless a different locale has been set for the match
1486     (using the /L modifier). In this case, it uses isprint() to decide.
1488     4. Fixed a major bug that caused incorrect computation of the amount of memory
1489     required for a compiled pattern when options that changed within the
1490     pattern affected the logic of the preliminary scan that determines the
1491     length. The relevant options are -x, and -i in UTF-8 mode. The result was
1492     that the computed length was too small. The symptoms of this bug were
1493     either the PCRE error "internal error: code overflow" from pcre_compile(),
1494     or a glibc crash with a message such as "pcretest: free(): invalid next
1495     size (fast)". Examples of patterns that provoked this bug (shown in
1496     pcretest format) are:
1498     /(?-x: )/x
1499     /(?x)(?-x: \s*#\s*)/
1500     /((?i)[\x{c0}])/8
1501     /(?i:[\x{c0}])/8
1503     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1504     is now done differently.
1506     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1507     wrapper classes; (b) implement a new function in the C++ scanner that is
1508     more efficient than the old way of doing things because it avoids levels of
1509     recursion in the regex matching; (c) add a paragraph to the documentation
1510     for the FullMatch() function.
1512     6. The escape sequence \n was being treated as whatever was defined as
1513     "newline". Not only was this contrary to the documentation, which states
1514     that \n is character 10 (hex 0A), but it also went horribly wrong when
1515     "newline" was defined as CRLF. This has been fixed.
1517     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1518     was being set to -1 for the "end of line" case (supposedly a value that no
1519     character can have). Though this value is never used (the check for end of
1520     line is "zero bytes in current character"), it caused compiler complaints.
1521     I've changed it to 0xffffffff.
1523     8. In pcre_version.c, the version string was being built by a sequence of
1524     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1525     string (as it is for production releases) called a macro with an empty
1526     argument. The C standard says the result of this is undefined. The gcc
1527     compiler treats it as an empty string (which was what was wanted) but it is
1528     reported that Visual C gives an error. The source has been hacked around to
1529     avoid this problem.
1531     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1532     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1533     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1534     of them did).
1536     10. Originally, pcretest opened its input and output without "b"; then I was
1537     told that "b" was needed in some environments, so it was added for release
1538     5.0 to both the input and output. (It makes no difference on Unix-like
1539     systems.) Later I was told that it is wrong for the input on Windows. I've
1540     now abstracted the modes into two macros, to make it easier to fiddle with
1541     them, and removed "b" from the input mode under Windows.
1543     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1545     12. Added -help and --help to pcretest as an official way of being reminded
1546     of the options.
1548     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1549     and pcrecpp.cc because they annoy compilers at high warning levels.
1551     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1553     15. Fixed an occurrence of == in configure.ac that should have been = (shell
1554     scripts are not C programs :-) and which was not noticed because it works
1555     on Linux.
1557     16. pcretest is supposed to handle any length of pattern and data line (as one
1558     line or as a continued sequence of lines) by extending its input buffer if
1559     necessary. This feature was broken for very long pattern lines, leading to
1560     a string of junk being passed to pcre_compile() if the pattern was longer
1561     than about 50K.
1563     17. I have done a major re-factoring of the way pcre_compile() computes the
1564     amount of memory needed for a compiled pattern. Previously, there was code
1565     that made a preliminary scan of the pattern in order to do this. That was
1566     OK when PCRE was new, but as the facilities have expanded, it has become
1567     harder and harder to keep it in step with the real compile phase, and there
1568     have been a number of bugs (see for example, 4 above). I have now found a
1569     cunning way of running the real compile function in a "fake" mode that
1570     enables it to compute how much memory it would need, while actually only
1571     ever using a few hundred bytes of working memory and without too many
1572     tests of the mode. This should make future maintenance and development
1573     easier. A side effect of this work is that the limit of 200 on the nesting
1574     depth of parentheses has been removed (though this was never a serious
1575     limitation, I suspect). However, there is a downside: pcre_compile() now
1576     runs more slowly than before (30% or more, depending on the pattern). I
1577     hope this isn't a big issue. There is no effect on runtime performance.
1579     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1580     newline (only possible for the last line of a file) and it was a
1581     pattern that set a locale (followed by /Lsomething), pcretest crashed.
1583     19. Added additional timing features to pcretest. (1) The -tm option now times
1584     matching only, not compiling. (2) Both -t and -tm can be followed, as a
1585     separate command line item, by a number that specifies the number of
1586     repeats to use when timing. The default is 50000; this gives better
1587     precision, but takes uncomfortably long for very large patterns.
1589     20. Extended pcre_study() to be more clever in cases where a branch of a
1590     subpattern has no definite first character. For example, (a*|b*)[cd] would
1591     previously give no result from pcre_study(). Now it recognizes that the
1592     first character must be a, b, c, or d.
1594     21. There was an incorrect error "recursive call could loop indefinitely" if
1595     a subpattern (or the entire pattern) that was being tested for matching an
1596     empty string contained only one non-empty item after a nested subpattern.
1597     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1598     incorrectly, because the \d was being skipped in the check.
1600     22. The pcretest program now has a new pattern option /B and a command line
1601     option -b, which is equivalent to adding /B to every pattern. This causes
1602     it to show the compiled bytecode, without the additional information that
1603     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1604     is the same as /B/I).
1606     23. A new optimization is now able automatically to treat some sequences such
1607     as a*b as a*+b. More specifically, if something simple (such as a character
1608     or a simple class like \d) has an unlimited quantifier, and is followed by
1609     something that cannot possibly match the quantified thing, the quantifier
1610     is automatically "possessified".
1612     24. A recursive reference to a subpattern whose number was greater than 39
1613     went wrong under certain circumstances in UTF-8 mode. This bug could also
1614     have affected the operation of pcre_study().
1616     25. Realized that a little bit of performance could be had by replacing
1617     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1619     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1621     27. Possessive quantifiers such as a++ were previously implemented by turning
1622     them into atomic groups such as ($>a+). Now they have their own opcodes,
1623     which improves performance. This includes the automatically created ones
1624     from 23 above.
1626     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1627     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1628     the first matched character to be a colon. This applied both to named and
1629     numbered groups.
1631     29. The ucpinternal.h header file was missing its idempotency #ifdef.
1633     30. I was sent a "project" file called libpcre.a.dev which I understand makes
1634     building PCRE on Windows easier, so I have included it in the distribution.
1636     31. There is now a check in pcretest against a ridiculously large number being
1637     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1638     loop, the loop is abandoned.
1640     32. Forward references to subpatterns in conditions such as (?(2)...) where
1641     subpattern 2 is defined later cause pcre_compile() to search forwards in
1642     the pattern for the relevant set of parentheses. This search went wrong
1643     when there were unescaped parentheses in a character class, parentheses
1644     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1646     33. "Subroutine" calls and backreferences were previously restricted to
1647     referencing subpatterns earlier in the regex. This restriction has now
1648     been removed.
1650     34. Added a number of extra features that are going to be in Perl 5.10. On the
1651     whole, these are just syntactic alternatives for features that PCRE had
1652     previously implemented using the Python syntax or my own invention. The
1653     other formats are all retained for compatibility.
1655     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1656     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1657     also .NET compatible.
1659     (b) A recursion or subroutine call to a named group can now be defined as
1660     (?&name) as well as (?P>name).
1662     (c) A backreference to a named group can now be defined as \k<name> or
1663     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1664     5.10, are also .NET compatible.
1666     (d) A conditional reference to a named group can now use the syntax
1667     (?(<name>) or (?('name') as well as (?(name).
1669     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1670     groups (named and numbered) that are never evaluated inline, but can be
1671     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1672     is always false. There may be only one alternative in such a group.
1674     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1675     as the simple (?(R). The condition is true only if the most recent
1676     recursion is that of the given number or name. It does not search out
1677     through the entire recursion stack.
1679     (g) The escape \gN or \g{N} has been added, where N is a positive or
1680     negative number, specifying an absolute or relative reference.
1682     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1683     some "unreachable code" warnings.
1685     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1686     things, this adds five new scripts.
1688     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1689     There were also incompatibilities regarding the handling of \Q..\E inside
1690     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1691     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1693     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1694     matches an empty string, and forcibly breaks the loop. There were bugs in
1695     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1696     against aaaa the result was just "a" rather than "aaaa", for example. Two
1697     separate and independent bugs (that affected different cases) have been
1698     fixed.
1700     39. Refactored the code to abolish the use of different opcodes for small
1701     capturing bracket numbers. This is a tidy that I avoided doing when I
1702     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1703     The new approach is not only tidier, it makes it possible to reduce the
1704     memory needed to fix the previous bug (38).
1706     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1707     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1708     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1709     mode.
1711     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1712     report.
1714     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1715     copy construction and assignment in the C++ wrapper.
1717     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1718     couple of bugs that could have given wrong results in the "--newline=crlf"
1719     case.
1721     44. Added a number of casts and did some reorganization of signed/unsigned int
1722     variables following suggestions from Dair Grant. Also renamed the variable
1723     "this" as "item" because it is a C++ keyword.
1725     45. Arranged for dftables to add
1727     #include "pcre_internal.h"
1729     to pcre_chartables.c because without it, gcc 4.x may remove the array
1730     definition from the final binary if PCRE is built into a static library and
1731     dead code stripping is activated.
1733     46. For an unanchored pattern, if a match attempt fails at the start of a
1734     newline sequence, and the newline setting is CRLF or ANY, and the next two
1735     characters are CRLF, advance by two characters instead of one.
1738 nigel 91 Version 6.7 04-Jul-06
1739     ---------------------
1741     1. In order to handle tests when input lines are enormously long, pcretest has
1742     been re-factored so that it automatically extends its buffers when
1743     necessary. The code is crude, but this _is_ just a test program. The
1744     default size has been increased from 32K to 50K.
