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Revision 265 - (hide annotations) (download)
Wed Nov 14 11:35:48 2007 UTC (7 years, 5 months ago) by ph10
File size: 142385 byte(s)
Fix negative POSIX class bug with Unicode characters.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 263 Version 7.5 12-Nov-07
5     ---------------------
7     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
8     values in parens when parsing an RE using the C++ wrapper."
9 ph10 264
10     2. Negative specials like \S did not work in character classes in UTF-8 mode.
11     Characters greater than 255 were excluded from the class instead of being
12     included.
13 ph10 265
14     3. The same bug as (2) above applied to negated POSIX classes such as
15     [:^space:].
16 ph10 263
18 ph10 260 Version 7.4 21-Sep-07
19 ph10 230 ---------------------
21     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
22 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
23     LF". That isn't really right - the whole point of the change was to try to
24     help when there was an actual mention of one of the two characters. So now
25     the change happens only if \r or \n (or a literal CR or LF) character is
26 ph10 230 encountered.
27 ph10 231
28     2. The 32-bit options word was also used for 6 internal flags, but the numbers
29     of both had grown to the point where there were only 3 bits left.
30     Fortunately, there was spare space in the data structure, and so I have
31     moved the internal flags into a new 16-bit field to free up more option
32 ph10 230 bits.
33 ph10 231
34     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
35     but did not set the internal JCHANGED flag - either of these is enough to
36     control the way the "get" function works - but the PCRE_INFO_JCHANGED
37     facility is supposed to tell if (?J) was ever used, so now (?J) at the
38 ph10 230 start sets both bits.
40 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
41     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
42 ph10 230
43 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
45     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
46 ph10 233 compatibility, even though it is no longer used.
47 ph10 243
48     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
49 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
50 ph10 259 windows.h file is present (where different names are used). [This was
51 ph10 257 reversed later after testing - see 16 below.]
52 ph10 243
53     8. Changed all #include <config.h> to #include "config.h". There were also
54 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
55 ph10 243
56 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
57 ph10 243 sequence off the lines that it output.
59     10. It was pointed out to me that arrays of string pointers cause lots of
60     relocations when a shared library is dynamically loaded. A technique of
61     using a single long string with a table of offsets can drastically reduce
62     these. I have refactored PCRE in four places to do this. The result is
63 ph10 240 dramatic:
64 ph10 243
65 ph10 240 Originally: 290
66     After changing UCP table: 187
67 ph10 243 After changing error message table: 43
68 ph10 240 After changing table of "verbs" 36
69     After changing table of Posix names 22
70 ph10 243
71 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
72 ph10 247
73 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
74 ph10 247 unicode-properties was also set.
76 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
77 ph10 231
78 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
79     checked only for CRLF.
80 ph10 233
81 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
83 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
84 ph10 253
85 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
86 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
87     entirely. This removes changes made in 7 above.
88 ph10 256
89 ph10 261 17. The CMake files have been updated, and there is now more information about
90     building with CMake in the NON-UNIX-USE document.
91 ph10 257
92 ph10 261
93 ph10 228 Version 7.3 28-Aug-07
94 ph10 157 ---------------------
96 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
97     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
98     brackets there is not right, since it causes compilers to look for an
99     installed pcre.h, not the version that is in the source that is being
100     compiled (which of course may be different). I have changed it back to:
101 ph10 197
102 ph10 189 #include "pcre.h"
103 ph10 197
104     I have a vague recollection that the change was concerned with compiling in
105     different directories, but in the new build system, that is taken care of
106     by the VPATH setting the Makefile.
108 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
109     when the subject happened to end in the byte 0x85 (e.g. if the last
110     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
111     characters but of course it shouldn't be taken as a newline when it is part
112     of another character. The bug was that, for an unlimited repeat of . in
113     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
114     characters when looking for a newline.
115 ph10 197
116     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
118     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
119     in debug output.
121 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
122     long printing in the pcrecpp unittest when running under MinGW.
123 ph10 189
124 ph10 197 6. ESC_K was left out of the EBCDIC table.
125 ph10 189
126 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
127     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
128     limit also applies to "virtual nesting" when a pattern is recursive, and in
129     this case 1000 isn't so big. I have been able to remove this limit at the
130     expense of backing off one optimization in certain circumstances. Normally,
131     when pcre_exec() would call its internal match() function recursively and
132     immediately return the result unconditionally, it uses a "tail recursion"
133     feature to save stack. However, when a subpattern that can match an empty
134     string has an unlimited repetition quantifier, it no longer makes this
135     optimization. That gives it a stack frame in which to save the data for
136     checking that an empty string has been matched. Previously this was taken
137     from the 1000-entry workspace that had been reserved. So now there is no
138     explicit limit, but more stack is used.
139 ph10 189
140 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
141     syntax that is required for Windows, and which was going wrong for the
142     pcreposix and pcrecpp parts of the library. These were overlooked when this
143     problem was solved for the main library.
144 ph10 197
145 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
146     the size of patterns that contain repeated groups with explicit upper
147     limits. As the maximum quantifier is 65535, the maximum group length was
148     set at 30,000 so that the product of these two numbers did not overflow a
149     32-bit integer. However, it turns out that people want to use groups that
150     are longer than 30,000 bytes (though not repeat them that many times).
151     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
152     made it possible to implement the integer overflow checks in a much more
153     dynamic way, which I have now done. The artificial limitation on group
154     length has been removed - we now have only the limit on the total length of
155     the compiled pattern, which depends on the LINK_SIZE setting.
156 ph10 208
157     10. Fixed a bug in the documentation for get/copy named substring when
158     duplicate names are permitted. If none of the named substrings are set, the
159     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
160     empty string.
162     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
163     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
164     because the ] is interpreted as the first data character and the
165     terminating ] is not found. PCRE has been made compatible with Perl in this
166     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
167     cause memory overwriting.
169 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
170     string has been matched (to stop an infinite loop). It was not recognizing
171 ph10 208 a conditional subpattern that could match an empty string if that
172 ph10 206 subpattern was within another subpattern. For example, it looped when
173 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
174 ph10 206 condition was not nested. This bug has been fixed.
175 ph10 208
176 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
177     past the start of the subject in the presence of bytes with the top bit
178     set, for example "\x8aBCD".
179 ph10 211
180 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
181     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
182 ph10 200
183 ph10 211 14. Optimized (?!) to (*FAIL).
184 ph10 202
185 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
186     This restricts code points to be within the range 0 to 0x10FFFF, excluding
187     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
188     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
189     does: it's just the validity check that is more restrictive.
190 ph10 220
191     16. Inserted checks for integer overflows during escape sequence (backslash)
192     processing, and also fixed erroneous offset values for syntax errors during
193     backslash processing.
195 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
196 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
198 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
199     caused an overrun.
200 ph10 220
201     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
202     something other than just ASCII characters) inside a group that had an
203     unlimited repeat caused a loop at compile time (while checking to see
204     whether the group could match an empty string).
206 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
207     [\P{Any}] did so. (Error in the code for printing property names.)
208 ph10 210
209 ph10 220 21. An orphan \E inside a character class could cause a crash.
211     22. A repeated capturing bracket such as (A)? could cause a wild memory
212 ph10 218 reference during compilation.
213 ph10 220
214     23. There are several functions in pcre_compile() that scan along a compiled
215     expression for various reasons (e.g. to see if it's fixed length for look
216 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
217 ph10 220 present in the pattern. These operators have additional parameters compared
218     with \d, etc, and these were not being taken into account when moving along
219 ph10 218 the compiled data. Specifically:
220 ph10 220
221     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
222     length.
224     (b) An item such as \pL+ within a repeated group could cause crashes or
225 ph10 218 loops.
226 ph10 220
227 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
228 ph10 220 "reference to non-existent subpattern" error.
230 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
232 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
233 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
234 ph10 211
235 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
236 ph10 218
237 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
238 ph10 223 character were causing crashes (broken optimization).
239 ph10 227
240 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
241 ph10 227 \p or \P) caused a compile-time loop.
243 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
244     break. For example, the unstudied pattern [\r\n]A does not match the string
245     "\r\nA" because change 7.0/46 below moves the current point on by two
246     characters after failing to match at the start. However, the pattern \nA
247 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
248     the same is true. There doesn't seem any very clean way out of this, but
249     what I have chosen to do makes the common cases work: PCRE now takes note
250     of whether there can be an explicit match for \r or \n anywhere in the
251     pattern, and if so, 7.0/46 no longer applies. As part of this change,
252     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
253     pattern has explicit CR or LF references.
254 ph10 222
255 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
256 ph10 223
257 ph10 227
258 ph10 189 Version 7.2 19-Jun-07
259     ---------------------
261 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
262     which is apparently normally available under Windows.
263 ph10 159
264     2. Re-jig the pcregrep tests with different newline settings in an attempt
265     to make them independent of the local environment's newline setting.
266 ph10 157
267 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
268 ph10 165
269 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
270     was not 2, because the output contained actual offsets. The recent new
271 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
272     usable with all link sizes.
274 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
275     stack recursion. This gives a massive performance boost under BSD, but just
276 ph10 165 a small improvement under Linux. However, it saves one field in the frame
277 ph10 164 in all cases.
278 ph10 172
279 ph10 166 6. Added more features from the forthcoming Perl 5.10:
280 ph10 172
281 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
282     recursion call. It refers to the nth most recently opened parentheses.
283 ph10 172
284 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
285 ph10 172 to be opened parentheses.
287     (c) Conditions that refer to capturing parentheses can be specified
288 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
289 ph10 172
290 ph10 168 (d) \K resets the start of the current match so that everything before
291 ph10 172 is not part of it.
293 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
294 ph10 172
295 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
296 ph10 172 reference syntax.
297 ph10 182
298 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
299 ph10 182 alternative starts with the same number.
300 ph10 172
301 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
303 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
306     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
307     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
308 ph10 170 for detecting groups that can match an empty string.
309 ph10 159
310 ph10 172 9. A pattern with a very large number of alternatives (more than several
311     hundred) was running out of internal workspace during the pre-compile
312     phase, where pcre_compile() figures out how much memory will be needed. A
313     bit of new cunning has reduced the workspace needed for groups with
314     alternatives. The 1000-alternative test pattern now uses 12 bytes of
315     workspace instead of running out of the 4096 that are available.
316 ph10 182
317 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
318 ph10 172
319 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
320     The report of the bug said:
321 ph10 182
322 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
323     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
324 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
325 ph10 185
326 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
327 ph10 185 it matched the wrong number of bytes.
328 ph10 172
329 ph10 179
330 ph10 155 Version 7.1 24-Apr-07
331 ph10 98 ---------------------
333 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
334 ph10 122 that is more "standard", making use of automake and other Autotools. There
335 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
336     on this.
337 ph10 111
338     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
339     for recursive directory scanning broke on some systems because the files
340     are not scanned in any specific order and on different systems the order
341     was different. A call to "sort" has been inserted into RunGrepTest for the
342     approprate test as a short-term fix. In the longer term there may be an
343 ph10 100 alternative.
344 ph10 111
345 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
346 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
347     people do their own conversions for various reasons). The problems
348     concerned the use of low-level troff macros .br and .in. I have therefore
349     removed all such uses from the man pages (some were redundant, some could
350 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
351     HTML has been updated to handle .nf/.fi and to complain if it encounters
352     .br or .in.
353 ph10 111
354 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
355 ph10 123 arranged for config.h to be included in the distribution, with the name
356 ph10 111 config.h.generic, for the benefit of those who have to compile without
357     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
359     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
360     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
361 ph10 127 makevp.bat for the current PCRE, using the additional files
362 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
363 ph10 111
364     6. A Windows user reported a minor discrepancy with test 2, which turned out
365     to be caused by a trailing space on an input line that had got lost in his
366 ph10 102 copy. The trailing space was an accident, so I've just removed it.
367 ph10 111
368 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
369 ph10 111 that is needed.
371 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
372     as "const" (a) because they are and (b) because it helps the PHP
373     maintainers who have recently made a script to detect big data structures
374 ph10 111 in the php code that should be moved to the .rodata section. I remembered
375     to update Builducptable as well, so it won't revert if ucptable.h is ever
376 ph10 105 re-created.
377 ph10 111
378     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
379 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
380 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
381     support is not required. This saves 1.5-2K of code, which is important in
382 ph10 107 some applications.
