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1 ChangeLog for PCRE
2 ------------------
3
4 Version 7.0 19-Dec-06
5 ---------------------
6
7 1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
8 moving to gcc 4.1.1.
9
10 2. The -S option for pcretest uses setrlimit(); I had omitted to #include
11 sys/time.h, which is documented as needed for this function. It doesn't
12 seem to matter on Linux, but it showed up on some releases of OS X.
13
14 3. It seems that there are systems where bytes whose values are greater than
15 127 match isprint() in the "C" locale. The "C" locale should be the
16 default when a C program starts up. In most systems, only ASCII printing
17 characters match isprint(). This difference caused the output from pcretest
18 to vary, making some of the tests fail. I have changed pcretest so that:
19
20 (a) When it is outputting text in the compiled version of a pattern, bytes
21 other than 32-126 are always shown as hex escapes.
22
23 (b) When it is outputting text that is a matched part of a subject string,
24 it does the same, unless a different locale has been set for the match
25 (using the /L modifier). In this case, it uses isprint() to decide.
26
27 4. Fixed a major bug that caused incorrect computation of the amount of memory
28 required for a compiled pattern when options that changed within the
29 pattern affected the logic of the preliminary scan that determines the
30 length. The relevant options are -x, and -i in UTF-8 mode. The result was
31 that the computed length was too small. The symptoms of this bug were
32 either the PCRE error "internal error: code overflow" from pcre_compile(),
33 or a glibc crash with a message such as "pcretest: free(): invalid next
34 size (fast)". Examples of patterns that provoked this bug (shown in
35 pcretest format) are:
36
37 /(?-x: )/x
38 /(?x)(?-x: \s*#\s*)/
39 /((?i)[\x{c0}])/8
40 /(?i:[\x{c0}])/8
41
42 HOWEVER: Change 17 below makes this fix obsolete as the memory computation
43 is now done differently.
44
45 5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
46 wrapper classes; (b) implement a new function in the C++ scanner that is
47 more efficient than the old way of doing things because it avoids levels of
48 recursion in the regex matching; (c) add a paragraph to the documentation
49 for the FullMatch() function.
50
51 6. The escape sequence \n was being treated as whatever was defined as
52 "newline". Not only was this contrary to the documentation, which states
53 that \n is character 10 (hex 0A), but it also went horribly wrong when
54 "newline" was defined as CRLF. This has been fixed.
55
56 7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
57 was being set to -1 for the "end of line" case (supposedly a value that no
58 character can have). Though this value is never used (the check for end of
59 line is "zero bytes in current character"), it caused compiler complaints.
60 I've changed it to 0xffffffff.
61
62 8. In pcre_version.c, the version string was being built by a sequence of
63 C macros that, in the event of PCRE_PRERELEASE being defined as an empty
64 string (as it is for production releases) called a macro with an empty
65 argument. The C standard says the result of this is undefined. The gcc
66 compiler treats it as an empty string (which was what was wanted) but it is
67 reported that Visual C gives an error. The source has been hacked around to
68 avoid this problem.
69
70 9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
71 builds of pcretest, and changed the call to _setmode() to use _O_BINARY
72 instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
73 of them did).
74
75 10. Originally, pcretest opened its input and output without "b"; then I was
76 told that "b" was needed in some environments, so it was added for release
77 5.0 to both the input and output. (It makes no difference on Unix-like
78 systems.) Later I was told that it is wrong for the input on Windows. I've
79 now abstracted the modes into two macros, to make it easier to fiddle with
80 them, and removed "b" from the input mode under Windows.
81
82 11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
83
84 12. Added -help and --help to pcretest as an official way of being reminded
85 of the options.
86
87 13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
88 and pcrecpp.cc because they annoy compilers at high warning levels.
89
90 14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
91
92 15. Fixed an occurrence of == in configure.ac that should have been = (shell
93 scripts are not C programs :-) and which was not noticed because it works
94 on Linux.
95
96 16. pcretest is supposed to handle any length of pattern and data line (as one
97 line or as a continued sequence of lines) by extending its input buffer if
98 necessary. This feature was broken for very long pattern lines, leading to
99 a string of junk being passed to pcre_compile() if the pattern was longer
100 than about 50K.
101
102 17. I have done a major re-factoring of the way pcre_compile() computes the
103 amount of memory needed for a compiled pattern. Previously, there was code
104 that made a preliminary scan of the pattern in order to do this. That was
105 OK when PCRE was new, but as the facilities have expanded, it has become
106 harder and harder to keep it in step with the real compile phase, and there
107 have been a number of bugs (see for example, 4 above). I have now found a
108 cunning way of running the real compile function in a "fake" mode that
109 enables it to compute how much memory it would need, while actually only
110 ever using a few hundred bytes of working memory and without too many
111 tests of the mode. This should make future maintenance and development
112 easier. A side effect of this work is that the limit of 200 on the nesting
113 depth of parentheses has been removed (though this was never a serious
114 limitation, I suspect). However, there is a downside: pcre_compile() now
115 runs more slowly than before (30% or more, depending on the pattern). I
116 hope this isn't a big issue. There is no effect on runtime performance.
117
118 18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
119 newline (only possible for the last line of a file) and it was a
120 pattern that set a locale (followed by /Lsomething), pcretest crashed.
121
122 19. Added additional timing features to pcretest. (1) The -tm option now times
123 matching only, not compiling. (2) Both -t and -tm can be followed, as a
124 separate command line item, by a number that specifies the number of
125 repeats to use when timing. The default is 50000; this gives better
126 precision, but takes uncomfortably long for very large patterns.
127
128 20. Extended pcre_study() to be more clever in cases where a branch of a
129 subpattern has no definite first character. For example, (a*|b*)[cd] would
130 previously give no result from pcre_study(). Now it recognizes that the
131 first character must be a, b, c, or d.
132
133 21. There was an incorrect error "recursive call could loop indefinitely" if
134 a subpattern (or the entire pattern) that was being tested for matching an
135 empty string contained only one non-empty item after a nested subpattern.
136 For example, the pattern (?>\x{100}*)\d(?R) provoked this error
137 incorrectly, because the \d was being skipped in the check.
138
139 22. The pcretest program now has a new pattern option /B and a command line
140 option -b, which is equivalent to adding /B to every pattern. This causes
141 it to show the compiled bytecode, without the additional information that
142 -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
143 is the same as /B/I).
144
145 23. A new optimization is now able automatically to treat some sequences such
146 as a*b as a*+b. More specifically, if something simple (such as a character
147 or a simple class like \d) has an unlimited quantifier, and is followed by
148 something that cannot possibly match the quantified thing, the quantifier
149 is automatically "possessified".
150
151 24. A recursive reference to a subpattern whose number was greater than 39
152 went wrong under certain circumstances in UTF-8 mode. This bug could also
153 have affected the operation of pcre_study().
154
155 25. Realized that a little bit of performance could be had by replacing
156 (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
157
158 26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
159
160 27. Possessive quantifiers such as a++ were previously implemented by turning
161 them into atomic groups such as ($>a+). Now they have their own opcodes,
162 which improves performance. This includes the automatically created ones
163 from 23 above.
164
165 28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
166 lookahead was broken if it was not anchored. PCRE was mistakenly expecting
167 the first matched character to be a colon. This applied both to named and
168 numbered groups.
169
170 29. The ucpinternal.h header file was missing its idempotency #ifdef.
171
172 30. I was sent a "project" file called libpcre.a.dev which I understand makes
173 building PCRE on Windows easier, so I have included it in the distribution.
174
175 31. There is now a check in pcretest against a ridiculously large number being
176 returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
177 loop, the loop is abandoned.
178
179 32. Forward references to subpatterns in conditions such as (?(2)...) where
180 subpattern 2 is defined later cause pcre_compile() to search forwards in
181 the pattern for the relevant set of parentheses. This search went wrong
182 when there were unescaped parentheses in a character class, parentheses
183 escaped with \Q...\E, or parentheses in a #-comment in /x mode.
184
185 33. "Subroutine" calls and backreferences were previously restricted to
186 referencing subpatterns earlier in the regex. This restriction has now
187 been removed.
188
189 34. Added a number of extra features that are going to be in Perl 5.10. On the
190 whole, these are just syntactic alternatives for features that PCRE had
191 previously implemented using the Python syntax or my own invention. The
192 other formats are all retained for compatibility.
193
194 (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
195 as (?P<name>...). The new forms, as well as being in Perl 5.10, are
196 also .NET compatible.
197
198 (b) A recursion or subroutine call to a named group can now be defined as
199 (?&name) as well as (?P>name).
200
201 (c) A backreference to a named group can now be defined as \k<name> or
202 \k'name' as well as (?P=name). The new forms, as well as being in Perl
203 5.10, are also .NET compatible.
204
205 (d) A conditional reference to a named group can now use the syntax
206 (?(<name>) or (?('name') as well as (?(name).
207
208 (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
209 groups (named and numbered) that are never evaluated inline, but can be
210 called as "subroutines" from elsewhere. In effect, the DEFINE condition
211 is always false. There may be only one alternative in such a group.
212
213 (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
214 as the simple (?(R). The condition is true only if the most recent
215 recursion is that of the given number or name. It does not search out
216 through the entire recursion stack.
217
218 (g) The escape \gN or \g{N} has been added, where N is a positive or
219 negative number, specifying an absolute or relative reference.
220
221 35. Tidied to get rid of some further signed/unsigned compiler warnings and
222 some "unreachable code" warnings.
223
224 36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
225 things, this adds five new scripts.
226
227 37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
228 There were also incompatibilities regarding the handling of \Q..\E inside
229 character classes, for example with patterns like [\Qa\E-\Qz\E] where the
230 hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
231
232 38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
233 matches an empty string, and forcibly breaks the loop. There were bugs in
234 this code in non-simple cases. For a pattern such as ^(a()*)* matched
235 against aaaa the result was just "a" rather than "aaaa", for example. Two
236 separate and independent bugs (that affected different cases) have been
237 fixed.
238
239 39. Refactored the code to abolish the use of different opcodes for small
240 capturing bracket numbers. This is a tidy that I avoided doing when I
241 removed the limit on the number of capturing brackets for 3.5 back in 2001.
242 The new approach is not only tidier, it makes it possible to reduce the
243 memory needed to fix the previous bug (38).
244
245 40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
246 sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
247 processing dot, circumflex, or dollar metacharacters, or #-comments in /x
248 mode.
249
250 41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
251 report.
252
253 42. Applied patch, originally from Ari Pollak, modified by Google, to allow
254 copy construction and assignment in the C++ wrapper.
255
256 43. Updated pcregrep to support "--newline=any". In the process, I fixed a
257 couple of bugs that could have given wrong results in the "--newline=crlf"
258 case.
259
260 44. Added a number of casts and did some reorganization of signed/unsigned int
261 variables following suggestions from Dair Grant. Also renamed the variable
262 "this" as "item" because it is a C++ keyword.
263
264 45. Arranged for dftables to add
265
266 #include "pcre_internal.h"
267
268 to pcre_chartables.c because without it, gcc 4.x may remove the array
269 definition from the final binary if PCRE is built into a static library and
270 dead code stripping is activated.
271
272 46. For an unanchored pattern, if a match attempt fails at the start of a
273 newline sequence, and the newline setting is CRLF or ANY, and the next two
274 characters are CRLF, advance by two characters instead of one.
275
276
277 Version 6.7 04-Jul-06
278 ---------------------
279
280 1. In order to handle tests when input lines are enormously long, pcretest has
281 been re-factored so that it automatically extends its buffers when
282 necessary. The code is crude, but this _is_ just a test program. The
283 default size has been increased from 32K to 50K.