1746     2. The code in pcre_study() was using the value of the re argument before
1747     testing it for NULL. (Of course, in any sensible call of the function, it
1748     won't be NULL.)
1750     3. The memmove() emulation function in pcre_internal.h, which is used on
1751     systems that lack both memmove() and bcopy() - that is, hardly ever -
1752     was missing a "static" storage class specifier.
1754     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1755     containing an extended class (one that cannot be represented by a bitmap
1756     because it contains high-valued characters or Unicode property items, e.g.
1757     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1758     pattern, but PCRE should not loop if you do not (it no longer does).
1759     [Detail: two cases were found: (a) a repeated subpattern containing an
1760     extended class; (b) a recursive reference to a subpattern that followed a
1761     previous extended class. It wasn't skipping over the extended class
1762     correctly when UTF-8 mode was not set.]
1764     5. A negated single-character class was not being recognized as fixed-length
1765     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1766     compile error "lookbehind assertion is not fixed length".
1768     6. The RunPerlTest auxiliary script was showing an unexpected difference
1769     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1770     write a Perl script that can interpret lines of an input file either as
1771     byte characters or as UTF-8, which is what "perltest" was being required to
1772     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1773     can't do is switch easily at run time between having the "use utf8;" pragma
1774     or not. In the end, I fudged it by using the RunPerlTest script to insert
1775     "use utf8;" explicitly for the UTF-8 tests.
1777     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1778     the end of the subject string, contrary to the documentation and to what
1779     Perl does. This was true of both matching functions. Now it matches only at
1780     the start of the subject and immediately after *internal* newlines.
1782     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1783     a pointer to an int instead of a pointer to an unsigned long int. This
1784     caused problems on 64-bit systems.
1786     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1787     instance of the 'standard' template library not being so standard".
1789     10. There was no check on the number of named subpatterns nor the maximum
1790     length of a subpattern name. The product of these values is used to compute
1791     the size of the memory block for a compiled pattern. By supplying a very
1792     long subpattern name and a large number of named subpatterns, the size
1793     computation could be caused to overflow. This is now prevented by limiting
1794     the length of names to 32 characters, and the number of named subpatterns
1795     to 10,000.
1797     11. Subpatterns that are repeated with specific counts have to be replicated in
1798     the compiled pattern. The size of memory for this was computed from the
1799     length of the subpattern and the repeat count. The latter is limited to
1800     65535, but there was no limit on the former, meaning that integer overflow
1801     could in principle occur. The compiled length of a repeated subpattern is
1802     now limited to 30,000 bytes in order to prevent this.
1804     12. Added the optional facility to have named substrings with the same name.
1806     13. Added the ability to use a named substring as a condition, using the
1807     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1808     are numbers (not recommended). Forward references are permitted.
1810     14. Added forward references in named backreferences (if you see what I mean).
1812     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1813     pattern could run off the end of the subject. For example, the pattern
1814     "(?s)(.{1,5})"8 did this with the subject "ab".
1816     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1817     PCRE_CASELESS was set when matching characters that were quantified with ?
1818     or *.
1820     17. A character class other than a single negated character that had a minimum
1821     but no maximum quantifier - for example [ab]{6,} - was not handled
1822     correctly by pce_dfa_exec(). It would match only one character.
1824     18. A valid (though odd) pattern that looked like a POSIX character
1825     class but used an invalid character after [ (for example [[,abc,]]) caused
1826     pcre_compile() to give the error "Failed: internal error: code overflow" or
1827     in some cases to crash with a glibc free() error. This could even happen if
1828     the pattern terminated after [[ but there just happened to be a sequence of
1829     letters, a binary zero, and a closing ] in the memory that followed.
1831     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1832     over the years. Originally (before any Unicode support), just the bottom 8
1833     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1834     output from "man perlunicode" includes this:
1836     The regular expression compiler produces polymorphic opcodes. That
1837     is, the pattern adapts to the data and automatically switches to
1838     the Unicode character scheme when presented with Unicode data--or
1839     instead uses a traditional byte scheme when presented with byte
1840     data.
1842     Sadly, a wide octal escape does not cause a switch, and in a string with
1843     no other multibyte characters, these octal escapes are treated as before.
1844     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1845     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1846     Unicode string.
1848     I have not perpetrated such confusion in PCRE. Up till now, it took just
1849     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1850     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1851     translate to the appropriate multibyte character.
1853     29. Applied some refactoring to reduce the number of warnings from Microsoft
1854     and Borland compilers. This has included removing the fudge introduced
1855     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1856     a warning about an unused variable.
1858     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1859     characters since release 4.0, because Perl (from release 5.004) does not.
1860     [Or at least, is documented not to: some releases seem to be in conflict
1861     with the documentation.] However, when a pattern was studied with
1862     pcre_study() and all its branches started with \s, PCRE still included VT
1863     as a possible starting character. Of course, this did no harm; it just
1864     caused an unnecessary match attempt.
1866     22. Removed a now-redundant internal flag bit that recorded the fact that case
1867     dependency changed within the pattern. This was once needed for "required
1868     byte" processing, but is no longer used. This recovers a now-scarce options
1869     bit. Also moved the least significant internal flag bit to the most-
1870     significant bit of the word, which was not previously used (hangover from
1871     the days when it was an int rather than a uint) to free up another bit for
1872     the future.
1874     23. Added support for CRLF line endings as well as CR and LF. As well as the
1875     default being selectable at build time, it can now be changed at runtime
1876     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1877     specify that it is scanning data with non-default line endings.
1879     24. Changed the definition of CXXLINK to make it agree with the definition of
1880     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1882     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1883     recursions. This makes a big different to stack usage for some patterns.
1885     26. If a subpattern containing a named recursion or subroutine reference such
1886     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1887     the space required for the compiled pattern went wrong and gave too small a
1888     value. Depending on the environment, this could lead to "Failed: internal
1889     error: code overflow at offset 49" or "glibc detected double free or
1890     corruption" errors.
1892     27. Applied patches from Google (a) to support the new newline modes and (b) to
1893     advance over multibyte UTF-8 characters in GlobalReplace.
1895     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1896     difference for some implementation of PCRE in some Windows version.
1898     29. Added some extra testing facilities to pcretest:
1900     \q<number> in a data line sets the "match limit" value
1901     \Q<number> in a data line sets the "match recursion limt" value
1902     -S <number> sets the stack size, where <number> is in megabytes
1904     The -S option isn't available for Windows.
1907 nigel 89 Version 6.6 06-Feb-06
1908     ---------------------
1910     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1911     in pcreposix.h. I have copied the definition from pcre.h.
1913     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1914     because pcre.h is no longer a built file.
1916     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1917     not normally included in the compiled code.
1920 nigel 87 Version 6.5 01-Feb-06
1921     ---------------------
1923     1. When using the partial match feature with pcre_dfa_exec(), it was not
1924     anchoring the second and subsequent partial matches at the new starting
1925     point. This could lead to incorrect results. For example, with the pattern
1926     /1234/, partially matching against "123" and then "a4" gave a match.
1928     2. Changes to pcregrep:
1930     (a) All non-match returns from pcre_exec() were being treated as failures
1931     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1932     error message is output. Some extra information is given for the
1934     probably the only errors that are likely to be caused by users (by
1935     specifying a regex that has nested indefinite repeats, for instance).
1936     If there are more than 20 of these errors, pcregrep is abandoned.
1938     (b) A binary zero was treated as data while matching, but terminated the
1939     output line if it was written out. This has been fixed: binary zeroes
1940     are now no different to any other data bytes.
1942     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1943     used to set a locale for matching. The --locale=xxxx long option has
1944     been added (no short equivalent) to specify a locale explicitly on the
1945     pcregrep command, overriding the environment variables.
1947     (d) When -B was used with -n, some line numbers in the output were one less
1948     than they should have been.
1950     (e) Added the -o (--only-matching) option.
1952     (f) If -A or -C was used with -c (count only), some lines of context were
1953     accidentally printed for the final match.
1955     (g) Added the -H (--with-filename) option.
1957     (h) The combination of options -rh failed to suppress file names for files
1958     that were found from directory arguments.
1960     (i) Added the -D (--devices) and -d (--directories) options.
1962     (j) Added the -F (--fixed-strings) option.
1964     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1966     (l) Added the --colo(u)r option.
1968     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1969     is not present by default.
1971     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1972     items such as (?R) or (?1), when the recursion could match a number of
1973     alternatives. If it matched one of the alternatives, but subsequently,
1974     outside the recursion, there was a failure, the code tried to back up into
1975     the recursion. However, because of the way PCRE is implemented, this is not
1976     possible, and the result was an incorrect result from the match.
1978     In order to prevent this happening, the specification of recursion has
1979     been changed so that all such subpatterns are automatically treated as
1980     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1982     4. I had overlooked the fact that, in some locales, there are characters for
1983     which isalpha() is true but neither isupper() nor islower() are true. In
1984     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1985     and ordfeminine) are like this. This affected the treatment of \w and \W
1986     when they appeared in character classes, but not when they appeared outside
1987     a character class. The bit map for "word" characters is now created
1988     separately from the results of isalnum() instead of just taking it from the
1989     upper, lower, and digit maps. (Plus the underscore character, of course.)
1991     5. The above bug also affected the handling of POSIX character classes such as
1992     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1993     permanent tables. Instead, the bit maps for such a class were previously
1994     created as the appropriate unions of the upper, lower, and digit bitmaps.
1995     Now they are created by subtraction from the [[:word:]] class, which has
1996     its own bitmap.