383 ph10 111
384 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
385 ph10 111 so as not to refer to the tables, even though these functions will never be
386     called when UTF-8 support is disabled. Otherwise there are problems with a
387     shared library.
389 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
391     (a) It was defining its arguments as char * instead of void *.
393 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
394     a long time ago when I wrote it, but is no longer the case.
396 ph10 118 The emulated memove() is provided for those environments that have neither
397 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
398 ph10 118 is clearly not the case, as these two bugs were recently reported.
399 ph10 123
400 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
401 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
402     pages, and it removes trailing spaces from listed files. It also creates
403     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
404     case, it wraps all the #defines with #ifndefs. This script should be run
405 ph10 111 before "make dist".
406 ph10 123
407 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
408     with Unicode property support.
409 ph10 123
410     (a) For a maximizing quantifier, if the two different cases of the
411     character were of different lengths in their UTF-8 codings (there are
412     some cases like this - I found 11), and the matching function had to
413 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
414     were both the same length.
415 ph10 123
416     (b) When PCRE was configured to use the heap rather than the stack for
417     recursion during matching, it was not correctly preserving the data for
418     the other case of a UTF-8 character when checking ahead for a match
419     while processing a minimizing repeat. If the check also involved
420 ph10 115 matching a wide character, but failed, corruption could cause an
421     erroneous result when trying to check for a repeat of the original
422     character.
423 ph10 123
424 ph10 116 13. Some tidying changes to the testing mechanism:
425 ph10 98
426 ph10 116 (a) The RunTest script now detects the internal link size and whether there
427     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
428 ph10 123 values substituted by "configure". (The RunGrepTest script already did
429     this for UTF-8.) The configure.ac script no longer substitutes the
430     relevant variables.
432 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
433     with length and offset values. This means that the output is different
434     for different internal link sizes. Test 2 is skipped for link sizes
435     other than 2 because of this, bypassing the problem. Unfortunately,
436     there was also a test in test 3 (the locale tests) that used /B and
437 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
438     I have added a new /Z option to pcretest that replaces the length and
439     offset values with spaces. This is now used to make test 3 independent
440 ph10 122 of link size. (Test 2 will be tidied up later.)
441 ph10 123
442     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
443 ph10 122 segmentation fault instead of returning the appropriate error message.
444 ph10 134
445 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
446 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
447     This doesn't seem right; it now treats the CRLF combination as the line
448     ending, and so does not match in that case. It's only a pattern such as ^$
449     that would hit this one: something like ^ABC$ would have failed after \r
450     and then tried again after \r\n.
452 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
453 ph10 134 in an attempt to make files that differ only in their line terminators
454     compare equal. This works on Linux.
455 ph10 142
456 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
457     as it exited. This is now fixed, thanks to valgrind.
458 ph10 142
459 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
460 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
461     was because its rules for how to advance for /g after matching an empty
462 ph10 143 string at the end of a line did not allow for this case. They now check for
463     it specially.
464 ph10 150
465     20. pcretest is supposed to handle patterns and data of any length, by
466     extending its buffers when necessary. It was getting this wrong when the
467 ph10 147 buffer for a data line had to be extended.
468 ph10 150
469 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
470 ph10 150 CRLF as a newline sequence.
471 ph10 152
472 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
473 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
474     I have nevertheless tidied it up.
475 ph10 111
476 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
477 ph10 123
478 ph10 153 24. Added a man page for pcre-config.
479 ph10 152
480 ph10 153
481 nigel 93 Version 7.0 19-Dec-06
482     ---------------------
484     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
485     moving to gcc 4.1.1.
487     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
488     sys/time.h, which is documented as needed for this function. It doesn't
489     seem to matter on Linux, but it showed up on some releases of OS X.
491     3. It seems that there are systems where bytes whose values are greater than
492     127 match isprint() in the "C" locale. The "C" locale should be the
493     default when a C program starts up. In most systems, only ASCII printing
494     characters match isprint(). This difference caused the output from pcretest
495     to vary, making some of the tests fail. I have changed pcretest so that:
497     (a) When it is outputting text in the compiled version of a pattern, bytes
498     other than 32-126 are always shown as hex escapes.
500     (b) When it is outputting text that is a matched part of a subject string,
501     it does the same, unless a different locale has been set for the match
502     (using the /L modifier). In this case, it uses isprint() to decide.
504     4. Fixed a major bug that caused incorrect computation of the amount of memory
505     required for a compiled pattern when options that changed within the
506     pattern affected the logic of the preliminary scan that determines the
507     length. The relevant options are -x, and -i in UTF-8 mode. The result was
508     that the computed length was too small. The symptoms of this bug were
509     either the PCRE error "internal error: code overflow" from pcre_compile(),
510     or a glibc crash with a message such as "pcretest: free(): invalid next
511     size (fast)". Examples of patterns that provoked this bug (shown in
512     pcretest format) are:
514     /(?-x: )/x
515     /(?x)(?-x: \s*#\s*)/
516     /((?i)[\x{c0}])/8
517     /(?i:[\x{c0}])/8
519     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
520     is now done differently.
522     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
523     wrapper classes; (b) implement a new function in the C++ scanner that is
524     more efficient than the old way of doing things because it avoids levels of
525     recursion in the regex matching; (c) add a paragraph to the documentation
526     for the FullMatch() function.
528     6. The escape sequence \n was being treated as whatever was defined as
529     "newline". Not only was this contrary to the documentation, which states
530     that \n is character 10 (hex 0A), but it also went horribly wrong when
531     "newline" was defined as CRLF. This has been fixed.
533     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
534     was being set to -1 for the "end of line" case (supposedly a value that no
535     character can have). Though this value is never used (the check for end of
536     line is "zero bytes in current character"), it caused compiler complaints.
537     I've changed it to 0xffffffff.
539     8. In pcre_version.c, the version string was being built by a sequence of
540     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
541     string (as it is for production releases) called a macro with an empty
542     argument. The C standard says the result of this is undefined. The gcc
543     compiler treats it as an empty string (which was what was wanted) but it is
544     reported that Visual C gives an error. The source has been hacked around to
545     avoid this problem.
547     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
548     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
549     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
550     of them did).
552     10. Originally, pcretest opened its input and output without "b"; then I was
553     told that "b" was needed in some environments, so it was added for release
554     5.0 to both the input and output. (It makes no difference on Unix-like
555     systems.) Later I was told that it is wrong for the input on Windows. I've
556     now abstracted the modes into two macros, to make it easier to fiddle with
557     them, and removed "b" from the input mode under Windows.
559     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
561     12. Added -help and --help to pcretest as an official way of being reminded
562     of the options.
564     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
565     and pcrecpp.cc because they annoy compilers at high warning levels.
567     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
569     15. Fixed an occurrence of == in configure.ac that should have been = (shell
570     scripts are not C programs :-) and which was not noticed because it works
571     on Linux.
573     16. pcretest is supposed to handle any length of pattern and data line (as one
574     line or as a continued sequence of lines) by extending its input buffer if
575     necessary. This feature was broken for very long pattern lines, leading to
576     a string of junk being passed to pcre_compile() if the pattern was longer
577     than about 50K.
579     17. I have done a major re-factoring of the way pcre_compile() computes the
580     amount of memory needed for a compiled pattern. Previously, there was code
581     that made a preliminary scan of the pattern in order to do this. That was
582     OK when PCRE was new, but as the facilities have expanded, it has become
583     harder and harder to keep it in step with the real compile phase, and there
584     have been a number of bugs (see for example, 4 above). I have now found a
585     cunning way of running the real compile function in a "fake" mode that
586     enables it to compute how much memory it would need, while actually only
587     ever using a few hundred bytes of working memory and without too many
588     tests of the mode. This should make future maintenance and development
589     easier. A side effect of this work is that the limit of 200 on the nesting
590     depth of parentheses has been removed (though this was never a serious
591     limitation, I suspect). However, there is a downside: pcre_compile() now
592     runs more slowly than before (30% or more, depending on the pattern). I
593     hope this isn't a big issue. There is no effect on runtime performance.
595     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
596     newline (only possible for the last line of a file) and it was a
597     pattern that set a locale (followed by /Lsomething), pcretest crashed.
599     19. Added additional timing features to pcretest. (1) The -tm option now times
600     matching only, not compiling. (2) Both -t and -tm can be followed, as a
601     separate command line item, by a number that specifies the number of
602     repeats to use when timing. The default is 50000; this gives better
603     precision, but takes uncomfortably long for very large patterns.
605     20. Extended pcre_study() to be more clever in cases where a branch of a
606     subpattern has no definite first character. For example, (a*|b*)[cd] would
607     previously give no result from pcre_study(). Now it recognizes that the
608     first character must be a, b, c, or d.
610     21. There was an incorrect error "recursive call could loop indefinitely" if
611     a subpattern (or the entire pattern) that was being tested for matching an
612     empty string contained only one non-empty item after a nested subpattern.
613     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
614     incorrectly, because the \d was being skipped in the check.
616     22. The pcretest program now has a new pattern option /B and a command line
617     option -b, which is equivalent to adding /B to every pattern. This causes
618     it to show the compiled bytecode, without the additional information that
619     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
620     is the same as /B/I).
622     23. A new optimization is now able automatically to treat some sequences such
623     as a*b as a*+b. More specifically, if something simple (such as a character
624     or a simple class like \d) has an unlimited quantifier, and is followed by
625     something that cannot possibly match the quantified thing, the quantifier
626     is automatically "possessified".
628     24. A recursive reference to a subpattern whose number was greater than 39
629     went wrong under certain circumstances in UTF-8 mode. This bug could also
630     have affected the operation of pcre_study().
632     25. Realized that a little bit of performance could be had by replacing
633     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
635     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
637     27. Possessive quantifiers such as a++ were previously implemented by turning
638     them into atomic groups such as ($>a+). Now they have their own opcodes,
639     which improves performance. This includes the automatically created ones
640     from 23 above.
642     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
643     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
644     the first matched character to be a colon. This applied both to named and
645     numbered groups.
647     29. The ucpinternal.h header file was missing its idempotency #ifdef.
649     30. I was sent a "project" file called libpcre.a.dev which I understand makes
650     building PCRE on Windows easier, so I have included it in the distribution.
652     31. There is now a check in pcretest against a ridiculously large number being
653     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
654     loop, the loop is abandoned.
656     32. Forward references to subpatterns in conditions such as (?(2)...) where
657     subpattern 2 is defined later cause pcre_compile() to search forwards in
658     the pattern for the relevant set of parentheses. This search went wrong
659     when there were unescaped parentheses in a character class, parentheses
660     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
662     33. "Subroutine" calls and backreferences were previously restricted to
663     referencing subpatterns earlier in the regex. This restriction has now
664     been removed.
666     34. Added a number of extra features that are going to be in Perl 5.10. On the
667     whole, these are just syntactic alternatives for features that PCRE had
668     previously implemented using the Python syntax or my own invention. The
669     other formats are all retained for compatibility.
671     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
672     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
673     also .NET compatible.
675     (b) A recursion or subroutine call to a named group can now be defined as
676     (?&name) as well as (?P>name).
678     (c) A backreference to a named group can now be defined as \k<name> or
679     \k'name' as well as (?P=name). The new forms, as well as being in Perl
680     5.10, are also .NET compatible.
682     (d) A conditional reference to a named group can now use the syntax
683     (?(<name>) or (?('name') as well as (?(name).
685     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
686     groups (named and numbered) that are never evaluated inline, but can be
687     called as "subroutines" from elsewhere. In effect, the DEFINE condition
688     is always false. There may be only one alternative in such a group.
690     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
691     as the simple (?(R). The condition is true only if the most recent
692     recursion is that of the given number or name. It does not search out
693     through the entire recursion stack.
695     (g) The escape \gN or \g{N} has been added, where N is a positive or
696     negative number, specifying an absolute or relative reference.
698     35. Tidied to get rid of some further signed/unsigned compiler warnings and
699     some "unreachable code" warnings.
701     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
702     things, this adds five new scripts.
704     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
705     There were also incompatibilities regarding the handling of \Q..\E inside
706     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
707     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
709     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
710     matches an empty string, and forcibly breaks the loop. There were bugs in
711     this code in non-simple cases. For a pattern such as ^(a()*)* matched
712     against aaaa the result was just "a" rather than "aaaa", for example. Two
713     separate and independent bugs (that affected different cases) have been
714     fixed.
