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Revision 553 - (hide annotations) (download)
Fri Oct 22 15:57:50 2010 UTC (4 years, 5 months ago) by ph10
File size: 191779 byte(s)
Change the way PCRE_PARTIAL_HARD handles \z, \Z, \b, \B, and $.

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 550
43 ph10 553
44 ph10 548 Version 8.10 25-Jun-2010
45 ph10 510 ------------------------
47 ph10 512 1. Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
48 ph10 510 THEN.
50 ph10 512 2. (*ACCEPT) was not working when inside an atomic group.
51 ph10 510
52 ph10 535 3. Inside a character class, \B is treated as a literal by default, but
53     faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
54 ph10 513 causes the error). The code is unchanged, but I tidied the documentation.
55 ph10 535
56     4. Inside a character class, PCRE always treated \R and \X as literals,
57 ph10 513 whereas Perl faults them if its -w option is set. I have changed PCRE so
58     that it faults them when PCRE_EXTRA is set.
59 ph10 535
60 ph10 514 5. Added support for \N, which always matches any character other than
61     newline. (It is the same as "." when PCRE_DOTALL is not set.)
62 ph10 535
63 ph10 515 6. When compiling pcregrep with newer versions of gcc which may have
64 ph10 535 FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
65 ph10 515 declared with attribute warn_unused_result" were given. Just casting the
66 ph10 535 result to (void) does not stop the warnings; a more elaborate fudge is
67     needed. I've used a macro to implement this.
68 ph10 512
69 ph10 535 7. Minor change to pcretest.c to avoid a compiler warning.
71 ph10 517 8. Added four artifical Unicode properties to help with an option to make
72 ph10 518 \s etc use properties (see next item). The new properties are: Xan
73     (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
74 ph10 535
75 ph10 518 9. Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
76 ph10 535 use Unicode properties. (*UCP) at the start of a pattern can be used to set
77 ph10 518 this option. Modified pcretest to add /W to test this facility. Added
78     REG_UCP to make it available via the POSIX interface.
79 ph10 513
80 ph10 535 10. Added --line-buffered to pcregrep.
82     11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
83     studied, and the match started with a letter with a code point greater than
84 ph10 520 127 whose first byte was different to the first byte of the other case of
85 ph10 545 the letter, the other case of this starting letter was not recognized
86 ph10 536 (#976).
87 ph10 535
88 ph10 536 12. If a pattern that was studied started with a repeated Unicode property
89 ph10 523 test, for example, \p{Nd}+, there was the theoretical possibility of
90 ph10 535 setting up an incorrect bitmap of starting bytes, but fortunately it could
91     not have actually happened in practice until change 8 above was made (it
92 ph10 523 added property types that matched character-matching opcodes).
93 ph10 535
94 ph10 536 13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
95 ph10 535 possible starting bytes for non-anchored patterns.
97 ph10 536 14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
98 ph10 535 \R, and also a number of cases that involve Unicode properties, both
99 ph10 532 explicit and implicit when PCRE_UCP is set.
100 ph10 529
101 ph10 536 15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
102 ph10 535 input, it could crash or give wrong results if characters with values
103     greater than 0xc0 were present in the subject string. (Detail: it assumed
104 ph10 529 UTF-8 input when processing these items.)
105 ph10 535
106 ph10 536 16. Added a lot of (int) casts to avoid compiler warnings in systems where
107     size_t is 64-bit (#991).
108 ph10 535
109 ph10 536 17. Added a check for running out of memory when PCRE is compiled with
110     --disable-stack-for-recursion (#990).
111 ph10 545
112 ph10 537 18. If the last data line in a file for pcretest does not have a newline on
113 ph10 545 the end, a newline was missing in the output.
115     19. The default pcre_chartables.c file recognizes only ASCII characters (values
116     less than 128) in its various bitmaps. However, there is a facility for
117     generating tables according to the current locale when PCRE is compiled. It
118     turns out that in some environments, 0x85 and 0xa0, which are Unicode space
119     characters, are recognized by isspace() and therefore were getting set in
120 ph10 541 these tables, and indeed these tables seem to approximate to ISO 8859. This
121     caused a problem in UTF-8 mode when pcre_study() was used to create a list
122     of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
123     which of course cannot start UTF-8 characters. I have changed the code so
124     that only real ASCII characters (less than 128) and the correct starting
125 ph10 545 bytes for UTF-8 encodings are set for characters greater than 127 when in
126 ph10 541 UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
127     altogether.)
128 ph10 545
129 ph10 541 20. Added the /T option to pcretest so as to be able to run tests with non-
130     standard character tables, thus making it possible to include the tests
131 ph10 545 used for 19 above in the standard set of tests.
133     21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
134     reference to a subpattern the other side of a comment that contains an
135     opening parenthesis caused either an internal compiling error, or a
136 ph10 544 reference to the wrong subpattern.
137 ph10 517
138 ph10 520
139 ph10 508 Version 8.02 19-Mar-2010
140 ph10 491 ------------------------
142     1. The Unicode data tables have been updated to Unicode 5.2.0.
144 ph10 492 2. Added the option --libs-cpp to pcre-config, but only when C++ support is
145     configured.
146 ph10 507
147 ph10 493 3. Updated the licensing terms in the pcregexp.pas file, as agreed with the
148 ph10 507 original author of that file, following a query about its status.
150     4. On systems that do not have stdint.h (e.g. Solaris), check for and include
151 ph10 494 inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
152 ph10 507
153 ph10 496 5. A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
154     quantifier applied to a forward-referencing subroutine call, could compile
155     incorrect code or give the error "internal error: previously-checked
156     referenced subpattern not found".
157 ph10 507
158     6. Both MS Visual Studio and Symbian OS have problems with initializing
159 ph10 497 variables to point to external functions. For these systems, therefore,
160     pcre_malloc etc. are now initialized to local functions that call the
161     relevant global functions.
162 ph10 507
163 ph10 498 7. There were two entries missing in the vectors called coptable and poptable
164     in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
165 ph10 507 I've fixed the data, and added a kludgy way of testing at compile time that
166     the lengths are correct (equal to the number of opcodes).
168     8. Following on from 7, I added a similar kludge to check the length of the
169     eint vector in pcreposix.c.
171     9. Error texts for pcre_compile() are held as one long string to avoid too
172     much relocation at load time. To find a text, the string is searched,
173 ph10 499 counting zeros. There was no check for running off the end of the string,
174     which could happen if a new error number was added without updating the
175 ph10 507 string.
177     10. \K gave a compile-time error if it appeared in a lookbehind assersion.
179 ph10 500 11. \K was not working if it appeared in an atomic group or in a group that
180 ph10 507 was called as a "subroutine", or in an assertion. Perl 5.11 documents that
181     \K is "not well defined" if used in an assertion. PCRE now accepts it if
182     the assertion is positive, but not if it is negative.
184 ph10 501 12. Change 11 fortuitously reduced the size of the stack frame used in the
185 ph10 507 "match()" function of pcre_exec.c by one pointer. Forthcoming
186     implementation of support for (*MARK) will need an extra pointer on the
187 ph10 501 stack; I have reserved it now, so that the stack frame size does not
188     decrease.
189 ph10 507
190     13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
191     item in branch that calls a recursion is a subroutine call - as in the
192 ph10 503 second branch in the above example - was incorrectly given the compile-
193     time error "recursive call could loop indefinitely" because pcre_compile()
194 ph10 507 was not correctly checking the subroutine for matching a non-empty string.
196 ph10 505 14. The checks for overrunning compiling workspace could trigger after an
197 ph10 507 overrun had occurred. This is a "should never occur" error, but it can be
198 ph10 505 triggered by pathological patterns such as hundreds of nested parentheses.
199 ph10 507 The checks now trigger 100 bytes before the end of the workspace.
200 ph10 491
201 ph10 507 15. Fix typo in configure.ac: "srtoq" should be "strtoq".
202 ph10 492
203 ph10 507
204 ph10 489 Version 8.01 19-Jan-2010
205     ------------------------
206 ph10 471
207     1. If a pattern contained a conditional subpattern with only one branch (in
208 ph10 489 particular, this includes all (*DEFINE) patterns), a call to pcre_study()
209 ph10 473 computed the wrong minimum data length (which is of course zero for such
210 ph10 489 subpatterns). This could cause incorrect "no match" results.
211 ph10 473
212     2. For patterns such as (?i)a(?-i)b|c where an option setting at the start of
213 ph10 472 the pattern is reset in the first branch, pcre_compile() failed with
214     "internal error: code overflow at offset...". This happened only when
215 ph10 473 the reset was to the original external option setting. (An optimization
216     abstracts leading options settings into an external setting, which was the
217 ph10 472 cause of this.)
218 ph10 471
219 ph10 473 3. A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
220     of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
221     assertion pattern did not match (meaning that the assertion was true), it
222     was incorrectly treated as false if the SKIP had been reached during the
223     matching. This also applied to assertions used as conditions.
224 ph10 471
225 ph10 473 4. If an item that is not supported by pcre_dfa_exec() was encountered in an
226     assertion subpattern, including such a pattern used as a condition,
227     unpredictable results occurred, instead of the error return
229 ph10 478
230 ph10 474 5. The C++ GlobalReplace function was not working like Perl for the special
231     situation when an empty string is matched. It now does the fancy magic
232 ph10 478 stuff that is necessary.
234     6. In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
235 ph10 475 removed. (These were left over from very, very early versions of PCRE.)
236 ph10 478
237 ph10 475 7. Some cosmetic changes to the code to make life easier when compiling it
238     as part of something else:
239 ph10 478
240     (a) Change DEBUG to PCRE_DEBUG.
242     (b) In pcre_compile(), rename the member of the "branch_chain" structure
243     called "current" as "current_branch", to prevent a collision with the
244 ph10 475 Linux macro when compiled as a kernel module.
245 ph10 478
246     (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
247     prevent a collision with the Linux macro when compiled as a kernel
248 ph10 475 module.
249 ph10 478
250 ph10 475 8. In pcre_compile() there are some checks for integer overflows that used to
251     cast potentially large values to (double). This has been changed to that
252 ph10 478 when building, a check for int64_t is made, and if it is found, it is used
253     instead, thus avoiding the use of floating point arithmetic. (There is no
254     other use of FP in PCRE.) If int64_t is not found, the fallback is to
255     double.
257     9. Added two casts to avoid signed/unsigned warnings from VS Studio Express
258 ph10 476 2005 (difference between two addresses compared to an unsigned value).
259 ph10 473
260 ph10 478 10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
261     custom one, because of the following reported problem in Windows:
262 ph10 473
263 ph10 478 - libbz2 uses the Pascal calling convention (WINAPI) for the functions
264 ph10 489 under Win32.
265 ph10 478 - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
266 ph10 489 therefore missing the function definition.
267 ph10 478 - The compiler thus generates a "C" signature for the test function.
268     - The linker fails to find the "C" function.
269     - PCRE fails to configure if asked to do so against libbz2.
270 ph10 486
271 ph10 479 11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
272     messages were output:
273 ph10 478
274 ph10 479 Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
275     rerunning libtoolize, to keep the correct libtool macros in-tree.
276     Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
277 ph10 486
278 ph10 479 I have done both of these things.
279 ph10 486
280 ph10 480 12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
281 ph10 486 most of the time, it *can* run out if it is given a pattern that contains a
282     runaway infinite recursion. I updated the discussion in the pcrestack man
283     page.
285     13. Now that we have gone to the x.xx style of version numbers, the minor
286     version may start with zero. Using 08 or 09 is a bad idea because users
287     might check the value of PCRE_MINOR in their code, and 08 or 09 may be
288     interpreted as invalid octal numbers. I've updated the previous comment in
289     configure.ac, and also added a check that gives an error if 08 or 09 are
290 ph10 481 used.
291 ph10 486
292 ph10 482 14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
293 ph10 483 causing partial matching to fail when the end of the subject matched \W
294     in a UTF-8 pattern where \W was quantified with a minimum of 3.
295 ph10 486
296 ph10 483 15. There were some discrepancies between the declarations in pcre_internal.h
297 ph10 486 of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
298 ph10 483 their definitions. The declarations used "const uschar *" and the
299     definitions used USPTR. Even though USPTR is normally defined as "const
300     unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
301     reported that: "This difference in casting confuses some C++ compilers, for
302     example, SunCC recognizes above declarations as different functions and
303 ph10 486 generates broken code for hbpcre." I have changed the declarations to use
304 ph10 483 USPTR.
305 ph10 486
306     16. GNU libtool is named differently on some systems. The autogen.sh script now
307 ph10 484 tries several variants such as glibtoolize (MacOSX) and libtoolize1x
308     (FreeBSD).
309 ph10 478
310 ph10 486 17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
311     (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
312     comment: "Figure out how to create a longlong from a string: strtoll and
313     equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
314     instance, but it only takes 2 args instead of 3!"
315 ph10 479
316 ph10 488 18. A subtle bug concerned with back references has been fixed by a change of
317     specification, with a corresponding code fix. A pattern such as
318     ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
319     refers, was giving matches when it shouldn't. For example, xa=xaaa would
320     match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
321     same bug. Such groups have to be quantified to be useful, or contained
322     inside another quantified group. (If there's no repetition, the reference
323     can never match.) The problem arises because, having left the group and
324     moved on to the rest of the pattern, a later failure that backtracks into
325     the group uses the captured value from the final iteration of the group
326     rather than the correct earlier one. I have fixed this in PCRE by forcing
327     any group that contains a reference to itself to be an atomic group; that
328     is, there cannot be any backtracking into it once it has completed. This is
329     similar to recursive and subroutine calls.
330 ph10 486
331 ph10 488
332 ph10 469 Version 8.00 19-Oct-09
333 ph10 418 ----------------------
335     1. The table for translating pcre_compile() error codes into POSIX error codes
336 ph10 461 was out-of-date, and there was no check on the pcre_compile() error code
337     being within the table. This could lead to an OK return being given in
338 ph10 418 error.
339 ph10 461
340     2. Changed the call to open a subject file in pcregrep from fopen(pathname,
341     "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
342     in a Windows environment.
344 ph10 420 3. The pcregrep --count option prints the count for each file even when it is
345     zero, as does GNU grep. However, pcregrep was also printing all files when
346     --files-with-matches was added. Now, when both options are given, it prints
347     counts only for those files that have at least one match. (GNU grep just
348 ph10 461 prints the file name in this circumstance, but including the count seems
349     more useful - otherwise, why use --count?) Also ensured that the
350 ph10 420 combination -clh just lists non-zero counts, with no names.
351 ph10 461
352     4. The long form of the pcregrep -F option was incorrectly implemented as
353     --fixed_strings instead of --fixed-strings. This is an incompatible change,
354     but it seems right to fix it, and I didn't think it was worth preserving
355     the old behaviour.
357     5. The command line items --regex=pattern and --regexp=pattern were not
358 ph10 422 recognized by pcregrep, which required --regex pattern or --regexp pattern
359 ph10 461 (with a space rather than an '='). The man page documented the '=' forms,
360 ph10 422 which are compatible with GNU grep; these now work.
361 ph10 461
362     6. No libpcreposix.pc file was created for pkg-config; there was just
363 ph10 423 libpcre.pc and libpcrecpp.pc. The omission has been rectified.
364 ph10 461
365 ph10 425 7. Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
366 ph10 461 when UCP support is not needed, by modifying the Python script that
367 ph10 425 generates it from Unicode data files. This should not matter if the module
368     is correctly used as a library, but I received one complaint about 50K of
369     unwanted data. My guess is that the person linked everything into his
370     program rather than using a library. Anyway, it does no harm.
371 ph10 461
372 ph10 426 8. A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
373 ph10 461 was a minimum greater than 1 for a wide character in a possessive
374 ph10 431 repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
375     which had an unlimited repeat of a nested, fixed maximum repeat of a wide
376     character. Chaos in the form of incorrect output or a compiling loop could
377     result.
378 ph10 461
379 ph10 426 9. The restrictions on what a pattern can contain when partial matching is
380 ph10 461 requested for pcre_exec() have been removed. All patterns can now be
381 ph10 426 partially matched by this function. In addition, if there are at least two
382 ph10 435 slots in the offset vector, the offset of the earliest inspected character
383     for the match and the offset of the end of the subject are set in them when
384 ph10 461 PCRE_ERROR_PARTIAL is returned.
386 ph10 428 10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
387     synonymous with PCRE_PARTIAL, for backwards compatibility, and
388     PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
389 ph10 462 and may be more useful for multi-segment matching.