284
285 2. The code in pcre_study() was using the value of the re argument before
286 testing it for NULL. (Of course, in any sensible call of the function, it
287 won't be NULL.)
288
289 3. The memmove() emulation function in pcre_internal.h, which is used on
290 systems that lack both memmove() and bcopy() - that is, hardly ever -
291 was missing a "static" storage class specifier.
292
293 4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
294 containing an extended class (one that cannot be represented by a bitmap
295 because it contains high-valued characters or Unicode property items, e.g.
296 [\pZ]). Almost always one would set UTF-8 mode when processing such a
297 pattern, but PCRE should not loop if you do not (it no longer does).
298 [Detail: two cases were found: (a) a repeated subpattern containing an
299 extended class; (b) a recursive reference to a subpattern that followed a
300 previous extended class. It wasn't skipping over the extended class
301 correctly when UTF-8 mode was not set.]
302
303 5. A negated single-character class was not being recognized as fixed-length
304 in lookbehind assertions such as (?<=[^f]), leading to an incorrect
305 compile error "lookbehind assertion is not fixed length".
306
307 6. The RunPerlTest auxiliary script was showing an unexpected difference
308 between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
309 write a Perl script that can interpret lines of an input file either as
310 byte characters or as UTF-8, which is what "perltest" was being required to
311 do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
312 can't do is switch easily at run time between having the "use utf8;" pragma
313 or not. In the end, I fudged it by using the RunPerlTest script to insert
314 "use utf8;" explicitly for the UTF-8 tests.
315
316 7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
317 the end of the subject string, contrary to the documentation and to what
318 Perl does. This was true of both matching functions. Now it matches only at
319 the start of the subject and immediately after *internal* newlines.
320
321 8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
322 a pointer to an int instead of a pointer to an unsigned long int. This
323 caused problems on 64-bit systems.
324
325 9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
326 instance of the 'standard' template library not being so standard".
327
328 10. There was no check on the number of named subpatterns nor the maximum
329 length of a subpattern name. The product of these values is used to compute
330 the size of the memory block for a compiled pattern. By supplying a very
331 long subpattern name and a large number of named subpatterns, the size
332 computation could be caused to overflow. This is now prevented by limiting
333 the length of names to 32 characters, and the number of named subpatterns
334 to 10,000.
335
336 11. Subpatterns that are repeated with specific counts have to be replicated in
337 the compiled pattern. The size of memory for this was computed from the
338 length of the subpattern and the repeat count. The latter is limited to
339 65535, but there was no limit on the former, meaning that integer overflow
340 could in principle occur. The compiled length of a repeated subpattern is
341 now limited to 30,000 bytes in order to prevent this.
342
343 12. Added the optional facility to have named substrings with the same name.
344
345 13. Added the ability to use a named substring as a condition, using the
346 Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
347 are numbers (not recommended). Forward references are permitted.
348
349 14. Added forward references in named backreferences (if you see what I mean).
350
351 15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
352 pattern could run off the end of the subject. For example, the pattern
353 "(?s)(.{1,5})"8 did this with the subject "ab".
354
355 16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
356 PCRE_CASELESS was set when matching characters that were quantified with ?
357 or *.
358
359 17. A character class other than a single negated character that had a minimum
360 but no maximum quantifier - for example [ab]{6,} - was not handled
361 correctly by pce_dfa_exec(). It would match only one character.
362
363 18. A valid (though odd) pattern that looked like a POSIX character
364 class but used an invalid character after [ (for example [[,abc,]]) caused
365 pcre_compile() to give the error "Failed: internal error: code overflow" or
366 in some cases to crash with a glibc free() error. This could even happen if
367 the pattern terminated after [[ but there just happened to be a sequence of
368 letters, a binary zero, and a closing ] in the memory that followed.
369
370 19. Perl's treatment of octal escapes in the range \400 to \777 has changed
371 over the years. Originally (before any Unicode support), just the bottom 8
372 bits were taken. Thus, for example, \500 really meant \100. Nowadays the
373 output from "man perlunicode" includes this:
374
375 The regular expression compiler produces polymorphic opcodes. That
376 is, the pattern adapts to the data and automatically switches to
377 the Unicode character scheme when presented with Unicode data--or
378 instead uses a traditional byte scheme when presented with byte
379 data.
380
381 Sadly, a wide octal escape does not cause a switch, and in a string with
382 no other multibyte characters, these octal escapes are treated as before.
383 Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
384 /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
385 Unicode string.
386
387 I have not perpetrated such confusion in PCRE. Up till now, it took just
388 the bottom 8 bits, as in old Perl. I have now made octal escapes with
389 values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
390 translate to the appropriate multibyte character.
391
392 29. Applied some refactoring to reduce the number of warnings from Microsoft
393 and Borland compilers. This has included removing the fudge introduced
394 seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
395 a warning about an unused variable.
396
397 21. PCRE has not included VT (character 0x0b) in the set of whitespace
398 characters since release 4.0, because Perl (from release 5.004) does not.
399 [Or at least, is documented not to: some releases seem to be in conflict
400 with the documentation.] However, when a pattern was studied with
401 pcre_study() and all its branches started with \s, PCRE still included VT
402 as a possible starting character. Of course, this did no harm; it just
403 caused an unnecessary match attempt.
404
405 22. Removed a now-redundant internal flag bit that recorded the fact that case
406 dependency changed within the pattern. This was once needed for "required
407 byte" processing, but is no longer used. This recovers a now-scarce options
408 bit. Also moved the least significant internal flag bit to the most-
409 significant bit of the word, which was not previously used (hangover from
410 the days when it was an int rather than a uint) to free up another bit for
411 the future.
412
413 23. Added support for CRLF line endings as well as CR and LF. As well as the
414 default being selectable at build time, it can now be changed at runtime
415 via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
416 specify that it is scanning data with non-default line endings.
417
418 24. Changed the definition of CXXLINK to make it agree with the definition of
419 LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
420
421 25. Applied Ian Taylor's patches to avoid using another stack frame for tail
422 recursions. This makes a big different to stack usage for some patterns.
423
424 26. If a subpattern containing a named recursion or subroutine reference such
425 as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
426 the space required for the compiled pattern went wrong and gave too small a
427 value. Depending on the environment, this could lead to "Failed: internal
428 error: code overflow at offset 49" or "glibc detected double free or
429 corruption" errors.
430
431 27. Applied patches from Google (a) to support the new newline modes and (b) to
432 advance over multibyte UTF-8 characters in GlobalReplace.
433
434 28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
435 difference for some implementation of PCRE in some Windows version.
436
437 29. Added some extra testing facilities to pcretest:
438
439 \q<number> in a data line sets the "match limit" value
440 \Q<number> in a data line sets the "match recursion limt" value
441 -S <number> sets the stack size, where <number> is in megabytes
442
443 The -S option isn't available for Windows.
444
445
446 Version 6.6 06-Feb-06
447 ---------------------
448
449 1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
450 in pcreposix.h. I have copied the definition from pcre.h.
451
452 2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
453 because pcre.h is no longer a built file.
454
455 3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
456 not normally included in the compiled code.
457
458
459 Version 6.5 01-Feb-06
460 ---------------------
461
462 1. When using the partial match feature with pcre_dfa_exec(), it was not
463 anchoring the second and subsequent partial matches at the new starting
464 point. This could lead to incorrect results. For example, with the pattern
465 /1234/, partially matching against "123" and then "a4" gave a match.
466
467 2. Changes to pcregrep:
468
469 (a) All non-match returns from pcre_exec() were being treated as failures
470 to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
471 error message is output. Some extra information is given for the
472 PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
473 probably the only errors that are likely to be caused by users (by
474 specifying a regex that has nested indefinite repeats, for instance).
475 If there are more than 20 of these errors, pcregrep is abandoned.
476
477 (b) A binary zero was treated as data while matching, but terminated the
478 output line if it was written out. This has been fixed: binary zeroes
479 are now no different to any other data bytes.
480
481 (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
482 used to set a locale for matching. The --locale=xxxx long option has
483 been added (no short equivalent) to specify a locale explicitly on the
484 pcregrep command, overriding the environment variables.
485
486 (d) When -B was used with -n, some line numbers in the output were one less
487 than they should have been.
488
489 (e) Added the -o (--only-matching) option.
490
491 (f) If -A or -C was used with -c (count only), some lines of context were
492 accidentally printed for the final match.
493
494 (g) Added the -H (--with-filename) option.
495
496 (h) The combination of options -rh failed to suppress file names for files
497 that were found from directory arguments.
498
499 (i) Added the -D (--devices) and -d (--directories) options.
500
501 (j) Added the -F (--fixed-strings) option.
502
503 (k) Allow "-" to be used as a file name for -f as well as for a data file.
504
505 (l) Added the --colo(u)r option.
506
507 (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
508 is not present by default.
509
510 3. A nasty bug was discovered in the handling of recursive patterns, that is,
511 items such as (?R) or (?1), when the recursion could match a number of
512 alternatives. If it matched one of the alternatives, but subsequently,
513 outside the recursion, there was a failure, the code tried to back up into
514 the recursion. However, because of the way PCRE is implemented, this is not
515 possible, and the result was an incorrect result from the match.
516
517 In order to prevent this happening, the specification of recursion has
518 been changed so that all such subpatterns are automatically treated as
519 atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
520
521 4. I had overlooked the fact that, in some locales, there are characters for
522 which isalpha() is true but neither isupper() nor islower() are true. In
523 the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
524 and ordfeminine) are like this. This affected the treatment of \w and \W
525 when they appeared in character classes, but not when they appeared outside
526 a character class. The bit map for "word" characters is now created
527 separately from the results of isalnum() instead of just taking it from the
528 upper, lower, and digit maps. (Plus the underscore character, of course.)
529
530 5. The above bug also affected the handling of POSIX character classes such as
531 [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
532 permanent tables. Instead, the bit maps for such a class were previously
533 created as the appropriate unions of the upper, lower, and digit bitmaps.
534 Now they are created by subtraction from the [[:word:]] class, which has
535 its own bitmap.
536
537 6. The [[:blank:]] character class matches horizontal, but not vertical space.
538 It is created by subtracting the vertical space characters (\x09, \x0a,
539 \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
540 subtraction was done in the overall bitmap for a character class, meaning
541 that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
542 be recognized. This bug has been fixed.
543
544 7. Patches from the folks at Google:
545
546 (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
547 real life, but is still worth protecting against".
548
549 (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
550 regular expressions".
551
552 (c) pcre_scanner.cc: avoid use of std::count() because not all systems
553 have it.
554
555 (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
556 "configure" and the latter not, in order to fix a problem somebody had
557 with compiling the Arg class on HP-UX.
558
559 (e) Improve the error-handling of the C++ wrapper a little bit.
560
561 (f) New tests for checking recursion limiting.
562
563 8. The pcre_memmove() function, which is used only if the environment does not
564 have a standard memmove() function (and is therefore rarely compiled),
565 contained two bugs: (a) use of int instead of size_t, and (b) it was not
566 returning a result (though PCRE never actually uses the result).
567
568 9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
569 large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
570 returned instead of calling malloc() with an overflowing number that would
571 most likely cause subsequent chaos.
572
573 10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
574
575 11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
576 with this option is matched, the nmatch and pmatch options of regexec() are
577 ignored.
578
579 12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
580 provided in case anyone wants to the the POSIX interface with UTF-8
581 strings.
582
583 13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
584 C++ linking (needed for some HP-UX environments).
585
586 14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
587 (unused parameter) and in the pcre_printint() function (omitted "default"
588 switch label when the default is to do nothing).
589
590 15. Added some code to make it possible, when PCRE is compiled as a C++
591 library, to replace subject pointers for pcre_exec() with a smart pointer
592 class, thus making it possible to process discontinuous strings.