716     39. Refactored the code to abolish the use of different opcodes for small
717     capturing bracket numbers. This is a tidy that I avoided doing when I
718     removed the limit on the number of capturing brackets for 3.5 back in 2001.
719     The new approach is not only tidier, it makes it possible to reduce the
720     memory needed to fix the previous bug (38).
722     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
723     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
724     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
725     mode.
727     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
728     report.
730     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
731     copy construction and assignment in the C++ wrapper.
733     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
734     couple of bugs that could have given wrong results in the "--newline=crlf"
735     case.
737     44. Added a number of casts and did some reorganization of signed/unsigned int
738     variables following suggestions from Dair Grant. Also renamed the variable
739     "this" as "item" because it is a C++ keyword.
741     45. Arranged for dftables to add
743     #include "pcre_internal.h"
745     to pcre_chartables.c because without it, gcc 4.x may remove the array
746     definition from the final binary if PCRE is built into a static library and
747     dead code stripping is activated.
749     46. For an unanchored pattern, if a match attempt fails at the start of a
750     newline sequence, and the newline setting is CRLF or ANY, and the next two
751     characters are CRLF, advance by two characters instead of one.
754 nigel 91 Version 6.7 04-Jul-06
755     ---------------------
757     1. In order to handle tests when input lines are enormously long, pcretest has
758     been re-factored so that it automatically extends its buffers when
759     necessary. The code is crude, but this _is_ just a test program. The
760     default size has been increased from 32K to 50K.
762     2. The code in pcre_study() was using the value of the re argument before
763     testing it for NULL. (Of course, in any sensible call of the function, it
764     won't be NULL.)
766     3. The memmove() emulation function in pcre_internal.h, which is used on
767     systems that lack both memmove() and bcopy() - that is, hardly ever -
768     was missing a "static" storage class specifier.
770     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
771     containing an extended class (one that cannot be represented by a bitmap
772     because it contains high-valued characters or Unicode property items, e.g.
773     [\pZ]). Almost always one would set UTF-8 mode when processing such a
774     pattern, but PCRE should not loop if you do not (it no longer does).
775     [Detail: two cases were found: (a) a repeated subpattern containing an
776     extended class; (b) a recursive reference to a subpattern that followed a
777     previous extended class. It wasn't skipping over the extended class
778     correctly when UTF-8 mode was not set.]
780     5. A negated single-character class was not being recognized as fixed-length
781     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
782     compile error "lookbehind assertion is not fixed length".
784     6. The RunPerlTest auxiliary script was showing an unexpected difference
785     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
786     write a Perl script that can interpret lines of an input file either as
787     byte characters or as UTF-8, which is what "perltest" was being required to
788     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
789     can't do is switch easily at run time between having the "use utf8;" pragma
790     or not. In the end, I fudged it by using the RunPerlTest script to insert
791     "use utf8;" explicitly for the UTF-8 tests.
793     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
794     the end of the subject string, contrary to the documentation and to what
795     Perl does. This was true of both matching functions. Now it matches only at
796     the start of the subject and immediately after *internal* newlines.
798     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
799     a pointer to an int instead of a pointer to an unsigned long int. This
800     caused problems on 64-bit systems.
802     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
803     instance of the 'standard' template library not being so standard".
805     10. There was no check on the number of named subpatterns nor the maximum
806     length of a subpattern name. The product of these values is used to compute
807     the size of the memory block for a compiled pattern. By supplying a very
808     long subpattern name and a large number of named subpatterns, the size
809     computation could be caused to overflow. This is now prevented by limiting
810     the length of names to 32 characters, and the number of named subpatterns
811     to 10,000.
813     11. Subpatterns that are repeated with specific counts have to be replicated in
814     the compiled pattern. The size of memory for this was computed from the
815     length of the subpattern and the repeat count. The latter is limited to
816     65535, but there was no limit on the former, meaning that integer overflow
817     could in principle occur. The compiled length of a repeated subpattern is
818     now limited to 30,000 bytes in order to prevent this.
820     12. Added the optional facility to have named substrings with the same name.
822     13. Added the ability to use a named substring as a condition, using the
823     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
824     are numbers (not recommended). Forward references are permitted.
826     14. Added forward references in named backreferences (if you see what I mean).
828     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
829     pattern could run off the end of the subject. For example, the pattern
830     "(?s)(.{1,5})"8 did this with the subject "ab".
832     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
833     PCRE_CASELESS was set when matching characters that were quantified with ?
834     or *.
836     17. A character class other than a single negated character that had a minimum
837     but no maximum quantifier - for example [ab]{6,} - was not handled
838     correctly by pce_dfa_exec(). It would match only one character.
840     18. A valid (though odd) pattern that looked like a POSIX character
841     class but used an invalid character after [ (for example [[,abc,]]) caused
842     pcre_compile() to give the error "Failed: internal error: code overflow" or
843     in some cases to crash with a glibc free() error. This could even happen if
844     the pattern terminated after [[ but there just happened to be a sequence of
845     letters, a binary zero, and a closing ] in the memory that followed.
847     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
848     over the years. Originally (before any Unicode support), just the bottom 8
849     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
850     output from "man perlunicode" includes this:
852     The regular expression compiler produces polymorphic opcodes. That
853     is, the pattern adapts to the data and automatically switches to
854     the Unicode character scheme when presented with Unicode data--or
855     instead uses a traditional byte scheme when presented with byte
856     data.
858     Sadly, a wide octal escape does not cause a switch, and in a string with
859     no other multibyte characters, these octal escapes are treated as before.
860     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
861     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
862     Unicode string.
864     I have not perpetrated such confusion in PCRE. Up till now, it took just
865     the bottom 8 bits, as in old Perl. I have now made octal escapes with
866     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
867     translate to the appropriate multibyte character.
869     29. Applied some refactoring to reduce the number of warnings from Microsoft
870     and Borland compilers. This has included removing the fudge introduced
871     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
872     a warning about an unused variable.
874     21. PCRE has not included VT (character 0x0b) in the set of whitespace
875     characters since release 4.0, because Perl (from release 5.004) does not.
876     [Or at least, is documented not to: some releases seem to be in conflict
877     with the documentation.] However, when a pattern was studied with
878     pcre_study() and all its branches started with \s, PCRE still included VT
879     as a possible starting character. Of course, this did no harm; it just
880     caused an unnecessary match attempt.
882     22. Removed a now-redundant internal flag bit that recorded the fact that case
883     dependency changed within the pattern. This was once needed for "required
884     byte" processing, but is no longer used. This recovers a now-scarce options
885     bit. Also moved the least significant internal flag bit to the most-
886     significant bit of the word, which was not previously used (hangover from
887     the days when it was an int rather than a uint) to free up another bit for
888     the future.
890     23. Added support for CRLF line endings as well as CR and LF. As well as the
891     default being selectable at build time, it can now be changed at runtime
892     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
893     specify that it is scanning data with non-default line endings.
895     24. Changed the definition of CXXLINK to make it agree with the definition of
896     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
898     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
899     recursions. This makes a big different to stack usage for some patterns.
901     26. If a subpattern containing a named recursion or subroutine reference such
902     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
903     the space required for the compiled pattern went wrong and gave too small a
904     value. Depending on the environment, this could lead to "Failed: internal
905     error: code overflow at offset 49" or "glibc detected double free or
906     corruption" errors.
908     27. Applied patches from Google (a) to support the new newline modes and (b) to
909     advance over multibyte UTF-8 characters in GlobalReplace.
911     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
912     difference for some implementation of PCRE in some Windows version.
914     29. Added some extra testing facilities to pcretest:
916     \q<number> in a data line sets the "match limit" value
917     \Q<number> in a data line sets the "match recursion limt" value
918     -S <number> sets the stack size, where <number> is in megabytes
920     The -S option isn't available for Windows.
923 nigel 89 Version 6.6 06-Feb-06
924     ---------------------
926     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
927     in pcreposix.h. I have copied the definition from pcre.h.
929     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
930     because pcre.h is no longer a built file.
932     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
933     not normally included in the compiled code.
936 nigel 87 Version 6.5 01-Feb-06
937     ---------------------
939     1. When using the partial match feature with pcre_dfa_exec(), it was not
940     anchoring the second and subsequent partial matches at the new starting
941     point. This could lead to incorrect results. For example, with the pattern
942     /1234/, partially matching against "123" and then "a4" gave a match.
944     2. Changes to pcregrep:
946     (a) All non-match returns from pcre_exec() were being treated as failures
947     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
948     error message is output. Some extra information is given for the
950     probably the only errors that are likely to be caused by users (by
951     specifying a regex that has nested indefinite repeats, for instance).
952     If there are more than 20 of these errors, pcregrep is abandoned.
954     (b) A binary zero was treated as data while matching, but terminated the
955     output line if it was written out. This has been fixed: binary zeroes
956     are now no different to any other data bytes.
958     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
959     used to set a locale for matching. The --locale=xxxx long option has
960     been added (no short equivalent) to specify a locale explicitly on the
961     pcregrep command, overriding the environment variables.
963     (d) When -B was used with -n, some line numbers in the output were one less
964     than they should have been.
966     (e) Added the -o (--only-matching) option.
968     (f) If -A or -C was used with -c (count only), some lines of context were
969     accidentally printed for the final match.
971     (g) Added the -H (--with-filename) option.
973     (h) The combination of options -rh failed to suppress file names for files
974     that were found from directory arguments.
976     (i) Added the -D (--devices) and -d (--directories) options.
978     (j) Added the -F (--fixed-strings) option.
980     (k) Allow "-" to be used as a file name for -f as well as for a data file.
982     (l) Added the --colo(u)r option.
984     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
985     is not present by default.
987     3. A nasty bug was discovered in the handling of recursive patterns, that is,
988     items such as (?R) or (?1), when the recursion could match a number of
989     alternatives. If it matched one of the alternatives, but subsequently,
990     outside the recursion, there was a failure, the code tried to back up into
991     the recursion. However, because of the way PCRE is implemented, this is not
992     possible, and the result was an incorrect result from the match.
994     In order to prevent this happening, the specification of recursion has
995     been changed so that all such subpatterns are automatically treated as
996     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
998     4. I had overlooked the fact that, in some locales, there are characters for
999     which isalpha() is true but neither isupper() nor islower() are true. In
1000     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1001     and ordfeminine) are like this. This affected the treatment of \w and \W
1002     when they appeared in character classes, but not when they appeared outside
1003     a character class. The bit map for "word" characters is now created
1004     separately from the results of isalnum() instead of just taking it from the
1005     upper, lower, and digit maps. (Plus the underscore character, of course.)
1007     5. The above bug also affected the handling of POSIX character classes such as
1008     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1009     permanent tables. Instead, the bit maps for such a class were previously
1010     created as the appropriate unions of the upper, lower, and digit bitmaps.
1011     Now they are created by subtraction from the [[:word:]] class, which has
1012     its own bitmap.
1014     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1015     It is created by subtracting the vertical space characters (\x09, \x0a,
1016     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1017     subtraction was done in the overall bitmap for a character class, meaning
1018     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1019     be recognized. This bug has been fixed.
1021     7. Patches from the folks at Google:
1023     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1024     real life, but is still worth protecting against".
1026     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1027     regular expressions".
1029     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1030     have it.
1032     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1033     "configure" and the latter not, in order to fix a problem somebody had
1034     with compiling the Arg class on HP-UX.
1036     (e) Improve the error-handling of the C++ wrapper a little bit.
1038     (f) New tests for checking recursion limiting.
1040     8. The pcre_memmove() function, which is used only if the environment does not
1041     have a standard memmove() function (and is therefore rarely compiled),
1042     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1043     returning a result (though PCRE never actually uses the result).
1045     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1046     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1047     returned instead of calling malloc() with an overflowing number that would
1048     most likely cause subsequent chaos.
1050     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1052     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1053     with this option is matched, the nmatch and pmatch options of regexec() are
1054     ignored.
1056     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1057     provided in case anyone wants to the the POSIX interface with UTF-8
1058     strings.
1060     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1061     C++ linking (needed for some HP-UX environments).
1063     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1064     (unused parameter) and in the pcre_printint() function (omitted "default"
1065     switch label when the default is to do nothing).
1067     15. Added some code to make it possible, when PCRE is compiled as a C++
1068     library, to replace subject pointers for pcre_exec() with a smart pointer
1069     class, thus making it possible to process discontinuous strings.