390 ph10 461
391     11. Partial matching with pcre_exec() is now more intuitive. A partial match
392     used to be given if ever the end of the subject was reached; now it is
393     given only if matching could not proceed because another character was
394     needed. This makes a difference in some odd cases such as Z(*FAIL) with the
395     string "Z", which now yields "no match" instead of "partial match". In the
396     case of pcre_dfa_exec(), "no match" is given if every matching path for the
397     final character ended with (*FAIL).
399 ph10 428 12. Restarting a match using pcre_dfa_exec() after a partial match did not work
400 ph10 461 if the pattern had a "must contain" character that was already found in the
401 ph10 428 earlier partial match, unless partial matching was again requested. For
402     example, with the pattern /dog.(body)?/, the "must contain" character is
403     "g". If the first part-match was for the string "dog", restarting with
404 ph10 435 "sbody" failed. This bug has been fixed.
405 ph10 461
406     13. The string returned by pcre_dfa_exec() after a partial match has been
407     changed so that it starts at the first inspected character rather than the
408     first character of the match. This makes a difference only if the pattern
409     starts with a lookbehind assertion or \b or \B (\K is not supported by
410     pcre_dfa_exec()). It's an incompatible change, but it makes the two
411 ph10 435 matching functions compatible, and I think it's the right thing to do.
412 ph10 461
413 ph10 435 14. Added a pcredemo man page, created automatically from the pcredemo.c file,
414 ph10 461 so that the demonstration program is easily available in environments where
415     PCRE has not been installed from source.
417 ph10 435 15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
418 ph10 430 libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
419     library.
420 ph10 461
421 ph10 435 16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
422 ph10 432 It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
423 ph10 461 is not the first non-POSIX option to be added. Clearly some people find
424 ph10 433 these options useful.
425 ph10 461
426     17. If a caller to the POSIX matching function regexec() passes a non-zero
427 ph10 438 value for nmatch with a NULL value for pmatch, the value of
428 ph10 461 nmatch is forced to zero.
430 ph10 437 18. RunGrepTest did not have a test for the availability of the -u option of
431 ph10 461 the diff command, as RunTest does. It now checks in the same way as
432 ph10 437 RunTest, and also checks for the -b option.
433 ph10 461
434 ph10 438 19. If an odd number of negated classes containing just a single character
435     interposed, within parentheses, between a forward reference to a named
436 ph10 461 subpattern and the definition of the subpattern, compilation crashed with
437     an internal error, complaining that it could not find the referenced
438 ph10 438 subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
439 ph10 461 [The bug was that it was starting one character too far in when skipping
440     over the character class, thus treating the ] as data rather than
441     terminating the class. This meant it could skip too much.]
443 ph10 442 20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
444 ph10 461 /g option in pcretest when the pattern contains \K, which makes it possible
445 ph10 442 to have an empty string match not at the start, even when the pattern is
446 ph10 461 anchored. Updated pcretest and pcredemo to use this option.
448 ph10 446 21. If the maximum number of capturing subpatterns in a recursion was greater
449 ph10 461 than the maximum at the outer level, the higher number was returned, but
450     with unset values at the outer level. The correct (outer level) value is
451 ph10 446 now given.
452 ph10 461
453 ph10 447 22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
454     PCRE did not set those parentheses (unlike Perl). I have now found a way to
455     make it do so. The string so far is captured, making this feature
456     compatible with Perl.
457 ph10 461
458     23. The tests have been re-organized, adding tests 11 and 12, to make it
459 ph10 448 possible to check the Perl 5.10 features against Perl 5.10.
460 ph10 461
461 ph10 454 24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
462 ph10 461 pattern matches a fixed length string. PCRE did not allow this; now it
463     does. Neither allows recursion.
465     25. I finally figured out how to implement a request to provide the minimum
466     length of subject string that was needed in order to match a given pattern.
467     (It was back references and recursion that I had previously got hung up
468     on.) This code has now been added to pcre_study(); it finds a lower bound
469 ph10 455 to the length of subject needed. It is not necessarily the greatest lower
470     bound, but using it to avoid searching strings that are too short does give
471     some useful speed-ups. The value is available to calling programs via
472     pcre_fullinfo().
473 ph10 461
474 ph10 455 26. While implementing 25, I discovered to my embarrassment that pcretest had
475     not been passing the result of pcre_study() to pcre_dfa_exec(), so the
476     study optimizations had never been tested with that matching function.
477     Oops. What is worse, even when it was passed study data, there was a bug in
478     pcre_dfa_exec() that meant it never actually used it. Double oops. There
479     were also very few tests of studied patterns with pcre_dfa_exec().
480 ph10 461
481 ph10 457 27. If (?| is used to create subpatterns with duplicate numbers, they are now
482     allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
483     on the other side of the coin, they are no longer allowed to have different
484     names, because these cannot be distinguished in PCRE, and this has caused
485     confusion. (This is a difference from Perl.)
486 ph10 461
487     28. When duplicate subpattern names are present (necessarily with different
488     numbers, as required by 27 above), and a test is made by name in a
489     conditional pattern, either for a subpattern having been matched, or for
490     recursion in such a pattern, all the associated numbered subpatterns are
491 ph10 459 tested, and the overall condition is true if the condition is true for any
492     one of them. This is the way Perl works, and is also more like the way
493     testing by number works.
494 ph10 418
495 ph10 461
496 ph10 412 Version 7.9 11-Apr-09
497 ph10 376 ---------------------
499 ph10 392 1. When building with support for bzlib/zlib (pcregrep) and/or readline
500 ph10 376 (pcretest), all targets were linked against these libraries. This included
501     libpcre, libpcreposix, and libpcrecpp, even though they do not use these
502     libraries. This caused unwanted dependencies to be created. This problem
503 ph10 392 has been fixed, and now only pcregrep is linked with bzlib/zlib and only
504 ph10 376 pcretest is linked with readline.
505 ph10 392
506 ph10 376 2. The "typedef int BOOL" in pcre_internal.h that was included inside the
507     "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
508     moved outside it again, because FALSE and TRUE are already defined in AIX,
509     but BOOL is not.
510 ph10 392
511     3. The pcre_config() function was treating the PCRE_MATCH_LIMIT and
512 ph10 409 PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
513 ph10 392
514 ph10 376 4. The pcregrep documentation said spaces were inserted as well as colons (or
515     hyphens) following file names and line numbers when outputting matching
516 ph10 392 lines. This is not true; no spaces are inserted. I have also clarified the
517 ph10 376 wording for the --colour (or --color) option.
518 ph10 392
519 ph10 378 5. In pcregrep, when --colour was used with -o, the list of matching strings
520     was not coloured; this is different to GNU grep, so I have changed it to be
521     the same.
522 ph10 392
523 ph10 378 6. When --colo(u)r was used in pcregrep, only the first matching substring in
524 ph10 392 each matching line was coloured. Now it goes on to look for further matches
525     of any of the test patterns, which is the same behaviour as GNU grep.
527     7. A pattern that could match an empty string could cause pcregrep to loop; it
528     doesn't make sense to accept an empty string match in pcregrep, so I have
529 ph10 379 locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
530     seems to be how GNU grep behaves.
531 ph10 392
532 ph10 380 8. The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
533 ph10 392 start or after a newline", because the conditional assertion was not being
534     correctly handled. The rule now is that both the assertion and what follows
535     in the first alternative must satisfy the test.
537 ph10 405 9. If auto-callout was enabled in a pattern with a conditional group whose
538 ph10 399 condition was an assertion, PCRE could crash during matching, both with
539     pcre_exec() and pcre_dfa_exec().
540 ph10 392
541     10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
542     used for matching.
544     11. Unicode property support in character classes was not working for
545 ph10 385 characters (bytes) greater than 127 when not in UTF-8 mode.
546 ph10 388
547 ph10 392 12. Added the -M command line option to pcretest.
549 ph10 388 14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
550 ph10 389
551     15. Added the PCRE_NO_START_OPTIMIZE match-time option.
552 ph10 390
553 ph10 392 16. Added comments and documentation about mis-use of no_arg in the C++
554 ph10 390 wrapper.
555 ph10 392
556 ph10 391 17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
557 ph10 392 from Martin Jerabek that uses macro names for all relevant character and
558 ph10 391 string constants.
559 ph10 405
560 ph10 393 18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
561     SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
562 ph10 405 SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
563     these, but not everybody uses configure.
565     19. A conditional group that had only one branch was not being correctly
566     recognized as an item that could match an empty string. This meant that an
567     enclosing group might also not be so recognized, causing infinite looping
568     (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
569     with the subject "ab", where knowledge that the repeated group can match
570 ph10 396 nothing is needed in order to break the loop.
571 ph10 405
572 ph10 397 20. If a pattern that was compiled with callouts was matched using pcre_dfa_
573 ph10 405 exec(), but without supplying a callout function, matching went wrong.
575     21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
576     leak if the size of the offset vector was greater than 30. When the vector
577     is smaller, the saved offsets during recursion go onto a local stack
578     vector, but for larger vectors malloc() is used. It was failing to free
579     when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
580 ph10 400 error, in fact).
581 ph10 405
582 ph10 402 22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
583 ph10 405 heapframe that is used only when UTF-8 support is enabled. This caused no
584     problem, but was untidy.
585 ph10 376
586 ph10 405 23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
587     CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
588     included within another project.
589 ph10 411
590 ph10 407 24. Steven Van Ingelgem's patches to add more options to the CMake support,
591     slightly modified by me:
592 ph10 411
593     (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
594     not building pcregrep.
596 ph10 407 (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
597 ph10 411 if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
599 ph10 408 25. Forward references, both numeric and by name, in patterns that made use of
600     duplicate group numbers, could behave incorrectly or give incorrect errors,
601     because when scanning forward to find the reference group, PCRE was not
602     taking into account the duplicate group numbers. A pattern such as
603     ^X(?3)(a)(?|(b)|(q))(Y) is an example.
604 ph10 411
605     26. Changed a few more instances of "const unsigned char *" to USPTR, making
606     the feature of a custom pointer more persuasive (as requested by a user).
607 ph10 416
608 ph10 411 27. Wrapped the definitions of fileno and isatty for Windows, which appear in
609 ph10 416 pcretest.c, inside #ifndefs, because it seems they are sometimes already
610     pre-defined.
611 ph10 392
612 ph10 416 28. Added support for (*UTF8) at the start of a pattern.
614 ph10 413 29. Arrange for flags added by the "release type" setting in CMake to be shown
615     in the configuration summary.
616 ph10 405
617 ph10 411
618 ph10 374 Version 7.8 05-Sep-08
619 ph10 349 ---------------------
621     1. Replaced UCP searching code with optimized version as implemented for Ad
622     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
623 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
624     to 5 times on some simple patterns that I tested. Permission was given to
625     distribute the MultiStage2.py script that generates the tables (it's not in
626     the tarball, but is in the Subversion repository).
627 ph10 349
628 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
629     scripts.
630 ph10 358
631 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
632     a group with a zero qualifier. The result of the study could be incorrect,
633 ph10 358 or the function might crash, depending on the pattern.
635     4. Caseless matching was not working for non-ASCII characters in back
636 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
637 ph10 358 It now works when Unicode Property Support is available.
639 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
640     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
641     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
642 ph10 358 truncation.
643 ph10 349
644 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
646 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
647     pointers, in case they are 64-bit values.
648 ph10 371
649     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
650     test 2 if it fails.
652 ph10 359 9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
653 ph10 371 and a #define of that name to empty if it is not externally set. This is to
654     allow users of MSVC to set it if necessary.
656     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
657 ph10 359 the convenience functions in the pcre_get.c source file.
658 ph10 371
659 ph10 360 11. An option change at the start of a pattern that had top-level alternatives
660     could cause overwriting and/or a crash. This command provoked a crash in
661 ph10 371 some environments:
663     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
665 ph10 360 This potential security problem was recorded as CVE-2008-2371.
666 ph10 371
667 ph10 361 12. For a pattern where the match had to start at the beginning or immediately
668     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
669 ph10 371 pcre_dfa_exec() could read past the end of the passed subject if there was
670 ph10 361 no match. To help with detecting such bugs (e.g. with valgrind), I modified
671     pcretest so that it places the subject at the end of its malloc-ed buffer.
672 ph10 371
673 ph10 364 13. The change to pcretest in 12 above threw up a couple more cases when pcre_
674 ph10 371 exec() might read past the end of the data buffer in UTF-8 mode.
676 ph10 364 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
677 ph10 371 the data contained the byte 0x85 as part of a UTF-8 character within its
678     first line. This applied both to normal and DFA matching.
680 ph10 366 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
681 ph10 371 /^[^d]*?$/8 failed to match "abc".
682 ph10 351
683 ph10 371 16. Added a missing copyright notice to pcrecpp_internal.h.
685     17. Make it more clear in the documentation that values returned from
686 ph10 368 pcre_exec() in ovector are byte offsets, not character counts.
687 ph10 357
688 ph10 371 18. Tidied a few places to stop certain compilers from issuing warnings.
689 ph10 368
690 ph10 373 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
691     supplied by Stefan Weber. I made a further small update for 7.8 because
692 ph10 374 there is a change of source arrangements: the pcre_searchfuncs.c module is
693     replaced by pcre_ucd.c.
694 ph10 371
695 ph10 373
696 ph10 347 Version 7.7 07-May-08
697 ph10 321 ---------------------
699     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
700 ph10 345 a string to a long long, pretend we don't even have a long long." This is
701 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
702 ph10 345
703 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
704     pre-7.6 versions, which defined a global no_arg variable instead of putting
705 ph10 332 it in the RE class. (See also #8 below.)
706 ph10 345
707     3. Remove a line of dead code, identified by coverity and reported by Nuno
708     Lopes.
710 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
711 ph10 321
712 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
713 ph10 345 of files, instead of just to the final components.
715 ph10 324 (2) If there was more than one level of directory, the subdirectories were
716     skipped unless they satisfied the include/exclude conditions. This is
717     inconsistent with GNU grep (and could even be seen as contrary to the
718     pcregrep specification - which I improved to make it absolutely clear).
719     The action now is always to scan all levels of directory, and just
720     apply the include/exclude patterns to regular files.
721 ph10 345
722 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
723 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
725 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
726 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
727 ph10 326 doesn't support NULs in patterns.
728 ph10 345
729     7. Added some missing "const"s to declarations of static tables in
730     pcre_compile.c and pcre_dfa_exec.c.
732 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
733 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
734 ph10 345 first patch. And a third patch - this was a messy problem.)
735 ph10 321
736 ph10 345 9. Applied Craig's patch to remove the use of push_back().
738 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
739     matching function regexec().
740 ph10 345
741     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
742     which, however, unlike Perl's \g{...}, are subroutine calls, not back
743 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
744     Oniguruma does).
745 ph10 345
746     12. Previously, a group with a zero repeat such as (...){0} was completely
747 ph10 335 omitted from the compiled regex. However, this means that if the group
748     was called as a subroutine from elsewhere in the pattern, things went wrong
749 ph10 345 (an internal error was given). Such groups are now left in the compiled
750     pattern, with a new opcode that causes them to be skipped at execution
751 ph10 335 time.
752 ph10 345
753 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
754     to the way PCRE behaves:
755 ph10 345
756 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
757 ph10 345
758     (b) A back reference to an unmatched subpattern matches an empty string
759 ph10 336 (Perl fails the current match path).
760 ph10 345
761 ph10 341 (c) A data ] in a character class must be notated as \] because if the
762 ph10 345 first data character in a class is ], it defines an empty class. (In
763 ph10 341 Perl it is not possible to have an empty class.) The empty class []
764     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
765     The negative empty class [^] matches any one character, independently
766     of the DOTALL setting.
767 ph10 345
768     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
769 ph10 340 non-existent subpattern following a character class starting with ']' and
770     containing () gave an internal compiling error instead of "reference to
771     non-existent subpattern". Fortunately, when the pattern did exist, the
772 ph10 345 compiled code was correct. (When scanning forwards to check for the
773 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
774 ph10 345 the class, so got the count wrong. When actually compiling, the reference
775 ph10 340 was subsequently set up correctly.)
776 ph10 345
777 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
778 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
779     other assertions are supported. I have made pcre_dfa_exec() support
780     (*FAIL).
782 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
783 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
784     cannot be changed at match time, I realized I could make a small
785     improvement to matching performance by compiling OP_ALLANY instead of
786     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
787     on the OP_ANY path.