593
594 16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
595 much the same function. They were added by different people who were trying
596 to make PCRE easy to compile on non-Unix systems. It has been suggested
597 that PCRE_EXPORT be abolished now that there is more automatic apparatus
598 for compiling on Windows systems. I have therefore replaced it with
599 PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
600 defaults to "extern" for C or "extern C" for C++, which works fine on
601 Unix-like systems. It is now possible to override the value of PCRE_DATA_
602 SCOPE with something explicit in config.h. In addition:
603
604 (a) pcreposix.h still had just "extern" instead of either of these macros;
605 I have replaced it with PCRE_DATA_SCOPE.
606
607 (b) Functions such as _pcre_xclass(), which are internal to the library,
608 but external in the C sense, all had PCRE_EXPORT in their definitions.
609 This is apparently wrong for the Windows case, so I have removed it.
610 (It makes no difference on Unix-like systems.)
611
612 17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
613 of recursive calls to match(). This is different to MATCH_LIMIT because
614 that limits the total number of calls to match(), not all of which increase
615 the depth of recursion. Limiting the recursion depth limits the amount of
616 stack (or heap if NO_RECURSE is set) that is used. The default can be set
617 when PCRE is compiled, and changed at run time. A patch from Google adds
618 this functionality to the C++ interface.
619
620 18. Changes to the handling of Unicode character properties:
621
622 (a) Updated the table to Unicode 4.1.0.
623
624 (b) Recognize characters that are not in the table as "Cn" (undefined).
625
626 (c) I revised the way the table is implemented to a much improved format
627 which includes recognition of ranges. It now supports the ranges that
628 are defined in UnicodeData.txt, and it also amalgamates other
629 characters into ranges. This has reduced the number of entries in the
630 table from around 16,000 to around 3,000, thus reducing its size
631 considerably. I realized I did not need to use a tree structure after
632 all - a binary chop search is just as efficient. Having reduced the
633 number of entries, I extended their size from 6 bytes to 8 bytes to
634 allow for more data.
635
636 (d) Added support for Unicode script names via properties such as \p{Han}.
637
638 19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
639 matching that character.
640
641 20. When matching a repeated Unicode property with a minimum greater than zero,
642 (for example \pL{2,}), PCRE could look past the end of the subject if it
643 reached it while seeking the minimum number of characters. This could
644 happen only if some of the characters were more than one byte long, because
645 there is a check for at least the minimum number of bytes.
646
647 21. Refactored the implementation of \p and \P so as to be more general, to
648 allow for more different types of property in future. This has changed the
649 compiled form incompatibly. Anybody with saved compiled patterns that use
650 \p or \P will have to recompile them.
651
652 22. Added "Any" and "L&" to the supported property types.
653
654 23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
655 but give a compile time error if the value is greater than 0xff.
656
657 24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
658 accidentally not being installed or uninstalled.
659
660 25. The pcre.h file was built from pcre.h.in, but the only changes that were
661 made were to insert the current release number. This seemed silly, because
662 it made things harder for people building PCRE on systems that don't run
663 "configure". I have turned pcre.h into a distributed file, no longer built
664 by "configure", with the version identification directly included. There is
665 no longer a pcre.h.in file.
666
667 However, this change necessitated a change to the pcre-config script as
668 well. It is built from pcre-config.in, and one of the substitutions was the
669 release number. I have updated configure.ac so that ./configure now finds
670 the release number by grepping pcre.h.
671
672 26. Added the ability to run the tests under valgrind.
673
674
675 Version 6.4 05-Sep-05
676 ---------------------
677
678 1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
679 "--" to be printed when multiple files were scanned, even when none of the
680 -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
681 consider it to be a bug, and have restored the previous behaviour.
682
683 2. A couple of code tidies to get rid of compiler warnings.
684
685 3. The pcretest program used to cheat by referring to symbols in the library
686 whose names begin with _pcre_. These are internal symbols that are not
687 really supposed to be visible externally, and in some environments it is
688 possible to suppress them. The cheating is now confined to including
689 certain files from the library's source, which is a bit cleaner.
690
691 4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
692 file's purpose clearer.
693
694 5. Reorganized pcre_ucp_findchar().
695
696
697 Version 6.3 15-Aug-05
698 ---------------------
699
700 1. The file libpcre.pc.in did not have general read permission in the tarball.
701
702 2. There were some problems when building without C++ support:
703
704 (a) If C++ support was not built, "make install" and "make test" still
705 tried to test it.
706
707 (b) There were problems when the value of CXX was explicitly set. Some
708 changes have been made to try to fix these, and ...
709
710 (c) --disable-cpp can now be used to explicitly disable C++ support.
711
712 (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
713 backslash in a target when C++ was disabled. This confuses some
714 versions of "make", apparently. Using an intermediate variable solves
715 this. (Same for CPP_LOBJ.)
716
717 3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
718 (non-Windows) now includes $(CFLAGS) because these flags are sometimes
719 necessary on certain architectures.
720
721 4. Added a setting of -export-symbols-regex to the link command to remove
722 those symbols that are exported in the C sense, but actually are local
723 within the library, and not documented. Their names all begin with
724 "_pcre_". This is not a perfect job, because (a) we have to except some
725 symbols that pcretest ("illegally") uses, and (b) the facility isn't always
726 available (and never for static libraries). I have made a note to try to
727 find a way round (a) in the future.
728
729
730 Version 6.2 01-Aug-05
731 ---------------------
732
733 1. There was no test for integer overflow of quantifier values. A construction
734 such as {1111111111111111} would give undefined results. What is worse, if
735 a minimum quantifier for a parenthesized subpattern overflowed and became
736 negative, the calculation of the memory size went wrong. This could have
737 led to memory overwriting.
738
739 2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
740
741 3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
742 operating environments where this matters.
743
744 4. Applied Giuseppe Maxia's patch to add additional features for controlling
745 PCRE options from within the C++ wrapper.
746
747 5. Named capturing subpatterns were not being correctly counted when a pattern
748 was compiled. This caused two problems: (a) If there were more than 100
749 such subpatterns, the calculation of the memory needed for the whole
750 compiled pattern went wrong, leading to an overflow error. (b) Numerical
751 back references of the form \12, where the number was greater than 9, were
752 not recognized as back references, even though there were sufficient
753 previous subpatterns.
754
755 6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
756 versions of gcc, e.g. 2.95.4.
757
758
759 Version 6.1 21-Jun-05
760 ---------------------
761
762 1. There was one reference to the variable "posix" in pcretest.c that was not
763 surrounded by "#if !defined NOPOSIX".
764
765 2. Make it possible to compile pcretest without DFA support, UTF8 support, or
766 the cross-check on the old pcre_info() function, for the benefit of the
767 cut-down version of PCRE that is currently imported into Exim.
768
769 3. A (silly) pattern starting with (?i)(?-i) caused an internal space
770 allocation error. I've done the easy fix, which wastes 2 bytes for sensible
771 patterns that start (?i) but I don't think that matters. The use of (?i) is
772 just an example; this all applies to the other options as well.
773
774 4. Since libtool seems to echo the compile commands it is issuing, the output
775 from "make" can be reduced a bit by putting "@" in front of each libtool
776 compile command.
777
778 5. Patch from the folks at Google for configure.in to be a bit more thorough
779 in checking for a suitable C++ installation before trying to compile the
780 C++ stuff. This should fix a reported problem when a compiler was present,
781 but no suitable headers.
782
783 6. The man pages all had just "PCRE" as their title. I have changed them to
784 be the relevant file name. I have also arranged that these names are
785 retained in the file doc/pcre.txt, which is a concatenation in text format
786 of all the man pages except the little individual ones for each function.
787
788 7. The NON-UNIX-USE file had not been updated for the different set of source
789 files that come with release 6. I also added a few comments about the C++
790 wrapper.
791
792
793 Version 6.0 07-Jun-05
794 ---------------------
795
796 1. Some minor internal re-organization to help with my DFA experiments.
797
798 2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
799 didn't matter for the library itself when fully configured, but did matter
800 when compiling without UCP support, or within Exim, where the ucp files are
801 not imported.
802
803 3. Refactoring of the library code to split up the various functions into
804 different source modules. The addition of the new DFA matching code (see
805 below) to a single monolithic source would have made it really too
806 unwieldy, quite apart from causing all the code to be include in a
807 statically linked application, when only some functions are used. This is
808 relevant even without the DFA addition now that patterns can be compiled in
809 one application and matched in another.
810
811 The downside of splitting up is that there have to be some external
812 functions and data tables that are used internally in different modules of
813 the library but which are not part of the API. These have all had their
814 names changed to start with "_pcre_" so that they are unlikely to clash
815 with other external names.
816
817 4. Added an alternate matching function, pcre_dfa_exec(), which matches using
818 a different (DFA) algorithm. Although it is slower than the original
819 function, it does have some advantages for certain types of matching
820 problem.
821
822 5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
823 including restarting after a partial match.
824
825 6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
826 defined when compiling for Windows was sent to me. I have put it into the
827 code, though I have no means of testing or verifying it.
828
829 7. Added the pcre_refcount() auxiliary function.
830
831 8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
832 match before or at the first newline in the subject string. In pcretest,
833 the /f option on a pattern can be used to set this.
834
835 9. A repeated \w when used in UTF-8 mode with characters greater than 256
836 would behave wrongly. This has been present in PCRE since release 4.0.
837
838 10. A number of changes to the pcregrep command:
839
840 (a) Refactored how -x works; insert ^(...)$ instead of setting
841 PCRE_ANCHORED and checking the length, in preparation for adding
842 something similar for -w.
843
844 (b) Added the -w (match as a word) option.
845
846 (c) Refactored the way lines are read and buffered so as to have more
847 than one at a time available.
848
849 (d) Implemented a pcregrep test script.
850
851 (e) Added the -M (multiline match) option. This allows patterns to match
852 over several lines of the subject. The buffering ensures that at least
853 8K, or the rest of the document (whichever is the shorter) is available
854 for matching (and similarly the previous 8K for lookbehind assertions).
855
856 (f) Changed the --help output so that it now says
857
858 -w, --word-regex(p)
859
860 instead of two lines, one with "regex" and the other with "regexp"
861 because that confused at least one person since the short forms are the
862 same. (This required a bit of code, as the output is generated
863 automatically from a table. It wasn't just a text change.)
864
865 (g) -- can be used to terminate pcregrep options if the next thing isn't an
866 option but starts with a hyphen. Could be a pattern or a path name
867 starting with a hyphen, for instance.
868
869 (h) "-" can be given as a file name to represent stdin.
870
871 (i) When file names are being printed, "(standard input)" is used for
872 the standard input, for compatibility with GNU grep. Previously
873 "<stdin>" was used.
874
875 (j) The option --label=xxx can be used to supply a name to be used for
876 stdin when file names are being printed. There is no short form.
877
878 (k) Re-factored the options decoding logic because we are going to add
879 two more options that take data. Such options can now be given in four
880 different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
881
882 (l) Added the -A, -B, and -C options for requesting that lines of context
883 around matches be printed.
884
885 (m) Added the -L option to print the names of files that do not contain
886 any matching lines, that is, the complement of -l.
887
888 (n) The return code is 2 if any file cannot be opened, but pcregrep does
889 continue to scan other files.
890
891 (o) The -s option was incorrectly implemented. For compatibility with other
892 greps, it now suppresses the error message for a non-existent or non-
893 accessible file (but not the return code). There is a new option called
894 -q that suppresses the output of matching lines, which was what -s was
895 previously doing.
896
897 (p) Added --include and --exclude options to specify files for inclusion
898 and exclusion when recursing.