1998     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1999     It is created by subtracting the vertical space characters (\x09, \x0a,
2000     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2001     subtraction was done in the overall bitmap for a character class, meaning
2002     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2003     be recognized. This bug has been fixed.
2005     7. Patches from the folks at Google:
2007     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2008     real life, but is still worth protecting against".
2010     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2011     regular expressions".
2013     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2014     have it.
2016     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2017     "configure" and the latter not, in order to fix a problem somebody had
2018     with compiling the Arg class on HP-UX.
2020     (e) Improve the error-handling of the C++ wrapper a little bit.
2022     (f) New tests for checking recursion limiting.
2024     8. The pcre_memmove() function, which is used only if the environment does not
2025     have a standard memmove() function (and is therefore rarely compiled),
2026     contained two bugs: (a) use of int instead of size_t, and (b) it was not
2027     returning a result (though PCRE never actually uses the result).
2029     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2030     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2031     returned instead of calling malloc() with an overflowing number that would
2032     most likely cause subsequent chaos.
2034     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2036     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2037     with this option is matched, the nmatch and pmatch options of regexec() are
2038     ignored.
2040     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2041     provided in case anyone wants to the the POSIX interface with UTF-8
2042     strings.
2044     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2045     C++ linking (needed for some HP-UX environments).
2047     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2048     (unused parameter) and in the pcre_printint() function (omitted "default"
2049     switch label when the default is to do nothing).
2051     15. Added some code to make it possible, when PCRE is compiled as a C++
2052     library, to replace subject pointers for pcre_exec() with a smart pointer
2053     class, thus making it possible to process discontinuous strings.
2055     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2056     much the same function. They were added by different people who were trying
2057     to make PCRE easy to compile on non-Unix systems. It has been suggested
2058     that PCRE_EXPORT be abolished now that there is more automatic apparatus
2059     for compiling on Windows systems. I have therefore replaced it with
2060     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2061     defaults to "extern" for C or "extern C" for C++, which works fine on
2062     Unix-like systems. It is now possible to override the value of PCRE_DATA_
2063     SCOPE with something explicit in config.h. In addition:
2065     (a) pcreposix.h still had just "extern" instead of either of these macros;
2066     I have replaced it with PCRE_DATA_SCOPE.
2068     (b) Functions such as _pcre_xclass(), which are internal to the library,
2069     but external in the C sense, all had PCRE_EXPORT in their definitions.
2070     This is apparently wrong for the Windows case, so I have removed it.
2071     (It makes no difference on Unix-like systems.)
2073     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2074     of recursive calls to match(). This is different to MATCH_LIMIT because
2075     that limits the total number of calls to match(), not all of which increase
2076     the depth of recursion. Limiting the recursion depth limits the amount of
2077     stack (or heap if NO_RECURSE is set) that is used. The default can be set
2078     when PCRE is compiled, and changed at run time. A patch from Google adds
2079     this functionality to the C++ interface.
2081     18. Changes to the handling of Unicode character properties:
2083     (a) Updated the table to Unicode 4.1.0.
2085     (b) Recognize characters that are not in the table as "Cn" (undefined).
2087     (c) I revised the way the table is implemented to a much improved format
2088     which includes recognition of ranges. It now supports the ranges that
2089     are defined in UnicodeData.txt, and it also amalgamates other
2090     characters into ranges. This has reduced the number of entries in the
2091     table from around 16,000 to around 3,000, thus reducing its size
2092     considerably. I realized I did not need to use a tree structure after
2093     all - a binary chop search is just as efficient. Having reduced the
2094     number of entries, I extended their size from 6 bytes to 8 bytes to
2095     allow for more data.
2097     (d) Added support for Unicode script names via properties such as \p{Han}.
2099     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2100     matching that character.
2102     20. When matching a repeated Unicode property with a minimum greater than zero,
2103     (for example \pL{2,}), PCRE could look past the end of the subject if it
2104     reached it while seeking the minimum number of characters. This could
2105     happen only if some of the characters were more than one byte long, because
2106     there is a check for at least the minimum number of bytes.
2108     21. Refactored the implementation of \p and \P so as to be more general, to
2109     allow for more different types of property in future. This has changed the
2110     compiled form incompatibly. Anybody with saved compiled patterns that use
2111     \p or \P will have to recompile them.
2113     22. Added "Any" and "L&" to the supported property types.
2115     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2116     but give a compile time error if the value is greater than 0xff.
2118     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2119     accidentally not being installed or uninstalled.
2121     25. The pcre.h file was built from pcre.h.in, but the only changes that were
2122     made were to insert the current release number. This seemed silly, because
2123     it made things harder for people building PCRE on systems that don't run
2124     "configure". I have turned pcre.h into a distributed file, no longer built
2125     by "configure", with the version identification directly included. There is
2126     no longer a pcre.h.in file.
2128     However, this change necessitated a change to the pcre-config script as
2129     well. It is built from pcre-config.in, and one of the substitutions was the
2130     release number. I have updated configure.ac so that ./configure now finds
2131     the release number by grepping pcre.h.
2133     26. Added the ability to run the tests under valgrind.
2136 nigel 85 Version 6.4 05-Sep-05
2137     ---------------------
2139     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2140     "--" to be printed when multiple files were scanned, even when none of the
2141     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2142     consider it to be a bug, and have restored the previous behaviour.
2144     2. A couple of code tidies to get rid of compiler warnings.
2146     3. The pcretest program used to cheat by referring to symbols in the library
2147     whose names begin with _pcre_. These are internal symbols that are not
2148     really supposed to be visible externally, and in some environments it is
2149     possible to suppress them. The cheating is now confined to including
2150     certain files from the library's source, which is a bit cleaner.
2152     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2153     file's purpose clearer.
2155     5. Reorganized pcre_ucp_findchar().
2158 nigel 83 Version 6.3 15-Aug-05
2159     ---------------------
2161     1. The file libpcre.pc.in did not have general read permission in the tarball.
2163     2. There were some problems when building without C++ support:
2165     (a) If C++ support was not built, "make install" and "make test" still
2166     tried to test it.
2168     (b) There were problems when the value of CXX was explicitly set. Some
2169     changes have been made to try to fix these, and ...
2171     (c) --disable-cpp can now be used to explicitly disable C++ support.
2173     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2174     backslash in a target when C++ was disabled. This confuses some
2175     versions of "make", apparently. Using an intermediate variable solves
2176     this. (Same for CPP_LOBJ.)
2178     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2179     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2180     necessary on certain architectures.
2182     4. Added a setting of -export-symbols-regex to the link command to remove
2183     those symbols that are exported in the C sense, but actually are local
2184     within the library, and not documented. Their names all begin with
2185     "_pcre_". This is not a perfect job, because (a) we have to except some
2186     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2187     available (and never for static libraries). I have made a note to try to
2188     find a way round (a) in the future.
2191 nigel 81 Version 6.2 01-Aug-05
2192     ---------------------
2194     1. There was no test for integer overflow of quantifier values. A construction
2195     such as {1111111111111111} would give undefined results. What is worse, if
2196     a minimum quantifier for a parenthesized subpattern overflowed and became
2197     negative, the calculation of the memory size went wrong. This could have
2198     led to memory overwriting.
2200     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2202     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2203     operating environments where this matters.
2205     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2206     PCRE options from within the C++ wrapper.
2208     5. Named capturing subpatterns were not being correctly counted when a pattern
2209     was compiled. This caused two problems: (a) If there were more than 100
2210     such subpatterns, the calculation of the memory needed for the whole
2211     compiled pattern went wrong, leading to an overflow error. (b) Numerical
2212     back references of the form \12, where the number was greater than 9, were
2213     not recognized as back references, even though there were sufficient
2214     previous subpatterns.
2216     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2217     versions of gcc, e.g. 2.95.4.
2220 nigel 79 Version 6.1 21-Jun-05
2221     ---------------------
2223     1. There was one reference to the variable "posix" in pcretest.c that was not
2224     surrounded by "#if !defined NOPOSIX".
2226     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2227     the cross-check on the old pcre_info() function, for the benefit of the
2228     cut-down version of PCRE that is currently imported into Exim.
2230     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2231     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2232     patterns that start (?i) but I don't think that matters. The use of (?i) is
2233     just an example; this all applies to the other options as well.
2235     4. Since libtool seems to echo the compile commands it is issuing, the output
2236     from "make" can be reduced a bit by putting "@" in front of each libtool
2237     compile command.
2239     5. Patch from the folks at Google for configure.in to be a bit more thorough
2240     in checking for a suitable C++ installation before trying to compile the
2241     C++ stuff. This should fix a reported problem when a compiler was present,
2242     but no suitable headers.
2244     6. The man pages all had just "PCRE" as their title. I have changed them to
2245     be the relevant file name. I have also arranged that these names are
2246     retained in the file doc/pcre.txt, which is a concatenation in text format
2247     of all the man pages except the little individual ones for each function.
2249     7. The NON-UNIX-USE file had not been updated for the different set of source
2250     files that come with release 6. I also added a few comments about the C++
2251     wrapper.
2254 nigel 77 Version 6.0 07-Jun-05
2255     ---------------------
2257     1. Some minor internal re-organization to help with my DFA experiments.
2259     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2260     didn't matter for the library itself when fully configured, but did matter
2261     when compiling without UCP support, or within Exim, where the ucp files are
2262     not imported.
2264     3. Refactoring of the library code to split up the various functions into
2265     different source modules. The addition of the new DFA matching code (see
2266     below) to a single monolithic source would have made it really too
2267     unwieldy, quite apart from causing all the code to be include in a
2268     statically linked application, when only some functions are used. This is
2269     relevant even without the DFA addition now that patterns can be compiled in
2270     one application and matched in another.