789     17. Compiling pcretest on Windows with readline support failed without the
790 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
791 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
793 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
794 ph10 345 ncurses library to be included for pcretest when ReadLine support is
795     requested, but also to allow for it to be overridden. This patch came from
796     Daniel Bergström.
797 ph10 347
798 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
799 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
800     any errors with the current Unicode tables. Thanks to Peter Kankowski for
801     spotting this.
802 ph10 324
803 ph10 332
804 ph10 319 Version 7.6 28-Jan-08
805 ph10 300 ---------------------
807 ph10 302 1. A character class containing a very large number of characters with
808     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
809     overflow.
810 ph10 309
811     2. Patch to cut out the "long long" test in pcrecpp_unittest when
812     HAVE_LONG_LONG is not defined.
814 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
815 ph10 304 bring them up to date and include new features. This patch includes:
816 ph10 309
817 ph10 304 - Fixed PH's badly added libz and libbz2 support.
818     - Fixed a problem with static linking.
819 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
820 ph10 304 - Fixed dftables problem and added an option.
821     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
823     - Added readline support for pcretest.
824 ph10 309 - Added an listing of the option settings after cmake has run.
826 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
827     "pcre.dll" under mingw when using Configure/Make. I added stuff to
828     Makefile.am that cause it to include this special target, without
829     affecting anything else. Note that the same mingw target plus all
830     the other distribution libraries and programs are now supported
831     when configuring with CMake (see 6 below) instead of with
832     Configure/Make.
833 ph10 309
834 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
835     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
836 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
837     solves the problem, but it does no harm.
838 ph10 313
839 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
840 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
841 ph10 314 with CMake, and also correct the comment about stack recursion.
842 ph10 313
843 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
844 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
845     of a program that users should build themselves after PCRE is installed, so
846     building it automatically is not really right. What is more, it gave
847 ph10 312 trouble in some build environments.
848 ph10 300
849 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
850 ph10 308
851 ph10 319
852 ph10 298 Version 7.5 10-Jan-08
853 ph10 263 ---------------------
855     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
856     values in parens when parsing an RE using the C++ wrapper."
857 ph10 286
858 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
859     Characters greater than 255 were excluded from the class instead of being
860     included.
861 ph10 286
862     3. The same bug as (2) above applied to negated POSIX classes such as
863 ph10 265 [:^space:].
864 ph10 286
865 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
866     defined or documented. It seems to have been a typo for PCRE_STATIC, so
867 ph10 286 I have changed it.
869 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
870 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
871     first named subpattern whose name started with "a" (in other words, the
872 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
873     expected" is now given for (?&) (a zero-length name), and this patch also
874     makes it give the same error for \k'' (previously it complained that that
875     was a reference to a non-existent subpattern).
876 ph10 286
877 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
878 ph10 286 this is right because (?- can be followed by option settings as well as by
879 ph10 269 digits. I have, however, made the messages clearer.
880 ph10 286
881 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
882     than the number used in the conditional) now cause a compile-time error.
883     This is actually not compatible with Perl, which accepts such patterns, but
884     treats the conditional as always being FALSE (as PCRE used to), but it
885     seems to me that giving a diagnostic is better.
886 ph10 286
887 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
888 ph10 275 and messages.
889 ph10 286
890     9. Fix two occurrences of "backslash" in comments that should have been
891     "backspace".
893     10. Remove two redundant lines of code that can never be obeyed (their function
894     was moved elsewhere).
896     11. The program that makes PCRE's Unicode character property table had a bug
897     which caused it to generate incorrect table entries for sequences of
898 ph10 277 characters that have the same character type, but are in different scripts.
899 ph10 286 It amalgamated them into a single range, with the script of the first of
900 ph10 277 them. In other words, some characters were in the wrong script. There were
901     thirteen such cases, affecting characters in the following ranges:
902 ph10 286
903 ph10 277 U+002b0 - U+002c1
904     U+0060c - U+0060d
905 ph10 286 U+0061e - U+00612
906 ph10 277 U+0064b - U+0065e
907     U+0074d - U+0076d
908     U+01800 - U+01805
909     U+01d00 - U+01d77
910     U+01d9b - U+01dbf
911     U+0200b - U+0200f
912     U+030fc - U+030fe
913     U+03260 - U+0327f
914     U+0fb46 - U+0fbb1
915     U+10450 - U+1049d
916 ph10 286
917 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
918     compatible with GNU grep in that, if there was more than one match in a
919     line, it showed only the first of them. It now behaves in the same way as
920     GNU grep.
921 ph10 286
922     13. If the -o and -v options were combined for pcregrep, it printed a blank
923     line for every non-matching line. GNU grep prints nothing, and pcregrep now
924     does the same. The return code can be used to tell if there were any
925     non-matching lines.
927 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
929     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
930 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
931 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
932     and both kinds of lookbehind were skipped).
934 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
935 ph10 284 inclusion of <windows.h> to before rather than after the definition of
936     INVALID_FILE_ATTRIBUTES (patch from David Byron).
937 ph10 263
938 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
939 ph10 286 character property caused pcre_compile() to compile bad code, which led at
940     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
941     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
942     caused the error; without that there was no problem.
943 ph10 263
944 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
945 ph10 286
946 ph10 289 19. Added --enable-pcretest-libreadline.
947 ph10 286
948 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
949 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
950 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
951     later patch that removed the other one (the right fix) and added unit tests
952     that check the return values (which was not done before).
953 ph10 292
954 ph10 291 21. Several CMake things:
955 ph10 287
956 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
957 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
958 ph10 288
959 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
960     linked with the newly-built libraries, not previously installed ones.
961 ph10 291
963 ph10 298
964     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
965     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
966     UTF-8 newline character). The key issue is that the pattern starts .*;
967     this means that the match must be either at the beginning, or after a
968     newline. The bug was in the code for advancing after a failed match and
969     checking that the new position followed a newline. It was not taking
970 ph10 294 account of UTF-8 characters correctly.
971 ph10 298
972     23. PCRE was behaving differently from Perl in the way it recognized POSIX
973     character classes. PCRE was not treating the sequence [:...:] as a
974     character class unless the ... were all letters. Perl, however, seems to
975     allow any characters between [: and :], though of course it rejects as
976     unknown any "names" that contain non-letters, because all the known class
977     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
978     for example, whereas PCRE did not - it did not recognize a POSIX character
979     class. This seemed a bit dangerous, so the code has been changed to be
980     closer to Perl. The behaviour is not identical to Perl, because PCRE will
981     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
982     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
983     Perl does, and where it didn't before.
985 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
986     Windows environments %n is disabled by default.
987 ph10 292
989 ph10 260 Version 7.4 21-Sep-07
990 ph10 230 ---------------------
992     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
993 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
994     LF". That isn't really right - the whole point of the change was to try to
995     help when there was an actual mention of one of the two characters. So now
996     the change happens only if \r or \n (or a literal CR or LF) character is
997 ph10 230 encountered.
998 ph10 231
999     2. The 32-bit options word was also used for 6 internal flags, but the numbers
1000     of both had grown to the point where there were only 3 bits left.
1001     Fortunately, there was spare space in the data structure, and so I have
1002     moved the internal flags into a new 16-bit field to free up more option
1003 ph10 230 bits.
1004 ph10 231
1005     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1006     but did not set the internal JCHANGED flag - either of these is enough to
1007     control the way the "get" function works - but the PCRE_INFO_JCHANGED
1008     facility is supposed to tell if (?J) was ever used, so now (?J) at the
1009 ph10 230 start sets both bits.
1011 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
1012     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1013 ph10 230
1014 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
1016     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1017 ph10 233 compatibility, even though it is no longer used.
1018 ph10 243
1019     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1020 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1021 ph10 259 windows.h file is present (where different names are used). [This was
1022 ph10 257 reversed later after testing - see 16 below.]
1023 ph10 243
1024     8. Changed all #include <config.h> to #include "config.h". There were also
1025 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
1026 ph10 243
1027 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
1028 ph10 243 sequence off the lines that it output.
1030     10. It was pointed out to me that arrays of string pointers cause lots of
1031     relocations when a shared library is dynamically loaded. A technique of
1032     using a single long string with a table of offsets can drastically reduce
1033     these. I have refactored PCRE in four places to do this. The result is
1034 ph10 240 dramatic:
1035 ph10 243
1036 ph10 240 Originally: 290
1037     After changing UCP table: 187
1038 ph10 243 After changing error message table: 43
1039 ph10 240 After changing table of "verbs" 36
1040     After changing table of Posix names 22
1041 ph10 243
1042 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
1043 ph10 247
1044 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1045 ph10 247 unicode-properties was also set.
1047 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1048 ph10 231
1049 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1050     checked only for CRLF.
1051 ph10 233
1052 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
1054 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1055 ph10 253
1056 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1057 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1058     entirely. This removes changes made in 7 above.
1059 ph10 256
1060 ph10 261 17. The CMake files have been updated, and there is now more information about
1061     building with CMake in the NON-UNIX-USE document.
1062 ph10 257
1063 ph10 261
1064 ph10 228 Version 7.3 28-Aug-07
1065 ph10 157 ---------------------
1067 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
1068     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1069     brackets there is not right, since it causes compilers to look for an
1070     installed pcre.h, not the version that is in the source that is being
1071     compiled (which of course may be different). I have changed it back to:
1072 ph10 197
1073 ph10 189 #include "pcre.h"
1074 ph10 197
1075     I have a vague recollection that the change was concerned with compiling in
1076     different directories, but in the new build system, that is taken care of
1077     by the VPATH setting the Makefile.
1079 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1080     when the subject happened to end in the byte 0x85 (e.g. if the last
1081     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1082     characters but of course it shouldn't be taken as a newline when it is part
1083     of another character. The bug was that, for an unlimited repeat of . in
1084     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1085     characters when looking for a newline.
1086 ph10 197
1087     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1089     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1090     in debug output.
1092 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1093     long printing in the pcrecpp unittest when running under MinGW.
1094 ph10 189
1095 ph10 197 6. ESC_K was left out of the EBCDIC table.
1096 ph10 189
1097 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1098     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1099     limit also applies to "virtual nesting" when a pattern is recursive, and in
1100     this case 1000 isn't so big. I have been able to remove this limit at the
1101     expense of backing off one optimization in certain circumstances. Normally,
1102     when pcre_exec() would call its internal match() function recursively and
1103     immediately return the result unconditionally, it uses a "tail recursion"
1104     feature to save stack. However, when a subpattern that can match an empty
1105     string has an unlimited repetition quantifier, it no longer makes this
1106     optimization. That gives it a stack frame in which to save the data for
1107     checking that an empty string has been matched. Previously this was taken
1108     from the 1000-entry workspace that had been reserved. So now there is no
1109     explicit limit, but more stack is used.
1110 ph10 189
1111 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
1112     syntax that is required for Windows, and which was going wrong for the
1113     pcreposix and pcrecpp parts of the library. These were overlooked when this
1114     problem was solved for the main library.
1115 ph10 197
1116 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
1117     the size of patterns that contain repeated groups with explicit upper
1118     limits. As the maximum quantifier is 65535, the maximum group length was
1119     set at 30,000 so that the product of these two numbers did not overflow a
1120     32-bit integer. However, it turns out that people want to use groups that
1121     are longer than 30,000 bytes (though not repeat them that many times).
1122     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1123     made it possible to implement the integer overflow checks in a much more
1124     dynamic way, which I have now done. The artificial limitation on group
1125     length has been removed - we now have only the limit on the total length of
1126     the compiled pattern, which depends on the LINK_SIZE setting.
1127 ph10 208
1128     10. Fixed a bug in the documentation for get/copy named substring when
1129     duplicate names are permitted. If none of the named substrings are set, the
1130     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1131     empty string.
1133     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1134     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1135     because the ] is interpreted as the first data character and the
1136     terminating ] is not found. PCRE has been made compatible with Perl in this
1137     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1138     cause memory overwriting.
1140 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1141     string has been matched (to stop an infinite loop). It was not recognizing
1142 ph10 208 a conditional subpattern that could match an empty string if that
1143 ph10 206 subpattern was within another subpattern. For example, it looped when
1144 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
1145 ph10 206 condition was not nested. This bug has been fixed.
1146 ph10 208
1147 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1148     past the start of the subject in the presence of bytes with the top bit
1149     set, for example "\x8aBCD".
1150 ph10 211
1151 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1152     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1153 ph10 200
1154 ph10 211 14. Optimized (?!) to (*FAIL).
1155 ph10 202
1156 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1157     This restricts code points to be within the range 0 to 0x10FFFF, excluding
1158     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1159     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1160     does: it's just the validity check that is more restrictive.
1161 ph10 220
1162     16. Inserted checks for integer overflows during escape sequence (backslash)
1163     processing, and also fixed erroneous offset values for syntax errors during
1164     backslash processing.
1166 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1167 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1169 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1170     caused an overrun.
1171 ph10 220
1172     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1173     something other than just ASCII characters) inside a group that had an
1174     unlimited repeat caused a loop at compile time (while checking to see
1175     whether the group could match an empty string).
1177 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
1178     [\P{Any}] did so. (Error in the code for printing property names.)
1179 ph10 210
1180 ph10 220 21. An orphan \E inside a character class could cause a crash.
1182     22. A repeated capturing bracket such as (A)? could cause a wild memory
1183 ph10 218 reference during compilation.
1184 ph10 220
1185     23. There are several functions in pcre_compile() that scan along a compiled
1186     expression for various reasons (e.g. to see if it's fixed length for look
1187 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
1188 ph10 220 present in the pattern. These operators have additional parameters compared
1189     with \d, etc, and these were not being taken into account when moving along
1190 ph10 218 the compiled data. Specifically:
1191 ph10 220
1192     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1193     length.
1195     (b) An item such as \pL+ within a repeated group could cause crashes or
1196 ph10 218 loops.
1197 ph10 220
1198 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1199 ph10 220 "reference to non-existent subpattern" error.
1201 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1203 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1204 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1205 ph10 211
1206 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1207 ph10 218
1208 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1209 ph10 223 character were causing crashes (broken optimization).
1210 ph10 227
1211 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1212 ph10 227 \p or \P) caused a compile-time loop.
1214 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
1215     break. For example, the unstudied pattern [\r\n]A does not match the string
1216     "\r\nA" because change 7.0/46 below moves the current point on by two
1217     characters after failing to match at the start. However, the pattern \nA
1218 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1219     the same is true. There doesn't seem any very clean way out of this, but
1220     what I have chosen to do makes the common cases work: PCRE now takes note
1221     of whether there can be an explicit match for \r or \n anywhere in the
1222     pattern, and if so, 7.0/46 no longer applies. As part of this change,
1223     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1224     pattern has explicit CR or LF references.
1225 ph10 222
1226 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
1227 ph10 223
1228 ph10 227
1229 ph10 189 Version 7.2 19-Jun-07
1230     ---------------------
1232 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1233     which is apparently normally available under Windows.
1234 ph10 159
1235     2. Re-jig the pcregrep tests with different newline settings in an attempt
1236     to make them independent of the local environment's newline setting.
1237 ph10 157
1238 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1239 ph10 165
1240 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
1241     was not 2, because the output contained actual offsets. The recent new
1242 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
1243     usable with all link sizes.
1245 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1246     stack recursion. This gives a massive performance boost under BSD, but just
1247 ph10 165 a small improvement under Linux. However, it saves one field in the frame
1248 ph10 164 in all cases.
1249 ph10 172
1250 ph10 166 6. Added more features from the forthcoming Perl 5.10:
1251 ph10 172
1252 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
1253     recursion call. It refers to the nth most recently opened parentheses.
1254 ph10 172
1255 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
1256 ph10 172 to be opened parentheses.
1258     (c) Conditions that refer to capturing parentheses can be specified
1259 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
1260 ph10 172
1261 ph10 168 (d) \K resets the start of the current match so that everything before
1262 ph10 172 is not part of it.
1264 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1265 ph10 172
1266 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
1267 ph10 172 reference syntax.
1268 ph10 182
1269 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
1270 ph10 182 alternative starts with the same number.
1271 ph10 172
1272 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1274 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1277     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
1278     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1279 ph10 170 for detecting groups that can match an empty string.
1280 ph10 159
1281 ph10 172 9. A pattern with a very large number of alternatives (more than several
1282     hundred) was running out of internal workspace during the pre-compile
1283     phase, where pcre_compile() figures out how much memory will be needed. A
1284     bit of new cunning has reduced the workspace needed for groups with
1285     alternatives. The 1000-alternative test pattern now uses 12 bytes of
1286     workspace instead of running out of the 4096 that are available.