899
900 11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
901 Hopefully, it now does.
902
903 12. Missing cast in pcre_study().
904
905 13. Added an "uninstall" target to the makefile.
906
907 14. Replaced "extern" in the function prototypes in Makefile.in with
908 "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
909 world, but is set differently for Windows.
910
911 15. Added a second compiling function called pcre_compile2(). The only
912 difference is that it has an extra argument, which is a pointer to an
913 integer error code. When there is a compile-time failure, this is set
914 non-zero, in addition to the error test pointer being set to point to an
915 error message. The new argument may be NULL if no error number is required
916 (but then you may as well call pcre_compile(), which is now just a
917 wrapper). This facility is provided because some applications need a
918 numeric error indication, but it has also enabled me to tidy up the way
919 compile-time errors are handled in the POSIX wrapper.
920
921 16. Added VPATH=.libs to the makefile; this should help when building with one
922 prefix path and installing with another. (Or so I'm told by someone who
923 knows more about this stuff than I do.)
924
925 17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
926 passes PCRE_DOTALL to the pcre_compile() function, making the "." character
927 match everything, including newlines. This is not POSIX-compatible, but
928 somebody wanted the feature. From pcretest it can be activated by using
929 both the P and the s flags.
930
931 18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
932
933 19. libpcre.pc was being incorrectly installed as executable.
934
935 20. A couple of places in pcretest check for end-of-line by looking for '\n';
936 it now also looks for '\r' so that it will work unmodified on Windows.
937
938 21. Added Google's contributed C++ wrapper to the distribution.
939
940 22. Added some untidy missing memory free() calls in pcretest, to keep
941 Electric Fence happy when testing.
942
943
944
945 Version 5.0 13-Sep-04
946 ---------------------
947
948 1. Internal change: literal characters are no longer packed up into items
949 containing multiple characters in a single byte-string. Each character
950 is now matched using a separate opcode. However, there may be more than one
951 byte in the character in UTF-8 mode.
952
953 2. The pcre_callout_block structure has two new fields: pattern_position and
954 next_item_length. These contain the offset in the pattern to the next match
955 item, and its length, respectively.
956
957 3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
958 insertion of callouts before each pattern item. Added the /C option to
959 pcretest to make use of this.
960
961 4. On the advice of a Windows user, the lines
962
963 #if defined(_WIN32) || defined(WIN32)
964 _setmode( _fileno( stdout ), 0x8000 );
965 #endif /* defined(_WIN32) || defined(WIN32) */
966
967 have been added to the source of pcretest. This apparently does useful
968 magic in relation to line terminators.
969
970 5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
971 for the benefit of those environments where the "b" makes a difference.
972
973 6. The icc compiler has the same options as gcc, but "configure" doesn't seem
974 to know about it. I have put a hack into configure.in that adds in code
975 to set GCC=yes if CC=icc. This seems to end up at a point in the
976 generated configure script that is early enough to affect the setting of
977 compiler options, which is what is needed, but I have no means of testing
978 whether it really works. (The user who reported this had patched the
979 generated configure script, which of course I cannot do.)
980
981 LATER: After change 22 below (new libtool files), the configure script
982 seems to know about icc (and also ecc). Therefore, I have commented out
983 this hack in configure.in.
984
985 7. Added support for pkg-config (2 patches were sent in).
986
987 8. Negated POSIX character classes that used a combination of internal tables
988 were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
989 [[:^ascii]]. Typically, they would match almost any characters. The other
990 POSIX classes were not broken in this way.
991
992 9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
993 to find the match, as PCRE was deluded into thinking that the match had to
994 start at the start point or following a newline. The same bug applied to
995 patterns with negative forward assertions or any backward assertions
996 preceding ".*" at the start, unless the pattern required a fixed first
997 character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
998
999 10. In UTF-8 mode, when moving forwards in the subject after a failed match
1000 starting at the last subject character, bytes beyond the end of the subject
1001 string were read.
1002
1003 11. Renamed the variable "class" as "classbits" to make life easier for C++
1004 users. (Previously there was a macro definition, but it apparently wasn't
1005 enough.)
1006
1007 12. Added the new field "tables" to the extra data so that tables can be passed
1008 in at exec time, or the internal tables can be re-selected. This allows
1009 a compiled regex to be saved and re-used at a later time by a different
1010 program that might have everything at different addresses.
1011
1012 13. Modified the pcre-config script so that, when run on Solaris, it shows a
1013 -R library as well as a -L library.
1014
1015 14. The debugging options of pcretest (-d on the command line or D on a
1016 pattern) showed incorrect output for anything following an extended class
1017 that contained multibyte characters and which was followed by a quantifier.
1018
1019 15. Added optional support for general category Unicode character properties
1020 via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1021 support. It adds about 90K to the size of the library. The meanings of the
1022 inbuilt class escapes such as \d and \s have NOT been changed.
1023
1024 16. Updated pcredemo.c to include calls to free() to release the memory for the
1025 compiled pattern.
1026
1027 17. The generated file chartables.c was being created in the source directory
1028 instead of in the building directory. This caused the build to fail if the
1029 source directory was different from the building directory, and was
1030 read-only.
1031
1032 18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1033 file. No doubt somebody will tell me if they don't make sense... Also added
1034 Dan Mooney's comments about building on OpenVMS.
1035
1036 19. Added support for partial matching via the PCRE_PARTIAL option for
1037 pcre_exec() and the \P data escape in pcretest.
1038
1039 20. Extended pcretest with 3 new pattern features:
1040
1041 (i) A pattern option of the form ">rest-of-line" causes pcretest to
1042 write the compiled pattern to the file whose name is "rest-of-line".
1043 This is a straight binary dump of the data, with the saved pointer to
1044 the character tables forced to be NULL. The study data, if any, is
1045 written too. After writing, pcretest reads a new pattern.
1046
1047 (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1048 compiled pattern from the given file. There must not be any
1049 occurrences of "<" in the file name (pretty unlikely); if there are,
1050 pcretest will instead treat the initial "<" as a pattern delimiter.
1051 After reading in the pattern, pcretest goes on to read data lines as
1052 usual.
1053
1054 (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1055 and 16-bit fields in a compiled pattern, to simulate a pattern that
1056 was compiled on a host of opposite endianness.
1057
1058 21. The pcre-exec() function can now cope with patterns that were compiled on
1059 hosts of opposite endianness, with this restriction:
1060
1061 As for any compiled expression that is saved and used later, the tables
1062 pointer field cannot be preserved; the extra_data field in the arguments
1063 to pcre_exec() should be used to pass in a tables address if a value
1064 other than the default internal tables were used at compile time.
1065
1066 22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1067 now diagnosed as an error. Previously, most of the time, a negative number
1068 would have been treated as zero, but if in addition "ovector" was passed as
1069 NULL, a crash could occur.
1070
1071 23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1072 new versions from the libtool 1.5 distribution (the last one is a copy of
1073 a file called libtool.m4). This seems to have fixed the need to patch
1074 "configure" to support Darwin 1.3 (which I used to do). However, I still
1075 had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1076 workstation).
1077
1078 24. Changed the PCRE licence to be the more standard "BSD" licence.
1079
1080
1081 Version 4.5 01-Dec-03
1082 ---------------------
1083
1084 1. There has been some re-arrangement of the code for the match() function so
1085 that it can be compiled in a version that does not call itself recursively.
1086 Instead, it keeps those local variables that need separate instances for
1087 each "recursion" in a frame on the heap, and gets/frees frames whenever it
1088 needs to "recurse". Keeping track of where control must go is done by means
1089 of setjmp/longjmp. The whole thing is implemented by a set of macros that
1090 hide most of the details from the main code, and operates only if
1091 NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1092 "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1093 operating.
1094
1095 To make it easier for callers to provide specially tailored get/free
1096 functions for this usage, two new functions, pcre_stack_malloc, and
1097 pcre_stack_free, are used. They are always called in strict stacking order,
1098 and the size of block requested is always the same.
1099
1100 The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1101 PCRE has been compiled to use the stack or the heap for recursion. The
1102 -C option of pcretest uses this to show which version is compiled.
1103
1104 A new data escape \S, is added to pcretest; it causes the amounts of store
1105 obtained and freed by both kinds of malloc/free at match time to be added
1106 to the output.
1107
1108 2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1109 what's available on my current Linux desktop machine.
1110
1111 3. When matching a UTF-8 string, the test for a valid string at the start has
1112 been extended. If start_offset is not zero, PCRE now checks that it points
1113 to a byte that is the start of a UTF-8 character. If not, it returns
1114 PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1115 this is necessary because there may be backward assertions in the pattern.
1116 When matching the same subject several times, it may save resources to use
1117 PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1118
1119 4. The code for checking the validity of UTF-8 strings has been tightened so
1120 that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1121 containing "overlong sequences".
1122
1123 5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1124 I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1125 should have been "&", but it just so happened that all the cases this let
1126 through by mistake were picked up later in the function.
1127
1128 6. I had used a variable called "isblank" - this is a C99 function, causing
1129 some compilers to warn. To avoid this, I renamed it (as "blankclass").
1130
1131 7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1132 prompting; (b) run "./pcretest /dev/null" at the start of the test script
1133 so the version is shown; (c) stop "make test" echoing "./RunTest".
1134
1135 8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1136
1137 9. The prototype for memmove() for systems that don't have it was using
1138 size_t, but the inclusion of the header that defines size_t was later. I've
1139 moved the #includes for the C headers earlier to avoid this.
1140
1141 10. Added some adjustments to the code to make it easier to compiler on certain
1142 special systems:
1143
1144 (a) Some "const" qualifiers were missing.
1145 (b) Added the macro EXPORT before all exported functions; by default this
1146 is defined to be empty.
1147 (c) Changed the dftables auxiliary program (that builds chartables.c) so
1148 that it reads its output file name as an argument instead of writing
1149 to the standard output and assuming this can be redirected.
1150
1151 11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1152 class containing characters with values greater than 255, PCRE compilation
1153 went into a loop.
1154
1155 12. A recursive reference to a subpattern that was within another subpattern
1156 that had a minimum quantifier of zero caused PCRE to crash. For example,
1157 (x(y(?2))z)? provoked this bug with a subject that got as far as the
1158 recursion. If the recursively-called subpattern itself had a zero repeat,
1159 that was OK.
1160
1161 13. In pcretest, the buffer for reading a data line was set at 30K, but the
1162 buffer into which it was copied (for escape processing) was still set at
1163 1024, so long lines caused crashes.
1164
1165 14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1166 "internal error: code overflow...". This applied to any character class
1167 that was followed by a possessive quantifier.
1168
1169 15. Modified the Makefile to add libpcre.la as a prerequisite for
1170 libpcreposix.la because I was told this is needed for a parallel build to
1171 work.
1172
1173 16. If a pattern that contained .* following optional items at the start was
1174 studied, the wrong optimizing data was generated, leading to matching
1175 errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1176 matching string must start with a or b or c. The correct conclusion for
1177 this pattern is that a match can start with any character.
1178
1179
1180 Version 4.4 13-Aug-03
1181 ---------------------
1182
1183 1. In UTF-8 mode, a character class containing characters with values between
1184 127 and 255 was not handled correctly if the compiled pattern was studied.
1185 In fixing this, I have also improved the studying algorithm for such
1186 classes (slightly).
1187
1188 2. Three internal functions had redundant arguments passed to them. Removal
1189 might give a very teeny performance improvement.
1190
1191 3. Documentation bug: the value of the capture_top field in a callout is *one
1192 more than* the number of the hightest numbered captured substring.
1193
1194 4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1195 in incorrectly linking with a previously installed version. They now link
1196 explicitly with libpcre.la.