1071     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1072     much the same function. They were added by different people who were trying
1073     to make PCRE easy to compile on non-Unix systems. It has been suggested
1074     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1075     for compiling on Windows systems. I have therefore replaced it with
1076     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1077     defaults to "extern" for C or "extern C" for C++, which works fine on
1078     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1079     SCOPE with something explicit in config.h. In addition:
1081     (a) pcreposix.h still had just "extern" instead of either of these macros;
1082     I have replaced it with PCRE_DATA_SCOPE.
1084     (b) Functions such as _pcre_xclass(), which are internal to the library,
1085     but external in the C sense, all had PCRE_EXPORT in their definitions.
1086     This is apparently wrong for the Windows case, so I have removed it.
1087     (It makes no difference on Unix-like systems.)
1089     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1090     of recursive calls to match(). This is different to MATCH_LIMIT because
1091     that limits the total number of calls to match(), not all of which increase
1092     the depth of recursion. Limiting the recursion depth limits the amount of
1093     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1094     when PCRE is compiled, and changed at run time. A patch from Google adds
1095     this functionality to the C++ interface.
1097     18. Changes to the handling of Unicode character properties:
1099     (a) Updated the table to Unicode 4.1.0.
1101     (b) Recognize characters that are not in the table as "Cn" (undefined).
1103     (c) I revised the way the table is implemented to a much improved format
1104     which includes recognition of ranges. It now supports the ranges that
1105     are defined in UnicodeData.txt, and it also amalgamates other
1106     characters into ranges. This has reduced the number of entries in the
1107     table from around 16,000 to around 3,000, thus reducing its size
1108     considerably. I realized I did not need to use a tree structure after
1109     all - a binary chop search is just as efficient. Having reduced the
1110     number of entries, I extended their size from 6 bytes to 8 bytes to
1111     allow for more data.
1113     (d) Added support for Unicode script names via properties such as \p{Han}.
1115     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1116     matching that character.
1118     20. When matching a repeated Unicode property with a minimum greater than zero,
1119     (for example \pL{2,}), PCRE could look past the end of the subject if it
1120     reached it while seeking the minimum number of characters. This could
1121     happen only if some of the characters were more than one byte long, because
1122     there is a check for at least the minimum number of bytes.
1124     21. Refactored the implementation of \p and \P so as to be more general, to
1125     allow for more different types of property in future. This has changed the
1126     compiled form incompatibly. Anybody with saved compiled patterns that use
1127     \p or \P will have to recompile them.
1129     22. Added "Any" and "L&" to the supported property types.
1131     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1132     but give a compile time error if the value is greater than 0xff.
1134     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1135     accidentally not being installed or uninstalled.
1137     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1138     made were to insert the current release number. This seemed silly, because
1139     it made things harder for people building PCRE on systems that don't run
1140     "configure". I have turned pcre.h into a distributed file, no longer built
1141     by "configure", with the version identification directly included. There is
1142     no longer a pcre.h.in file.
1144     However, this change necessitated a change to the pcre-config script as
1145     well. It is built from pcre-config.in, and one of the substitutions was the
1146     release number. I have updated configure.ac so that ./configure now finds
1147     the release number by grepping pcre.h.
1149     26. Added the ability to run the tests under valgrind.
1152 nigel 85 Version 6.4 05-Sep-05
1153     ---------------------
1155     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1156     "--" to be printed when multiple files were scanned, even when none of the
1157     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1158     consider it to be a bug, and have restored the previous behaviour.
1160     2. A couple of code tidies to get rid of compiler warnings.
1162     3. The pcretest program used to cheat by referring to symbols in the library
1163     whose names begin with _pcre_. These are internal symbols that are not
1164     really supposed to be visible externally, and in some environments it is
1165     possible to suppress them. The cheating is now confined to including
1166     certain files from the library's source, which is a bit cleaner.
1168     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1169     file's purpose clearer.
1171     5. Reorganized pcre_ucp_findchar().
1174 nigel 83 Version 6.3 15-Aug-05
1175     ---------------------
1177     1. The file libpcre.pc.in did not have general read permission in the tarball.
1179     2. There were some problems when building without C++ support:
1181     (a) If C++ support was not built, "make install" and "make test" still
1182     tried to test it.
1184     (b) There were problems when the value of CXX was explicitly set. Some
1185     changes have been made to try to fix these, and ...
1187     (c) --disable-cpp can now be used to explicitly disable C++ support.
1189     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1190     backslash in a target when C++ was disabled. This confuses some
1191     versions of "make", apparently. Using an intermediate variable solves
1192     this. (Same for CPP_LOBJ.)
1194     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1195     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1196     necessary on certain architectures.
1198     4. Added a setting of -export-symbols-regex to the link command to remove
1199     those symbols that are exported in the C sense, but actually are local
1200     within the library, and not documented. Their names all begin with
1201     "_pcre_". This is not a perfect job, because (a) we have to except some
1202     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1203     available (and never for static libraries). I have made a note to try to
1204     find a way round (a) in the future.
1207 nigel 81 Version 6.2 01-Aug-05
1208     ---------------------
1210     1. There was no test for integer overflow of quantifier values. A construction
1211     such as {1111111111111111} would give undefined results. What is worse, if
1212     a minimum quantifier for a parenthesized subpattern overflowed and became
1213     negative, the calculation of the memory size went wrong. This could have
1214     led to memory overwriting.
1216     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1218     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1219     operating environments where this matters.
1221     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1222     PCRE options from within the C++ wrapper.
1224     5. Named capturing subpatterns were not being correctly counted when a pattern
1225     was compiled. This caused two problems: (a) If there were more than 100
1226     such subpatterns, the calculation of the memory needed for the whole
1227     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1228     back references of the form \12, where the number was greater than 9, were
1229     not recognized as back references, even though there were sufficient
1230     previous subpatterns.
1232     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1233     versions of gcc, e.g. 2.95.4.
1236 nigel 79 Version 6.1 21-Jun-05
1237     ---------------------
1239     1. There was one reference to the variable "posix" in pcretest.c that was not
1240     surrounded by "#if !defined NOPOSIX".
1242     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1243     the cross-check on the old pcre_info() function, for the benefit of the
1244     cut-down version of PCRE that is currently imported into Exim.
1246     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1247     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1248     patterns that start (?i) but I don't think that matters. The use of (?i) is
1249     just an example; this all applies to the other options as well.
1251     4. Since libtool seems to echo the compile commands it is issuing, the output
1252     from "make" can be reduced a bit by putting "@" in front of each libtool
1253     compile command.
1255     5. Patch from the folks at Google for configure.in to be a bit more thorough
1256     in checking for a suitable C++ installation before trying to compile the
1257     C++ stuff. This should fix a reported problem when a compiler was present,
1258     but no suitable headers.
1260     6. The man pages all had just "PCRE" as their title. I have changed them to
1261     be the relevant file name. I have also arranged that these names are
1262     retained in the file doc/pcre.txt, which is a concatenation in text format
1263     of all the man pages except the little individual ones for each function.
1265     7. The NON-UNIX-USE file had not been updated for the different set of source
1266     files that come with release 6. I also added a few comments about the C++
1267     wrapper.
1270 nigel 77 Version 6.0 07-Jun-05
1271     ---------------------
1273     1. Some minor internal re-organization to help with my DFA experiments.
1275     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1276     didn't matter for the library itself when fully configured, but did matter
1277     when compiling without UCP support, or within Exim, where the ucp files are
1278     not imported.
1280     3. Refactoring of the library code to split up the various functions into
1281     different source modules. The addition of the new DFA matching code (see
1282     below) to a single monolithic source would have made it really too
1283     unwieldy, quite apart from causing all the code to be include in a
1284     statically linked application, when only some functions are used. This is
1285     relevant even without the DFA addition now that patterns can be compiled in
1286     one application and matched in another.
1288     The downside of splitting up is that there have to be some external
1289     functions and data tables that are used internally in different modules of
1290     the library but which are not part of the API. These have all had their
1291     names changed to start with "_pcre_" so that they are unlikely to clash
1292     with other external names.
1294     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1295     a different (DFA) algorithm. Although it is slower than the original
1296     function, it does have some advantages for certain types of matching
1297     problem.
1299     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1300     including restarting after a partial match.
1302     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1303     defined when compiling for Windows was sent to me. I have put it into the
1304     code, though I have no means of testing or verifying it.
1306     7. Added the pcre_refcount() auxiliary function.
1308     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1309     match before or at the first newline in the subject string. In pcretest,
1310     the /f option on a pattern can be used to set this.
1312     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1313     would behave wrongly. This has been present in PCRE since release 4.0.
1315     10. A number of changes to the pcregrep command:
1317     (a) Refactored how -x works; insert ^(...)$ instead of setting
1318     PCRE_ANCHORED and checking the length, in preparation for adding
1319     something similar for -w.
1321     (b) Added the -w (match as a word) option.
1323     (c) Refactored the way lines are read and buffered so as to have more
1324     than one at a time available.
1326     (d) Implemented a pcregrep test script.
1328     (e) Added the -M (multiline match) option. This allows patterns to match
1329     over several lines of the subject. The buffering ensures that at least
1330     8K, or the rest of the document (whichever is the shorter) is available
1331     for matching (and similarly the previous 8K for lookbehind assertions).
1333     (f) Changed the --help output so that it now says
1335     -w, --word-regex(p)
1337     instead of two lines, one with "regex" and the other with "regexp"
1338     because that confused at least one person since the short forms are the
1339     same. (This required a bit of code, as the output is generated
1340     automatically from a table. It wasn't just a text change.)
1342     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1343     option but starts with a hyphen. Could be a pattern or a path name
1344     starting with a hyphen, for instance.
1346     (h) "-" can be given as a file name to represent stdin.
1348     (i) When file names are being printed, "(standard input)" is used for
1349     the standard input, for compatibility with GNU grep. Previously
1350     "<stdin>" was used.
1352     (j) The option --label=xxx can be used to supply a name to be used for
1353     stdin when file names are being printed. There is no short form.
1355     (k) Re-factored the options decoding logic because we are going to add
1356     two more options that take data. Such options can now be given in four
1357     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1359     (l) Added the -A, -B, and -C options for requesting that lines of context
1360     around matches be printed.
1362     (m) Added the -L option to print the names of files that do not contain
1363     any matching lines, that is, the complement of -l.
1365     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1366     continue to scan other files.
1368     (o) The -s option was incorrectly implemented. For compatibility with other
1369     greps, it now suppresses the error message for a non-existent or non-
1370     accessible file (but not the return code). There is a new option called
1371     -q that suppresses the output of matching lines, which was what -s was
1372     previously doing.
1374     (p) Added --include and --exclude options to specify files for inclusion
1375     and exclusion when recursing.
1377     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1378     Hopefully, it now does.
1380     12. Missing cast in pcre_study().
1382     13. Added an "uninstall" target to the makefile.
1384     14. Replaced "extern" in the function prototypes in Makefile.in with
1385     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1386     world, but is set differently for Windows.
1388     15. Added a second compiling function called pcre_compile2(). The only
1389     difference is that it has an extra argument, which is a pointer to an
1390     integer error code. When there is a compile-time failure, this is set
1391     non-zero, in addition to the error test pointer being set to point to an
1392     error message. The new argument may be NULL if no error number is required
1393     (but then you may as well call pcre_compile(), which is now just a
1394     wrapper). This facility is provided because some applications need a
1395     numeric error indication, but it has also enabled me to tidy up the way
1396     compile-time errors are handled in the POSIX wrapper.
1398     16. Added VPATH=.libs to the makefile; this should help when building with one
1399     prefix path and installing with another. (Or so I'm told by someone who
1400     knows more about this stuff than I do.)
1402     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1403     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1404     match everything, including newlines. This is not POSIX-compatible, but
1405     somebody wanted the feature. From pcretest it can be activated by using
1406     both the P and the s flags.
1408     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1410     19. libpcre.pc was being incorrectly installed as executable.
1412     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1413     it now also looks for '\r' so that it will work unmodified on Windows.
1415     21. Added Google's contributed C++ wrapper to the distribution.
1417     22. Added some untidy missing memory free() calls in pcretest, to keep
1418     Electric Fence happy when testing.
1422 nigel 75 Version 5.0 13-Sep-04
1423     ---------------------
1425     1. Internal change: literal characters are no longer packed up into items
1426     containing multiple characters in a single byte-string. Each character
1427     is now matched using a separate opcode. However, there may be more than one
1428     byte in the character in UTF-8 mode.