1287 ph10 182
1288 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1289 ph10 172
1290 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
1291     The report of the bug said:
1292 ph10 182
1293 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
1294     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1295 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1296 ph10 185
1297 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1298 ph10 185 it matched the wrong number of bytes.
1299 ph10 172
1300 ph10 179
1301 ph10 155 Version 7.1 24-Apr-07
1302 ph10 98 ---------------------
1304 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1305 ph10 122 that is more "standard", making use of automake and other Autotools. There
1306 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
1307     on this.
1308 ph10 111
1309     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1310     for recursive directory scanning broke on some systems because the files
1311     are not scanned in any specific order and on different systems the order
1312     was different. A call to "sort" has been inserted into RunGrepTest for the
1313     approprate test as a short-term fix. In the longer term there may be an
1314 ph10 100 alternative.
1315 ph10 111
1316 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
1317 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
1318     people do their own conversions for various reasons). The problems
1319     concerned the use of low-level troff macros .br and .in. I have therefore
1320     removed all such uses from the man pages (some were redundant, some could
1321 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
1322     HTML has been updated to handle .nf/.fi and to complain if it encounters
1323     .br or .in.
1324 ph10 111
1325 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
1326 ph10 123 arranged for config.h to be included in the distribution, with the name
1327 ph10 111 config.h.generic, for the benefit of those who have to compile without
1328     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1330     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1331     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1332 ph10 127 makevp.bat for the current PCRE, using the additional files
1333 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1334 ph10 111
1335     6. A Windows user reported a minor discrepancy with test 2, which turned out
1336     to be caused by a trailing space on an input line that had got lost in his
1337 ph10 102 copy. The trailing space was an accident, so I've just removed it.
1338 ph10 111
1339 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1340 ph10 111 that is needed.
1342 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1343     as "const" (a) because they are and (b) because it helps the PHP
1344     maintainers who have recently made a script to detect big data structures
1345 ph10 111 in the php code that should be moved to the .rodata section. I remembered
1346     to update Builducptable as well, so it won't revert if ucptable.h is ever
1347 ph10 105 re-created.
1348 ph10 111
1349     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1350 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1351 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
1352     support is not required. This saves 1.5-2K of code, which is important in
1353 ph10 107 some applications.
1354 ph10 111
1355 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1356 ph10 111 so as not to refer to the tables, even though these functions will never be
1357     called when UTF-8 support is disabled. Otherwise there are problems with a
1358     shared library.
1360 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1362     (a) It was defining its arguments as char * instead of void *.
1364 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
1365     a long time ago when I wrote it, but is no longer the case.
1367 ph10 118 The emulated memove() is provided for those environments that have neither
1368 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
1369 ph10 118 is clearly not the case, as these two bugs were recently reported.
1370 ph10 123
1371 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1372 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
1373     pages, and it removes trailing spaces from listed files. It also creates
1374     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1375     case, it wraps all the #defines with #ifndefs. This script should be run
1376 ph10 111 before "make dist".
1377 ph10 123
1378 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1379     with Unicode property support.
1380 ph10 123
1381     (a) For a maximizing quantifier, if the two different cases of the
1382     character were of different lengths in their UTF-8 codings (there are
1383     some cases like this - I found 11), and the matching function had to
1384 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
1385     were both the same length.
1386 ph10 123
1387     (b) When PCRE was configured to use the heap rather than the stack for
1388     recursion during matching, it was not correctly preserving the data for
1389     the other case of a UTF-8 character when checking ahead for a match
1390     while processing a minimizing repeat. If the check also involved
1391 ph10 115 matching a wide character, but failed, corruption could cause an
1392     erroneous result when trying to check for a repeat of the original
1393     character.
1394 ph10 123
1395 ph10 116 13. Some tidying changes to the testing mechanism:
1396 ph10 98
1397 ph10 116 (a) The RunTest script now detects the internal link size and whether there
1398     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1399 ph10 123 values substituted by "configure". (The RunGrepTest script already did
1400     this for UTF-8.) The configure.ac script no longer substitutes the
1401     relevant variables.
1403 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
1404     with length and offset values. This means that the output is different
1405     for different internal link sizes. Test 2 is skipped for link sizes
1406     other than 2 because of this, bypassing the problem. Unfortunately,
1407     there was also a test in test 3 (the locale tests) that used /B and
1408 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
1409     I have added a new /Z option to pcretest that replaces the length and
1410     offset values with spaces. This is now used to make test 3 independent
1411 ph10 122 of link size. (Test 2 will be tidied up later.)
1412 ph10 123
1413     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1414 ph10 122 segmentation fault instead of returning the appropriate error message.
1415 ph10 134
1416 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
1417 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1418     This doesn't seem right; it now treats the CRLF combination as the line
1419     ending, and so does not match in that case. It's only a pattern such as ^$
1420     that would hit this one: something like ^ABC$ would have failed after \r
1421     and then tried again after \r\n.
1423 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1424 ph10 134 in an attempt to make files that differ only in their line terminators
1425     compare equal. This works on Linux.
1426 ph10 142
1427 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
1428     as it exited. This is now fixed, thanks to valgrind.
1429 ph10 142
1430 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1431 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1432     was because its rules for how to advance for /g after matching an empty
1433 ph10 143 string at the end of a line did not allow for this case. They now check for
1434     it specially.
1435 ph10 150
1436     20. pcretest is supposed to handle patterns and data of any length, by
1437     extending its buffers when necessary. It was getting this wrong when the
1438 ph10 147 buffer for a data line had to be extended.
1439 ph10 150
1440 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1441 ph10 150 CRLF as a newline sequence.
1442 ph10 152
1443 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1444 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1445     I have nevertheless tidied it up.
1446 ph10 111
1447 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
1448 ph10 123
1449 ph10 153 24. Added a man page for pcre-config.
1450 ph10 152
1451 ph10 153
1452 nigel 93 Version 7.0 19-Dec-06
1453     ---------------------
1455     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1456     moving to gcc 4.1.1.
1458     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1459     sys/time.h, which is documented as needed for this function. It doesn't
1460     seem to matter on Linux, but it showed up on some releases of OS X.
1462     3. It seems that there are systems where bytes whose values are greater than
1463     127 match isprint() in the "C" locale. The "C" locale should be the
1464     default when a C program starts up. In most systems, only ASCII printing
1465     characters match isprint(). This difference caused the output from pcretest
1466     to vary, making some of the tests fail. I have changed pcretest so that:
1468     (a) When it is outputting text in the compiled version of a pattern, bytes
1469     other than 32-126 are always shown as hex escapes.
1471     (b) When it is outputting text that is a matched part of a subject string,
1472     it does the same, unless a different locale has been set for the match
1473     (using the /L modifier). In this case, it uses isprint() to decide.
1475     4. Fixed a major bug that caused incorrect computation of the amount of memory
1476     required for a compiled pattern when options that changed within the
1477     pattern affected the logic of the preliminary scan that determines the
1478     length. The relevant options are -x, and -i in UTF-8 mode. The result was
1479     that the computed length was too small. The symptoms of this bug were
1480     either the PCRE error "internal error: code overflow" from pcre_compile(),
1481     or a glibc crash with a message such as "pcretest: free(): invalid next
1482     size (fast)". Examples of patterns that provoked this bug (shown in
1483     pcretest format) are:
1485     /(?-x: )/x
1486     /(?x)(?-x: \s*#\s*)/
1487     /((?i)[\x{c0}])/8
1488     /(?i:[\x{c0}])/8
1490     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1491     is now done differently.
1493     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1494     wrapper classes; (b) implement a new function in the C++ scanner that is
1495     more efficient than the old way of doing things because it avoids levels of
1496     recursion in the regex matching; (c) add a paragraph to the documentation
1497     for the FullMatch() function.
1499     6. The escape sequence \n was being treated as whatever was defined as
1500     "newline". Not only was this contrary to the documentation, which states
1501     that \n is character 10 (hex 0A), but it also went horribly wrong when
1502     "newline" was defined as CRLF. This has been fixed.
1504     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1505     was being set to -1 for the "end of line" case (supposedly a value that no
1506     character can have). Though this value is never used (the check for end of
1507     line is "zero bytes in current character"), it caused compiler complaints.
1508     I've changed it to 0xffffffff.
1510     8. In pcre_version.c, the version string was being built by a sequence of
1511     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1512     string (as it is for production releases) called a macro with an empty
1513     argument. The C standard says the result of this is undefined. The gcc
1514     compiler treats it as an empty string (which was what was wanted) but it is
1515     reported that Visual C gives an error. The source has been hacked around to
1516     avoid this problem.
1518     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1519     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1520     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1521     of them did).
1523     10. Originally, pcretest opened its input and output without "b"; then I was
1524     told that "b" was needed in some environments, so it was added for release
1525     5.0 to both the input and output. (It makes no difference on Unix-like
1526     systems.) Later I was told that it is wrong for the input on Windows. I've
1527     now abstracted the modes into two macros, to make it easier to fiddle with
1528     them, and removed "b" from the input mode under Windows.
1530     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1532     12. Added -help and --help to pcretest as an official way of being reminded
1533     of the options.
1535     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1536     and pcrecpp.cc because they annoy compilers at high warning levels.
1538     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1540     15. Fixed an occurrence of == in configure.ac that should have been = (shell
1541     scripts are not C programs :-) and which was not noticed because it works
1542     on Linux.
1544     16. pcretest is supposed to handle any length of pattern and data line (as one
1545     line or as a continued sequence of lines) by extending its input buffer if
1546     necessary. This feature was broken for very long pattern lines, leading to
1547     a string of junk being passed to pcre_compile() if the pattern was longer
1548     than about 50K.
1550     17. I have done a major re-factoring of the way pcre_compile() computes the
1551     amount of memory needed for a compiled pattern. Previously, there was code
1552     that made a preliminary scan of the pattern in order to do this. That was
1553     OK when PCRE was new, but as the facilities have expanded, it has become
1554     harder and harder to keep it in step with the real compile phase, and there
1555     have been a number of bugs (see for example, 4 above). I have now found a
1556     cunning way of running the real compile function in a "fake" mode that
1557     enables it to compute how much memory it would need, while actually only
1558     ever using a few hundred bytes of working memory and without too many
1559     tests of the mode. This should make future maintenance and development
1560     easier. A side effect of this work is that the limit of 200 on the nesting
1561     depth of parentheses has been removed (though this was never a serious
1562     limitation, I suspect). However, there is a downside: pcre_compile() now
1563     runs more slowly than before (30% or more, depending on the pattern). I
1564     hope this isn't a big issue. There is no effect on runtime performance.
1566     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1567     newline (only possible for the last line of a file) and it was a
1568     pattern that set a locale (followed by /Lsomething), pcretest crashed.
1570     19. Added additional timing features to pcretest. (1) The -tm option now times
1571     matching only, not compiling. (2) Both -t and -tm can be followed, as a
1572     separate command line item, by a number that specifies the number of
1573     repeats to use when timing. The default is 50000; this gives better
1574     precision, but takes uncomfortably long for very large patterns.
1576     20. Extended pcre_study() to be more clever in cases where a branch of a
1577     subpattern has no definite first character. For example, (a*|b*)[cd] would
1578     previously give no result from pcre_study(). Now it recognizes that the
1579     first character must be a, b, c, or d.
1581     21. There was an incorrect error "recursive call could loop indefinitely" if
1582     a subpattern (or the entire pattern) that was being tested for matching an
1583     empty string contained only one non-empty item after a nested subpattern.
1584     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1585     incorrectly, because the \d was being skipped in the check.
1587     22. The pcretest program now has a new pattern option /B and a command line
1588     option -b, which is equivalent to adding /B to every pattern. This causes
1589     it to show the compiled bytecode, without the additional information that
1590     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1591     is the same as /B/I).
1593     23. A new optimization is now able automatically to treat some sequences such
1594     as a*b as a*+b. More specifically, if something simple (such as a character
1595     or a simple class like \d) has an unlimited quantifier, and is followed by
1596     something that cannot possibly match the quantified thing, the quantifier
1597     is automatically "possessified".
1599     24. A recursive reference to a subpattern whose number was greater than 39
1600     went wrong under certain circumstances in UTF-8 mode. This bug could also
1601     have affected the operation of pcre_study().
1603     25. Realized that a little bit of performance could be had by replacing
1604     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1606     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1608     27. Possessive quantifiers such as a++ were previously implemented by turning
1609     them into atomic groups such as ($>a+). Now they have their own opcodes,
1610     which improves performance. This includes the automatically created ones
1611     from 23 above.
1613     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1614     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1615     the first matched character to be a colon. This applied both to named and
1616     numbered groups.
1618     29. The ucpinternal.h header file was missing its idempotency #ifdef.
1620     30. I was sent a "project" file called libpcre.a.dev which I understand makes
1621     building PCRE on Windows easier, so I have included it in the distribution.
1623     31. There is now a check in pcretest against a ridiculously large number being
1624     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1625     loop, the loop is abandoned.
1627     32. Forward references to subpatterns in conditions such as (?(2)...) where
1628     subpattern 2 is defined later cause pcre_compile() to search forwards in
1629     the pattern for the relevant set of parentheses. This search went wrong
1630     when there were unescaped parentheses in a character class, parentheses
1631     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1633     33. "Subroutine" calls and backreferences were previously restricted to
1634     referencing subpatterns earlier in the regex. This restriction has now
1635     been removed.
1637     34. Added a number of extra features that are going to be in Perl 5.10. On the
1638     whole, these are just syntactic alternatives for features that PCRE had
1639     previously implemented using the Python syntax or my own invention. The
1640     other formats are all retained for compatibility.
1642     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1643     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1644     also .NET compatible.
1646     (b) A recursion or subroutine call to a named group can now be defined as
1647     (?&name) as well as (?P>name).
1649     (c) A backreference to a named group can now be defined as \k<name> or
1650     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1651     5.10, are also .NET compatible.
1653     (d) A conditional reference to a named group can now use the syntax
1654     (?(<name>) or (?('name') as well as (?(name).
1656     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1657     groups (named and numbered) that are never evaluated inline, but can be
1658     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1659     is always false. There may be only one alternative in such a group.
1661     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1662     as the simple (?(R). The condition is true only if the most recent
1663     recursion is that of the given number or name. It does not search out
1664     through the entire recursion stack.
1666     (g) The escape \gN or \g{N} has been added, where N is a positive or
1667     negative number, specifying an absolute or relative reference.
1669     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1670     some "unreachable code" warnings.
1672     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1673     things, this adds five new scripts.
1675     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1676     There were also incompatibilities regarding the handling of \Q..\E inside
1677     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1678     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1680     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1681     matches an empty string, and forcibly breaks the loop. There were bugs in
1682     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1683     against aaaa the result was just "a" rather than "aaaa", for example. Two
1684     separate and independent bugs (that affected different cases) have been
1685     fixed.
1687     39. Refactored the code to abolish the use of different opcodes for small
1688     capturing bracket numbers. This is a tidy that I avoided doing when I
1689     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1690     The new approach is not only tidier, it makes it possible to reduce the
1691     memory needed to fix the previous bug (38).
1693     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1694     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1695     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1696     mode.
1698     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1699     report.
1701     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1702     copy construction and assignment in the C++ wrapper.
1704     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1705     couple of bugs that could have given wrong results in the "--newline=crlf"
1706     case.
1708     44. Added a number of casts and did some reorganization of signed/unsigned int
1709     variables following suggestions from Dair Grant. Also renamed the variable
1710     "this" as "item" because it is a C++ keyword.
1712     45. Arranged for dftables to add
1714     #include "pcre_internal.h"
1716     to pcre_chartables.c because without it, gcc 4.x may remove the array
1717     definition from the final binary if PCRE is built into a static library and
1718     dead code stripping is activated.
1720     46. For an unanchored pattern, if a match attempt fails at the start of a
1721     newline sequence, and the newline setting is CRLF or ANY, and the next two
1722     characters are CRLF, advance by two characters instead of one.
1725 nigel 91 Version 6.7 04-Jul-06
1726     ---------------------
1728     1. In order to handle tests when input lines are enormously long, pcretest has
1729     been re-factored so that it automatically extends its buffers when
1730     necessary. The code is crude, but this _is_ just a test program. The
1731     default size has been increased from 32K to 50K.
1733     2. The code in pcre_study() was using the value of the re argument before
1734     testing it for NULL. (Of course, in any sensible call of the function, it
1735     won't be NULL.)