1197
1198 5. configure.in no longer needs to recognize Cygwin specially.
1199
1200 6. A problem in pcre.in for Windows platforms is fixed.
1201
1202 7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1203 pcretest, it used to include the size of the study block as part of its
1204 output. Unfortunately, the structure contains a field that has a different
1205 size on different hardware architectures. This meant that the tests that
1206 showed this size failed. As the block is currently always of a fixed size,
1207 this information isn't actually particularly useful in pcretest output, so
1208 I have just removed it.
1209
1210 8. Three pre-processor statements accidentally did not start in column 1.
1211 Sadly, there are *still* compilers around that complain, even though
1212 standard C has not required this for well over a decade. Sigh.
1213
1214 9. In pcretest, the code for checking callouts passed small integers in the
1215 callout_data field, which is a void * field. However, some picky compilers
1216 complained about the casts involved for this on 64-bit systems. Now
1217 pcretest passes the address of the small integer instead, which should get
1218 rid of the warnings.
1219
1220 10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1221 both compile and run time, and gives an error if an invalid UTF-8 sequence
1222 is found. There is a option for disabling this check in cases where the
1223 string is known to be correct and/or the maximum performance is wanted.
1224
1225 11. In response to a bug report, I changed one line in Makefile.in from
1226
1227 -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1228 to
1229 -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1230
1231 to look similar to other lines, but I have no way of telling whether this
1232 is the right thing to do, as I do not use Windows. No doubt I'll get told
1233 if it's wrong...
1234
1235
1236 Version 4.3 21-May-03
1237 ---------------------
1238
1239 1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1240 Makefile.
1241
1242 2. Some refactoring to improve the quality of the code:
1243
1244 (i) The utf8_table... variables are now declared "const".
1245
1246 (ii) The code for \cx, which used the "case flipping" table to upper case
1247 lower case letters, now just substracts 32. This is ASCII-specific,
1248 but the whole concept of \cx is ASCII-specific, so it seems
1249 reasonable.
1250
1251 (iii) PCRE was using its character types table to recognize decimal and
1252 hexadecimal digits in the pattern. This is silly, because it handles
1253 only 0-9, a-f, and A-F, but the character types table is locale-
1254 specific, which means strange things might happen. A private
1255 table is now used for this - though it costs 256 bytes, a table is
1256 much faster than multiple explicit tests. Of course, the standard
1257 character types table is still used for matching digits in subject
1258 strings against \d.
1259
1260 (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1261 ending in _t are). So I've renamed it as ESC_tee.
1262
1263 3. The first argument for regexec() in the POSIX wrapper should have been
1264 defined as "const".
1265
1266 4. Changed pcretest to use malloc() for its buffers so that they can be
1267 Electric Fenced for debugging.
1268
1269 5. There were several places in the code where, in UTF-8 mode, PCRE would try
1270 to read one or more bytes before the start of the subject string. Often this
1271 had no effect on PCRE's behaviour, but in some circumstances it could
1272 provoke a segmentation fault.
1273
1274 6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1275 to try to read one or more bytes before the start of the subject string.
1276
1277 7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1278 UTF-8 support could misbehave in various ways if the subject string
1279 contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1280 area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1281 back over UTF-8 characters.)
1282
1283
1284 Version 4.2 14-Apr-03
1285 ---------------------
1286
1287 1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1288
1289 2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1290 [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1291 [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1292 [WIN_PREFIX]: new variable, "cyg" for Cygwin
1293 * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1294 and BUILD_EXEEXT
1295 Note: automatic setting of the BUILD variables is not yet working
1296 set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1297 compile-time but not at link-time
1298 [LINK]: use for linking executables only
1299 make different versions for Windows and non-Windows
1300 [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1301 libraries
1302 [LINK_FOR_BUILD]: new variable
1303 [OBJEXT]: use throughout
1304 [EXEEXT]: use throughout
1305 <winshared>: new target
1306 <wininstall>: new target
1307 <dftables.o>: use native compiler
1308 <dftables>: use native linker
1309 <install>: handle Windows platform correctly
1310 <clean>: ditto
1311 <check>: ditto
1312 copy DLL to top builddir before testing
1313
1314 As part of these changes, -no-undefined was removed again. This was reported
1315 to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1316 in any case.
1317
1318 3. Some tidies to get rid of compiler warnings:
1319
1320 . In the match_data structure, match_limit was an unsigned long int, whereas
1321 match_call_count was an int. I've made them both unsigned long ints.
1322
1323 . In pcretest the fact that a const uschar * doesn't automatically cast to
1324 a void * provoked a warning.
1325
1326 . Turning on some more compiler warnings threw up some "shadow" variables
1327 and a few more missing casts.
1328
1329 4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1330 option, a class that contained a single character with a value between 128
1331 and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1332
1333 5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1334 option, a class that contained several characters, but with at least one
1335 whose value was between 128 and 255 caused PCRE to crash.
1336
1337
1338 Version 4.1 12-Mar-03
1339 ---------------------
1340
1341 1. Compiling with gcc -pedantic found a couple of places where casts were
1342 needed, and a string in dftables.c that was longer than standard compilers are
1343 required to support.
1344
1345 2. Compiling with Sun's compiler found a few more places where the code could
1346 be tidied up in order to avoid warnings.
1347
1348 3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1349 first of these names is deprecated in the latest Autoconf in favour of the name
1350 CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1351 compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1352 analogy I have changed it to CFLAGS_FOR_BUILD.
1353
1354 4. Added -no-undefined to the linking command in the Makefile, because this is
1355 apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1356 linking step for the pcreposix library.
1357
1358 5. PCRE was failing to diagnose the case of two named groups with the same
1359 name.
1360
1361 6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1362 literal character that is needed in the subject for a match, and scans along to
1363 ensure that it is present before embarking on the full matching process. This
1364 saves time in cases of nested unlimited repeats that are never going to match.
1365 Problem: the scan can take a lot of time if the subject is very long (e.g.
1366 megabytes), thus penalizing straightforward matches. It is now done only if the
1367 amount of subject to be scanned is less than 1000 bytes.
1368
1369 7. A lesser problem with the same optimization is that it was recording the
1370 first character of an anchored pattern as "needed", thus provoking a search
1371 right along the subject, even when the first match of the pattern was going to
1372 fail. The "needed" character is now not set for anchored patterns, unless it
1373 follows something in the pattern that is of non-fixed length. Thus, it still
1374 fulfils its original purpose of finding quick non-matches in cases of nested
1375 unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1376
1377
1378 Version 4.0 17-Feb-03
1379 ---------------------
1380
1381 1. If a comment in an extended regex that started immediately after a meta-item
1382 extended to the end of string, PCRE compiled incorrect data. This could lead to
1383 all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1384
1385 2. Moved to autoconf 2.53 and libtool 1.4.2.
1386
1387 3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1388 the special perltest8 script is no longer needed - all the tests can be run
1389 from a single perltest script.
1390
1391 4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1392 by \s. It has now been removed in PCRE. This means it isn't recognized as
1393 whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1394 class [:space:] *does* include VT, thereby creating a mess.
1395
1396 5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1397 space and tab.
1398
1399 6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1400 its new features into the main test script, reducing the number of scripts.
1401
1402 7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1403 were backward compatible, and made the (?i) apply to the whole pattern, as if
1404 /i were given. Now it behaves more logically, and applies the option setting
1405 only to what follows. PCRE has been changed to follow suit. However, if it
1406 finds options settings right at the start of the pattern, it extracts them into
1407 the global options, as before. Thus, they show up in the info data.
1408
1409 8. Added support for the \Q...\E escape sequence. Characters in between are
1410 treated as literals. This is slightly different from Perl in that $ and @ are
1411 also handled as literals inside the quotes. In Perl, they will cause variable
1412 interpolation. Note the following examples:
1413
1414 Pattern PCRE matches Perl matches
1415
1416 \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1417 \Qabc\$xyz\E abc\$xyz abc\$xyz
1418 \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1419
1420 For compatibility with Perl, \Q...\E sequences are recognized inside character
1421 classes as well as outside them.
1422
1423 9. Re-organized 3 code statements in pcretest to avoid "overflow in
1424 floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1425 (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1426 signed/unsigned warnings.
1427
1428 10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1429 option for pcretest, so I've replaced it by a simple function that does just
1430 that job.
1431
1432 11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1433 "pcregrep -".
1434
1435 12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1436 Java package. This provides some syntactic sugar for simple cases of what my
1437 documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1438 as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1439 item, you can use this simplified notation. Note that only makes sense with
1440 greedy quantifiers. Consequently, the use of the possessive quantifier forces
1441 greediness, whatever the setting of the PCRE_UNGREEDY option.
1442
1443 13. A change of greediness default within a pattern was not taking effect at
1444 the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1445 subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1446 was abstracted outside.
1447
1448 14. PCRE now supports the \G assertion. It is true when the current matching
1449 position is at the start point of the match. This differs from \A when the
1450 starting offset is non-zero. Used with the /g option of pcretest (or similar
1451 code), it works in the same way as it does for Perl's /g option. If all
1452 alternatives of a regex begin with \G, the expression is anchored to the start
1453 match position, and the "anchored" flag is set in the compiled expression.
1454
1455 15. Some bugs concerning the handling of certain option changes within patterns
1456 have been fixed. These applied to options other than (?ims). For example,
1457 "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1458 been the other way round. Some of this was related to change 7 above.
1459
1460 16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1461 features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1462 and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1463 POSIX classes only within a class (e.g. /[[:alpha:]]/).
1464
1465 17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1466 mode. Unlike ".", it always matches newline, whatever the setting of
1467 PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1468 assertions. Perl allows it, but it doesn't (in general) work because it can't
1469 calculate the length of the lookbehind. At least, that's the case for Perl
1470 5.8.0 - I've been told they are going to document that it doesn't work in
1471 future.
1472
1473 18. Added an error diagnosis for escapes that PCRE does not support: these are
1474 \L, \l, \N, \P, \p, \U, \u, and \X.
1475
1476 19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1477 reading past the end of the pattern in cases such as /[abcd/.
1478
1479 20. PCRE was getting more memory than necessary for patterns with classes that
1480 contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1481
1482 21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1483 compiling PCRE for use with Virtual Pascal.
1484
1485 22. Small fix to the Makefile to make it work properly if the build is done
1486 outside the source tree.
1487
1488 23. Added a new extension: a condition to go with recursion. If a conditional
1489 subpattern starts with (?(R) the "true" branch is used if recursion has
1490 happened, whereas the "false" branch is used only at the top level.
1491
1492 24. When there was a very long string of literal characters (over 255 bytes
1493 without UTF support, over 250 bytes with UTF support), the computation of how
1494 much memory was required could be incorrect, leading to segfaults or other
1495 strange effects.
1496
1497 25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1498 start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1499 there was a subsequent back reference to those brackets. This meant that, for
1500 example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1501 possible to check for precisely this case. All we can do is abandon the
1502 optimization if .* occurs inside capturing brackets when there are any back
1503 references whatsoever. (See below for a better fix that came later.)
1504
1505 26. The handling of the optimization for finding the first character of a
1506 non-anchored pattern, and for finding a character that is required later in the
1507 match were failing in some cases. This didn't break the matching; it just
1508 failed to optimize when it could. The way this is done has been re-implemented.
1509
1510 27. Fixed typo in error message for invalid (?R item (it said "(?p").