2272     The downside of splitting up is that there have to be some external
2273     functions and data tables that are used internally in different modules of
2274     the library but which are not part of the API. These have all had their
2275     names changed to start with "_pcre_" so that they are unlikely to clash
2276     with other external names.
2278     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2279     a different (DFA) algorithm. Although it is slower than the original
2280     function, it does have some advantages for certain types of matching
2281     problem.
2283     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2284     including restarting after a partial match.
2286     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2287     defined when compiling for Windows was sent to me. I have put it into the
2288     code, though I have no means of testing or verifying it.
2290     7. Added the pcre_refcount() auxiliary function.
2292     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2293     match before or at the first newline in the subject string. In pcretest,
2294     the /f option on a pattern can be used to set this.
2296     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2297     would behave wrongly. This has been present in PCRE since release 4.0.
2299     10. A number of changes to the pcregrep command:
2301     (a) Refactored how -x works; insert ^(...)$ instead of setting
2302     PCRE_ANCHORED and checking the length, in preparation for adding
2303     something similar for -w.
2305     (b) Added the -w (match as a word) option.
2307     (c) Refactored the way lines are read and buffered so as to have more
2308     than one at a time available.
2310     (d) Implemented a pcregrep test script.
2312     (e) Added the -M (multiline match) option. This allows patterns to match
2313     over several lines of the subject. The buffering ensures that at least
2314     8K, or the rest of the document (whichever is the shorter) is available
2315     for matching (and similarly the previous 8K for lookbehind assertions).
2317     (f) Changed the --help output so that it now says
2319     -w, --word-regex(p)
2321     instead of two lines, one with "regex" and the other with "regexp"
2322     because that confused at least one person since the short forms are the
2323     same. (This required a bit of code, as the output is generated
2324     automatically from a table. It wasn't just a text change.)
2326     (g) -- can be used to terminate pcregrep options if the next thing isn't an
2327     option but starts with a hyphen. Could be a pattern or a path name
2328     starting with a hyphen, for instance.
2330     (h) "-" can be given as a file name to represent stdin.
2332     (i) When file names are being printed, "(standard input)" is used for
2333     the standard input, for compatibility with GNU grep. Previously
2334     "<stdin>" was used.
2336     (j) The option --label=xxx can be used to supply a name to be used for
2337     stdin when file names are being printed. There is no short form.
2339     (k) Re-factored the options decoding logic because we are going to add
2340     two more options that take data. Such options can now be given in four
2341     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2343     (l) Added the -A, -B, and -C options for requesting that lines of context
2344     around matches be printed.
2346     (m) Added the -L option to print the names of files that do not contain
2347     any matching lines, that is, the complement of -l.
2349     (n) The return code is 2 if any file cannot be opened, but pcregrep does
2350     continue to scan other files.
2352     (o) The -s option was incorrectly implemented. For compatibility with other
2353     greps, it now suppresses the error message for a non-existent or non-
2354     accessible file (but not the return code). There is a new option called
2355     -q that suppresses the output of matching lines, which was what -s was
2356     previously doing.
2358     (p) Added --include and --exclude options to specify files for inclusion
2359     and exclusion when recursing.
2361     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2362     Hopefully, it now does.
2364     12. Missing cast in pcre_study().
2366     13. Added an "uninstall" target to the makefile.
2368     14. Replaced "extern" in the function prototypes in Makefile.in with
2369     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2370     world, but is set differently for Windows.
2372     15. Added a second compiling function called pcre_compile2(). The only
2373     difference is that it has an extra argument, which is a pointer to an
2374     integer error code. When there is a compile-time failure, this is set
2375     non-zero, in addition to the error test pointer being set to point to an
2376     error message. The new argument may be NULL if no error number is required
2377     (but then you may as well call pcre_compile(), which is now just a
2378     wrapper). This facility is provided because some applications need a
2379     numeric error indication, but it has also enabled me to tidy up the way
2380     compile-time errors are handled in the POSIX wrapper.
2382     16. Added VPATH=.libs to the makefile; this should help when building with one
2383     prefix path and installing with another. (Or so I'm told by someone who
2384     knows more about this stuff than I do.)
2386     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2387     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2388     match everything, including newlines. This is not POSIX-compatible, but
2389     somebody wanted the feature. From pcretest it can be activated by using
2390     both the P and the s flags.
2392     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2394     19. libpcre.pc was being incorrectly installed as executable.
2396     20. A couple of places in pcretest check for end-of-line by looking for '\n';
2397     it now also looks for '\r' so that it will work unmodified on Windows.
2399     21. Added Google's contributed C++ wrapper to the distribution.
2401     22. Added some untidy missing memory free() calls in pcretest, to keep
2402     Electric Fence happy when testing.
2406 nigel 75 Version 5.0 13-Sep-04
2407     ---------------------
2409     1. Internal change: literal characters are no longer packed up into items
2410     containing multiple characters in a single byte-string. Each character
2411     is now matched using a separate opcode. However, there may be more than one
2412     byte in the character in UTF-8 mode.
2414     2. The pcre_callout_block structure has two new fields: pattern_position and
2415     next_item_length. These contain the offset in the pattern to the next match
2416     item, and its length, respectively.
2418     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2419     insertion of callouts before each pattern item. Added the /C option to
2420     pcretest to make use of this.
2422     4. On the advice of a Windows user, the lines
2424     #if defined(_WIN32) || defined(WIN32)
2425     _setmode( _fileno( stdout ), 0x8000 );
2426     #endif /* defined(_WIN32) || defined(WIN32) */
2428     have been added to the source of pcretest. This apparently does useful
2429     magic in relation to line terminators.
2431     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2432     for the benefit of those environments where the "b" makes a difference.
2434     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2435     to know about it. I have put a hack into configure.in that adds in code
2436     to set GCC=yes if CC=icc. This seems to end up at a point in the
2437     generated configure script that is early enough to affect the setting of
2438     compiler options, which is what is needed, but I have no means of testing
2439     whether it really works. (The user who reported this had patched the
2440     generated configure script, which of course I cannot do.)
2442     LATER: After change 22 below (new libtool files), the configure script
2443     seems to know about icc (and also ecc). Therefore, I have commented out
2444     this hack in configure.in.
2446     7. Added support for pkg-config (2 patches were sent in).
2448     8. Negated POSIX character classes that used a combination of internal tables
2449     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2450     [[:^ascii]]. Typically, they would match almost any characters. The other
2451     POSIX classes were not broken in this way.
2453     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2454     to find the match, as PCRE was deluded into thinking that the match had to
2455     start at the start point or following a newline. The same bug applied to
2456     patterns with negative forward assertions or any backward assertions
2457     preceding ".*" at the start, unless the pattern required a fixed first
2458     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2460     10. In UTF-8 mode, when moving forwards in the subject after a failed match
2461     starting at the last subject character, bytes beyond the end of the subject
2462     string were read.
2464     11. Renamed the variable "class" as "classbits" to make life easier for C++
2465     users. (Previously there was a macro definition, but it apparently wasn't
2466     enough.)
2468     12. Added the new field "tables" to the extra data so that tables can be passed
2469     in at exec time, or the internal tables can be re-selected. This allows
2470     a compiled regex to be saved and re-used at a later time by a different
2471     program that might have everything at different addresses.
2473     13. Modified the pcre-config script so that, when run on Solaris, it shows a
2474     -R library as well as a -L library.
2476     14. The debugging options of pcretest (-d on the command line or D on a
2477     pattern) showed incorrect output for anything following an extended class
2478     that contained multibyte characters and which was followed by a quantifier.
2480     15. Added optional support for general category Unicode character properties
2481     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2482     support. It adds about 90K to the size of the library. The meanings of the
2483     inbuilt class escapes such as \d and \s have NOT been changed.
2485     16. Updated pcredemo.c to include calls to free() to release the memory for the
2486     compiled pattern.
2488     17. The generated file chartables.c was being created in the source directory
2489     instead of in the building directory. This caused the build to fail if the
2490     source directory was different from the building directory, and was
2491     read-only.
2493     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2494     file. No doubt somebody will tell me if they don't make sense... Also added
2495     Dan Mooney's comments about building on OpenVMS.
2497     19. Added support for partial matching via the PCRE_PARTIAL option for
2498     pcre_exec() and the \P data escape in pcretest.
2500     20. Extended pcretest with 3 new pattern features:
2502     (i) A pattern option of the form ">rest-of-line" causes pcretest to
2503     write the compiled pattern to the file whose name is "rest-of-line".
2504     This is a straight binary dump of the data, with the saved pointer to
2505     the character tables forced to be NULL. The study data, if any, is
2506     written too. After writing, pcretest reads a new pattern.
2508     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2509     compiled pattern from the given file. There must not be any
2510     occurrences of "<" in the file name (pretty unlikely); if there are,
2511     pcretest will instead treat the initial "<" as a pattern delimiter.
2512     After reading in the pattern, pcretest goes on to read data lines as
2513     usual.
2515     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2516     and 16-bit fields in a compiled pattern, to simulate a pattern that
2517     was compiled on a host of opposite endianness.
2519     21. The pcre-exec() function can now cope with patterns that were compiled on
2520     hosts of opposite endianness, with this restriction:
2522     As for any compiled expression that is saved and used later, the tables
2523     pointer field cannot be preserved; the extra_data field in the arguments
2524     to pcre_exec() should be used to pass in a tables address if a value
2525     other than the default internal tables were used at compile time.
2527     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2528     now diagnosed as an error. Previously, most of the time, a negative number
2529     would have been treated as zero, but if in addition "ovector" was passed as
2530     NULL, a crash could occur.
2532     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2533     new versions from the libtool 1.5 distribution (the last one is a copy of
2534     a file called libtool.m4). This seems to have fixed the need to patch
2535     "configure" to support Darwin 1.3 (which I used to do). However, I still
2536     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2537     workstation).