1737     3. The memmove() emulation function in pcre_internal.h, which is used on
1738     systems that lack both memmove() and bcopy() - that is, hardly ever -
1739     was missing a "static" storage class specifier.
1741     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1742     containing an extended class (one that cannot be represented by a bitmap
1743     because it contains high-valued characters or Unicode property items, e.g.
1744     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1745     pattern, but PCRE should not loop if you do not (it no longer does).
1746     [Detail: two cases were found: (a) a repeated subpattern containing an
1747     extended class; (b) a recursive reference to a subpattern that followed a
1748     previous extended class. It wasn't skipping over the extended class
1749     correctly when UTF-8 mode was not set.]
1751     5. A negated single-character class was not being recognized as fixed-length
1752     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1753     compile error "lookbehind assertion is not fixed length".
1755     6. The RunPerlTest auxiliary script was showing an unexpected difference
1756     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1757     write a Perl script that can interpret lines of an input file either as
1758     byte characters or as UTF-8, which is what "perltest" was being required to
1759     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1760     can't do is switch easily at run time between having the "use utf8;" pragma
1761     or not. In the end, I fudged it by using the RunPerlTest script to insert
1762     "use utf8;" explicitly for the UTF-8 tests.
1764     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1765     the end of the subject string, contrary to the documentation and to what
1766     Perl does. This was true of both matching functions. Now it matches only at
1767     the start of the subject and immediately after *internal* newlines.
1769     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1770     a pointer to an int instead of a pointer to an unsigned long int. This
1771     caused problems on 64-bit systems.
1773     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1774     instance of the 'standard' template library not being so standard".
1776     10. There was no check on the number of named subpatterns nor the maximum
1777     length of a subpattern name. The product of these values is used to compute
1778     the size of the memory block for a compiled pattern. By supplying a very
1779     long subpattern name and a large number of named subpatterns, the size
1780     computation could be caused to overflow. This is now prevented by limiting
1781     the length of names to 32 characters, and the number of named subpatterns
1782     to 10,000.
1784     11. Subpatterns that are repeated with specific counts have to be replicated in
1785     the compiled pattern. The size of memory for this was computed from the
1786     length of the subpattern and the repeat count. The latter is limited to
1787     65535, but there was no limit on the former, meaning that integer overflow
1788     could in principle occur. The compiled length of a repeated subpattern is
1789     now limited to 30,000 bytes in order to prevent this.
1791     12. Added the optional facility to have named substrings with the same name.
1793     13. Added the ability to use a named substring as a condition, using the
1794     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1795     are numbers (not recommended). Forward references are permitted.
1797     14. Added forward references in named backreferences (if you see what I mean).
1799     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1800     pattern could run off the end of the subject. For example, the pattern
1801     "(?s)(.{1,5})"8 did this with the subject "ab".
1803     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1804     PCRE_CASELESS was set when matching characters that were quantified with ?
1805     or *.
1807     17. A character class other than a single negated character that had a minimum
1808     but no maximum quantifier - for example [ab]{6,} - was not handled
1809     correctly by pce_dfa_exec(). It would match only one character.
1811     18. A valid (though odd) pattern that looked like a POSIX character
1812     class but used an invalid character after [ (for example [[,abc,]]) caused
1813     pcre_compile() to give the error "Failed: internal error: code overflow" or
1814     in some cases to crash with a glibc free() error. This could even happen if
1815     the pattern terminated after [[ but there just happened to be a sequence of
1816     letters, a binary zero, and a closing ] in the memory that followed.
1818     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1819     over the years. Originally (before any Unicode support), just the bottom 8
1820     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1821     output from "man perlunicode" includes this:
1823     The regular expression compiler produces polymorphic opcodes. That
1824     is, the pattern adapts to the data and automatically switches to
1825     the Unicode character scheme when presented with Unicode data--or
1826     instead uses a traditional byte scheme when presented with byte
1827     data.
1829     Sadly, a wide octal escape does not cause a switch, and in a string with
1830     no other multibyte characters, these octal escapes are treated as before.
1831     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1832     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1833     Unicode string.
1835     I have not perpetrated such confusion in PCRE. Up till now, it took just
1836     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1837     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1838     translate to the appropriate multibyte character.
1840     29. Applied some refactoring to reduce the number of warnings from Microsoft
1841     and Borland compilers. This has included removing the fudge introduced
1842     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1843     a warning about an unused variable.
1845     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1846     characters since release 4.0, because Perl (from release 5.004) does not.
1847     [Or at least, is documented not to: some releases seem to be in conflict
1848     with the documentation.] However, when a pattern was studied with
1849     pcre_study() and all its branches started with \s, PCRE still included VT
1850     as a possible starting character. Of course, this did no harm; it just
1851     caused an unnecessary match attempt.
1853     22. Removed a now-redundant internal flag bit that recorded the fact that case
1854     dependency changed within the pattern. This was once needed for "required
1855     byte" processing, but is no longer used. This recovers a now-scarce options
1856     bit. Also moved the least significant internal flag bit to the most-
1857     significant bit of the word, which was not previously used (hangover from
1858     the days when it was an int rather than a uint) to free up another bit for
1859     the future.
1861     23. Added support for CRLF line endings as well as CR and LF. As well as the
1862     default being selectable at build time, it can now be changed at runtime
1863     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1864     specify that it is scanning data with non-default line endings.
1866     24. Changed the definition of CXXLINK to make it agree with the definition of
1867     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1869     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1870     recursions. This makes a big different to stack usage for some patterns.
1872     26. If a subpattern containing a named recursion or subroutine reference such
1873     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1874     the space required for the compiled pattern went wrong and gave too small a
1875     value. Depending on the environment, this could lead to "Failed: internal
1876     error: code overflow at offset 49" or "glibc detected double free or
1877     corruption" errors.
1879     27. Applied patches from Google (a) to support the new newline modes and (b) to
1880     advance over multibyte UTF-8 characters in GlobalReplace.
1882     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1883     difference for some implementation of PCRE in some Windows version.
1885     29. Added some extra testing facilities to pcretest:
1887     \q<number> in a data line sets the "match limit" value
1888     \Q<number> in a data line sets the "match recursion limt" value
1889     -S <number> sets the stack size, where <number> is in megabytes
1891     The -S option isn't available for Windows.
1894 nigel 89 Version 6.6 06-Feb-06
1895     ---------------------
1897     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1898     in pcreposix.h. I have copied the definition from pcre.h.
1900     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1901     because pcre.h is no longer a built file.
1903     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1904     not normally included in the compiled code.
1907 nigel 87 Version 6.5 01-Feb-06
1908     ---------------------
1910     1. When using the partial match feature with pcre_dfa_exec(), it was not
1911     anchoring the second and subsequent partial matches at the new starting
1912     point. This could lead to incorrect results. For example, with the pattern
1913     /1234/, partially matching against "123" and then "a4" gave a match.
1915     2. Changes to pcregrep:
1917     (a) All non-match returns from pcre_exec() were being treated as failures
1918     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1919     error message is output. Some extra information is given for the
1921     probably the only errors that are likely to be caused by users (by
1922     specifying a regex that has nested indefinite repeats, for instance).
1923     If there are more than 20 of these errors, pcregrep is abandoned.
1925     (b) A binary zero was treated as data while matching, but terminated the
1926     output line if it was written out. This has been fixed: binary zeroes
1927     are now no different to any other data bytes.
1929     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1930     used to set a locale for matching. The --locale=xxxx long option has
1931     been added (no short equivalent) to specify a locale explicitly on the
1932     pcregrep command, overriding the environment variables.
1934     (d) When -B was used with -n, some line numbers in the output were one less
1935     than they should have been.
1937     (e) Added the -o (--only-matching) option.
1939     (f) If -A or -C was used with -c (count only), some lines of context were
1940     accidentally printed for the final match.
1942     (g) Added the -H (--with-filename) option.
1944     (h) The combination of options -rh failed to suppress file names for files
1945     that were found from directory arguments.
1947     (i) Added the -D (--devices) and -d (--directories) options.
1949     (j) Added the -F (--fixed-strings) option.
1951     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1953     (l) Added the --colo(u)r option.
1955     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1956     is not present by default.
1958     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1959     items such as (?R) or (?1), when the recursion could match a number of
1960     alternatives. If it matched one of the alternatives, but subsequently,
1961     outside the recursion, there was a failure, the code tried to back up into
1962     the recursion. However, because of the way PCRE is implemented, this is not
1963     possible, and the result was an incorrect result from the match.
1965     In order to prevent this happening, the specification of recursion has
1966     been changed so that all such subpatterns are automatically treated as
1967     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1969     4. I had overlooked the fact that, in some locales, there are characters for
1970     which isalpha() is true but neither isupper() nor islower() are true. In
1971     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1972     and ordfeminine) are like this. This affected the treatment of \w and \W
1973     when they appeared in character classes, but not when they appeared outside
1974     a character class. The bit map for "word" characters is now created
1975     separately from the results of isalnum() instead of just taking it from the
1976     upper, lower, and digit maps. (Plus the underscore character, of course.)
1978     5. The above bug also affected the handling of POSIX character classes such as
1979     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1980     permanent tables. Instead, the bit maps for such a class were previously
1981     created as the appropriate unions of the upper, lower, and digit bitmaps.
1982     Now they are created by subtraction from the [[:word:]] class, which has
1983     its own bitmap.
1985     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1986     It is created by subtracting the vertical space characters (\x09, \x0a,
1987     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1988     subtraction was done in the overall bitmap for a character class, meaning
1989     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1990     be recognized. This bug has been fixed.
1992     7. Patches from the folks at Google:
1994     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1995     real life, but is still worth protecting against".
1997     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1998     regular expressions".
2000     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2001     have it.
2003     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2004     "configure" and the latter not, in order to fix a problem somebody had
2005     with compiling the Arg class on HP-UX.
2007     (e) Improve the error-handling of the C++ wrapper a little bit.
2009     (f) New tests for checking recursion limiting.
2011     8. The pcre_memmove() function, which is used only if the environment does not
2012     have a standard memmove() function (and is therefore rarely compiled),
2013     contained two bugs: (a) use of int instead of size_t, and (b) it was not
2014     returning a result (though PCRE never actually uses the result).
2016     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2017     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2018     returned instead of calling malloc() with an overflowing number that would
2019     most likely cause subsequent chaos.
2021     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2023     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2024     with this option is matched, the nmatch and pmatch options of regexec() are
2025     ignored.
2027     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2028     provided in case anyone wants to the the POSIX interface with UTF-8
2029     strings.
2031     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2032     C++ linking (needed for some HP-UX environments).
2034     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2035     (unused parameter) and in the pcre_printint() function (omitted "default"
2036     switch label when the default is to do nothing).
2038     15. Added some code to make it possible, when PCRE is compiled as a C++
2039     library, to replace subject pointers for pcre_exec() with a smart pointer
2040     class, thus making it possible to process discontinuous strings.
2042     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2043     much the same function. They were added by different people who were trying
2044     to make PCRE easy to compile on non-Unix systems. It has been suggested
2045     that PCRE_EXPORT be abolished now that there is more automatic apparatus
2046     for compiling on Windows systems. I have therefore replaced it with
2047     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2048     defaults to "extern" for C or "extern C" for C++, which works fine on
2049     Unix-like systems. It is now possible to override the value of PCRE_DATA_
2050     SCOPE with something explicit in config.h. In addition:
2052     (a) pcreposix.h still had just "extern" instead of either of these macros;
2053     I have replaced it with PCRE_DATA_SCOPE.
2055     (b) Functions such as _pcre_xclass(), which are internal to the library,
2056     but external in the C sense, all had PCRE_EXPORT in their definitions.
2057     This is apparently wrong for the Windows case, so I have removed it.
2058     (It makes no difference on Unix-like systems.)
2060     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2061     of recursive calls to match(). This is different to MATCH_LIMIT because
2062     that limits the total number of calls to match(), not all of which increase
2063     the depth of recursion. Limiting the recursion depth limits the amount of
2064     stack (or heap if NO_RECURSE is set) that is used. The default can be set
2065     when PCRE is compiled, and changed at run time. A patch from Google adds
2066     this functionality to the C++ interface.
2068     18. Changes to the handling of Unicode character properties:
2070     (a) Updated the table to Unicode 4.1.0.
2072     (b) Recognize characters that are not in the table as "Cn" (undefined).
2074     (c) I revised the way the table is implemented to a much improved format
2075     which includes recognition of ranges. It now supports the ranges that
2076     are defined in UnicodeData.txt, and it also amalgamates other
2077     characters into ranges. This has reduced the number of entries in the
2078     table from around 16,000 to around 3,000, thus reducing its size
2079     considerably. I realized I did not need to use a tree structure after
2080     all - a binary chop search is just as efficient. Having reduced the
2081     number of entries, I extended their size from 6 bytes to 8 bytes to
2082     allow for more data.
2084     (d) Added support for Unicode script names via properties such as \p{Han}.
2086     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2087     matching that character.
2089     20. When matching a repeated Unicode property with a minimum greater than zero,
2090     (for example \pL{2,}), PCRE could look past the end of the subject if it
2091     reached it while seeking the minimum number of characters. This could
2092     happen only if some of the characters were more than one byte long, because
2093     there is a check for at least the minimum number of bytes.
2095     21. Refactored the implementation of \p and \P so as to be more general, to
2096     allow for more different types of property in future. This has changed the
2097     compiled form incompatibly. Anybody with saved compiled patterns that use
2098     \p or \P will have to recompile them.
2100     22. Added "Any" and "L&" to the supported property types.
2102     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2103     but give a compile time error if the value is greater than 0xff.
2105     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2106     accidentally not being installed or uninstalled.
2108     25. The pcre.h file was built from pcre.h.in, but the only changes that were
2109     made were to insert the current release number. This seemed silly, because
2110     it made things harder for people building PCRE on systems that don't run
2111     "configure". I have turned pcre.h into a distributed file, no longer built
2112     by "configure", with the version identification directly included. There is
2113     no longer a pcre.h.in file.
2115     However, this change necessitated a change to the pcre-config script as
2116     well. It is built from pcre-config.in, and one of the substitutions was the
2117     release number. I have updated configure.ac so that ./configure now finds
2118     the release number by grepping pcre.h.
2120     26. Added the ability to run the tests under valgrind.
2123 nigel 85 Version 6.4 05-Sep-05
2124     ---------------------
2126     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2127     "--" to be printed when multiple files were scanned, even when none of the
2128     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2129     consider it to be a bug, and have restored the previous behaviour.
2131     2. A couple of code tidies to get rid of compiler warnings.
2133     3. The pcretest program used to cheat by referring to symbols in the library
2134     whose names begin with _pcre_. These are internal symbols that are not
2135     really supposed to be visible externally, and in some environments it is
2136     possible to suppress them. The cheating is now confined to including
2137     certain files from the library's source, which is a bit cleaner.
2139     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2140     file's purpose clearer.
2142     5. Reorganized pcre_ucp_findchar().
2145 nigel 83 Version 6.3 15-Aug-05
2146     ---------------------
2148     1. The file libpcre.pc.in did not have general read permission in the tarball.
2150     2. There were some problems when building without C++ support:
2152     (a) If C++ support was not built, "make install" and "make test" still
2153     tried to test it.
2155     (b) There were problems when the value of CXX was explicitly set. Some
2156     changes have been made to try to fix these, and ...
2158     (c) --disable-cpp can now be used to explicitly disable C++ support.
2160     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2161     backslash in a target when C++ was disabled. This confuses some
2162     versions of "make", apparently. Using an intermediate variable solves
2163     this. (Same for CPP_LOBJ.)
2165     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2166     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2167     necessary on certain architectures.
2169     4. Added a setting of -export-symbols-regex to the link command to remove
2170     those symbols that are exported in the C sense, but actually are local
2171     within the library, and not documented. Their names all begin with
2172     "_pcre_". This is not a perfect job, because (a) we have to except some
2173     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2174     available (and never for static libraries). I have made a note to try to
2175     find a way round (a) in the future.
2178 nigel 81 Version 6.2 01-Aug-05
2179     ---------------------
2181     1. There was no test for integer overflow of quantifier values. A construction
2182     such as {1111111111111111} would give undefined results. What is worse, if
2183     a minimum quantifier for a parenthesized subpattern overflowed and became
2184     negative, the calculation of the memory size went wrong. This could have
2185     led to memory overwriting.
2187     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2189     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2190     operating environments where this matters.
2192     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2193     PCRE options from within the C++ wrapper.