1511
1512 28. Added a new feature that provides some of the functionality that Perl
1513 provides with (?{...}). The facility is termed a "callout". The way it is done
1514 in PCRE is for the caller to provide an optional function, by setting
1515 pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1516 global variable. By default it is unset, which disables all calling out. To get
1517 the function called, the regex must include (?C) at appropriate points. This
1518 is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1519 This provides a means of identifying different callout points. When PCRE
1520 reaches such a point in the regex, if pcre_callout has been set, the external
1521 function is called. It is provided with data in a structure called
1522 pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1523 matching continues; if it returns a non-zero value, the match at the current
1524 point fails. However, backtracking will occur if possible. [This was changed
1525 later and other features added - see item 49 below.]
1526
1527 29. pcretest is upgraded to test the callout functionality. It provides a
1528 callout function that displays information. By default, it shows the start of
1529 the match and the current position in the text. There are some new data escapes
1530 to vary what happens:
1531
1532 \C+ in addition, show current contents of captured substrings
1533 \C- do not supply a callout function
1534 \C!n return 1 when callout number n is reached
1535 \C!n!m return 1 when callout number n is reached for the mth time
1536
1537 30. If pcregrep was called with the -l option and just a single file name, it
1538 output "<stdin>" if a match was found, instead of the file name.
1539
1540 31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1541 slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1542 pcre_exec(). This saves a malloc/free per call. The default value of
1543 POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1544 when configuring.
1545
1546 32. The default maximum size of a compiled pattern is 64K. There have been a
1547 few cases of people hitting this limit. The code now uses macros to handle the
1548 storing of links as offsets within the compiled pattern. It defaults to 2-byte
1549 links, but this can be changed to 3 or 4 bytes by --with-link-size when
1550 configuring. Tests 2 and 5 work only with 2-byte links because they output
1551 debugging information about compiled patterns.
1552
1553 33. Internal code re-arrangements:
1554
1555 (a) Moved the debugging function for printing out a compiled regex into
1556 its own source file (printint.c) and used #include to pull it into
1557 pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1558 separate copies.
1559
1560 (b) Defined the list of op-code names for debugging as a macro in
1561 internal.h so that it is next to the definition of the opcodes.
1562
1563 (c) Defined a table of op-code lengths for simpler skipping along compiled
1564 code. This is again a macro in internal.h so that it is next to the
1565 definition of the opcodes.
1566
1567 34. Added support for recursive calls to individual subpatterns, along the
1568 lines of Robin Houston's patch (but implemented somewhat differently).
1569
1570 35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1571 allow it to read and process whole directories in Win32. This code was
1572 contributed by Lionel Fourquaux; it has not been tested by me.
1573
1574 36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1575 used to name a group. Names consist of alphanumerics and underscores, and must
1576 be unique. Back references use the syntax (?P=name) and recursive calls use
1577 (?P>name) which is a PCRE extension to the Python extension. Groups still have
1578 numbers. The function pcre_fullinfo() can be used after compilation to extract
1579 a name/number map. There are three relevant calls:
1580
1581 PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1582 PCRE_INFO_NAMECOUNT yields the number of entries
1583 PCRE_INFO_NAMETABLE yields a pointer to the map.
1584
1585 The map is a vector of fixed-size entries. The size of each entry depends on
1586 the length of the longest name used. The first two bytes of each entry are the
1587 group number, most significant byte first. There follows the corresponding
1588 name, zero terminated. The names are in alphabetical order.
1589
1590 37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1591 case instead of 255. Making it the same both with and without UTF-8 support
1592 means that the same test output works with both.
1593
1594 38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1595 calling malloc() with a zero argument.
1596
1597 39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1598 optimization. I've improved things by keeping a bitmap of backreferences with
1599 numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1600 fact referenced, the optimization can be applied. It is unlikely that a
1601 relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1602 the match to follow \n) will appear inside brackets with a number greater than
1603 31, but if it does, any back reference > 31 suppresses the optimization.
1604
1605 40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1606 of disabling numbered capturing parentheses. Any opening parenthesis that is
1607 not followed by ? behaves as if it were followed by ?: but named parentheses
1608 can still be used for capturing (and they will acquire numbers in the usual
1609 way).
1610
1611 41. Redesigned the return codes from the match() function into yes/no/error so
1612 that errors can be passed back from deep inside the nested calls. A malloc
1613 failure while inside a recursive subpattern call now causes the
1614 PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1615
1616 42. It is now possible to set a limit on the number of times the match()
1617 function is called in a call to pcre_exec(). This facility makes it possible to
1618 limit the amount of recursion and backtracking, though not in a directly
1619 obvious way, because the match() function is used in a number of different
1620 circumstances. The count starts from zero for each position in the subject
1621 string (for non-anchored patterns). The default limit is, for compatibility, a
1622 large number, namely 10 000 000. You can change this in two ways:
1623
1624 (a) When configuring PCRE before making, you can use --with-match-limit=n
1625 to set a default value for the compiled library.
1626
1627 (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1628 a different value is set. See 45 below.
1629
1630 If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1631
1632 43. Added a new function pcre_config(int, void *) to enable run-time extraction
1633 of things that can be changed at compile time. The first argument specifies
1634 what is wanted and the second points to where the information is to be placed.
1635 The current list of available information is:
1636
1637 PCRE_CONFIG_UTF8
1638
1639 The output is an integer that is set to one if UTF-8 support is available;
1640 otherwise it is set to zero.
1641
1642 PCRE_CONFIG_NEWLINE
1643
1644 The output is an integer that it set to the value of the code that is used for
1645 newline. It is either LF (10) or CR (13).
1646
1647 PCRE_CONFIG_LINK_SIZE
1648
1649 The output is an integer that contains the number of bytes used for internal
1650 linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1651
1652 PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1653
1654 The output is an integer that contains the threshold above which the POSIX
1655 interface uses malloc() for output vectors. See item 31 above.
1656
1657 PCRE_CONFIG_MATCH_LIMIT
1658
1659 The output is an unsigned integer that contains the default limit of the number
1660 of match() calls in a pcre_exec() execution. See 42 above.
1661
1662 44. pcretest has been upgraded by the addition of the -C option. This causes it
1663 to extract all the available output from the new pcre_config() function, and to
1664 output it. The program then exits immediately.
1665
1666 45. A need has arisen to pass over additional data with calls to pcre_exec() in
1667 order to support additional features. One way would have been to define
1668 pcre_exec2() (for example) with extra arguments, but this would not have been
1669 extensible, and would also have required all calls to the original function to
1670 be mapped to the new one. Instead, I have chosen to extend the mechanism that
1671 is used for passing in "extra" data from pcre_study().
1672
1673 The pcre_extra structure is now exposed and defined in pcre.h. It currently
1674 contains the following fields:
1675
1676 flags a bitmap indicating which of the following fields are set
1677 study_data opaque data from pcre_study()
1678 match_limit a way of specifying a limit on match() calls for a specific
1679 call to pcre_exec()
1680 callout_data data for callouts (see 49 below)
1681
1682 The flag bits are also defined in pcre.h, and are
1683
1684 PCRE_EXTRA_STUDY_DATA
1685 PCRE_EXTRA_MATCH_LIMIT
1686 PCRE_EXTRA_CALLOUT_DATA
1687
1688 The pcre_study() function now returns one of these new pcre_extra blocks, with
1689 the actual study data pointed to by the study_data field, and the
1690 PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1691 before. That is, this change is entirely upwards-compatible and requires no
1692 change to existing code.
1693
1694 If you want to pass in additional data to pcre_exec(), you can either place it
1695 in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1696 block.
1697
1698 46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1699 data string contains the escape sequence \M, pcretest calls pcre_exec() several
1700 times with different match limits, until it finds the minimum value needed for
1701 pcre_exec() to complete. The value is then output. This can be instructive; for
1702 most simple matches the number is quite small, but for pathological cases it
1703 gets very large very quickly.
1704
1705 47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1706 returns the size of the data block pointed to by the study_data field in a
1707 pcre_extra block, that is, the value that was passed as the argument to
1708 pcre_malloc() when PCRE was getting memory in which to place the information
1709 created by pcre_study(). The fourth argument should point to a size_t variable.
1710 pcretest has been extended so that this information is shown after a successful
1711 pcre_study() call when information about the compiled regex is being displayed.
1712
1713 48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1714 because what follows is always an absolute path. (Later: it turns out that this
1715 is more than cosmetic for MinGW, because it doesn't like empty path
1716 components.)
1717
1718 49. Some changes have been made to the callout feature (see 28 above):
1719
1720 (i) A callout function now has three choices for what it returns:
1721
1722 0 => success, carry on matching
1723 > 0 => failure at this point, but backtrack if possible
1724 < 0 => serious error, return this value from pcre_exec()
1725
1726 Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1727 values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1728 "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1729 use by callout functions. It will never be used by PCRE itself.
1730
1731 (ii) The pcre_extra structure (see 45 above) has a void * field called
1732 callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1733 pcre_callout_block structure has a field of the same name. The contents of
1734 the field passed in the pcre_extra structure are passed to the callout
1735 function in the corresponding field in the callout block. This makes it
1736 easier to use the same callout-containing regex from multiple threads. For
1737 testing, the pcretest program has a new data escape
1738
1739 \C*n pass the number n (may be negative) as callout_data
1740
1741 If the callout function in pcretest receives a non-zero value as
1742 callout_data, it returns that value.
1743
1744 50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1745 there were some redundant $(CFLAGS) in commands that are now specified as
1746 $(LINK), which already includes $(CFLAGS).
1747
1748 51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1749 has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1750 with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1751 one-byte characters throughout. Note that case-insensitive matching applies
1752 only to characters whose values are less than 256. PCRE doesn't support the
1753 notion of cases for higher-valued characters.
1754
1755 (i) A character class whose characters are all within 0-255 is handled as
1756 a bit map, and the map is inverted for negative classes. Previously, a
1757 character > 255 always failed to match such a class; however it should
1758 match if the class was a negative one (e.g. [^ab]). This has been fixed.
1759
1760 (ii) A negated character class with a single character < 255 is coded as
1761 "not this character" (OP_NOT). This wasn't working properly when the test
1762 character was multibyte, either singly or repeated.
1763
1764 (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1765 mode, for example: \x{100}{2,3}.
1766
1767 (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1768 singly or repeated) now correctly test multibyte characters. However,
1769 PCRE doesn't recognize any characters with values greater than 255 as
1770 digits, spaces, or word characters. Such characters always match \D, \S,
1771 and \W, and never match \d, \s, or \w.
1772
1773 (v) Classes may now contain characters and character ranges with values
1774 greater than 255. For example: [ab\x{100}-\x{400}].
1775
1776 (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1777 PCRE in UTF-8 mode.
1778
1779 52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1780 PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1781 retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1782 value.)
1783
1784 53. The single man page has become too large. I have therefore split it up into
1785 a number of separate man pages. These also give rise to individual HTML pages;
1786 these are now put in a separate directory, and there is an index.html page that
1787 lists them all. Some hyperlinking between the pages has been installed.
1788
1789 54. Added convenience functions for handling named capturing parentheses.
1790
1791 55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1792 aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1793 true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1794 are faulted.
1795
1796 56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1797 calling configure. These values are used when compiling the dftables.c program
1798 which is run to generate the source of the default character tables. They
1799 default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1800 you will need to set these values.
1801
1802 57. Updated the building process for Windows DLL, as provided by Fred Cox.
1803
1804
1805 Version 3.9 02-Jan-02
1806 ---------------------
1807
1808 1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1809
1810 2. If --disable-static was given, the building process failed when trying to
1811 build pcretest and pcregrep. (For some reason it was using libtool to compile
1812 them, which is not right, as they aren't part of the library.)
1813
1814
1815 Version 3.8 18-Dec-01
1816 ---------------------
1817
1818 1. The experimental UTF-8 code was completely screwed up. It was packing the
1819 bytes in the wrong order. How dumb can you get?