1430     2. The pcre_callout_block structure has two new fields: pattern_position and
1431     next_item_length. These contain the offset in the pattern to the next match
1432     item, and its length, respectively.
1434     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1435     insertion of callouts before each pattern item. Added the /C option to
1436     pcretest to make use of this.
1438     4. On the advice of a Windows user, the lines
1440     #if defined(_WIN32) || defined(WIN32)
1441     _setmode( _fileno( stdout ), 0x8000 );
1442     #endif /* defined(_WIN32) || defined(WIN32) */
1444     have been added to the source of pcretest. This apparently does useful
1445     magic in relation to line terminators.
1447     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1448     for the benefit of those environments where the "b" makes a difference.
1450     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1451     to know about it. I have put a hack into configure.in that adds in code
1452     to set GCC=yes if CC=icc. This seems to end up at a point in the
1453     generated configure script that is early enough to affect the setting of
1454     compiler options, which is what is needed, but I have no means of testing
1455     whether it really works. (The user who reported this had patched the
1456     generated configure script, which of course I cannot do.)
1458     LATER: After change 22 below (new libtool files), the configure script
1459     seems to know about icc (and also ecc). Therefore, I have commented out
1460     this hack in configure.in.
1462     7. Added support for pkg-config (2 patches were sent in).
1464     8. Negated POSIX character classes that used a combination of internal tables
1465     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1466     [[:^ascii]]. Typically, they would match almost any characters. The other
1467     POSIX classes were not broken in this way.
1469     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1470     to find the match, as PCRE was deluded into thinking that the match had to
1471     start at the start point or following a newline. The same bug applied to
1472     patterns with negative forward assertions or any backward assertions
1473     preceding ".*" at the start, unless the pattern required a fixed first
1474     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1476     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1477     starting at the last subject character, bytes beyond the end of the subject
1478     string were read.
1480     11. Renamed the variable "class" as "classbits" to make life easier for C++
1481     users. (Previously there was a macro definition, but it apparently wasn't
1482     enough.)
1484     12. Added the new field "tables" to the extra data so that tables can be passed
1485     in at exec time, or the internal tables can be re-selected. This allows
1486     a compiled regex to be saved and re-used at a later time by a different
1487     program that might have everything at different addresses.
1489     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1490     -R library as well as a -L library.
1492     14. The debugging options of pcretest (-d on the command line or D on a
1493     pattern) showed incorrect output for anything following an extended class
1494     that contained multibyte characters and which was followed by a quantifier.
1496     15. Added optional support for general category Unicode character properties
1497     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1498     support. It adds about 90K to the size of the library. The meanings of the
1499     inbuilt class escapes such as \d and \s have NOT been changed.
1501     16. Updated pcredemo.c to include calls to free() to release the memory for the
1502     compiled pattern.
1504     17. The generated file chartables.c was being created in the source directory
1505     instead of in the building directory. This caused the build to fail if the
1506     source directory was different from the building directory, and was
1507     read-only.
1509     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1510     file. No doubt somebody will tell me if they don't make sense... Also added
1511     Dan Mooney's comments about building on OpenVMS.
1513     19. Added support for partial matching via the PCRE_PARTIAL option for
1514     pcre_exec() and the \P data escape in pcretest.
1516     20. Extended pcretest with 3 new pattern features:
1518     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1519     write the compiled pattern to the file whose name is "rest-of-line".
1520     This is a straight binary dump of the data, with the saved pointer to
1521     the character tables forced to be NULL. The study data, if any, is
1522     written too. After writing, pcretest reads a new pattern.
1524     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1525     compiled pattern from the given file. There must not be any
1526     occurrences of "<" in the file name (pretty unlikely); if there are,
1527     pcretest will instead treat the initial "<" as a pattern delimiter.
1528     After reading in the pattern, pcretest goes on to read data lines as
1529     usual.
1531     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1532     and 16-bit fields in a compiled pattern, to simulate a pattern that
1533     was compiled on a host of opposite endianness.
1535     21. The pcre-exec() function can now cope with patterns that were compiled on
1536     hosts of opposite endianness, with this restriction:
1538     As for any compiled expression that is saved and used later, the tables
1539     pointer field cannot be preserved; the extra_data field in the arguments
1540     to pcre_exec() should be used to pass in a tables address if a value
1541     other than the default internal tables were used at compile time.
1543     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1544     now diagnosed as an error. Previously, most of the time, a negative number
1545     would have been treated as zero, but if in addition "ovector" was passed as
1546     NULL, a crash could occur.
1548     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1549     new versions from the libtool 1.5 distribution (the last one is a copy of
1550     a file called libtool.m4). This seems to have fixed the need to patch
1551     "configure" to support Darwin 1.3 (which I used to do). However, I still
1552     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1553     workstation).
1555     24. Changed the PCRE licence to be the more standard "BSD" licence.
1558 nigel 73 Version 4.5 01-Dec-03
1559     ---------------------
1561     1. There has been some re-arrangement of the code for the match() function so
1562     that it can be compiled in a version that does not call itself recursively.
1563     Instead, it keeps those local variables that need separate instances for
1564     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1565     needs to "recurse". Keeping track of where control must go is done by means
1566     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1567     hide most of the details from the main code, and operates only if
1568     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1569     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1570     operating.
1572     To make it easier for callers to provide specially tailored get/free
1573     functions for this usage, two new functions, pcre_stack_malloc, and
1574     pcre_stack_free, are used. They are always called in strict stacking order,
1575     and the size of block requested is always the same.
1577     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1578     PCRE has been compiled to use the stack or the heap for recursion. The
1579     -C option of pcretest uses this to show which version is compiled.
1581     A new data escape \S, is added to pcretest; it causes the amounts of store
1582     obtained and freed by both kinds of malloc/free at match time to be added
1583     to the output.
1585     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1586     what's available on my current Linux desktop machine.
1588     3. When matching a UTF-8 string, the test for a valid string at the start has
1589     been extended. If start_offset is not zero, PCRE now checks that it points
1590     to a byte that is the start of a UTF-8 character. If not, it returns
1591     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1592     this is necessary because there may be backward assertions in the pattern.
1593     When matching the same subject several times, it may save resources to use
1594     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1596     4. The code for checking the validity of UTF-8 strings has been tightened so
1597     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1598     containing "overlong sequences".
1600     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1601     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1602     should have been "&", but it just so happened that all the cases this let
1603     through by mistake were picked up later in the function.
1605     6. I had used a variable called "isblank" - this is a C99 function, causing
1606     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1608     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1609     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1610     so the version is shown; (c) stop "make test" echoing "./RunTest".
1612     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1614     9. The prototype for memmove() for systems that don't have it was using
1615     size_t, but the inclusion of the header that defines size_t was later. I've
1616     moved the #includes for the C headers earlier to avoid this.
1618     10. Added some adjustments to the code to make it easier to compiler on certain
1619     special systems:
1621     (a) Some "const" qualifiers were missing.
1622     (b) Added the macro EXPORT before all exported functions; by default this
1623     is defined to be empty.
1624     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1625     that it reads its output file name as an argument instead of writing
1626     to the standard output and assuming this can be redirected.
1628     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1629     class containing characters with values greater than 255, PCRE compilation
1630     went into a loop.
1632     12. A recursive reference to a subpattern that was within another subpattern
1633     that had a minimum quantifier of zero caused PCRE to crash. For example,
1634     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1635     recursion. If the recursively-called subpattern itself had a zero repeat,
1636     that was OK.
1638     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1639     buffer into which it was copied (for escape processing) was still set at
1640     1024, so long lines caused crashes.
1642     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1643     "internal error: code overflow...". This applied to any character class
1644     that was followed by a possessive quantifier.
1646     15. Modified the Makefile to add libpcre.la as a prerequisite for
1647     libpcreposix.la because I was told this is needed for a parallel build to
1648     work.
1650     16. If a pattern that contained .* following optional items at the start was
1651     studied, the wrong optimizing data was generated, leading to matching
1652     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1653     matching string must start with a or b or c. The correct conclusion for
1654     this pattern is that a match can start with any character.
1657 nigel 71 Version 4.4 13-Aug-03
1658     ---------------------
1660     1. In UTF-8 mode, a character class containing characters with values between
1661     127 and 255 was not handled correctly if the compiled pattern was studied.
1662     In fixing this, I have also improved the studying algorithm for such
1663     classes (slightly).
1665     2. Three internal functions had redundant arguments passed to them. Removal
1666     might give a very teeny performance improvement.
1668     3. Documentation bug: the value of the capture_top field in a callout is *one
1669     more than* the number of the hightest numbered captured substring.
1671     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1672     in incorrectly linking with a previously installed version. They now link
1673     explicitly with libpcre.la.
1675     5. configure.in no longer needs to recognize Cygwin specially.
1677     6. A problem in pcre.in for Windows platforms is fixed.
1679     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1680     pcretest, it used to include the size of the study block as part of its
1681     output. Unfortunately, the structure contains a field that has a different
1682     size on different hardware architectures. This meant that the tests that
1683     showed this size failed. As the block is currently always of a fixed size,
1684     this information isn't actually particularly useful in pcretest output, so
1685     I have just removed it.
1687     8. Three pre-processor statements accidentally did not start in column 1.
1688     Sadly, there are *still* compilers around that complain, even though
1689     standard C has not required this for well over a decade. Sigh.
1691     9. In pcretest, the code for checking callouts passed small integers in the
1692     callout_data field, which is a void * field. However, some picky compilers
1693     complained about the casts involved for this on 64-bit systems. Now
1694     pcretest passes the address of the small integer instead, which should get
1695     rid of the warnings.
1697     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1698     both compile and run time, and gives an error if an invalid UTF-8 sequence
1699     is found. There is a option for disabling this check in cases where the
1700     string is known to be correct and/or the maximum performance is wanted.
1702     11. In response to a bug report, I changed one line in Makefile.in from
1704     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1705     to
1706     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1708     to look similar to other lines, but I have no way of telling whether this
1709     is the right thing to do, as I do not use Windows. No doubt I'll get told
1710     if it's wrong...
1713 nigel 69 Version 4.3 21-May-03
1714     ---------------------
1716     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1717     Makefile.
1719     2. Some refactoring to improve the quality of the code:
1721     (i) The utf8_table... variables are now declared "const".
1723     (ii) The code for \cx, which used the "case flipping" table to upper case
1724     lower case letters, now just substracts 32. This is ASCII-specific,
1725     but the whole concept of \cx is ASCII-specific, so it seems
1726     reasonable.
1728     (iii) PCRE was using its character types table to recognize decimal and
1729     hexadecimal digits in the pattern. This is silly, because it handles
1730     only 0-9, a-f, and A-F, but the character types table is locale-
1731     specific, which means strange things might happen. A private
1732     table is now used for this - though it costs 256 bytes, a table is
1733     much faster than multiple explicit tests. Of course, the standard
1734     character types table is still used for matching digits in subject
1735     strings against \d.
1737     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1738     ending in _t are). So I've renamed it as ESC_tee.
1740     3. The first argument for regexec() in the POSIX wrapper should have been
1741     defined as "const".
1743     4. Changed pcretest to use malloc() for its buffers so that they can be
1744     Electric Fenced for debugging.
1746     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1747     to read one or more bytes before the start of the subject string. Often this
1748     had no effect on PCRE's behaviour, but in some circumstances it could
1749     provoke a segmentation fault.
1751     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1752     to try to read one or more bytes before the start of the subject string.
1754     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1755     UTF-8 support could misbehave in various ways if the subject string
1756     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1757     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1758     back over UTF-8 characters.)
1761 nigel 67 Version 4.2 14-Apr-03
1762     ---------------------
1764     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1766     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1767     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1768     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1769     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1770     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1771     and BUILD_EXEEXT
1772     Note: automatic setting of the BUILD variables is not yet working
1773     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1774     compile-time but not at link-time
1775     [LINK]: use for linking executables only
1776     make different versions for Windows and non-Windows
1777     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1778     libraries
1779     [LINK_FOR_BUILD]: new variable
1780     [OBJEXT]: use throughout
1781     [EXEEXT]: use throughout
1782     <winshared>: new target
1783     <wininstall>: new target
1784     <dftables.o>: use native compiler
1785     <dftables>: use native linker
1786     <install>: handle Windows platform correctly
1787     <clean>: ditto
1788     <check>: ditto
1789     copy DLL to top builddir before testing
1791     As part of these changes, -no-undefined was removed again. This was reported
1792     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1793     in any case.