2195     5. Named capturing subpatterns were not being correctly counted when a pattern
2196     was compiled. This caused two problems: (a) If there were more than 100
2197     such subpatterns, the calculation of the memory needed for the whole
2198     compiled pattern went wrong, leading to an overflow error. (b) Numerical
2199     back references of the form \12, where the number was greater than 9, were
2200     not recognized as back references, even though there were sufficient
2201     previous subpatterns.
2203     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2204     versions of gcc, e.g. 2.95.4.
2207 nigel 79 Version 6.1 21-Jun-05
2208     ---------------------
2210     1. There was one reference to the variable "posix" in pcretest.c that was not
2211     surrounded by "#if !defined NOPOSIX".
2213     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2214     the cross-check on the old pcre_info() function, for the benefit of the
2215     cut-down version of PCRE that is currently imported into Exim.
2217     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2218     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2219     patterns that start (?i) but I don't think that matters. The use of (?i) is
2220     just an example; this all applies to the other options as well.
2222     4. Since libtool seems to echo the compile commands it is issuing, the output
2223     from "make" can be reduced a bit by putting "@" in front of each libtool
2224     compile command.
2226     5. Patch from the folks at Google for configure.in to be a bit more thorough
2227     in checking for a suitable C++ installation before trying to compile the
2228     C++ stuff. This should fix a reported problem when a compiler was present,
2229     but no suitable headers.
2231     6. The man pages all had just "PCRE" as their title. I have changed them to
2232     be the relevant file name. I have also arranged that these names are
2233     retained in the file doc/pcre.txt, which is a concatenation in text format
2234     of all the man pages except the little individual ones for each function.
2236     7. The NON-UNIX-USE file had not been updated for the different set of source
2237     files that come with release 6. I also added a few comments about the C++
2238     wrapper.
2241 nigel 77 Version 6.0 07-Jun-05
2242     ---------------------
2244     1. Some minor internal re-organization to help with my DFA experiments.
2246     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2247     didn't matter for the library itself when fully configured, but did matter
2248     when compiling without UCP support, or within Exim, where the ucp files are
2249     not imported.
2251     3. Refactoring of the library code to split up the various functions into
2252     different source modules. The addition of the new DFA matching code (see
2253     below) to a single monolithic source would have made it really too
2254     unwieldy, quite apart from causing all the code to be include in a
2255     statically linked application, when only some functions are used. This is
2256     relevant even without the DFA addition now that patterns can be compiled in
2257     one application and matched in another.
2259     The downside of splitting up is that there have to be some external
2260     functions and data tables that are used internally in different modules of
2261     the library but which are not part of the API. These have all had their
2262     names changed to start with "_pcre_" so that they are unlikely to clash
2263     with other external names.
2265     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2266     a different (DFA) algorithm. Although it is slower than the original
2267     function, it does have some advantages for certain types of matching
2268     problem.
2270     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2271     including restarting after a partial match.
2273     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2274     defined when compiling for Windows was sent to me. I have put it into the
2275     code, though I have no means of testing or verifying it.
2277     7. Added the pcre_refcount() auxiliary function.
2279     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2280     match before or at the first newline in the subject string. In pcretest,
2281     the /f option on a pattern can be used to set this.
2283     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2284     would behave wrongly. This has been present in PCRE since release 4.0.
2286     10. A number of changes to the pcregrep command:
2288     (a) Refactored how -x works; insert ^(...)$ instead of setting
2289     PCRE_ANCHORED and checking the length, in preparation for adding
2290     something similar for -w.
2292     (b) Added the -w (match as a word) option.
2294     (c) Refactored the way lines are read and buffered so as to have more
2295     than one at a time available.
2297     (d) Implemented a pcregrep test script.
2299     (e) Added the -M (multiline match) option. This allows patterns to match
2300     over several lines of the subject. The buffering ensures that at least
2301     8K, or the rest of the document (whichever is the shorter) is available
2302     for matching (and similarly the previous 8K for lookbehind assertions).
2304     (f) Changed the --help output so that it now says
2306     -w, --word-regex(p)
2308     instead of two lines, one with "regex" and the other with "regexp"
2309     because that confused at least one person since the short forms are the
2310     same. (This required a bit of code, as the output is generated
2311     automatically from a table. It wasn't just a text change.)
2313     (g) -- can be used to terminate pcregrep options if the next thing isn't an
2314     option but starts with a hyphen. Could be a pattern or a path name
2315     starting with a hyphen, for instance.
2317     (h) "-" can be given as a file name to represent stdin.
2319     (i) When file names are being printed, "(standard input)" is used for
2320     the standard input, for compatibility with GNU grep. Previously
2321     "<stdin>" was used.
2323     (j) The option --label=xxx can be used to supply a name to be used for
2324     stdin when file names are being printed. There is no short form.
2326     (k) Re-factored the options decoding logic because we are going to add
2327     two more options that take data. Such options can now be given in four
2328     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2330     (l) Added the -A, -B, and -C options for requesting that lines of context
2331     around matches be printed.
2333     (m) Added the -L option to print the names of files that do not contain
2334     any matching lines, that is, the complement of -l.
2336     (n) The return code is 2 if any file cannot be opened, but pcregrep does
2337     continue to scan other files.
2339     (o) The -s option was incorrectly implemented. For compatibility with other
2340     greps, it now suppresses the error message for a non-existent or non-
2341     accessible file (but not the return code). There is a new option called
2342     -q that suppresses the output of matching lines, which was what -s was
2343     previously doing.
2345     (p) Added --include and --exclude options to specify files for inclusion
2346     and exclusion when recursing.
2348     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2349     Hopefully, it now does.
2351     12. Missing cast in pcre_study().
2353     13. Added an "uninstall" target to the makefile.
2355     14. Replaced "extern" in the function prototypes in Makefile.in with
2356     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2357     world, but is set differently for Windows.
2359     15. Added a second compiling function called pcre_compile2(). The only
2360     difference is that it has an extra argument, which is a pointer to an
2361     integer error code. When there is a compile-time failure, this is set
2362     non-zero, in addition to the error test pointer being set to point to an
2363     error message. The new argument may be NULL if no error number is required
2364     (but then you may as well call pcre_compile(), which is now just a
2365     wrapper). This facility is provided because some applications need a
2366     numeric error indication, but it has also enabled me to tidy up the way
2367     compile-time errors are handled in the POSIX wrapper.
2369     16. Added VPATH=.libs to the makefile; this should help when building with one
2370     prefix path and installing with another. (Or so I'm told by someone who
2371     knows more about this stuff than I do.)
2373     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2374     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2375     match everything, including newlines. This is not POSIX-compatible, but
2376     somebody wanted the feature. From pcretest it can be activated by using
2377     both the P and the s flags.
2379     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2381     19. libpcre.pc was being incorrectly installed as executable.
2383     20. A couple of places in pcretest check for end-of-line by looking for '\n';
2384     it now also looks for '\r' so that it will work unmodified on Windows.
2386     21. Added Google's contributed C++ wrapper to the distribution.
2388     22. Added some untidy missing memory free() calls in pcretest, to keep
2389     Electric Fence happy when testing.
2393 nigel 75 Version 5.0 13-Sep-04
2394     ---------------------
2396     1. Internal change: literal characters are no longer packed up into items
2397     containing multiple characters in a single byte-string. Each character
2398     is now matched using a separate opcode. However, there may be more than one
2399     byte in the character in UTF-8 mode.
2401     2. The pcre_callout_block structure has two new fields: pattern_position and
2402     next_item_length. These contain the offset in the pattern to the next match
2403     item, and its length, respectively.
2405     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2406     insertion of callouts before each pattern item. Added the /C option to
2407     pcretest to make use of this.
2409     4. On the advice of a Windows user, the lines
2411     #if defined(_WIN32) || defined(WIN32)
2412     _setmode( _fileno( stdout ), 0x8000 );
2413     #endif /* defined(_WIN32) || defined(WIN32) */
2415     have been added to the source of pcretest. This apparently does useful
2416     magic in relation to line terminators.
2418     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2419     for the benefit of those environments where the "b" makes a difference.
2421     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2422     to know about it. I have put a hack into configure.in that adds in code
2423     to set GCC=yes if CC=icc. This seems to end up at a point in the
2424     generated configure script that is early enough to affect the setting of
2425     compiler options, which is what is needed, but I have no means of testing
2426     whether it really works. (The user who reported this had patched the
2427     generated configure script, which of course I cannot do.)
2429     LATER: After change 22 below (new libtool files), the configure script
2430     seems to know about icc (and also ecc). Therefore, I have commented out
2431     this hack in configure.in.
2433     7. Added support for pkg-config (2 patches were sent in).
2435     8. Negated POSIX character classes that used a combination of internal tables
2436     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2437     [[:^ascii]]. Typically, they would match almost any characters. The other
2438     POSIX classes were not broken in this way.
2440     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2441     to find the match, as PCRE was deluded into thinking that the match had to
2442     start at the start point or following a newline. The same bug applied to
2443     patterns with negative forward assertions or any backward assertions
2444     preceding ".*" at the start, unless the pattern required a fixed first
2445     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2447     10. In UTF-8 mode, when moving forwards in the subject after a failed match
2448     starting at the last subject character, bytes beyond the end of the subject
2449     string were read.
2451     11. Renamed the variable "class" as "classbits" to make life easier for C++
2452     users. (Previously there was a macro definition, but it apparently wasn't
2453     enough.)
2455     12. Added the new field "tables" to the extra data so that tables can be passed
2456     in at exec time, or the internal tables can be re-selected. This allows
2457     a compiled regex to be saved and re-used at a later time by a different
2458     program that might have everything at different addresses.
2460     13. Modified the pcre-config script so that, when run on Solaris, it shows a
2461     -R library as well as a -L library.
2463     14. The debugging options of pcretest (-d on the command line or D on a
2464     pattern) showed incorrect output for anything following an extended class
2465     that contained multibyte characters and which was followed by a quantifier.
2467     15. Added optional support for general category Unicode character properties
2468     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2469     support. It adds about 90K to the size of the library. The meanings of the
2470     inbuilt class escapes such as \d and \s have NOT been changed.
2472     16. Updated pcredemo.c to include calls to free() to release the memory for the
2473     compiled pattern.
2475     17. The generated file chartables.c was being created in the source directory
2476     instead of in the building directory. This caused the build to fail if the
2477     source directory was different from the building directory, and was
2478     read-only.
2480     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2481     file. No doubt somebody will tell me if they don't make sense... Also added
2482     Dan Mooney's comments about building on OpenVMS.
2484     19. Added support for partial matching via the PCRE_PARTIAL option for
2485     pcre_exec() and the \P data escape in pcretest.
2487     20. Extended pcretest with 3 new pattern features:
2489     (i) A pattern option of the form ">rest-of-line" causes pcretest to
2490     write the compiled pattern to the file whose name is "rest-of-line".
2491     This is a straight binary dump of the data, with the saved pointer to
2492     the character tables forced to be NULL. The study data, if any, is
2493     written too. After writing, pcretest reads a new pattern.
2495     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2496     compiled pattern from the given file. There must not be any
2497     occurrences of "<" in the file name (pretty unlikely); if there are,
2498     pcretest will instead treat the initial "<" as a pattern delimiter.
2499     After reading in the pattern, pcretest goes on to read data lines as
2500     usual.
2502     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2503     and 16-bit fields in a compiled pattern, to simulate a pattern that
2504     was compiled on a host of opposite endianness.
2506     21. The pcre-exec() function can now cope with patterns that were compiled on
2507     hosts of opposite endianness, with this restriction:
2509     As for any compiled expression that is saved and used later, the tables
2510     pointer field cannot be preserved; the extra_data field in the arguments
2511     to pcre_exec() should be used to pass in a tables address if a value
2512     other than the default internal tables were used at compile time.
2514     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2515     now diagnosed as an error. Previously, most of the time, a negative number
2516     would have been treated as zero, but if in addition "ovector" was passed as
2517     NULL, a crash could occur.
2519     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2520     new versions from the libtool 1.5 distribution (the last one is a copy of
2521     a file called libtool.m4). This seems to have fixed the need to patch
2522     "configure" to support Darwin 1.3 (which I used to do). However, I still
2523     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2524     workstation).
2526     24. Changed the PCRE licence to be the more standard "BSD" licence.
2529 nigel 73 Version 4.5 01-Dec-03
2530     ---------------------
2532     1. There has been some re-arrangement of the code for the match() function so
2533     that it can be compiled in a version that does not call itself recursively.
2534     Instead, it keeps those local variables that need separate instances for
2535     each "recursion" in a frame on the heap, and gets/frees frames whenever it
2536     needs to "recurse". Keeping track of where control must go is done by means
2537     of setjmp/longjmp. The whole thing is implemented by a set of macros that
2538     hide most of the details from the main code, and operates only if
2539     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2540     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2541     operating.
2543     To make it easier for callers to provide specially tailored get/free
2544     functions for this usage, two new functions, pcre_stack_malloc, and
2545     pcre_stack_free, are used. They are always called in strict stacking order,
2546     and the size of block requested is always the same.
2548     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2549     PCRE has been compiled to use the stack or the heap for recursion. The
2550     -C option of pcretest uses this to show which version is compiled.
2552     A new data escape \S, is added to pcretest; it causes the amounts of store
2553     obtained and freed by both kinds of malloc/free at match time to be added
2554     to the output.
2556     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2557     what's available on my current Linux desktop machine.
2559     3. When matching a UTF-8 string, the test for a valid string at the start has
2560     been extended. If start_offset is not zero, PCRE now checks that it points
2561     to a byte that is the start of a UTF-8 character. If not, it returns
2562     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2563     this is necessary because there may be backward assertions in the pattern.
2564     When matching the same subject several times, it may save resources to use
2565     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2567     4. The code for checking the validity of UTF-8 strings has been tightened so
2568     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2569     containing "overlong sequences".
2571     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2572     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2573     should have been "&", but it just so happened that all the cases this let
2574     through by mistake were picked up later in the function.
2576     6. I had used a variable called "isblank" - this is a C99 function, causing
2577     some compilers to warn. To avoid this, I renamed it (as "blankclass").
2579     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2580     prompting; (b) run "./pcretest /dev/null" at the start of the test script
2581     so the version is shown; (c) stop "make test" echoing "./RunTest".
2583     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2585     9. The prototype for memmove() for systems that don't have it was using
2586     size_t, but the inclusion of the header that defines size_t was later. I've
2587     moved the #includes for the C headers earlier to avoid this.
2589     10. Added some adjustments to the code to make it easier to compiler on certain
2590     special systems:
2592     (a) Some "const" qualifiers were missing.
2593     (b) Added the macro EXPORT before all exported functions; by default this
2594     is defined to be empty.
2595     (c) Changed the dftables auxiliary program (that builds chartables.c) so
2596     that it reads its output file name as an argument instead of writing
2597     to the standard output and assuming this can be redirected.
2599     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2600     class containing characters with values greater than 255, PCRE compilation
2601     went into a loop.
2603     12. A recursive reference to a subpattern that was within another subpattern
2604     that had a minimum quantifier of zero caused PCRE to crash. For example,
2605     (x(y(?2))z)? provoked this bug with a subject that got as far as the
2606     recursion. If the recursively-called subpattern itself had a zero repeat,
2607     that was OK.
2609     13. In pcretest, the buffer for reading a data line was set at 30K, but the
2610     buffer into which it was copied (for escape processing) was still set at
2611     1024, so long lines caused crashes.
2613     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2614     "internal error: code overflow...". This applied to any character class
2615     that was followed by a possessive quantifier.
2617     15. Modified the Makefile to add libpcre.la as a prerequisite for
2618     libpcreposix.la because I was told this is needed for a parallel build to
2619     work.
2621     16. If a pattern that contained .* following optional items at the start was
2622     studied, the wrong optimizing data was generated, leading to matching
2623     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2624     matching string must start with a or b or c. The correct conclusion for
2625     this pattern is that a match can start with any character.
2628 nigel 71 Version 4.4 13-Aug-03
2629     ---------------------
2631     1. In UTF-8 mode, a character class containing characters with values between
2632     127 and 255 was not handled correctly if the compiled pattern was studied.
2633     In fixing this, I have also improved the studying algorithm for such
2634     classes (slightly).
2636     2. Three internal functions had redundant arguments passed to them. Removal
2637     might give a very teeny performance improvement.
2639     3. Documentation bug: the value of the capture_top field in a callout is *one
2640     more than* the number of the hightest numbered captured substring.
2642     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2643     in incorrectly linking with a previously installed version. They now link
2644     explicitly with libpcre.la.