1820
1821
1822 Version 3.7 29-Oct-01
1823 ---------------------
1824
1825 1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1826 This caused pcretest, when used on the test data, to segfault. Unfortunately,
1827 this didn't happen under Solaris 8, where I normally test things.
1828
1829 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1830 doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1831 isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1832 this fix an hour or so after the initial 3.7 release.)
1833
1834
1835 Version 3.6 23-Oct-01
1836 ---------------------
1837
1838 1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1839 offsets passed as NULL with zero offset count.
1840
1841 2. The config.guess and config.sub files had not been updated when I moved to
1842 the latest autoconf.
1843
1844
1845 Version 3.5 15-Aug-01
1846 ---------------------
1847
1848 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1849 had been forgotten.
1850
1851 2. By using declared but undefined structures, we can avoid using "void"
1852 definitions in pcre.h while keeping the internal definitions of the structures
1853 private.
1854
1855 3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1856 user point of view, this means that both static and shared libraries are built
1857 by default, but this can be individually controlled. More of the work of
1858 handling this static/shared cases is now inside libtool instead of PCRE's make
1859 file.
1860
1861 4. The pcretest utility is now installed along with pcregrep because it is
1862 useful for users (to test regexs) and by doing this, it automatically gets
1863 relinked by libtool. The documentation has been turned into a man page, so
1864 there are now .1, .txt, and .html versions in /doc.
1865
1866 5. Upgrades to pcregrep:
1867 (i) Added long-form option names like gnu grep.
1868 (ii) Added --help to list all options with an explanatory phrase.
1869 (iii) Added -r, --recursive to recurse into sub-directories.
1870 (iv) Added -f, --file to read patterns from a file.
1871
1872 6. pcre_exec() was referring to its "code" argument before testing that
1873 argument for NULL (and giving an error if it was NULL).
1874
1875 7. Upgraded Makefile.in to allow for compiling in a different directory from
1876 the source directory.
1877
1878 8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
1879 options bits, the pointer it was passed was to an int instead of to an unsigned
1880 long int. This mattered only on 64-bit systems.
1881
1882 9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
1883 generated) instead of pcre.in, which it its source. Also made the same change
1884 in several of the .c files.
1885
1886 10. A new release of gcc defines printf() as a macro, which broke pcretest
1887 because it had an ifdef in the middle of a string argument for printf(). Fixed
1888 by using separate calls to printf().
1889
1890 11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
1891 script, to force use of CR or LF instead of \n in the source. On non-Unix
1892 systems, the value can be set in config.h.
1893
1894 12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
1895 absolute limit. Changed the text of the error message to make this clear, and
1896 likewise updated the man page.
1897
1898 13. The limit of 99 on the number of capturing subpatterns has been removed.
1899 The new limit is 65535, which I hope will not be a "real" limit.
1900
1901
1902 Version 3.4 22-Aug-00
1903 ---------------------
1904
1905 1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
1906
1907 2. Diagnose condition (?(0) as an error instead of crashing on matching.
1908
1909
1910 Version 3.3 01-Aug-00
1911 ---------------------
1912
1913 1. If an octal character was given, but the value was greater than \377, it
1914 was not getting masked to the least significant bits, as documented. This could
1915 lead to crashes in some systems.
1916
1917 2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
1918 the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
1919
1920 3. Added the functions pcre_free_substring() and pcre_free_substring_list().
1921 These just pass their arguments on to (pcre_free)(), but they are provided
1922 because some uses of PCRE bind it to non-C systems that can call its functions,
1923 but cannot call free() or pcre_free() directly.
1924
1925 4. Add "make test" as a synonym for "make check". Corrected some comments in
1926 the Makefile.
1927
1928 5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
1929 Makefile.
1930
1931 6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
1932 command called pgrep for grepping around the active processes.
1933
1934 7. Added the beginnings of support for UTF-8 character strings.
1935
1936 8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
1937 RANLIB to ./ltconfig so that they are used by libtool. I think these are all
1938 the relevant ones. (AR is not passed because ./ltconfig does its own figuring
1939 out for the ar command.)
1940
1941
1942 Version 3.2 12-May-00
1943 ---------------------
1944
1945 This is purely a bug fixing release.
1946
1947 1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
1948 of ZA. This was just one example of several cases that could provoke this bug,
1949 which was introduced by change 9 of version 2.00. The code for breaking
1950 infinite loops after an iteration that matches an empty string was't working
1951 correctly.
1952
1953 2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
1954 when matched against abbab (for example). After matching an empty string, it
1955 wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
1956 caused it to match further down the string than it should.
1957
1958 3. The code contained an inclusion of sys/types.h. It isn't clear why this
1959 was there because it doesn't seem to be needed, and it causes trouble on some
1960 systems, as it is not a Standard C header. It has been removed.
1961
1962 4. Made 4 silly changes to the source to avoid stupid compiler warnings that
1963 were reported on the Macintosh. The changes were from
1964
1965 while ((c = *(++ptr)) != 0 && c != '\n');
1966 to
1967 while ((c = *(++ptr)) != 0 && c != '\n') ;
1968
1969 Totally extraordinary, but if that's what it takes...
1970
1971 5. PCRE is being used in one environment where neither memmove() nor bcopy() is
1972 available. Added HAVE_BCOPY and an autoconf test for it; if neither
1973 HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
1974 assumes the way PCRE uses memmove() (always moving upwards).
1975
1976 6. PCRE is being used in one environment where strchr() is not available. There
1977 was only one use in pcre.c, and writing it out to avoid strchr() probably gives
1978 faster code anyway.
1979
1980
1981 Version 3.1 09-Feb-00
1982 ---------------------
1983
1984 The only change in this release is the fixing of some bugs in Makefile.in for
1985 the "install" target:
1986
1987 (1) It was failing to install pcreposix.h.
1988
1989 (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
1990
1991
1992 Version 3.0 01-Feb-00
1993 ---------------------
1994
1995 1. Add support for the /+ modifier to perltest (to output $` like it does in
1996 pcretest).
1997
1998 2. Add support for the /g modifier to perltest.
1999
2000 3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2001 matches null strings.
2002
2003 4. Fix perltest so that it doesn't do unwanted things when fed an empty
2004 pattern. Perl treats empty patterns specially - it reuses the most recent
2005 pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2006 effect.
2007
2008 5. The POSIX interface was broken in that it was just handing over the POSIX
2009 captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2010 required a bigger vector, with some working space on the end. This means that
2011 the POSIX wrapper now has to get and free some memory, and copy the results.
2012
2013 6. Added some simple autoconf support, placing the test data and the
2014 documentation in separate directories, re-organizing some of the
2015 information files, and making it build pcre-config (a GNU standard). Also added
2016 libtool support for building PCRE as a shared library, which is now the
2017 default.
2018
2019 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2020 09 are not valid octal constants. Single digits will be used for minor values
2021 less than 10.
2022
2023 8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2024 existing programs that set these in the POSIX interface can use PCRE without
2025 modification.
2026
2027 9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2028 return all that pcre_info() returns, plus additional data. The pcre_info()
2029 function is retained for compatibility, but is considered to be obsolete.
2030
2031 10. Added experimental recursion feature (?R) to handle one common case that
2032 Perl 5.6 will be able to do with (?p{...}).
2033
2034 11. Added support for POSIX character classes like [:alpha:], which Perl is
2035 adopting.
2036
2037
2038 Version 2.08 31-Aug-99
2039 ----------------------
2040
2041 1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2042 trying to match at the startoffset position, but instead was moving forward to
2043 the next newline as if a previous match had failed.
2044
2045 2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2046 and could get into a loop if a null string was matched other than at the start
2047 of the subject.
2048
2049 3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2050 be distinguished at compile time, and for completeness also added PCRE_DATE.
2051
2052 5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2053 in GnuWin32 environments.
2054
2055
2056 Version 2.07 29-Jul-99
2057 ----------------------
2058
2059 1. The documentation is now supplied in plain text form and HTML as well as in
2060 the form of man page sources.
2061
2062 2. C++ compilers don't like assigning (void *) values to other pointer types.
2063 In particular this affects malloc(). Although there is no problem in Standard
2064 C, I've put in casts to keep C++ compilers happy.
2065
2066 3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2067 should be (const char *).
2068
2069 4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2070 be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2071 However, I haven't made this a standard facility. The documentation doesn't
2072 mention it, and the Makefile doesn't support it.
2073
2074 5. The Makefile now contains an "install" target, with editable destinations at
2075 the top of the file. The pcretest program is not installed.
2076
2077 6. pgrep -V now gives the PCRE version number and date.
2078
2079 7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2080 causing the entire string to be ignored, instead of just the last character.
2081
2082 8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2083 non-matching string, it can take a very, very long time, even for strings of
2084 quite modest length, because of the nested recursion. PCRE now does better in
2085 some of these cases. It does this by remembering the last required literal
2086 character in the pattern, and pre-searching the subject to ensure it is present
2087 before running the real match. In other words, it applies a heuristic to detect
2088 some types of certain failure quickly, and in the above example, if presented
2089 with a string that has no trailing " it gives "no match" very quickly.
2090
2091 9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2092 other alternatives are tried instead.
2093
2094
2095 Version 2.06 09-Jun-99
2096 ----------------------
2097
2098 1. Change pcretest's output for amount of store used to show just the code
2099 space, because the remainder (the data block) varies in size between 32-bit and
2100 64-bit systems.
2101
2102 2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2103 start matching at. This allows lookbehinds to work when searching for multiple
2104 occurrences in a string.
2105
2106 3. Added additional options to pcretest for testing multiple occurrences:
2107
2108 /+ outputs the rest of the string that follows a match
2109 /g loops for multiple occurrences, using the new startoffset argument
2110 /G loops for multiple occurrences by passing an incremented pointer
2111
2112 4. PCRE wasn't doing the "first character" optimization for patterns starting
2113 with \b or \B, though it was doing it for other lookbehind assertions. That is,
2114 it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2115 the letter 'x'. On long subject strings, this gives a significant speed-up.
2116
2117
2118 Version 2.05 21-Apr-99
2119 ----------------------
2120
2121 1. Changed the type of magic_number from int to long int so that it works
2122 properly on 16-bit systems.
2123
2124 2. Fixed a bug which caused patterns starting with .* not to work correctly
2125 when the subject string contained newline characters. PCRE was assuming
2126 anchoring for such patterns in all cases, which is not correct because .* will
2127 not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2128 DOTALL is set at top level; otherwise it knows that patterns starting with .*
2129 must be retried after every newline in the subject.
2130
2131
2132 Version 2.04 18-Feb-99
2133 ----------------------
2134
2135 1. For parenthesized subpatterns with repeats whose minimum was zero, the
2136 computation of the store needed to hold the pattern was incorrect (too large).
2137 If such patterns were nested a few deep, this could multiply and become a real
2138 problem.
2139
2140 2. Added /M option to pcretest to show the memory requirement of a specific
2141 pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2142
2143 3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2144 compiled in such a way that the backtracking after subsequent failure was
2145 pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2146 ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2147
2148
2149 Version 2.03 02-Feb-99
2150 ----------------------
2151
2152 1. Fixed typo and small mistake in man page.
2153
2154 2. Added 4th condition (GPL supersedes if conflict) and created separate
2155 LICENCE file containing the conditions.
2156
2157 3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2158 Perl, that is the internal \ allows the delimiter to be included in the
2159 pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2160 the final delimiter, add \ to the end of the pattern (to test the error).
2161
2162 4. Added the convenience functions for extracting substrings after a successful
2163 match. Updated pcretest to make it able to test these functions.
2164
2165
2166 Version 2.02 14-Jan-99
2167 ----------------------
2168
2169 1. Initialized the working variables associated with each extraction so that
2170 their saving and restoring doesn't refer to uninitialized store.