2539     24. Changed the PCRE licence to be the more standard "BSD" licence.
2542 nigel 73 Version 4.5 01-Dec-03
2543     ---------------------
2545     1. There has been some re-arrangement of the code for the match() function so
2546     that it can be compiled in a version that does not call itself recursively.
2547     Instead, it keeps those local variables that need separate instances for
2548     each "recursion" in a frame on the heap, and gets/frees frames whenever it
2549     needs to "recurse". Keeping track of where control must go is done by means
2550     of setjmp/longjmp. The whole thing is implemented by a set of macros that
2551     hide most of the details from the main code, and operates only if
2552     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2553     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2554     operating.
2556     To make it easier for callers to provide specially tailored get/free
2557     functions for this usage, two new functions, pcre_stack_malloc, and
2558     pcre_stack_free, are used. They are always called in strict stacking order,
2559     and the size of block requested is always the same.
2561     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2562     PCRE has been compiled to use the stack or the heap for recursion. The
2563     -C option of pcretest uses this to show which version is compiled.
2565     A new data escape \S, is added to pcretest; it causes the amounts of store
2566     obtained and freed by both kinds of malloc/free at match time to be added
2567     to the output.
2569     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2570     what's available on my current Linux desktop machine.
2572     3. When matching a UTF-8 string, the test for a valid string at the start has
2573     been extended. If start_offset is not zero, PCRE now checks that it points
2574     to a byte that is the start of a UTF-8 character. If not, it returns
2575     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2576     this is necessary because there may be backward assertions in the pattern.
2577     When matching the same subject several times, it may save resources to use
2578     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2580     4. The code for checking the validity of UTF-8 strings has been tightened so
2581     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2582     containing "overlong sequences".
2584     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2585     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2586     should have been "&", but it just so happened that all the cases this let
2587     through by mistake were picked up later in the function.
2589     6. I had used a variable called "isblank" - this is a C99 function, causing
2590     some compilers to warn. To avoid this, I renamed it (as "blankclass").
2592     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2593     prompting; (b) run "./pcretest /dev/null" at the start of the test script
2594     so the version is shown; (c) stop "make test" echoing "./RunTest".
2596     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2598     9. The prototype for memmove() for systems that don't have it was using
2599     size_t, but the inclusion of the header that defines size_t was later. I've
2600     moved the #includes for the C headers earlier to avoid this.
2602     10. Added some adjustments to the code to make it easier to compiler on certain
2603     special systems:
2605     (a) Some "const" qualifiers were missing.
2606     (b) Added the macro EXPORT before all exported functions; by default this
2607     is defined to be empty.
2608     (c) Changed the dftables auxiliary program (that builds chartables.c) so
2609     that it reads its output file name as an argument instead of writing
2610     to the standard output and assuming this can be redirected.
2612     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2613     class containing characters with values greater than 255, PCRE compilation
2614     went into a loop.
2616     12. A recursive reference to a subpattern that was within another subpattern
2617     that had a minimum quantifier of zero caused PCRE to crash. For example,
2618     (x(y(?2))z)? provoked this bug with a subject that got as far as the
2619     recursion. If the recursively-called subpattern itself had a zero repeat,
2620     that was OK.
2622     13. In pcretest, the buffer for reading a data line was set at 30K, but the
2623     buffer into which it was copied (for escape processing) was still set at
2624     1024, so long lines caused crashes.
2626     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2627     "internal error: code overflow...". This applied to any character class
2628     that was followed by a possessive quantifier.
2630     15. Modified the Makefile to add libpcre.la as a prerequisite for
2631     libpcreposix.la because I was told this is needed for a parallel build to
2632     work.
2634     16. If a pattern that contained .* following optional items at the start was
2635     studied, the wrong optimizing data was generated, leading to matching
2636     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2637     matching string must start with a or b or c. The correct conclusion for
2638     this pattern is that a match can start with any character.
2641 nigel 71 Version 4.4 13-Aug-03
2642     ---------------------
2644     1. In UTF-8 mode, a character class containing characters with values between
2645     127 and 255 was not handled correctly if the compiled pattern was studied.
2646     In fixing this, I have also improved the studying algorithm for such
2647     classes (slightly).
2649     2. Three internal functions had redundant arguments passed to them. Removal
2650     might give a very teeny performance improvement.
2652     3. Documentation bug: the value of the capture_top field in a callout is *one
2653     more than* the number of the hightest numbered captured substring.
2655     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2656     in incorrectly linking with a previously installed version. They now link
2657     explicitly with libpcre.la.
2659     5. configure.in no longer needs to recognize Cygwin specially.
2661     6. A problem in pcre.in for Windows platforms is fixed.
2663     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2664     pcretest, it used to include the size of the study block as part of its
2665     output. Unfortunately, the structure contains a field that has a different
2666     size on different hardware architectures. This meant that the tests that
2667     showed this size failed. As the block is currently always of a fixed size,
2668     this information isn't actually particularly useful in pcretest output, so
2669     I have just removed it.
2671     8. Three pre-processor statements accidentally did not start in column 1.
2672     Sadly, there are *still* compilers around that complain, even though
2673     standard C has not required this for well over a decade. Sigh.
2675     9. In pcretest, the code for checking callouts passed small integers in the
2676     callout_data field, which is a void * field. However, some picky compilers
2677     complained about the casts involved for this on 64-bit systems. Now
2678     pcretest passes the address of the small integer instead, which should get
2679     rid of the warnings.
2681     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2682     both compile and run time, and gives an error if an invalid UTF-8 sequence
2683     is found. There is a option for disabling this check in cases where the
2684     string is known to be correct and/or the maximum performance is wanted.
2686     11. In response to a bug report, I changed one line in Makefile.in from
2688     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2689     to
2690     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2692     to look similar to other lines, but I have no way of telling whether this
2693     is the right thing to do, as I do not use Windows. No doubt I'll get told
2694     if it's wrong...
2697 nigel 69 Version 4.3 21-May-03
2698     ---------------------
2700     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2701     Makefile.
2703     2. Some refactoring to improve the quality of the code:
2705     (i) The utf8_table... variables are now declared "const".
2707     (ii) The code for \cx, which used the "case flipping" table to upper case
2708     lower case letters, now just substracts 32. This is ASCII-specific,
2709     but the whole concept of \cx is ASCII-specific, so it seems
2710     reasonable.
2712     (iii) PCRE was using its character types table to recognize decimal and
2713     hexadecimal digits in the pattern. This is silly, because it handles
2714     only 0-9, a-f, and A-F, but the character types table is locale-
2715     specific, which means strange things might happen. A private
2716     table is now used for this - though it costs 256 bytes, a table is
2717     much faster than multiple explicit tests. Of course, the standard
2718     character types table is still used for matching digits in subject
2719     strings against \d.
2721     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2722     ending in _t are). So I've renamed it as ESC_tee.
2724     3. The first argument for regexec() in the POSIX wrapper should have been
2725     defined as "const".
2727     4. Changed pcretest to use malloc() for its buffers so that they can be
2728     Electric Fenced for debugging.
2730     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2731     to read one or more bytes before the start of the subject string. Often this
2732     had no effect on PCRE's behaviour, but in some circumstances it could
2733     provoke a segmentation fault.
2735     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2736     to try to read one or more bytes before the start of the subject string.
2738     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2739     UTF-8 support could misbehave in various ways if the subject string
2740     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2741     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2742     back over UTF-8 characters.)
2745 nigel 67 Version 4.2 14-Apr-03
2746     ---------------------
2748     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2750     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2751     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2752     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2753     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2754     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2755     and BUILD_EXEEXT
2756     Note: automatic setting of the BUILD variables is not yet working
2757     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2758     compile-time but not at link-time
2759     [LINK]: use for linking executables only
2760     make different versions for Windows and non-Windows
2761     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2762     libraries
2763     [LINK_FOR_BUILD]: new variable
2764     [OBJEXT]: use throughout
2765     [EXEEXT]: use throughout
2766     <winshared>: new target
2767     <wininstall>: new target
2768     <dftables.o>: use native compiler
2769     <dftables>: use native linker
2770     <install>: handle Windows platform correctly
2771     <clean>: ditto
2772     <check>: ditto
2773     copy DLL to top builddir before testing
2775     As part of these changes, -no-undefined was removed again. This was reported
2776     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2777     in any case.
2779     3. Some tidies to get rid of compiler warnings:
2781     . In the match_data structure, match_limit was an unsigned long int, whereas
2782     match_call_count was an int. I've made them both unsigned long ints.
2784     . In pcretest the fact that a const uschar * doesn't automatically cast to
2785     a void * provoked a warning.
2787     . Turning on some more compiler warnings threw up some "shadow" variables
2788     and a few more missing casts.
2790     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2791     option, a class that contained a single character with a value between 128
2792     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2794     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2795     option, a class that contained several characters, but with at least one
2796     whose value was between 128 and 255 caused PCRE to crash.
2799 nigel 65 Version 4.1 12-Mar-03
2800     ---------------------
2801 nigel 63
2802 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2803     needed, and a string in dftables.c that was longer than standard compilers are
2804     required to support.
2806     2. Compiling with Sun's compiler found a few more places where the code could
2807     be tidied up in order to avoid warnings.
2809     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2810     first of these names is deprecated in the latest Autoconf in favour of the name
2811     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2812     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2813     analogy I have changed it to CFLAGS_FOR_BUILD.
2815     4. Added -no-undefined to the linking command in the Makefile, because this is
2816     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2817     linking step for the pcreposix library.
2819     5. PCRE was failing to diagnose the case of two named groups with the same
2820     name.