2646     5. configure.in no longer needs to recognize Cygwin specially.
2648     6. A problem in pcre.in for Windows platforms is fixed.
2650     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2651     pcretest, it used to include the size of the study block as part of its
2652     output. Unfortunately, the structure contains a field that has a different
2653     size on different hardware architectures. This meant that the tests that
2654     showed this size failed. As the block is currently always of a fixed size,
2655     this information isn't actually particularly useful in pcretest output, so
2656     I have just removed it.
2658     8. Three pre-processor statements accidentally did not start in column 1.
2659     Sadly, there are *still* compilers around that complain, even though
2660     standard C has not required this for well over a decade. Sigh.
2662     9. In pcretest, the code for checking callouts passed small integers in the
2663     callout_data field, which is a void * field. However, some picky compilers
2664     complained about the casts involved for this on 64-bit systems. Now
2665     pcretest passes the address of the small integer instead, which should get
2666     rid of the warnings.
2668     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2669     both compile and run time, and gives an error if an invalid UTF-8 sequence
2670     is found. There is a option for disabling this check in cases where the
2671     string is known to be correct and/or the maximum performance is wanted.
2673     11. In response to a bug report, I changed one line in Makefile.in from
2675     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2676     to
2677     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2679     to look similar to other lines, but I have no way of telling whether this
2680     is the right thing to do, as I do not use Windows. No doubt I'll get told
2681     if it's wrong...
2684 nigel 69 Version 4.3 21-May-03
2685     ---------------------
2687     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2688     Makefile.
2690     2. Some refactoring to improve the quality of the code:
2692     (i) The utf8_table... variables are now declared "const".
2694     (ii) The code for \cx, which used the "case flipping" table to upper case
2695     lower case letters, now just substracts 32. This is ASCII-specific,
2696     but the whole concept of \cx is ASCII-specific, so it seems
2697     reasonable.
2699     (iii) PCRE was using its character types table to recognize decimal and
2700     hexadecimal digits in the pattern. This is silly, because it handles
2701     only 0-9, a-f, and A-F, but the character types table is locale-
2702     specific, which means strange things might happen. A private
2703     table is now used for this - though it costs 256 bytes, a table is
2704     much faster than multiple explicit tests. Of course, the standard
2705     character types table is still used for matching digits in subject
2706     strings against \d.
2708     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2709     ending in _t are). So I've renamed it as ESC_tee.
2711     3. The first argument for regexec() in the POSIX wrapper should have been
2712     defined as "const".
2714     4. Changed pcretest to use malloc() for its buffers so that they can be
2715     Electric Fenced for debugging.
2717     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2718     to read one or more bytes before the start of the subject string. Often this
2719     had no effect on PCRE's behaviour, but in some circumstances it could
2720     provoke a segmentation fault.
2722     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2723     to try to read one or more bytes before the start of the subject string.
2725     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2726     UTF-8 support could misbehave in various ways if the subject string
2727     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2728     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2729     back over UTF-8 characters.)
2732 nigel 67 Version 4.2 14-Apr-03
2733     ---------------------
2735     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2737     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2738     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2739     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2740     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2741     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2742     and BUILD_EXEEXT
2743     Note: automatic setting of the BUILD variables is not yet working
2744     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2745     compile-time but not at link-time
2746     [LINK]: use for linking executables only
2747     make different versions for Windows and non-Windows
2748     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2749     libraries
2750     [LINK_FOR_BUILD]: new variable
2751     [OBJEXT]: use throughout
2752     [EXEEXT]: use throughout
2753     <winshared>: new target
2754     <wininstall>: new target
2755     <dftables.o>: use native compiler
2756     <dftables>: use native linker
2757     <install>: handle Windows platform correctly
2758     <clean>: ditto
2759     <check>: ditto
2760     copy DLL to top builddir before testing
2762     As part of these changes, -no-undefined was removed again. This was reported
2763     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2764     in any case.
2766     3. Some tidies to get rid of compiler warnings:
2768     . In the match_data structure, match_limit was an unsigned long int, whereas
2769     match_call_count was an int. I've made them both unsigned long ints.
2771     . In pcretest the fact that a const uschar * doesn't automatically cast to
2772     a void * provoked a warning.
2774     . Turning on some more compiler warnings threw up some "shadow" variables
2775     and a few more missing casts.
2777     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2778     option, a class that contained a single character with a value between 128
2779     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2781     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2782     option, a class that contained several characters, but with at least one
2783     whose value was between 128 and 255 caused PCRE to crash.
2786 nigel 65 Version 4.1 12-Mar-03
2787     ---------------------
2788 nigel 63
2789 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2790     needed, and a string in dftables.c that was longer than standard compilers are
2791     required to support.
2793     2. Compiling with Sun's compiler found a few more places where the code could
2794     be tidied up in order to avoid warnings.
2796     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2797     first of these names is deprecated in the latest Autoconf in favour of the name
2798     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2799     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2800     analogy I have changed it to CFLAGS_FOR_BUILD.
2802     4. Added -no-undefined to the linking command in the Makefile, because this is
2803     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2804     linking step for the pcreposix library.
2806     5. PCRE was failing to diagnose the case of two named groups with the same
2807     name.
2809     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2810     literal character that is needed in the subject for a match, and scans along to
2811     ensure that it is present before embarking on the full matching process. This
2812     saves time in cases of nested unlimited repeats that are never going to match.
2813     Problem: the scan can take a lot of time if the subject is very long (e.g.
2814     megabytes), thus penalizing straightforward matches. It is now done only if the
2815     amount of subject to be scanned is less than 1000 bytes.
2817     7. A lesser problem with the same optimization is that it was recording the
2818     first character of an anchored pattern as "needed", thus provoking a search
2819     right along the subject, even when the first match of the pattern was going to
2820     fail. The "needed" character is now not set for anchored patterns, unless it
2821     follows something in the pattern that is of non-fixed length. Thus, it still
2822     fulfils its original purpose of finding quick non-matches in cases of nested
2823     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2826     Version 4.0 17-Feb-03
2827     ---------------------
2829 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2830     extended to the end of string, PCRE compiled incorrect data. This could lead to
2831     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2833     2. Moved to autoconf 2.53 and libtool 1.4.2.
2835     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2836     the special perltest8 script is no longer needed - all the tests can be run
2837     from a single perltest script.
2839     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2840     by \s. It has now been removed in PCRE. This means it isn't recognized as
2841     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2842     class [:space:] *does* include VT, thereby creating a mess.
2844     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2845     space and tab.
2847     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2848     its new features into the main test script, reducing the number of scripts.
2850     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2851     were backward compatible, and made the (?i) apply to the whole pattern, as if
2852     /i were given. Now it behaves more logically, and applies the option setting
2853     only to what follows. PCRE has been changed to follow suit. However, if it
2854     finds options settings right at the start of the pattern, it extracts them into
2855     the global options, as before. Thus, they show up in the info data.
2857     8. Added support for the \Q...\E escape sequence. Characters in between are
2858     treated as literals. This is slightly different from Perl in that $ and @ are
2859     also handled as literals inside the quotes. In Perl, they will cause variable
2860     interpolation. Note the following examples:
2862     Pattern PCRE matches Perl matches
2864     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2865     \Qabc\$xyz\E abc\$xyz abc\$xyz
2866     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2868     For compatibility with Perl, \Q...\E sequences are recognized inside character
2869     classes as well as outside them.
2871     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2872     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2873     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2874     signed/unsigned warnings.
2876     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2877     option for pcretest, so I've replaced it by a simple function that does just
2878     that job.
2880     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2881     "pcregrep -".
2883     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2884     Java package. This provides some syntactic sugar for simple cases of what my
2885     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2886     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2887     item, you can use this simplified notation. Note that only makes sense with
2888     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2889     greediness, whatever the setting of the PCRE_UNGREEDY option.
2891     13. A change of greediness default within a pattern was not taking effect at
2892     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2893     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2894     was abstracted outside.
2896     14. PCRE now supports the \G assertion. It is true when the current matching
2897     position is at the start point of the match. This differs from \A when the
2898     starting offset is non-zero. Used with the /g option of pcretest (or similar
2899     code), it works in the same way as it does for Perl's /g option. If all
2900     alternatives of a regex begin with \G, the expression is anchored to the start
2901     match position, and the "anchored" flag is set in the compiled expression.
2903     15. Some bugs concerning the handling of certain option changes within patterns
2904     have been fixed. These applied to options other than (?ims). For example,
2905     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2906     been the other way round. Some of this was related to change 7 above.
2908     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2909     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2910     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2911     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2913     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2914     mode. Unlike ".", it always matches newline, whatever the setting of
2915     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2916     assertions. Perl allows it, but it doesn't (in general) work because it can't
2917     calculate the length of the lookbehind. At least, that's the case for Perl
2918     5.8.0 - I've been told they are going to document that it doesn't work in
2919     future.
2921     18. Added an error diagnosis for escapes that PCRE does not support: these are
2922     \L, \l, \N, \P, \p, \U, \u, and \X.
2924     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2925     reading past the end of the pattern in cases such as /[abcd/.
2927     20. PCRE was getting more memory than necessary for patterns with classes that
2928     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2930     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2931     compiling PCRE for use with Virtual Pascal.
2933     22. Small fix to the Makefile to make it work properly if the build is done
2934     outside the source tree.
2936     23. Added a new extension: a condition to go with recursion. If a conditional
2937     subpattern starts with (?(R) the "true" branch is used if recursion has
2938     happened, whereas the "false" branch is used only at the top level.
2940     24. When there was a very long string of literal characters (over 255 bytes
2941     without UTF support, over 250 bytes with UTF support), the computation of how
2942     much memory was required could be incorrect, leading to segfaults or other
2943     strange effects.
2945     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2946     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2947     there was a subsequent back reference to those brackets. This meant that, for
2948     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2949     possible to check for precisely this case. All we can do is abandon the
2950     optimization if .* occurs inside capturing brackets when there are any back
2951     references whatsoever. (See below for a better fix that came later.)
2953     26. The handling of the optimization for finding the first character of a
2954     non-anchored pattern, and for finding a character that is required later in the
2955     match were failing in some cases. This didn't break the matching; it just
2956     failed to optimize when it could. The way this is done has been re-implemented.
2958     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2960     28. Added a new feature that provides some of the functionality that Perl
2961     provides with (?{...}). The facility is termed a "callout". The way it is done
2962     in PCRE is for the caller to provide an optional function, by setting
2963     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2964     global variable. By default it is unset, which disables all calling out. To get
2965     the function called, the regex must include (?C) at appropriate points. This
2966     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2967     This provides a means of identifying different callout points. When PCRE
2968     reaches such a point in the regex, if pcre_callout has been set, the external
2969     function is called. It is provided with data in a structure called
2970     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2971     matching continues; if it returns a non-zero value, the match at the current
2972     point fails. However, backtracking will occur if possible. [This was changed
2973     later and other features added - see item 49 below.]
2975     29. pcretest is upgraded to test the callout functionality. It provides a
2976     callout function that displays information. By default, it shows the start of
2977     the match and the current position in the text. There are some new data escapes
2978     to vary what happens:
2980     \C+ in addition, show current contents of captured substrings
2981     \C- do not supply a callout function
2982     \C!n return 1 when callout number n is reached
2983     \C!n!m return 1 when callout number n is reached for the mth time
2985     30. If pcregrep was called with the -l option and just a single file name, it
2986     output "<stdin>" if a match was found, instead of the file name.
2988     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2989     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2990     pcre_exec(). This saves a malloc/free per call. The default value of
2991     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2992     when configuring.
2994     32. The default maximum size of a compiled pattern is 64K. There have been a
2995     few cases of people hitting this limit. The code now uses macros to handle the
2996     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2997     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2998     configuring. Tests 2 and 5 work only with 2-byte links because they output
2999     debugging information about compiled patterns.
3001     33. Internal code re-arrangements:
3003     (a) Moved the debugging function for printing out a compiled regex into
3004     its own source file (printint.c) and used #include to pull it into
3005     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
3006     separate copies.
3008     (b) Defined the list of op-code names for debugging as a macro in
3009     internal.h so that it is next to the definition of the opcodes.
3011     (c) Defined a table of op-code lengths for simpler skipping along compiled
3012     code. This is again a macro in internal.h so that it is next to the
3013     definition of the opcodes.
3015     34. Added support for recursive calls to individual subpatterns, along the
3016     lines of Robin Houston's patch (but implemented somewhat differently).
3018     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
3019     allow it to read and process whole directories in Win32. This code was
3020     contributed by Lionel Fourquaux; it has not been tested by me.
3022     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
3023     used to name a group. Names consist of alphanumerics and underscores, and must
3024     be unique. Back references use the syntax (?P=name) and recursive calls use
3025     (?P>name) which is a PCRE extension to the Python extension. Groups still have
3026     numbers. The function pcre_fullinfo() can be used after compilation to extract
3027     a name/number map. There are three relevant calls:
3029     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
3030     PCRE_INFO_NAMECOUNT yields the number of entries
3031     PCRE_INFO_NAMETABLE yields a pointer to the map.
3033     The map is a vector of fixed-size entries. The size of each entry depends on
3034     the length of the longest name used. The first two bytes of each entry are the
3035     group number, most significant byte first. There follows the corresponding
3036     name, zero terminated. The names are in alphabetical order.
3038     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
3039     case instead of 255. Making it the same both with and without UTF-8 support
3040     means that the same test output works with both.
3042     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
3043     calling malloc() with a zero argument.
3045     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
3046     optimization. I've improved things by keeping a bitmap of backreferences with
3047     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
3048     fact referenced, the optimization can be applied. It is unlikely that a
3049     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
3050     the match to follow \n) will appear inside brackets with a number greater than
3051     31, but if it does, any back reference > 31 suppresses the optimization.
3053     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
3054     of disabling numbered capturing parentheses. Any opening parenthesis that is
3055     not followed by ? behaves as if it were followed by ?: but named parentheses
3056     can still be used for capturing (and they will acquire numbers in the usual
3057     way).
3059     41. Redesigned the return codes from the match() function into yes/no/error so
3060     that errors can be passed back from deep inside the nested calls. A malloc
3061     failure while inside a recursive subpattern call now causes the
3062     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
3064     42. It is now possible to set a limit on the number of times the match()
3065     function is called in a call to pcre_exec(). This facility makes it possible to
3066     limit the amount of recursion and backtracking, though not in a directly
3067     obvious way, because the match() function is used in a number of different
3068     circumstances. The count starts from zero for each position in the subject
3069     string (for non-anchored patterns). The default limit is, for compatibility, a
3070     large number, namely 10 000 000. You can change this in two ways:
3072     (a) When configuring PCRE before making, you can use --with-match-limit=n
3073     to set a default value for the compiled library.
3075     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
3076     a different value is set. See 45 below.
3078     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
3080     43. Added a new function pcre_config(int, void *) to enable run-time extraction
3081     of things that can be changed at compile time. The first argument specifies
3082     what is wanted and the second points to where the information is to be placed.
3083     The current list of available information is:
3087     The output is an integer that is set to one if UTF-8 support is available;
3088     otherwise it is set to zero.
3092     The output is an integer that it set to the value of the code that is used for
3093     newline. It is either LF (10) or CR (13).
3097     The output is an integer that contains the number of bytes used for internal
3098     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
3102     The output is an integer that contains the threshold above which the POSIX
3103     interface uses malloc() for output vectors. See item 31 above.
3107     The output is an unsigned integer that contains the default limit of the number
3108     of match() calls in a pcre_exec() execution. See 42 above.
3110     44. pcretest has been upgraded by the addition of the -C option. This causes it
3111     to extract all the available output from the new pcre_config() function, and to
3112     output it. The program then exits immediately.
3114     45. A need has arisen to pass over additional data with calls to pcre_exec() in
3115     order to support additional features. One way would have been to define
3116     pcre_exec2() (for example) with extra arguments, but this would not have been
3117     extensible, and would also have required all calls to the original function to
3118     be mapped to the new one. Instead, I have chosen to extend the mechanism that
3119     is used for passing in "extra" data from pcre_study().
3121     The pcre_extra structure is now exposed and defined in pcre.h. It currently
3122     contains the following fields:
3124     flags a bitmap indicating which of the following fields are set
3125     study_data opaque data from pcre_study()
3126     match_limit a way of specifying a limit on match() calls for a specific
3127     call to pcre_exec()
3128     callout_data data for callouts (see 49 below)
3130     The flag bits are also defined in pcre.h, and are
3136     The pcre_study() function now returns one of these new pcre_extra blocks, with
3137     the actual study data pointed to by the study_data field, and the
3138     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
3139     before. That is, this change is entirely upwards-compatible and requires no
3140     change to existing code.