1795     3. Some tidies to get rid of compiler warnings:
1797     . In the match_data structure, match_limit was an unsigned long int, whereas
1798     match_call_count was an int. I've made them both unsigned long ints.
1800     . In pcretest the fact that a const uschar * doesn't automatically cast to
1801     a void * provoked a warning.
1803     . Turning on some more compiler warnings threw up some "shadow" variables
1804     and a few more missing casts.
1806     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1807     option, a class that contained a single character with a value between 128
1808     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1810     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1811     option, a class that contained several characters, but with at least one
1812     whose value was between 128 and 255 caused PCRE to crash.
1815 nigel 65 Version 4.1 12-Mar-03
1816     ---------------------
1817 nigel 63
1818 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1819     needed, and a string in dftables.c that was longer than standard compilers are
1820     required to support.
1822     2. Compiling with Sun's compiler found a few more places where the code could
1823     be tidied up in order to avoid warnings.
1825     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1826     first of these names is deprecated in the latest Autoconf in favour of the name
1827     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1828     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1829     analogy I have changed it to CFLAGS_FOR_BUILD.
1831     4. Added -no-undefined to the linking command in the Makefile, because this is
1832     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1833     linking step for the pcreposix library.
1835     5. PCRE was failing to diagnose the case of two named groups with the same
1836     name.
1838     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1839     literal character that is needed in the subject for a match, and scans along to
1840     ensure that it is present before embarking on the full matching process. This
1841     saves time in cases of nested unlimited repeats that are never going to match.
1842     Problem: the scan can take a lot of time if the subject is very long (e.g.
1843     megabytes), thus penalizing straightforward matches. It is now done only if the
1844     amount of subject to be scanned is less than 1000 bytes.
1846     7. A lesser problem with the same optimization is that it was recording the
1847     first character of an anchored pattern as "needed", thus provoking a search
1848     right along the subject, even when the first match of the pattern was going to
1849     fail. The "needed" character is now not set for anchored patterns, unless it
1850     follows something in the pattern that is of non-fixed length. Thus, it still
1851     fulfils its original purpose of finding quick non-matches in cases of nested
1852     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1855     Version 4.0 17-Feb-03
1856     ---------------------
1858 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1859     extended to the end of string, PCRE compiled incorrect data. This could lead to
1860     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1862     2. Moved to autoconf 2.53 and libtool 1.4.2.
1864     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1865     the special perltest8 script is no longer needed - all the tests can be run
1866     from a single perltest script.
1868     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1869     by \s. It has now been removed in PCRE. This means it isn't recognized as
1870     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1871     class [:space:] *does* include VT, thereby creating a mess.
1873     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1874     space and tab.
1876     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1877     its new features into the main test script, reducing the number of scripts.
1879     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1880     were backward compatible, and made the (?i) apply to the whole pattern, as if
1881     /i were given. Now it behaves more logically, and applies the option setting
1882     only to what follows. PCRE has been changed to follow suit. However, if it
1883     finds options settings right at the start of the pattern, it extracts them into
1884     the global options, as before. Thus, they show up in the info data.
1886     8. Added support for the \Q...\E escape sequence. Characters in between are
1887     treated as literals. This is slightly different from Perl in that $ and @ are
1888     also handled as literals inside the quotes. In Perl, they will cause variable
1889     interpolation. Note the following examples:
1891     Pattern PCRE matches Perl matches
1893     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1894     \Qabc\$xyz\E abc\$xyz abc\$xyz
1895     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1897     For compatibility with Perl, \Q...\E sequences are recognized inside character
1898     classes as well as outside them.
1900     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1901     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1902     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1903     signed/unsigned warnings.
1905     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1906     option for pcretest, so I've replaced it by a simple function that does just
1907     that job.
1909     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1910     "pcregrep -".
1912     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1913     Java package. This provides some syntactic sugar for simple cases of what my
1914     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1915     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1916     item, you can use this simplified notation. Note that only makes sense with
1917     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1918     greediness, whatever the setting of the PCRE_UNGREEDY option.
1920     13. A change of greediness default within a pattern was not taking effect at
1921     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1922     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1923     was abstracted outside.
1925     14. PCRE now supports the \G assertion. It is true when the current matching
1926     position is at the start point of the match. This differs from \A when the
1927     starting offset is non-zero. Used with the /g option of pcretest (or similar
1928     code), it works in the same way as it does for Perl's /g option. If all
1929     alternatives of a regex begin with \G, the expression is anchored to the start
1930     match position, and the "anchored" flag is set in the compiled expression.
1932     15. Some bugs concerning the handling of certain option changes within patterns
1933     have been fixed. These applied to options other than (?ims). For example,
1934     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1935     been the other way round. Some of this was related to change 7 above.
1937     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1938     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1939     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1940     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1942     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1943     mode. Unlike ".", it always matches newline, whatever the setting of
1944     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1945     assertions. Perl allows it, but it doesn't (in general) work because it can't
1946     calculate the length of the lookbehind. At least, that's the case for Perl
1947     5.8.0 - I've been told they are going to document that it doesn't work in
1948     future.
1950     18. Added an error diagnosis for escapes that PCRE does not support: these are
1951     \L, \l, \N, \P, \p, \U, \u, and \X.
1953     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1954     reading past the end of the pattern in cases such as /[abcd/.
1956     20. PCRE was getting more memory than necessary for patterns with classes that
1957     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1959     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1960     compiling PCRE for use with Virtual Pascal.
1962     22. Small fix to the Makefile to make it work properly if the build is done
1963     outside the source tree.
1965     23. Added a new extension: a condition to go with recursion. If a conditional
1966     subpattern starts with (?(R) the "true" branch is used if recursion has
1967     happened, whereas the "false" branch is used only at the top level.
1969     24. When there was a very long string of literal characters (over 255 bytes
1970     without UTF support, over 250 bytes with UTF support), the computation of how
1971     much memory was required could be incorrect, leading to segfaults or other
1972     strange effects.
1974     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1975     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1976     there was a subsequent back reference to those brackets. This meant that, for
1977     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1978     possible to check for precisely this case. All we can do is abandon the
1979     optimization if .* occurs inside capturing brackets when there are any back
1980     references whatsoever. (See below for a better fix that came later.)
1982     26. The handling of the optimization for finding the first character of a
1983     non-anchored pattern, and for finding a character that is required later in the
1984     match were failing in some cases. This didn't break the matching; it just
1985     failed to optimize when it could. The way this is done has been re-implemented.
1987     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1989     28. Added a new feature that provides some of the functionality that Perl
1990     provides with (?{...}). The facility is termed a "callout". The way it is done
1991     in PCRE is for the caller to provide an optional function, by setting
1992     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1993     global variable. By default it is unset, which disables all calling out. To get
1994     the function called, the regex must include (?C) at appropriate points. This
1995     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1996     This provides a means of identifying different callout points. When PCRE
1997     reaches such a point in the regex, if pcre_callout has been set, the external
1998     function is called. It is provided with data in a structure called
1999     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2000     matching continues; if it returns a non-zero value, the match at the current
2001     point fails. However, backtracking will occur if possible. [This was changed
2002     later and other features added - see item 49 below.]
2004     29. pcretest is upgraded to test the callout functionality. It provides a
2005     callout function that displays information. By default, it shows the start of
2006     the match and the current position in the text. There are some new data escapes
2007     to vary what happens:
2009     \C+ in addition, show current contents of captured substrings
2010     \C- do not supply a callout function
2011     \C!n return 1 when callout number n is reached
2012     \C!n!m return 1 when callout number n is reached for the mth time
2014     30. If pcregrep was called with the -l option and just a single file name, it
2015     output "<stdin>" if a match was found, instead of the file name.
2017     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2018     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2019     pcre_exec(). This saves a malloc/free per call. The default value of
2020     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2021     when configuring.
2023     32. The default maximum size of a compiled pattern is 64K. There have been a
2024     few cases of people hitting this limit. The code now uses macros to handle the
2025     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2026     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2027     configuring. Tests 2 and 5 work only with 2-byte links because they output
2028     debugging information about compiled patterns.
2030     33. Internal code re-arrangements:
2032     (a) Moved the debugging function for printing out a compiled regex into
2033     its own source file (printint.c) and used #include to pull it into
2034     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2035     separate copies.
2037     (b) Defined the list of op-code names for debugging as a macro in
2038     internal.h so that it is next to the definition of the opcodes.
2040     (c) Defined a table of op-code lengths for simpler skipping along compiled
2041     code. This is again a macro in internal.h so that it is next to the
2042     definition of the opcodes.
2044     34. Added support for recursive calls to individual subpatterns, along the
2045     lines of Robin Houston's patch (but implemented somewhat differently).
2047     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2048     allow it to read and process whole directories in Win32. This code was
2049     contributed by Lionel Fourquaux; it has not been tested by me.
2051     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2052     used to name a group. Names consist of alphanumerics and underscores, and must
2053     be unique. Back references use the syntax (?P=name) and recursive calls use
2054     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2055     numbers. The function pcre_fullinfo() can be used after compilation to extract
2056     a name/number map. There are three relevant calls:
2058     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2059     PCRE_INFO_NAMECOUNT yields the number of entries
2060     PCRE_INFO_NAMETABLE yields a pointer to the map.
2062     The map is a vector of fixed-size entries. The size of each entry depends on
2063     the length of the longest name used. The first two bytes of each entry are the
2064     group number, most significant byte first. There follows the corresponding
2065     name, zero terminated. The names are in alphabetical order.
2067     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2068     case instead of 255. Making it the same both with and without UTF-8 support
2069     means that the same test output works with both.
2071     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2072     calling malloc() with a zero argument.
2074     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2075     optimization. I've improved things by keeping a bitmap of backreferences with
2076     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2077     fact referenced, the optimization can be applied. It is unlikely that a
2078     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2079     the match to follow \n) will appear inside brackets with a number greater than
2080     31, but if it does, any back reference > 31 suppresses the optimization.
2082     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2083     of disabling numbered capturing parentheses. Any opening parenthesis that is
2084     not followed by ? behaves as if it were followed by ?: but named parentheses
2085     can still be used for capturing (and they will acquire numbers in the usual
2086     way).
2088     41. Redesigned the return codes from the match() function into yes/no/error so
2089     that errors can be passed back from deep inside the nested calls. A malloc
2090     failure while inside a recursive subpattern call now causes the
2091     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2093     42. It is now possible to set a limit on the number of times the match()
2094     function is called in a call to pcre_exec(). This facility makes it possible to
2095     limit the amount of recursion and backtracking, though not in a directly
2096     obvious way, because the match() function is used in a number of different
2097     circumstances. The count starts from zero for each position in the subject
2098     string (for non-anchored patterns). The default limit is, for compatibility, a
2099     large number, namely 10 000 000. You can change this in two ways:
2101     (a) When configuring PCRE before making, you can use --with-match-limit=n
2102     to set a default value for the compiled library.
2104     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2105     a different value is set. See 45 below.
2107     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2109     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2110     of things that can be changed at compile time. The first argument specifies
2111     what is wanted and the second points to where the information is to be placed.
2112     The current list of available information is:
2116     The output is an integer that is set to one if UTF-8 support is available;
2117     otherwise it is set to zero.
2121     The output is an integer that it set to the value of the code that is used for
2122     newline. It is either LF (10) or CR (13).
2126     The output is an integer that contains the number of bytes used for internal
2127     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2131     The output is an integer that contains the threshold above which the POSIX
2132     interface uses malloc() for output vectors. See item 31 above.
2136     The output is an unsigned integer that contains the default limit of the number
2137     of match() calls in a pcre_exec() execution. See 42 above.
2139     44. pcretest has been upgraded by the addition of the -C option. This causes it
2140     to extract all the available output from the new pcre_config() function, and to
2141     output it. The program then exits immediately.
2143     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2144     order to support additional features. One way would have been to define
2145     pcre_exec2() (for example) with extra arguments, but this would not have been
2146     extensible, and would also have required all calls to the original function to
2147     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2148     is used for passing in "extra" data from pcre_study().