2171
2172 2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2173 compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2174 fix the problem.
2175
2176 3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2177 calls, and wasn't printing the correct value for compiling calls. Increased the
2178 default value of LOOPREPEAT, and the number of significant figures in the
2179 times.
2180
2181 4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2182
2183 5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2184 a building problem on Windows NT with a FAT file system.
2185
2186
2187 Version 2.01 21-Oct-98
2188 ----------------------
2189
2190 1. Changed the API for pcre_compile() to allow for the provision of a pointer
2191 to character tables built by pcre_maketables() in the current locale. If NULL
2192 is passed, the default tables are used.
2193
2194
2195 Version 2.00 24-Sep-98
2196 ----------------------
2197
2198 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2199 it any more.
2200
2201 2. Allow quantification of (?>) groups, and make it work correctly.
2202
2203 3. The first character computation wasn't working for (?>) groups.
2204
2205 4. Correct the implementation of \Z (it is permitted to match on the \n at the
2206 end of the subject) and add 5.005's \z, which really does match only at the
2207 very end of the subject.
2208
2209 5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2210
2211 6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2212 DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2213 localized options. All options to pcre_study() were also removed.
2214
2215 7. Add other new features from 5.005:
2216
2217 $(?<= positive lookbehind
2218 $(?<! negative lookbehind
2219 (?imsx-imsx) added the unsetting capability
2220 such a setting is global if at outer level; local otherwise
2221 (?imsx-imsx:) non-capturing groups with option setting
2222 (?(cond)re|re) conditional pattern matching
2223
2224 A backreference to itself in a repeated group matches the previous
2225 captured string.
2226
2227 8. General tidying up of studying (both automatic and via "study")
2228 consequential on the addition of new assertions.
2229
2230 9. As in 5.005, unlimited repeated groups that could match an empty substring
2231 are no longer faulted at compile time. Instead, the loop is forcibly broken at
2232 runtime if any iteration does actually match an empty substring.
2233
2234 10. Include the RunTest script in the distribution.
2235
2236 11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2237 discrepancies, some of which were old and were also with respect to 5.004. They
2238 have now been fixed.
2239
2240
2241 Version 1.09 28-Apr-98
2242 ----------------------
2243
2244 1. A negated single character class followed by a quantifier with a minimum
2245 value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2246 program crashes, or just wrong answers. This did not apply to negated classes
2247 containing more than one character, or to minima other than one.
2248
2249
2250 Version 1.08 27-Mar-98
2251 ----------------------
2252
2253 1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2254
2255 2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2256 latter must appear before anything that relies on it in the pattern.
2257
2258
2259 Version 1.07 16-Feb-98
2260 ----------------------
2261
2262 1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2263 repeat of a potentially empty string).
2264
2265
2266 Version 1.06 23-Jan-98
2267 ----------------------
2268
2269 1. Added Markus Oberhumer's little patches for C++.
2270
2271 2. Literal strings longer than 255 characters were broken.
2272
2273
2274 Version 1.05 23-Dec-97
2275 ----------------------
2276
2277 1. Negated character classes containing more than one character were failing if
2278 PCRE_CASELESS was set at run time.
2279
2280
2281 Version 1.04 19-Dec-97
2282 ----------------------
2283
2284 1. Corrected the man page, where some "const" qualifiers had been omitted.
2285
2286 2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2287 input syntax.
2288
2289 3. Fixed memory leak which occurred when a regex with back references was
2290 matched with an offsets vector that wasn't big enough. The temporary memory
2291 that is used in this case wasn't being freed if the match failed.
2292
2293 4. Tidied pcretest to ensure it frees memory that it gets.
2294
2295 5. Temporary memory was being obtained in the case where the passed offsets
2296 vector was exactly big enough.
2297
2298 6. Corrected definition of offsetof() from change 5 below.
2299
2300 7. I had screwed up change 6 below and broken the rules for the use of
2301 setjmp(). Now fixed.
2302
2303
2304 Version 1.03 18-Dec-97
2305 ----------------------
2306
2307 1. A erroneous regex with a missing opening parenthesis was correctly
2308 diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2309 on some systems.
2310
2311 2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2312 it was reported that one broken compiler failed on the former because "code" is
2313 also an independent variable.
2314
2315 3. The erroneous regex a[]b caused an array overrun reference.
2316
2317 4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2318 fail on data ending with that character. (It was going on too far, and checking
2319 the next character, typically a binary zero.) This was specific to the
2320 optimized code for single-character negative classes.
2321
2322 5. Added a contributed patch from the TIN world which does the following:
2323
2324 + Add an undef for memmove, in case the the system defines a macro for it.
2325
2326 + Add a definition of offsetof(), in case there isn't one. (I don't know
2327 the reason behind this - offsetof() is part of the ANSI standard - but
2328 it does no harm).
2329
2330 + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2331 most of the places where whitespace preceded '#'. I have given up and
2332 allowed the remaining 2 cases to be at the margin.
2333
2334 + Rename some variables in pcre to eliminate shadowing. This seems very
2335 pedantic, but does no harm, of course.
2336
2337 6. Moved the call to setjmp() into its own function, to get rid of warnings
2338 from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2339
2340 7. Constructs such as \d{8,} were compiling into the equivalent of
2341 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2342 outcome, but in this particular case used more store than had been allocated,
2343 which caused the bug to be discovered because it threw up an internal error.
2344
2345 8. The debugging code in both pcre and pcretest for outputting the compiled
2346 form of a regex was going wrong in the case of back references followed by
2347 curly-bracketed repeats.
2348
2349
2350 Version 1.02 12-Dec-97
2351 ----------------------
2352
2353 1. Typos in pcre.3 and comments in the source fixed.
2354
2355 2. Applied a contributed patch to get rid of places where it used to remove
2356 'const' from variables, and fixed some signed/unsigned and uninitialized
2357 variable warnings.
2358
2359 3. Added the "runtest" target to Makefile.
2360
2361 4. Set default compiler flag to -O2 rather than just -O.
2362
2363
2364 Version 1.01 19-Nov-97
2365 ----------------------
2366
2367 1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2368 like /([ab]*)*/, that is, for classes with more than one character in them.
2369
2370 2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2371 as /((?>a*))*/ (a PCRE_EXTRA facility).
2372
2373
2374 Version 1.00 18-Nov-97
2375 ----------------------
2376
2377 1. Added compile-time macros to support systems such as SunOS4 which don't have
2378 memmove() or strerror() but have other things that can be used instead.
2379
2380 2. Arranged that "make clean" removes the executables.
2381
2382
2383 Version 0.99 27-Oct-97
2384 ----------------------
2385
2386 1. Fixed bug in code for optimizing classes with only one character. It was
2387 initializing a 32-byte map regardless, which could cause it to run off the end
2388 of the memory it had got.
2389
2390 2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2391
2392
2393 Version 0.98 22-Oct-97
2394 ----------------------
2395
2396 1. Fixed bug in code for handling temporary memory usage when there are more
2397 back references than supplied space in the ovector. This could cause segfaults.
2398
2399
2400 Version 0.97 21-Oct-97
2401 ----------------------
2402
2403 1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2404
2405 2. Optimized negated single characters not to use a bit map.
2406
2407 3. Brought error texts together as macro definitions; clarified some of them;
2408 fixed one that was wrong - it said "range out of order" when it meant "invalid
2409 escape sequence".
2410
2411 4. Changed some char * arguments to const char *.
2412
2413 5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2414
2415 6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2416 pcretest.
2417
2418
2419 Version 0.96 16-Oct-97
2420 ----------------------
2421
2422 1. Added a simple "pgrep" utility to the distribution.
2423
2424 2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2425 unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2426 where "ddd" means "one or more decimal digits".
2427
2428 3. Fixed serious bug. If a pattern had a back reference, but the call to
2429 pcre_exec() didn't supply a large enough ovector to record the related
2430 identifying subpattern, the match always failed. PCRE now remembers the number
2431 of the largest back reference, and gets some temporary memory in which to save
2432 the offsets during matching if necessary, in order to ensure that
2433 backreferences always work.
2434
2435 4. Increased the compatibility with Perl in a number of ways:
2436
2437 (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2438 to request this handling. The option can be set at compile or exec time.
2439
2440 (b) $ matches before a terminating newline by default; an option
2441 PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2442 mode). The option can be set at compile or exec time.
2443
2444 (c) The handling of \ followed by a digit other than 0 is now supposed to be
2445 the same as Perl's. If the decimal number it represents is less than 10
2446 or there aren't that many previous left capturing parentheses, an octal
2447 escape is read. Inside a character class, it's always an octal escape,
2448 even if it is a single digit.
2449
2450 (d) An escaped but undefined alphabetic character is taken as a literal,
2451 unless PCRE_EXTRA is set. Currently this just reserves the remaining
2452 escapes.
2453
2454 (e) {0} is now permitted. (The previous item is removed from the compiled
2455 pattern).
2456
2457 5. Changed all the names of code files so that the basic parts are no longer
2458 than 10 characters, and abolished the teeny "globals.c" file.
2459
2460 6. Changed the handling of character classes; they are now done with a 32-byte
2461 bit map always.
2462
2463 7. Added the -d and /D options to pcretest to make it possible to look at the
2464 internals of compilation without having to recompile pcre.
2465
2466
2467 Version 0.95 23-Sep-97
2468 ----------------------
2469
2470 1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2471 \x20 at the start of a run of normal characters. These were being treated as
2472 real characters, instead of the source characters being re-checked.
2473
2474
2475 Version 0.94 18-Sep-97
2476 ----------------------
2477
2478 1. The functions are now thread-safe, with the caveat that the global variables
2479 containing pointers to malloc() and free() or alternative functions are the
2480 same for all threads.
2481
2482 2. Get pcre_study() to generate a bitmap of initial characters for non-
2483 anchored patterns when this is possible, and use it if passed to pcre_exec().
2484
2485
2486 Version 0.93 15-Sep-97
2487 ----------------------
2488
2489 1. /(b)|(:+)/ was computing an incorrect first character.
2490
2491 2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2492 but not actually doing anything yet.
2493
2494 3. Treat "-" characters in classes that cannot be part of ranges as literals,
2495 as Perl does (e.g. [-az] or [az-]).
2496
2497 4. Set the anchored flag if a branch starts with .* or .*? because that tests
2498 all possible positions.
2499
2500 5. Split up into different modules to avoid including unneeded functions in a
2501 compiled binary. However, compile and exec are still in one module. The "study"
2502 function is split off.
2503
2504 6. The character tables are now in a separate module whose source is generated
2505 by an auxiliary program - but can then be edited by hand if required. There are
2506 now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2507 toupper() in the code.
2508
2509 7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2510 make them global. Abolish the function for setting them, as the caller can now
2511 set them directly.
2512
2513
2514 Version 0.92 11-Sep-97
2515 ----------------------
2516
2517 1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2518 (e.g. /a{1,3}/) was broken (I mis-optimized it).
2519
2520 2. Caseless matching was not working in character classes if the characters in
2521 the pattern were in upper case.
2522
2523 3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2524
2525 4. Make PCRE_ANCHORED public and accept as a compile option.
2526
2527 5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2528 PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2529 pass them.
2530
2531 6. Give an error if bad option bits passed at compile or run time.
2532
2533 7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2534 pcretest to cause it to pass that flag.
2535
2536 8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2537 options, and the first character, if set.
2538
2539 9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2540
2541
2542 Version 0.91 10-Sep-97
2543 ----------------------
2544
2545 1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2546 match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2547
2548 2. PCRE was looping on encountering an indefinitely repeated back reference to
2549 a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2550 Perl does - treats the match as successful.
2551
2552 ****

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