3142     If you want to pass in additional data to pcre_exec(), you can either place it
3143     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
3144     block.
3146     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
3147     data string contains the escape sequence \M, pcretest calls pcre_exec() several
3148     times with different match limits, until it finds the minimum value needed for
3149     pcre_exec() to complete. The value is then output. This can be instructive; for
3150     most simple matches the number is quite small, but for pathological cases it
3151     gets very large very quickly.
3153     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
3154     returns the size of the data block pointed to by the study_data field in a
3155     pcre_extra block, that is, the value that was passed as the argument to
3156     pcre_malloc() when PCRE was getting memory in which to place the information
3157     created by pcre_study(). The fourth argument should point to a size_t variable.
3158     pcretest has been extended so that this information is shown after a successful
3159     pcre_study() call when information about the compiled regex is being displayed.
3161     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
3162     because what follows is always an absolute path. (Later: it turns out that this
3163     is more than cosmetic for MinGW, because it doesn't like empty path
3164     components.)
3166     49. Some changes have been made to the callout feature (see 28 above):
3168     (i) A callout function now has three choices for what it returns:
3170     0 => success, carry on matching
3171     > 0 => failure at this point, but backtrack if possible
3172     < 0 => serious error, return this value from pcre_exec()
3174     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
3175     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
3176     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
3177     use by callout functions. It will never be used by PCRE itself.
3179     (ii) The pcre_extra structure (see 45 above) has a void * field called
3180     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
3181     pcre_callout_block structure has a field of the same name. The contents of
3182     the field passed in the pcre_extra structure are passed to the callout
3183     function in the corresponding field in the callout block. This makes it
3184     easier to use the same callout-containing regex from multiple threads. For
3185     testing, the pcretest program has a new data escape
3187     \C*n pass the number n (may be negative) as callout_data
3189     If the callout function in pcretest receives a non-zero value as
3190     callout_data, it returns that value.
3192     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
3193     there were some redundant $(CFLAGS) in commands that are now specified as
3194     $(LINK), which already includes $(CFLAGS).
3196     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
3197     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
3198     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
3199     one-byte characters throughout. Note that case-insensitive matching applies
3200     only to characters whose values are less than 256. PCRE doesn't support the
3201     notion of cases for higher-valued characters.
3203     (i) A character class whose characters are all within 0-255 is handled as
3204     a bit map, and the map is inverted for negative classes. Previously, a
3205     character > 255 always failed to match such a class; however it should
3206     match if the class was a negative one (e.g. [^ab]). This has been fixed.
3208     (ii) A negated character class with a single character < 255 is coded as
3209     "not this character" (OP_NOT). This wasn't working properly when the test
3210     character was multibyte, either singly or repeated.
3212     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
3213     mode, for example: \x{100}{2,3}.
3215     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
3216     singly or repeated) now correctly test multibyte characters. However,
3217     PCRE doesn't recognize any characters with values greater than 255 as
3218     digits, spaces, or word characters. Such characters always match \D, \S,
3219     and \W, and never match \d, \s, or \w.
3221     (v) Classes may now contain characters and character ranges with values
3222     greater than 255. For example: [ab\x{100}-\x{400}].
3224     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
3225     PCRE in UTF-8 mode.
3227     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
3228     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
3229     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
3230     value.)
3232     53. The single man page has become too large. I have therefore split it up into
3233     a number of separate man pages. These also give rise to individual HTML pages;
3234     these are now put in a separate directory, and there is an index.html page that
3235     lists them all. Some hyperlinking between the pages has been installed.
3237     54. Added convenience functions for handling named capturing parentheses.
3239     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3240     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3241     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3242     are faulted.
3244     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3245     calling configure. These values are used when compiling the dftables.c program
3246     which is run to generate the source of the default character tables. They
3247     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3248     you will need to set these values.
3250     57. Updated the building process for Windows DLL, as provided by Fred Cox.
3253     Version 3.9 02-Jan-02
3254 nigel 61 ---------------------
3256     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3258     2. If --disable-static was given, the building process failed when trying to
3259     build pcretest and pcregrep. (For some reason it was using libtool to compile
3260     them, which is not right, as they aren't part of the library.)
3263 nigel 59 Version 3.8 18-Dec-01
3264     ---------------------
3266     1. The experimental UTF-8 code was completely screwed up. It was packing the
3267     bytes in the wrong order. How dumb can you get?
3270 nigel 57 Version 3.7 29-Oct-01
3271     ---------------------
3273     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
3274     This caused pcretest, when used on the test data, to segfault. Unfortunately,
3275     this didn't happen under Solaris 8, where I normally test things.
3277 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
3278     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
3279     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
3280     this fix an hour or so after the initial 3.7 release.)
3281 nigel 57
3282 nigel 59
3283 nigel 55 Version 3.6 23-Oct-01
3284     ---------------------
3286     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
3287     offsets passed as NULL with zero offset count.
3289     2. The config.guess and config.sub files had not been updated when I moved to
3290     the latest autoconf.
3293 nigel 53 Version 3.5 15-Aug-01
3294     ---------------------
3295 nigel 5
3296 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
3297     had been forgotten.
3299     2. By using declared but undefined structures, we can avoid using "void"
3300     definitions in pcre.h while keeping the internal definitions of the structures
3301     private.
3303     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3304     user point of view, this means that both static and shared libraries are built
3305     by default, but this can be individually controlled. More of the work of
3306     handling this static/shared cases is now inside libtool instead of PCRE's make
3307     file.
3309     4. The pcretest utility is now installed along with pcregrep because it is
3310     useful for users (to test regexs) and by doing this, it automatically gets
3311     relinked by libtool. The documentation has been turned into a man page, so
3312     there are now .1, .txt, and .html versions in /doc.
3314     5. Upgrades to pcregrep:
3315     (i) Added long-form option names like gnu grep.
3316     (ii) Added --help to list all options with an explanatory phrase.
3317     (iii) Added -r, --recursive to recurse into sub-directories.
3318     (iv) Added -f, --file to read patterns from a file.
3320     6. pcre_exec() was referring to its "code" argument before testing that
3321     argument for NULL (and giving an error if it was NULL).
3323     7. Upgraded Makefile.in to allow for compiling in a different directory from
3324     the source directory.
3326     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3327     options bits, the pointer it was passed was to an int instead of to an unsigned
3328     long int. This mattered only on 64-bit systems.
3330     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3331     generated) instead of pcre.in, which it its source. Also made the same change
3332     in several of the .c files.
3334     10. A new release of gcc defines printf() as a macro, which broke pcretest
3335     because it had an ifdef in the middle of a string argument for printf(). Fixed
3336     by using separate calls to printf().
3338     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3339     script, to force use of CR or LF instead of \n in the source. On non-Unix
3340     systems, the value can be set in config.h.
3342     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3343     absolute limit. Changed the text of the error message to make this clear, and
3344     likewise updated the man page.
3346     13. The limit of 99 on the number of capturing subpatterns has been removed.
3347     The new limit is 65535, which I hope will not be a "real" limit.
3350 nigel 51 Version 3.4 22-Aug-00
3351     ---------------------
3353     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3355     2. Diagnose condition (?(0) as an error instead of crashing on matching.
3358 nigel 49 Version 3.3 01-Aug-00
3359     ---------------------
3361     1. If an octal character was given, but the value was greater than \377, it
3362     was not getting masked to the least significant bits, as documented. This could
3363     lead to crashes in some systems.
3365     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3366     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3368     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3369     These just pass their arguments on to (pcre_free)(), but they are provided
3370     because some uses of PCRE bind it to non-C systems that can call its functions,
3371     but cannot call free() or pcre_free() directly.
3373     4. Add "make test" as a synonym for "make check". Corrected some comments in
3374     the Makefile.
3376     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3377     Makefile.
3379     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3380     command called pgrep for grepping around the active processes.
3382     7. Added the beginnings of support for UTF-8 character strings.
3384     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3385     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3386     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3387     out for the ar command.)
3390 nigel 47 Version 3.2 12-May-00
3391     ---------------------
3393     This is purely a bug fixing release.
3395     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3396     of ZA. This was just one example of several cases that could provoke this bug,
3397     which was introduced by change 9 of version 2.00. The code for breaking
3398     infinite loops after an iteration that matches an empty string was't working
3399     correctly.
3401     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3402     when matched against abbab (for example). After matching an empty string, it
3403     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3404     caused it to match further down the string than it should.
3406     3. The code contained an inclusion of sys/types.h. It isn't clear why this
3407     was there because it doesn't seem to be needed, and it causes trouble on some
3408     systems, as it is not a Standard C header. It has been removed.
3410     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3411     were reported on the Macintosh. The changes were from
3413     while ((c = *(++ptr)) != 0 && c != '\n');
3414     to
3415     while ((c = *(++ptr)) != 0 && c != '\n') ;
3417     Totally extraordinary, but if that's what it takes...
3419     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3420     available. Added HAVE_BCOPY and an autoconf test for it; if neither
3421     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3422     assumes the way PCRE uses memmove() (always moving upwards).
3424     6. PCRE is being used in one environment where strchr() is not available. There
3425     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3426     faster code anyway.
3429 nigel 45 Version 3.1 09-Feb-00
3430     ---------------------
3432     The only change in this release is the fixing of some bugs in Makefile.in for
3433     the "install" target:
3435     (1) It was failing to install pcreposix.h.
3437     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3440 nigel 43 Version 3.0 01-Feb-00
3441     ---------------------
3442 nigel 41
3443     1. Add support for the /+ modifier to perltest (to output $` like it does in
3444     pcretest).
3446     2. Add support for the /g modifier to perltest.
3448     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3449     matches null strings.
3451     4. Fix perltest so that it doesn't do unwanted things when fed an empty
3452     pattern. Perl treats empty patterns specially - it reuses the most recent
3453     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3454     effect.
3456     5. The POSIX interface was broken in that it was just handing over the POSIX
3457     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3458     required a bigger vector, with some working space on the end. This means that
3459     the POSIX wrapper now has to get and free some memory, and copy the results.
3461 nigel 43 6. Added some simple autoconf support, placing the test data and the
3462     documentation in separate directories, re-organizing some of the
3463     information files, and making it build pcre-config (a GNU standard). Also added
3464     libtool support for building PCRE as a shared library, which is now the
3465     default.
3466 nigel 41
3467 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3468     09 are not valid octal constants. Single digits will be used for minor values
3469     less than 10.
3471     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3472     existing programs that set these in the POSIX interface can use PCRE without
3473     modification.
3475     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3476     return all that pcre_info() returns, plus additional data. The pcre_info()
3477     function is retained for compatibility, but is considered to be obsolete.
3479     10. Added experimental recursion feature (?R) to handle one common case that
3480     Perl 5.6 will be able to do with (?p{...}).
3482     11. Added support for POSIX character classes like [:alpha:], which Perl is
3483     adopting.
3486 nigel 39 Version 2.08 31-Aug-99
3487     ----------------------
3489     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3490     trying to match at the startoffset position, but instead was moving forward to
3491     the next newline as if a previous match had failed.
3493     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3494     and could get into a loop if a null string was matched other than at the start
3495     of the subject.
3497     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3498     be distinguished at compile time, and for completeness also added PCRE_DATE.
3500     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3501     in GnuWin32 environments.
3504 nigel 37 Version 2.07 29-Jul-99
3505     ----------------------
3507     1. The documentation is now supplied in plain text form and HTML as well as in
3508     the form of man page sources.
3510     2. C++ compilers don't like assigning (void *) values to other pointer types.
3511     In particular this affects malloc(). Although there is no problem in Standard
3512     C, I've put in casts to keep C++ compilers happy.
3514     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3515     should be (const char *).
3517     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3518     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3519     However, I haven't made this a standard facility. The documentation doesn't
3520     mention it, and the Makefile doesn't support it.
3522     5. The Makefile now contains an "install" target, with editable destinations at
3523     the top of the file. The pcretest program is not installed.
3525     6. pgrep -V now gives the PCRE version number and date.
3527     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3528     causing the entire string to be ignored, instead of just the last character.
3530     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3531     non-matching string, it can take a very, very long time, even for strings of
3532     quite modest length, because of the nested recursion. PCRE now does better in
3533     some of these cases. It does this by remembering the last required literal
3534     character in the pattern, and pre-searching the subject to ensure it is present
3535     before running the real match. In other words, it applies a heuristic to detect
3536     some types of certain failure quickly, and in the above example, if presented
3537     with a string that has no trailing " it gives "no match" very quickly.
3539     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3540     other alternatives are tried instead.
3543 nigel 35 Version 2.06 09-Jun-99
3544     ----------------------
3546     1. Change pcretest's output for amount of store used to show just the code
3547     space, because the remainder (the data block) varies in size between 32-bit and
3548     64-bit systems.
3550     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3551     start matching at. This allows lookbehinds to work when searching for multiple
3552     occurrences in a string.
3554     3. Added additional options to pcretest for testing multiple occurrences:
3556     /+ outputs the rest of the string that follows a match
3557     /g loops for multiple occurrences, using the new startoffset argument
3558     /G loops for multiple occurrences by passing an incremented pointer
3560     4. PCRE wasn't doing the "first character" optimization for patterns starting
3561     with \b or \B, though it was doing it for other lookbehind assertions. That is,
3562     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3563     the letter 'x'. On long subject strings, this gives a significant speed-up.
3566 nigel 33 Version 2.05 21-Apr-99
3567     ----------------------
3569     1. Changed the type of magic_number from int to long int so that it works
3570     properly on 16-bit systems.
3572     2. Fixed a bug which caused patterns starting with .* not to work correctly
3573     when the subject string contained newline characters. PCRE was assuming
3574     anchoring for such patterns in all cases, which is not correct because .* will
3575     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3576     DOTALL is set at top level; otherwise it knows that patterns starting with .*
3577     must be retried after every newline in the subject.
3580 nigel 31 Version 2.04 18-Feb-99
3581     ----------------------
3583     1. For parenthesized subpatterns with repeats whose minimum was zero, the
3584     computation of the store needed to hold the pattern was incorrect (too large).
3585     If such patterns were nested a few deep, this could multiply and become a real
3586     problem.
3588     2. Added /M option to pcretest to show the memory requirement of a specific
3589     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3591     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3592     compiled in such a way that the backtracking after subsequent failure was
3593     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3594     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3597 nigel 29 Version 2.03 02-Feb-99
3598     ----------------------
3600     1. Fixed typo and small mistake in man page.
3602 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
3603     LICENCE file containing the conditions.
3604 nigel 29
3605     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3606     Perl, that is the internal \ allows the delimiter to be included in the
3607     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3608     the final delimiter, add \ to the end of the pattern (to test the error).
3610     4. Added the convenience functions for extracting substrings after a successful
3611     match. Updated pcretest to make it able to test these functions.
3614 nigel 27 Version 2.02 14-Jan-99
3615     ----------------------
3617     1. Initialized the working variables associated with each extraction so that
3618     their saving and restoring doesn't refer to uninitialized store.
3620     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3621     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3622     fix the problem.
3624     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3625     calls, and wasn't printing the correct value for compiling calls. Increased the
3626     default value of LOOPREPEAT, and the number of significant figures in the
3627     times.
3629     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3631     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3632     a building problem on Windows NT with a FAT file system.
3635 nigel 25 Version 2.01 21-Oct-98
3636     ----------------------
3638     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3639     to character tables built by pcre_maketables() in the current locale. If NULL
3640     is passed, the default tables are used.
3643 nigel 23 Version 2.00 24-Sep-98
3644 nigel 21 ----------------------
3646 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3647     it any more.
3649     2. Allow quantification of (?>) groups, and make it work correctly.
3651     3. The first character computation wasn't working for (?>) groups.
3653     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3654     end of the subject) and add 5.005's \z, which really does match only at the
3655     very end of the subject.
3657     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3659     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3660     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3661     localized options. All options to pcre_study() were also removed.
3663     7. Add other new features from 5.005:
3665     $(?<= positive lookbehind
3666     $(?<! negative lookbehind
3667     (?imsx-imsx) added the unsetting capability
3668     such a setting is global if at outer level; local otherwise
3669     (?imsx-imsx:) non-capturing groups with option setting
3670     (?(cond)re|re) conditional pattern matching
3672     A backreference to itself in a repeated group matches the previous
3673     captured string.