2822     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2823     literal character that is needed in the subject for a match, and scans along to
2824     ensure that it is present before embarking on the full matching process. This
2825     saves time in cases of nested unlimited repeats that are never going to match.
2826     Problem: the scan can take a lot of time if the subject is very long (e.g.
2827     megabytes), thus penalizing straightforward matches. It is now done only if the
2828     amount of subject to be scanned is less than 1000 bytes.
2830     7. A lesser problem with the same optimization is that it was recording the
2831     first character of an anchored pattern as "needed", thus provoking a search
2832     right along the subject, even when the first match of the pattern was going to
2833     fail. The "needed" character is now not set for anchored patterns, unless it
2834     follows something in the pattern that is of non-fixed length. Thus, it still
2835     fulfils its original purpose of finding quick non-matches in cases of nested
2836     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2839     Version 4.0 17-Feb-03
2840     ---------------------
2842 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2843     extended to the end of string, PCRE compiled incorrect data. This could lead to
2844     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2846     2. Moved to autoconf 2.53 and libtool 1.4.2.
2848     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2849     the special perltest8 script is no longer needed - all the tests can be run
2850     from a single perltest script.
2852     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2853     by \s. It has now been removed in PCRE. This means it isn't recognized as
2854     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2855     class [:space:] *does* include VT, thereby creating a mess.
2857     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2858     space and tab.
2860     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2861     its new features into the main test script, reducing the number of scripts.
2863     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2864     were backward compatible, and made the (?i) apply to the whole pattern, as if
2865     /i were given. Now it behaves more logically, and applies the option setting
2866     only to what follows. PCRE has been changed to follow suit. However, if it
2867     finds options settings right at the start of the pattern, it extracts them into
2868     the global options, as before. Thus, they show up in the info data.
2870     8. Added support for the \Q...\E escape sequence. Characters in between are
2871     treated as literals. This is slightly different from Perl in that $ and @ are
2872     also handled as literals inside the quotes. In Perl, they will cause variable
2873     interpolation. Note the following examples:
2875     Pattern PCRE matches Perl matches
2877     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2878     \Qabc\$xyz\E abc\$xyz abc\$xyz
2879     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2881     For compatibility with Perl, \Q...\E sequences are recognized inside character
2882     classes as well as outside them.
2884     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2885     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2886     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2887     signed/unsigned warnings.
2889     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2890     option for pcretest, so I've replaced it by a simple function that does just
2891     that job.
2893     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2894     "pcregrep -".
2896     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2897     Java package. This provides some syntactic sugar for simple cases of what my
2898     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2899     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2900     item, you can use this simplified notation. Note that only makes sense with
2901     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2902     greediness, whatever the setting of the PCRE_UNGREEDY option.
2904     13. A change of greediness default within a pattern was not taking effect at
2905     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2906     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2907     was abstracted outside.
2909     14. PCRE now supports the \G assertion. It is true when the current matching
2910     position is at the start point of the match. This differs from \A when the
2911     starting offset is non-zero. Used with the /g option of pcretest (or similar
2912     code), it works in the same way as it does for Perl's /g option. If all
2913     alternatives of a regex begin with \G, the expression is anchored to the start
2914     match position, and the "anchored" flag is set in the compiled expression.
2916     15. Some bugs concerning the handling of certain option changes within patterns
2917     have been fixed. These applied to options other than (?ims). For example,
2918     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2919     been the other way round. Some of this was related to change 7 above.
2921     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2922     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2923     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2924     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2926     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2927     mode. Unlike ".", it always matches newline, whatever the setting of
2928     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2929     assertions. Perl allows it, but it doesn't (in general) work because it can't
2930     calculate the length of the lookbehind. At least, that's the case for Perl
2931     5.8.0 - I've been told they are going to document that it doesn't work in
2932     future.
2934     18. Added an error diagnosis for escapes that PCRE does not support: these are
2935     \L, \l, \N, \P, \p, \U, \u, and \X.
2937     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2938     reading past the end of the pattern in cases such as /[abcd/.
2940     20. PCRE was getting more memory than necessary for patterns with classes that
2941     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2943     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2944     compiling PCRE for use with Virtual Pascal.
2946     22. Small fix to the Makefile to make it work properly if the build is done
2947     outside the source tree.
2949     23. Added a new extension: a condition to go with recursion. If a conditional
2950     subpattern starts with (?(R) the "true" branch is used if recursion has
2951     happened, whereas the "false" branch is used only at the top level.
2953     24. When there was a very long string of literal characters (over 255 bytes
2954     without UTF support, over 250 bytes with UTF support), the computation of how
2955     much memory was required could be incorrect, leading to segfaults or other
2956     strange effects.
2958     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2959     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2960     there was a subsequent back reference to those brackets. This meant that, for
2961     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2962     possible to check for precisely this case. All we can do is abandon the
2963     optimization if .* occurs inside capturing brackets when there are any back
2964     references whatsoever. (See below for a better fix that came later.)
2966     26. The handling of the optimization for finding the first character of a
2967     non-anchored pattern, and for finding a character that is required later in the
2968     match were failing in some cases. This didn't break the matching; it just
2969     failed to optimize when it could. The way this is done has been re-implemented.
2971     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2973     28. Added a new feature that provides some of the functionality that Perl
2974     provides with (?{...}). The facility is termed a "callout". The way it is done
2975     in PCRE is for the caller to provide an optional function, by setting
2976     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2977     global variable. By default it is unset, which disables all calling out. To get
2978     the function called, the regex must include (?C) at appropriate points. This
2979     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2980     This provides a means of identifying different callout points. When PCRE
2981     reaches such a point in the regex, if pcre_callout has been set, the external
2982     function is called. It is provided with data in a structure called
2983     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2984     matching continues; if it returns a non-zero value, the match at the current
2985     point fails. However, backtracking will occur if possible. [This was changed
2986     later and other features added - see item 49 below.]
2988     29. pcretest is upgraded to test the callout functionality. It provides a
2989     callout function that displays information. By default, it shows the start of
2990     the match and the current position in the text. There are some new data escapes
2991     to vary what happens:
2993     \C+ in addition, show current contents of captured substrings
2994     \C- do not supply a callout function
2995     \C!n return 1 when callout number n is reached
2996     \C!n!m return 1 when callout number n is reached for the mth time
2998     30. If pcregrep was called with the -l option and just a single file name, it
2999     output "<stdin>" if a match was found, instead of the file name.
3001     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
3002     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
3003     pcre_exec(). This saves a malloc/free per call. The default value of
3004     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
3005     when configuring.
3007     32. The default maximum size of a compiled pattern is 64K. There have been a
3008     few cases of people hitting this limit. The code now uses macros to handle the
3009     storing of links as offsets within the compiled pattern. It defaults to 2-byte
3010     links, but this can be changed to 3 or 4 bytes by --with-link-size when
3011     configuring. Tests 2 and 5 work only with 2-byte links because they output
3012     debugging information about compiled patterns.
3014     33. Internal code re-arrangements:
3016     (a) Moved the debugging function for printing out a compiled regex into
3017     its own source file (printint.c) and used #include to pull it into
3018     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
3019     separate copies.
3021     (b) Defined the list of op-code names for debugging as a macro in
3022     internal.h so that it is next to the definition of the opcodes.
3024     (c) Defined a table of op-code lengths for simpler skipping along compiled
3025     code. This is again a macro in internal.h so that it is next to the
3026     definition of the opcodes.
3028     34. Added support for recursive calls to individual subpatterns, along the
3029     lines of Robin Houston's patch (but implemented somewhat differently).
3031     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
3032     allow it to read and process whole directories in Win32. This code was
3033     contributed by Lionel Fourquaux; it has not been tested by me.
3035     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
3036     used to name a group. Names consist of alphanumerics and underscores, and must
3037     be unique. Back references use the syntax (?P=name) and recursive calls use
3038     (?P>name) which is a PCRE extension to the Python extension. Groups still have
3039     numbers. The function pcre_fullinfo() can be used after compilation to extract
3040     a name/number map. There are three relevant calls:
3042     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
3043     PCRE_INFO_NAMECOUNT yields the number of entries
3044     PCRE_INFO_NAMETABLE yields a pointer to the map.
3046     The map is a vector of fixed-size entries. The size of each entry depends on
3047     the length of the longest name used. The first two bytes of each entry are the
3048     group number, most significant byte first. There follows the corresponding
3049     name, zero terminated. The names are in alphabetical order.
3051     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
3052     case instead of 255. Making it the same both with and without UTF-8 support
3053     means that the same test output works with both.
3055     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
3056     calling malloc() with a zero argument.
3058     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
3059     optimization. I've improved things by keeping a bitmap of backreferences with
3060     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
3061     fact referenced, the optimization can be applied. It is unlikely that a
3062     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
3063     the match to follow \n) will appear inside brackets with a number greater than
3064     31, but if it does, any back reference > 31 suppresses the optimization.
3066     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
3067     of disabling numbered capturing parentheses. Any opening parenthesis that is
3068     not followed by ? behaves as if it were followed by ?: but named parentheses
3069     can still be used for capturing (and they will acquire numbers in the usual
3070     way).
3072     41. Redesigned the return codes from the match() function into yes/no/error so
3073     that errors can be passed back from deep inside the nested calls. A malloc
3074     failure while inside a recursive subpattern call now causes the
3075     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
3077     42. It is now possible to set a limit on the number of times the match()
3078     function is called in a call to pcre_exec(). This facility makes it possible to
3079     limit the amount of recursion and backtracking, though not in a directly
3080     obvious way, because the match() function is used in a number of different
3081     circumstances. The count starts from zero for each position in the subject
3082     string (for non-anchored patterns). The default limit is, for compatibility, a
3083     large number, namely 10 000 000. You can change this in two ways:
3085     (a) When configuring PCRE before making, you can use --with-match-limit=n
3086     to set a default value for the compiled library.