2150     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2151     contains the following fields:
2153     flags a bitmap indicating which of the following fields are set
2154     study_data opaque data from pcre_study()
2155     match_limit a way of specifying a limit on match() calls for a specific
2156     call to pcre_exec()
2157     callout_data data for callouts (see 49 below)
2159     The flag bits are also defined in pcre.h, and are
2165     The pcre_study() function now returns one of these new pcre_extra blocks, with
2166     the actual study data pointed to by the study_data field, and the
2167     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2168     before. That is, this change is entirely upwards-compatible and requires no
2169     change to existing code.
2171     If you want to pass in additional data to pcre_exec(), you can either place it
2172     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2173     block.
2175     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2176     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2177     times with different match limits, until it finds the minimum value needed for
2178     pcre_exec() to complete. The value is then output. This can be instructive; for
2179     most simple matches the number is quite small, but for pathological cases it
2180     gets very large very quickly.
2182     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2183     returns the size of the data block pointed to by the study_data field in a
2184     pcre_extra block, that is, the value that was passed as the argument to
2185     pcre_malloc() when PCRE was getting memory in which to place the information
2186     created by pcre_study(). The fourth argument should point to a size_t variable.
2187     pcretest has been extended so that this information is shown after a successful
2188     pcre_study() call when information about the compiled regex is being displayed.
2190     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2191     because what follows is always an absolute path. (Later: it turns out that this
2192     is more than cosmetic for MinGW, because it doesn't like empty path
2193     components.)
2195     49. Some changes have been made to the callout feature (see 28 above):
2197     (i) A callout function now has three choices for what it returns:
2199     0 => success, carry on matching
2200     > 0 => failure at this point, but backtrack if possible
2201     < 0 => serious error, return this value from pcre_exec()
2203     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2204     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2205     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2206     use by callout functions. It will never be used by PCRE itself.
2208     (ii) The pcre_extra structure (see 45 above) has a void * field called
2209     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2210     pcre_callout_block structure has a field of the same name. The contents of
2211     the field passed in the pcre_extra structure are passed to the callout
2212     function in the corresponding field in the callout block. This makes it
2213     easier to use the same callout-containing regex from multiple threads. For
2214     testing, the pcretest program has a new data escape
2216     \C*n pass the number n (may be negative) as callout_data
2218     If the callout function in pcretest receives a non-zero value as
2219     callout_data, it returns that value.
2221     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2222     there were some redundant $(CFLAGS) in commands that are now specified as
2223     $(LINK), which already includes $(CFLAGS).
2225     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2226     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2227     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2228     one-byte characters throughout. Note that case-insensitive matching applies
2229     only to characters whose values are less than 256. PCRE doesn't support the
2230     notion of cases for higher-valued characters.
2232     (i) A character class whose characters are all within 0-255 is handled as
2233     a bit map, and the map is inverted for negative classes. Previously, a
2234     character > 255 always failed to match such a class; however it should
2235     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2237     (ii) A negated character class with a single character < 255 is coded as
2238     "not this character" (OP_NOT). This wasn't working properly when the test
2239     character was multibyte, either singly or repeated.
2241     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2242     mode, for example: \x{100}{2,3}.
2244     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2245     singly or repeated) now correctly test multibyte characters. However,
2246     PCRE doesn't recognize any characters with values greater than 255 as
2247     digits, spaces, or word characters. Such characters always match \D, \S,
2248     and \W, and never match \d, \s, or \w.
2250     (v) Classes may now contain characters and character ranges with values
2251     greater than 255. For example: [ab\x{100}-\x{400}].
2253     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2254     PCRE in UTF-8 mode.
2256     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2257     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2258     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2259     value.)
2261     53. The single man page has become too large. I have therefore split it up into
2262     a number of separate man pages. These also give rise to individual HTML pages;
2263     these are now put in a separate directory, and there is an index.html page that
2264     lists them all. Some hyperlinking between the pages has been installed.
2266     54. Added convenience functions for handling named capturing parentheses.
2268     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2269     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2270     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2271     are faulted.
2273     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2274     calling configure. These values are used when compiling the dftables.c program
2275     which is run to generate the source of the default character tables. They
2276     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2277     you will need to set these values.
2279     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2282     Version 3.9 02-Jan-02
2283 nigel 61 ---------------------
2285     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2287     2. If --disable-static was given, the building process failed when trying to
2288     build pcretest and pcregrep. (For some reason it was using libtool to compile
2289     them, which is not right, as they aren't part of the library.)
2292 nigel 59 Version 3.8 18-Dec-01
2293     ---------------------
2295     1. The experimental UTF-8 code was completely screwed up. It was packing the
2296     bytes in the wrong order. How dumb can you get?
2299 nigel 57 Version 3.7 29-Oct-01
2300     ---------------------
2302     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2303     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2304     this didn't happen under Solaris 8, where I normally test things.
2306 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2307     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2308     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2309     this fix an hour or so after the initial 3.7 release.)
2310 nigel 57
2311 nigel 59
2312 nigel 55 Version 3.6 23-Oct-01
2313     ---------------------
2315     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2316     offsets passed as NULL with zero offset count.
2318     2. The config.guess and config.sub files had not been updated when I moved to
2319     the latest autoconf.
2322 nigel 53 Version 3.5 15-Aug-01
2323     ---------------------
2324 nigel 5
2325 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2326     had been forgotten.
2328     2. By using declared but undefined structures, we can avoid using "void"
2329     definitions in pcre.h while keeping the internal definitions of the structures
2330     private.
2332     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2333     user point of view, this means that both static and shared libraries are built
2334     by default, but this can be individually controlled. More of the work of
2335     handling this static/shared cases is now inside libtool instead of PCRE's make
2336     file.
2338     4. The pcretest utility is now installed along with pcregrep because it is
2339     useful for users (to test regexs) and by doing this, it automatically gets
2340     relinked by libtool. The documentation has been turned into a man page, so
2341     there are now .1, .txt, and .html versions in /doc.
2343     5. Upgrades to pcregrep:
2344     (i) Added long-form option names like gnu grep.
2345     (ii) Added --help to list all options with an explanatory phrase.
2346     (iii) Added -r, --recursive to recurse into sub-directories.
2347     (iv) Added -f, --file to read patterns from a file.
2349     6. pcre_exec() was referring to its "code" argument before testing that
2350     argument for NULL (and giving an error if it was NULL).
2352     7. Upgraded Makefile.in to allow for compiling in a different directory from
2353     the source directory.
2355     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2356     options bits, the pointer it was passed was to an int instead of to an unsigned
2357     long int. This mattered only on 64-bit systems.
2359     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2360     generated) instead of pcre.in, which it its source. Also made the same change
2361     in several of the .c files.
2363     10. A new release of gcc defines printf() as a macro, which broke pcretest
2364     because it had an ifdef in the middle of a string argument for printf(). Fixed
2365     by using separate calls to printf().
2367     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2368     script, to force use of CR or LF instead of \n in the source. On non-Unix
2369     systems, the value can be set in config.h.
2371     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2372     absolute limit. Changed the text of the error message to make this clear, and
2373     likewise updated the man page.
2375     13. The limit of 99 on the number of capturing subpatterns has been removed.
2376     The new limit is 65535, which I hope will not be a "real" limit.
2379 nigel 51 Version 3.4 22-Aug-00
2380     ---------------------
2382     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2384     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2387 nigel 49 Version 3.3 01-Aug-00
2388     ---------------------
2390     1. If an octal character was given, but the value was greater than \377, it
2391     was not getting masked to the least significant bits, as documented. This could
2392     lead to crashes in some systems.
2394     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2395     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2397     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2398     These just pass their arguments on to (pcre_free)(), but they are provided
2399     because some uses of PCRE bind it to non-C systems that can call its functions,
2400     but cannot call free() or pcre_free() directly.
2402     4. Add "make test" as a synonym for "make check". Corrected some comments in
2403     the Makefile.
2405     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2406     Makefile.
2408     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2409     command called pgrep for grepping around the active processes.
2411     7. Added the beginnings of support for UTF-8 character strings.
2413     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2414     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2415     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2416     out for the ar command.)
2419 nigel 47 Version 3.2 12-May-00
2420     ---------------------
2422     This is purely a bug fixing release.
2424     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2425     of ZA. This was just one example of several cases that could provoke this bug,
2426     which was introduced by change 9 of version 2.00. The code for breaking
2427     infinite loops after an iteration that matches an empty string was't working
2428     correctly.
2430     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2431     when matched against abbab (for example). After matching an empty string, it
2432     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2433     caused it to match further down the string than it should.
2435     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2436     was there because it doesn't seem to be needed, and it causes trouble on some
2437     systems, as it is not a Standard C header. It has been removed.
2439     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2440     were reported on the Macintosh. The changes were from
2442     while ((c = *(++ptr)) != 0 && c != '\n');
2443     to
2444     while ((c = *(++ptr)) != 0 && c != '\n') ;
2446     Totally extraordinary, but if that's what it takes...
2448     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2449     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2450     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2451     assumes the way PCRE uses memmove() (always moving upwards).
2453     6. PCRE is being used in one environment where strchr() is not available. There
2454     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2455     faster code anyway.
2458 nigel 45 Version 3.1 09-Feb-00
2459     ---------------------
2461     The only change in this release is the fixing of some bugs in Makefile.in for
2462     the "install" target:
2464     (1) It was failing to install pcreposix.h.
2466     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2469 nigel 43 Version 3.0 01-Feb-00
2470     ---------------------
2471 nigel 41
2472     1. Add support for the /+ modifier to perltest (to output $` like it does in
2473     pcretest).
2475     2. Add support for the /g modifier to perltest.
2477     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2478     matches null strings.
2480     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2481     pattern. Perl treats empty patterns specially - it reuses the most recent
2482     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2483     effect.
2485     5. The POSIX interface was broken in that it was just handing over the POSIX
2486     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2487     required a bigger vector, with some working space on the end. This means that
2488     the POSIX wrapper now has to get and free some memory, and copy the results.
2490 nigel 43 6. Added some simple autoconf support, placing the test data and the
2491     documentation in separate directories, re-organizing some of the
2492     information files, and making it build pcre-config (a GNU standard). Also added
2493     libtool support for building PCRE as a shared library, which is now the
2494     default.
2495 nigel 41
2496 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2497     09 are not valid octal constants. Single digits will be used for minor values
2498     less than 10.
2500     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2501     existing programs that set these in the POSIX interface can use PCRE without
2502     modification.
2504     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2505     return all that pcre_info() returns, plus additional data. The pcre_info()
2506     function is retained for compatibility, but is considered to be obsolete.
2508     10. Added experimental recursion feature (?R) to handle one common case that
2509     Perl 5.6 will be able to do with (?p{...}).
2511     11. Added support for POSIX character classes like [:alpha:], which Perl is
2512     adopting.
2515 nigel 39 Version 2.08 31-Aug-99
2516     ----------------------
2518     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2519     trying to match at the startoffset position, but instead was moving forward to
2520     the next newline as if a previous match had failed.
2522     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2523     and could get into a loop if a null string was matched other than at the start
2524     of the subject.
2526     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2527     be distinguished at compile time, and for completeness also added PCRE_DATE.
2529     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2530     in GnuWin32 environments.
2533 nigel 37 Version 2.07 29-Jul-99
2534     ----------------------
2536     1. The documentation is now supplied in plain text form and HTML as well as in
2537     the form of man page sources.
2539     2. C++ compilers don't like assigning (void *) values to other pointer types.
2540     In particular this affects malloc(). Although there is no problem in Standard
2541     C, I've put in casts to keep C++ compilers happy.
2543     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2544     should be (const char *).
2546     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2547     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2548     However, I haven't made this a standard facility. The documentation doesn't
2549     mention it, and the Makefile doesn't support it.
2551     5. The Makefile now contains an "install" target, with editable destinations at
2552     the top of the file. The pcretest program is not installed.
2554     6. pgrep -V now gives the PCRE version number and date.
2556     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2557     causing the entire string to be ignored, instead of just the last character.
2559     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2560     non-matching string, it can take a very, very long time, even for strings of
2561     quite modest length, because of the nested recursion. PCRE now does better in
2562     some of these cases. It does this by remembering the last required literal
2563     character in the pattern, and pre-searching the subject to ensure it is present
2564     before running the real match. In other words, it applies a heuristic to detect
2565     some types of certain failure quickly, and in the above example, if presented
2566     with a string that has no trailing " it gives "no match" very quickly.
2568     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2569     other alternatives are tried instead.