3088     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
3089     a different value is set. See 45 below.
3091     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
3093     43. Added a new function pcre_config(int, void *) to enable run-time extraction
3094     of things that can be changed at compile time. The first argument specifies
3095     what is wanted and the second points to where the information is to be placed.
3096     The current list of available information is:
3100     The output is an integer that is set to one if UTF-8 support is available;
3101     otherwise it is set to zero.
3105     The output is an integer that it set to the value of the code that is used for
3106     newline. It is either LF (10) or CR (13).
3110     The output is an integer that contains the number of bytes used for internal
3111     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
3115     The output is an integer that contains the threshold above which the POSIX
3116     interface uses malloc() for output vectors. See item 31 above.
3120     The output is an unsigned integer that contains the default limit of the number
3121     of match() calls in a pcre_exec() execution. See 42 above.
3123     44. pcretest has been upgraded by the addition of the -C option. This causes it
3124     to extract all the available output from the new pcre_config() function, and to
3125     output it. The program then exits immediately.
3127     45. A need has arisen to pass over additional data with calls to pcre_exec() in
3128     order to support additional features. One way would have been to define
3129     pcre_exec2() (for example) with extra arguments, but this would not have been
3130     extensible, and would also have required all calls to the original function to
3131     be mapped to the new one. Instead, I have chosen to extend the mechanism that
3132     is used for passing in "extra" data from pcre_study().
3134     The pcre_extra structure is now exposed and defined in pcre.h. It currently
3135     contains the following fields:
3137     flags a bitmap indicating which of the following fields are set
3138     study_data opaque data from pcre_study()
3139     match_limit a way of specifying a limit on match() calls for a specific
3140     call to pcre_exec()
3141     callout_data data for callouts (see 49 below)
3143     The flag bits are also defined in pcre.h, and are
3149     The pcre_study() function now returns one of these new pcre_extra blocks, with
3150     the actual study data pointed to by the study_data field, and the
3151     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
3152     before. That is, this change is entirely upwards-compatible and requires no
3153     change to existing code.
3155     If you want to pass in additional data to pcre_exec(), you can either place it
3156     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
3157     block.
3159     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
3160     data string contains the escape sequence \M, pcretest calls pcre_exec() several
3161     times with different match limits, until it finds the minimum value needed for
3162     pcre_exec() to complete. The value is then output. This can be instructive; for
3163     most simple matches the number is quite small, but for pathological cases it
3164     gets very large very quickly.
3166     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
3167     returns the size of the data block pointed to by the study_data field in a
3168     pcre_extra block, that is, the value that was passed as the argument to
3169     pcre_malloc() when PCRE was getting memory in which to place the information
3170     created by pcre_study(). The fourth argument should point to a size_t variable.
3171     pcretest has been extended so that this information is shown after a successful
3172     pcre_study() call when information about the compiled regex is being displayed.
3174     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
3175     because what follows is always an absolute path. (Later: it turns out that this
3176     is more than cosmetic for MinGW, because it doesn't like empty path
3177     components.)
3179     49. Some changes have been made to the callout feature (see 28 above):
3181     (i) A callout function now has three choices for what it returns:
3183     0 => success, carry on matching
3184     > 0 => failure at this point, but backtrack if possible
3185     < 0 => serious error, return this value from pcre_exec()
3187     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
3188     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
3189     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
3190     use by callout functions. It will never be used by PCRE itself.
3192     (ii) The pcre_extra structure (see 45 above) has a void * field called
3193     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
3194     pcre_callout_block structure has a field of the same name. The contents of
3195     the field passed in the pcre_extra structure are passed to the callout
3196     function in the corresponding field in the callout block. This makes it
3197     easier to use the same callout-containing regex from multiple threads. For
3198     testing, the pcretest program has a new data escape
3200     \C*n pass the number n (may be negative) as callout_data
3202     If the callout function in pcretest receives a non-zero value as
3203     callout_data, it returns that value.
3205     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
3206     there were some redundant $(CFLAGS) in commands that are now specified as
3207     $(LINK), which already includes $(CFLAGS).
3209     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
3210     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
3211     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
3212     one-byte characters throughout. Note that case-insensitive matching applies
3213     only to characters whose values are less than 256. PCRE doesn't support the
3214     notion of cases for higher-valued characters.
3216     (i) A character class whose characters are all within 0-255 is handled as
3217     a bit map, and the map is inverted for negative classes. Previously, a
3218     character > 255 always failed to match such a class; however it should
3219     match if the class was a negative one (e.g. [^ab]). This has been fixed.
3221     (ii) A negated character class with a single character < 255 is coded as
3222     "not this character" (OP_NOT). This wasn't working properly when the test
3223     character was multibyte, either singly or repeated.
3225     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
3226     mode, for example: \x{100}{2,3}.
3228     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
3229     singly or repeated) now correctly test multibyte characters. However,
3230     PCRE doesn't recognize any characters with values greater than 255 as
3231     digits, spaces, or word characters. Such characters always match \D, \S,
3232     and \W, and never match \d, \s, or \w.
3234     (v) Classes may now contain characters and character ranges with values
3235     greater than 255. For example: [ab\x{100}-\x{400}].
3237     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
3238     PCRE in UTF-8 mode.
3240     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
3241     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
3242     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
3243     value.)
3245     53. The single man page has become too large. I have therefore split it up into
3246     a number of separate man pages. These also give rise to individual HTML pages;
3247     these are now put in a separate directory, and there is an index.html page that
3248     lists them all. Some hyperlinking between the pages has been installed.
3250     54. Added convenience functions for handling named capturing parentheses.
3252     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3253     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3254     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3255     are faulted.
3257     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3258     calling configure. These values are used when compiling the dftables.c program
3259     which is run to generate the source of the default character tables. They
3260     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3261     you will need to set these values.
3263     57. Updated the building process for Windows DLL, as provided by Fred Cox.
3266     Version 3.9 02-Jan-02
3267 nigel 61 ---------------------
3269     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3271     2. If --disable-static was given, the building process failed when trying to
3272     build pcretest and pcregrep. (For some reason it was using libtool to compile
3273     them, which is not right, as they aren't part of the library.)
3276 nigel 59 Version 3.8 18-Dec-01
3277     ---------------------
3279     1. The experimental UTF-8 code was completely screwed up. It was packing the
3280     bytes in the wrong order. How dumb can you get?
3283 nigel 57 Version 3.7 29-Oct-01
3284     ---------------------
3286     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
3287     This caused pcretest, when used on the test data, to segfault. Unfortunately,
3288     this didn't happen under Solaris 8, where I normally test things.
3290 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
3291     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
3292     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
3293     this fix an hour or so after the initial 3.7 release.)
3294 nigel 57
3295 nigel 59
3296 nigel 55 Version 3.6 23-Oct-01
3297     ---------------------
3299     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
3300     offsets passed as NULL with zero offset count.
3302     2. The config.guess and config.sub files had not been updated when I moved to
3303     the latest autoconf.
3306 nigel 53 Version 3.5 15-Aug-01
3307     ---------------------
3308 nigel 5
3309 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
3310     had been forgotten.
3312     2. By using declared but undefined structures, we can avoid using "void"
3313     definitions in pcre.h while keeping the internal definitions of the structures
3314     private.
3316     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3317     user point of view, this means that both static and shared libraries are built
3318     by default, but this can be individually controlled. More of the work of
3319     handling this static/shared cases is now inside libtool instead of PCRE's make
3320     file.
3322     4. The pcretest utility is now installed along with pcregrep because it is
3323     useful for users (to test regexs) and by doing this, it automatically gets
3324     relinked by libtool. The documentation has been turned into a man page, so
3325     there are now .1, .txt, and .html versions in /doc.
3327     5. Upgrades to pcregrep:
3328     (i) Added long-form option names like gnu grep.
3329     (ii) Added --help to list all options with an explanatory phrase.
3330     (iii) Added -r, --recursive to recurse into sub-directories.
3331     (iv) Added -f, --file to read patterns from a file.
3333     6. pcre_exec() was referring to its "code" argument before testing that
3334     argument for NULL (and giving an error if it was NULL).
3336     7. Upgraded Makefile.in to allow for compiling in a different directory from
3337     the source directory.
3339     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3340     options bits, the pointer it was passed was to an int instead of to an unsigned
3341     long int. This mattered only on 64-bit systems.
3343     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3344     generated) instead of pcre.in, which it its source. Also made the same change
3345     in several of the .c files.
3347     10. A new release of gcc defines printf() as a macro, which broke pcretest
3348     because it had an ifdef in the middle of a string argument for printf(). Fixed
3349     by using separate calls to printf().
3351     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3352     script, to force use of CR or LF instead of \n in the source. On non-Unix
3353     systems, the value can be set in config.h.
3355     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3356     absolute limit. Changed the text of the error message to make this clear, and
3357     likewise updated the man page.
3359     13. The limit of 99 on the number of capturing subpatterns has been removed.
3360     The new limit is 65535, which I hope will not be a "real" limit.
3363 nigel 51 Version 3.4 22-Aug-00
3364     ---------------------
3366     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3368     2. Diagnose condition (?(0) as an error instead of crashing on matching.
3371 nigel 49 Version 3.3 01-Aug-00
3372     ---------------------
3374     1. If an octal character was given, but the value was greater than \377, it
3375     was not getting masked to the least significant bits, as documented. This could
3376     lead to crashes in some systems.
3378     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3379     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3381     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3382     These just pass their arguments on to (pcre_free)(), but they are provided
3383     because some uses of PCRE bind it to non-C systems that can call its functions,
3384     but cannot call free() or pcre_free() directly.
3386     4. Add "make test" as a synonym for "make check". Corrected some comments in
3387     the Makefile.
3389     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3390     Makefile.
3392     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3393     command called pgrep for grepping around the active processes.
3395     7. Added the beginnings of support for UTF-8 character strings.
3397     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3398     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3399     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3400     out for the ar command.)
3403 nigel 47 Version 3.2 12-May-00
3404     ---------------------
3406     This is purely a bug fixing release.
3408     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3409     of ZA. This was just one example of several cases that could provoke this bug,
3410     which was introduced by change 9 of version 2.00. The code for breaking
3411     infinite loops after an iteration that matches an empty string was't working
3412     correctly.
3414     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3415     when matched against abbab (for example). After matching an empty string, it
3416     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3417     caused it to match further down the string than it should.
3419     3. The code contained an inclusion of sys/types.h. It isn't clear why this
3420     was there because it doesn't seem to be needed, and it causes trouble on some
3421     systems, as it is not a Standard C header. It has been removed.
3423     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3424     were reported on the Macintosh. The changes were from
3426     while ((c = *(++ptr)) != 0 && c != '\n');
3427     to
3428     while ((c = *(++ptr)) != 0 && c != '\n') ;
3430     Totally extraordinary, but if that's what it takes...
3432     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3433     available. Added HAVE_BCOPY and an autoconf test for it; if neither
3434     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3435     assumes the way PCRE uses memmove() (always moving upwards).
3437     6. PCRE is being used in one environment where strchr() is not available. There
3438     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3439     faster code anyway.
3442 nigel 45 Version 3.1 09-Feb-00
3443     ---------------------
3445     The only change in this release is the fixing of some bugs in Makefile.in for
3446     the "install" target:
3448     (1) It was failing to install pcreposix.h.
3450     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3453 nigel 43 Version 3.0 01-Feb-00
3454     ---------------------
3455 nigel 41
3456     1. Add support for the /+ modifier to perltest (to output $` like it does in
3457     pcretest).
3459     2. Add support for the /g modifier to perltest.
3461     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3462     matches null strings.
3464     4. Fix perltest so that it doesn't do unwanted things when fed an empty
3465     pattern. Perl treats empty patterns specially - it reuses the most recent
3466     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3467     effect.
3469     5. The POSIX interface was broken in that it was just handing over the POSIX
3470     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3471     required a bigger vector, with some working space on the end. This means that
3472     the POSIX wrapper now has to get and free some memory, and copy the results.
3474 nigel 43 6. Added some simple autoconf support, placing the test data and the
3475     documentation in separate directories, re-organizing some of the
3476     information files, and making it build pcre-config (a GNU standard). Also added
3477     libtool support for building PCRE as a shared library, which is now the
3478     default.
3479 nigel 41
3480 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3481     09 are not valid octal constants. Single digits will be used for minor values
3482     less than 10.
3484     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3485     existing programs that set these in the POSIX interface can use PCRE without
3486     modification.
3488     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3489     return all that pcre_info() returns, plus additional data. The pcre_info()
3490     function is retained for compatibility, but is considered to be obsolete.
3492     10. Added experimental recursion feature (?R) to handle one common case that
3493     Perl 5.6 will be able to do with (?p{...}).
3495     11. Added support for POSIX character classes like [:alpha:], which Perl is
3496     adopting.
3499 nigel 39 Version 2.08 31-Aug-99
3500     ----------------------
3502     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3503     trying to match at the startoffset position, but instead was moving forward to
3504     the next newline as if a previous match had failed.
3506     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3507     and could get into a loop if a null string was matched other than at the start
3508     of the subject.
3510     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3511     be distinguished at compile time, and for completeness also added PCRE_DATE.
3513     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3514     in GnuWin32 environments.
3517 nigel 37 Version 2.07 29-Jul-99
3518     ----------------------
3520     1. The documentation is now supplied in plain text form and HTML as well as in
3521     the form of man page sources.
3523     2. C++ compilers don't like assigning (void *) values to other pointer types.
3524     In particular this affects malloc(). Although there is no problem in Standard
3525     C, I've put in casts to keep C++ compilers happy.
3527     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3528     should be (const char *).
3530     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3531     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3532     However, I haven't made this a standard facility. The documentation doesn't
3533     mention it, and the Makefile doesn't support it.
3535     5. The Makefile now contains an "install" target, with editable destinations at
3536     the top of the file. The pcretest program is not installed.
3538     6. pgrep -V now gives the PCRE version number and date.
3540     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3541     causing the entire string to be ignored, instead of just the last character.
3543     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3544     non-matching string, it can take a very, very long time, even for strings of
3545     quite modest length, because of the nested recursion. PCRE now does better in
3546     some of these cases. It does this by remembering the last required literal
3547     character in the pattern, and pre-searching the subject to ensure it is present
3548     before running the real match. In other words, it applies a heuristic to detect
3549     some types of certain failure quickly, and in the above example, if presented
3550     with a string that has no trailing " it gives "no match" very quickly.
3552     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3553     other alternatives are tried instead.
3556 nigel 35 Version 2.06 09-Jun-99
3557     ----------------------
3559     1. Change pcretest's output for amount of store used to show just the code
3560     space, because the remainder (the data block) varies in size between 32-bit and
3561     64-bit systems.
3563     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3564     start matching at. This allows lookbehinds to work when searching for multiple
3565     occurrences in a string.
3567     3. Added additional options to pcretest for testing multiple occurrences:
3569     /+ outputs the rest of the string that follows a match
3570     /g loops for multiple occurrences, using the new startoffset argument
3571     /G loops for multiple occurrences by passing an incremented pointer
3573     4. PCRE wasn't doing the "first character" optimization for patterns starting
3574     with \b or \B, though it was doing it for other lookbehind assertions. That is,
3575     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3576     the letter 'x'. On long subject strings, this gives a significant speed-up.
3579 nigel 33 Version 2.05 21-Apr-99
3580     ----------------------
3582     1. Changed the type of magic_number from int to long int so that it works
3583     properly on 16-bit systems.
3585     2. Fixed a bug which caused patterns starting with .* not to work correctly
3586     when the subject string contained newline characters. PCRE was assuming
3587     anchoring for such patterns in all cases, which is not correct because .* will
3588     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3589     DOTALL is set at top level; otherwise it knows that patterns starting with .*
3590     must be retried after every newline in the subject.
3593 nigel 31 Version 2.04 18-Feb-99
3594     ----------------------
3596     1. For parenthesized subpatterns with repeats whose minimum was zero, the
3597     computation of the store needed to hold the pattern was incorrect (too large).
3598     If such patterns were nested a few deep, this could multiply and become a real
3599     problem.
3601     2. Added /M option to pcretest to show the memory requirement of a specific
3602     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3604     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3605     compiled in such a way that the backtracking after subsequent failure was
3606     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3607     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3610 nigel 29 Version 2.03 02-Feb-99
3611     ----------------------
3613     1. Fixed typo and small mistake in man page.
3615 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
3616     LICENCE file containing the conditions.
3617 nigel 29
3618     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3619     Perl, that is the internal \ allows the delimiter to be included in the
3620     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3621     the final delimiter, add \ to the end of the pattern (to test the error).
3623     4. Added the convenience functions for extracting substrings after a successful
3624     match. Updated pcretest to make it able to test these functions.
3627 nigel 27 Version 2.02 14-Jan-99
3628     ----------------------
3630     1. Initialized the working variables associated with each extraction so that
3631     their saving and restoring doesn't refer to uninitialized store.
3633     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3634     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3635     fix the problem.
3637     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3638     calls, and wasn't printing the correct value for compiling calls. Increased the
3639     default value of LOOPREPEAT, and the number of significant figures in the
3640     times.
3642     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3644     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3645     a building problem on Windows NT with a FAT file system.
3648 nigel 25 Version 2.01 21-Oct-98
3649     ----------------------
3651     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3652     to character tables built by pcre_maketables() in the current locale. If NULL
3653     is passed, the default tables are used.
3656 nigel 23 Version 2.00 24-Sep-98
3657 nigel 21 ----------------------
3659 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3660     it any more.
3662     2. Allow quantification of (?>) groups, and make it work correctly.
3664     3. The first character computation wasn't working for (?>) groups.
3666     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3667     end of the subject) and add 5.005's \z, which really does match only at the
3668     very end of the subject.
3670     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3672     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3673     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3674     localized options. All options to pcre_study() were also removed.
3676     7. Add other new features from 5.005:
3678     $(?<= positive lookbehind
3679     $(?<! negative lookbehind
3680     (?imsx-imsx) added the unsetting capability
3681     such a setting is global if at outer level; local otherwise
3682     (?imsx-imsx:) non-capturing groups with option setting
3683     (?(cond)re|re) conditional pattern matching
3685     A backreference to itself in a repeated group matches the previous
3686     captured string.
3688     8. General tidying up of studying (both automatic and via "study")
3689     consequential on the addition of new assertions.
3691     9. As in 5.005, unlimited repeated groups that could match an empty substring
3692     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3693     runtime if any iteration does actually match an empty substring.
3695     10. Include the RunTest script in the distribution.
3697     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3698     discrepancies, some of which were old and were also with respect to 5.004. They
3699     have now been fixed.
3702     Version 1.09 28-Apr-98
3703     ----------------------
3705 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3706     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3707     program crashes, or just wrong answers. This did not apply to negated classes
3708     containing more than one character, or to minima other than one.
3711 nigel 19 Version 1.08 27-Mar-98
3712     ----------------------
3714     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3716     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3717     latter must appear before anything that relies on it in the pattern.
3720 nigel 17 Version 1.07 16-Feb-98