2572 nigel 35 Version 2.06 09-Jun-99
2573     ----------------------
2575     1. Change pcretest's output for amount of store used to show just the code
2576     space, because the remainder (the data block) varies in size between 32-bit and
2577     64-bit systems.
2579     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2580     start matching at. This allows lookbehinds to work when searching for multiple
2581     occurrences in a string.
2583     3. Added additional options to pcretest for testing multiple occurrences:
2585     /+ outputs the rest of the string that follows a match
2586     /g loops for multiple occurrences, using the new startoffset argument
2587     /G loops for multiple occurrences by passing an incremented pointer
2589     4. PCRE wasn't doing the "first character" optimization for patterns starting
2590     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2591     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2592     the letter 'x'. On long subject strings, this gives a significant speed-up.
2595 nigel 33 Version 2.05 21-Apr-99
2596     ----------------------
2598     1. Changed the type of magic_number from int to long int so that it works
2599     properly on 16-bit systems.
2601     2. Fixed a bug which caused patterns starting with .* not to work correctly
2602     when the subject string contained newline characters. PCRE was assuming
2603     anchoring for such patterns in all cases, which is not correct because .* will
2604     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2605     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2606     must be retried after every newline in the subject.
2609 nigel 31 Version 2.04 18-Feb-99
2610     ----------------------
2612     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2613     computation of the store needed to hold the pattern was incorrect (too large).
2614     If such patterns were nested a few deep, this could multiply and become a real
2615     problem.
2617     2. Added /M option to pcretest to show the memory requirement of a specific
2618     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2620     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2621     compiled in such a way that the backtracking after subsequent failure was
2622     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2623     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2626 nigel 29 Version 2.03 02-Feb-99
2627     ----------------------
2629     1. Fixed typo and small mistake in man page.
2631 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2632     LICENCE file containing the conditions.
2633 nigel 29
2634     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2635     Perl, that is the internal \ allows the delimiter to be included in the
2636     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2637     the final delimiter, add \ to the end of the pattern (to test the error).
2639     4. Added the convenience functions for extracting substrings after a successful
2640     match. Updated pcretest to make it able to test these functions.
2643 nigel 27 Version 2.02 14-Jan-99
2644     ----------------------
2646     1. Initialized the working variables associated with each extraction so that
2647     their saving and restoring doesn't refer to uninitialized store.
2649     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2650     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2651     fix the problem.
2653     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2654     calls, and wasn't printing the correct value for compiling calls. Increased the
2655     default value of LOOPREPEAT, and the number of significant figures in the
2656     times.
2658     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2660     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2661     a building problem on Windows NT with a FAT file system.
2664 nigel 25 Version 2.01 21-Oct-98
2665     ----------------------
2667     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2668     to character tables built by pcre_maketables() in the current locale. If NULL
2669     is passed, the default tables are used.
2672 nigel 23 Version 2.00 24-Sep-98
2673 nigel 21 ----------------------
2675 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2676     it any more.
2678     2. Allow quantification of (?>) groups, and make it work correctly.
2680     3. The first character computation wasn't working for (?>) groups.
2682     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2683     end of the subject) and add 5.005's \z, which really does match only at the
2684     very end of the subject.
2686     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2688     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2689     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2690     localized options. All options to pcre_study() were also removed.
2692     7. Add other new features from 5.005:
2694     $(?<= positive lookbehind
2695     $(?<! negative lookbehind
2696     (?imsx-imsx) added the unsetting capability
2697     such a setting is global if at outer level; local otherwise
2698     (?imsx-imsx:) non-capturing groups with option setting
2699     (?(cond)re|re) conditional pattern matching
2701     A backreference to itself in a repeated group matches the previous
2702     captured string.
2704     8. General tidying up of studying (both automatic and via "study")
2705     consequential on the addition of new assertions.
2707     9. As in 5.005, unlimited repeated groups that could match an empty substring
2708     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2709     runtime if any iteration does actually match an empty substring.
2711     10. Include the RunTest script in the distribution.
2713     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2714     discrepancies, some of which were old and were also with respect to 5.004. They
2715     have now been fixed.
2718     Version 1.09 28-Apr-98
2719     ----------------------
2721 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2722     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2723     program crashes, or just wrong answers. This did not apply to negated classes
2724     containing more than one character, or to minima other than one.
2727 nigel 19 Version 1.08 27-Mar-98
2728     ----------------------
2730     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2732     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2733     latter must appear before anything that relies on it in the pattern.
2736 nigel 17 Version 1.07 16-Feb-98
2737     ----------------------
2739     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2740     repeat of a potentially empty string).
2743 nigel 15 Version 1.06 23-Jan-98
2744     ----------------------
2746     1. Added Markus Oberhumer's little patches for C++.
2748     2. Literal strings longer than 255 characters were broken.
2751 nigel 13 Version 1.05 23-Dec-97
2752     ----------------------
2754     1. Negated character classes containing more than one character were failing if
2755     PCRE_CASELESS was set at run time.
2758 nigel 11 Version 1.04 19-Dec-97
2759     ----------------------
2761     1. Corrected the man page, where some "const" qualifiers had been omitted.
2763     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2764     input syntax.
2766     3. Fixed memory leak which occurred when a regex with back references was
2767     matched with an offsets vector that wasn't big enough. The temporary memory
2768     that is used in this case wasn't being freed if the match failed.
2770     4. Tidied pcretest to ensure it frees memory that it gets.
2772     5. Temporary memory was being obtained in the case where the passed offsets
2773     vector was exactly big enough.
2775     6. Corrected definition of offsetof() from change 5 below.
2777     7. I had screwed up change 6 below and broken the rules for the use of
2778     setjmp(). Now fixed.
2781 nigel 9 Version 1.03 18-Dec-97
2782     ----------------------
2784     1. A erroneous regex with a missing opening parenthesis was correctly
2785     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2786     on some systems.
2788     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2789     it was reported that one broken compiler failed on the former because "code" is
2790     also an independent variable.
2792     3. The erroneous regex a[]b caused an array overrun reference.
2794     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2795     fail on data ending with that character. (It was going on too far, and checking
2796     the next character, typically a binary zero.) This was specific to the
2797     optimized code for single-character negative classes.
2799     5. Added a contributed patch from the TIN world which does the following:
2801     + Add an undef for memmove, in case the the system defines a macro for it.
2803     + Add a definition of offsetof(), in case there isn't one. (I don't know
2804     the reason behind this - offsetof() is part of the ANSI standard - but
2805     it does no harm).
2807     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2808     most of the places where whitespace preceded '#'. I have given up and
2809     allowed the remaining 2 cases to be at the margin.
2811     + Rename some variables in pcre to eliminate shadowing. This seems very
2812     pedantic, but does no harm, of course.
2814     6. Moved the call to setjmp() into its own function, to get rid of warnings
2815     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2817     7. Constructs such as \d{8,} were compiling into the equivalent of
2818 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2819 nigel 9 outcome, but in this particular case used more store than had been allocated,
2820     which caused the bug to be discovered because it threw up an internal error.
2822     8. The debugging code in both pcre and pcretest for outputting the compiled
2823     form of a regex was going wrong in the case of back references followed by
2824     curly-bracketed repeats.
2827 nigel 7 Version 1.02 12-Dec-97
2828     ----------------------
2830     1. Typos in pcre.3 and comments in the source fixed.
2832     2. Applied a contributed patch to get rid of places where it used to remove
2833     'const' from variables, and fixed some signed/unsigned and uninitialized
2834     variable warnings.
2836     3. Added the "runtest" target to Makefile.
2838     4. Set default compiler flag to -O2 rather than just -O.
2841 nigel 5 Version 1.01 19-Nov-97
2842     ----------------------
2844     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2845     like /([ab]*)*/, that is, for classes with more than one character in them.
2847     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2848     as /((?>a*))*/ (a PCRE_EXTRA facility).
2851     Version 1.00 18-Nov-97
2852     ----------------------
2854     1. Added compile-time macros to support systems such as SunOS4 which don't have
2855     memmove() or strerror() but have other things that can be used instead.
2857     2. Arranged that "make clean" removes the executables.
2860 nigel 3 Version 0.99 27-Oct-97
2861     ----------------------
2863     1. Fixed bug in code for optimizing classes with only one character. It was
2864     initializing a 32-byte map regardless, which could cause it to run off the end
2865     of the memory it had got.
2867     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2870     Version 0.98 22-Oct-97
2871     ----------------------
2873     1. Fixed bug in code for handling temporary memory usage when there are more
2874     back references than supplied space in the ovector. This could cause segfaults.
2877     Version 0.97 21-Oct-97
2878     ----------------------
2880     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2882     2. Optimized negated single characters not to use a bit map.
2884     3. Brought error texts together as macro definitions; clarified some of them;
2885     fixed one that was wrong - it said "range out of order" when it meant "invalid
2886     escape sequence".
2888     4. Changed some char * arguments to const char *.
2890     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2892     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2893     pcretest.
2896     Version 0.96 16-Oct-97
2897     ----------------------
2899     1. Added a simple "pgrep" utility to the distribution.
2901     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2902     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2903     where "ddd" means "one or more decimal digits".
2905     3. Fixed serious bug. If a pattern had a back reference, but the call to
2906     pcre_exec() didn't supply a large enough ovector to record the related
2907     identifying subpattern, the match always failed. PCRE now remembers the number
2908     of the largest back reference, and gets some temporary memory in which to save
2909     the offsets during matching if necessary, in order to ensure that
2910     backreferences always work.
2912     4. Increased the compatibility with Perl in a number of ways:
2914     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2915     to request this handling. The option can be set at compile or exec time.
2917     (b) $ matches before a terminating newline by default; an option
2918     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2919     mode). The option can be set at compile or exec time.
2921     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2922     the same as Perl's. If the decimal number it represents is less than 10
2923     or there aren't that many previous left capturing parentheses, an octal
2924     escape is read. Inside a character class, it's always an octal escape,
2925     even if it is a single digit.
2927     (d) An escaped but undefined alphabetic character is taken as a literal,
2928     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2929     escapes.
2931     (e) {0} is now permitted. (The previous item is removed from the compiled
2932     pattern).
2934     5. Changed all the names of code files so that the basic parts are no longer
2935     than 10 characters, and abolished the teeny "globals.c" file.
2937     6. Changed the handling of character classes; they are now done with a 32-byte
2938     bit map always.
2940     7. Added the -d and /D options to pcretest to make it possible to look at the
2941     internals of compilation without having to recompile pcre.
2944     Version 0.95 23-Sep-97
2945     ----------------------
2947     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2948     \x20 at the start of a run of normal characters. These were being treated as
2949     real characters, instead of the source characters being re-checked.
2952     Version 0.94 18-Sep-97
2953     ----------------------
2955     1. The functions are now thread-safe, with the caveat that the global variables
2956     containing pointers to malloc() and free() or alternative functions are the
2957     same for all threads.
2959     2. Get pcre_study() to generate a bitmap of initial characters for non-
2960     anchored patterns when this is possible, and use it if passed to pcre_exec().
2963     Version 0.93 15-Sep-97
2964     ----------------------
2966     1. /(b)|(:+)/ was computing an incorrect first character.
2968     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2969     but not actually doing anything yet.
2971     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2972     as Perl does (e.g. [-az] or [az-]).
2974     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2975     all possible positions.
2977     5. Split up into different modules to avoid including unneeded functions in a
2978     compiled binary. However, compile and exec are still in one module. The "study"
2979     function is split off.
2981     6. The character tables are now in a separate module whose source is generated
2982     by an auxiliary program - but can then be edited by hand if required. There are
2983     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2984     toupper() in the code.
2986     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2987     make them global. Abolish the function for setting them, as the caller can now
2988     set them directly.
2991     Version 0.92 11-Sep-97
2992     ----------------------
2994     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2995     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2997     2. Caseless matching was not working in character classes if the characters in
2998     the pattern were in upper case.
3000     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3002     4. Make PCRE_ANCHORED public and accept as a compile option.
3004     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3005     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3006     pass them.
3008     6. Give an error if bad option bits passed at compile or run time.
3010     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3011     pcretest to cause it to pass that flag.
3013     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3014     options, and the first character, if set.
3016     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3019     Version 0.91 10-Sep-97
3020     ----------------------
3022     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3023     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3025     2. PCRE was looping on encountering an indefinitely repeated back reference to
3026     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3027     Perl does - treats the match as successful.
3029     ****


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