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Revision 274 - (hide annotations) (download)
Tue Nov 20 10:05:23 2007 UTC (6 years, 10 months ago) by ph10
File size: 143771 byte(s)
Change "alphameric" to "alphanumeric".

1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 ph10 263 Version 7.5 12-Nov-07
5     ---------------------
6    
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 267
17     4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18     defined or documented. It seems to have been a typo for PCRE_STATIC, so
19     I have changed it.
20 ph10 268
21     5. The construct (?&) was not diagnosed as a syntax error (it referenced the
22     first named subpattern) and a construct such as (?&a) would reference the
23     first named subpattern whose name started with "a" (in other words, the
24 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
25     expected" is now given for (?&) (a zero-length name), and this patch also
26     makes it give the same error for \k'' (previously it complained that that
27     was a reference to a non-existent subpattern).
28 ph10 269
29     6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
30     this is right because (?- can be followed by option settings as well as by
31     digits. I have, however, made the messages clearer.
32 ph10 270
33     7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34     than the number used in the conditional) now cause a compile-time error.
35     This is actually not compatible with Perl, which accepts such patterns, but
36     treats the conditional as always being FALSE (as PCRE used to), but it
37     seems to me that giving a diagnostic is better.
38 ph10 274
39     8. Change "alphameric" to the more common word "alphanumeric" in comments
40     and messages.
41 ph10 263
42    
43 ph10 260 Version 7.4 21-Sep-07
44 ph10 230 ---------------------
45    
46     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
47 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
48     LF". That isn't really right - the whole point of the change was to try to
49     help when there was an actual mention of one of the two characters. So now
50     the change happens only if \r or \n (or a literal CR or LF) character is
51 ph10 230 encountered.
52 ph10 231
53     2. The 32-bit options word was also used for 6 internal flags, but the numbers
54     of both had grown to the point where there were only 3 bits left.
55     Fortunately, there was spare space in the data structure, and so I have
56     moved the internal flags into a new 16-bit field to free up more option
57 ph10 230 bits.
58 ph10 231
59     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
60     but did not set the internal JCHANGED flag - either of these is enough to
61     control the way the "get" function works - but the PCRE_INFO_JCHANGED
62     facility is supposed to tell if (?J) was ever used, so now (?J) at the
63 ph10 230 start sets both bits.
64    
65 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
66     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
67 ph10 230
68 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
69    
70     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
71 ph10 233 compatibility, even though it is no longer used.
72 ph10 243
73     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
74 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
75 ph10 259 windows.h file is present (where different names are used). [This was
76 ph10 257 reversed later after testing - see 16 below.]
77 ph10 243
78     8. Changed all #include <config.h> to #include "config.h". There were also
79 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
80 ph10 243
81 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
82 ph10 243 sequence off the lines that it output.
83    
84     10. It was pointed out to me that arrays of string pointers cause lots of
85     relocations when a shared library is dynamically loaded. A technique of
86     using a single long string with a table of offsets can drastically reduce
87     these. I have refactored PCRE in four places to do this. The result is
88 ph10 240 dramatic:
89 ph10 243
90 ph10 240 Originally: 290
91     After changing UCP table: 187
92 ph10 243 After changing error message table: 43
93 ph10 240 After changing table of "verbs" 36
94     After changing table of Posix names 22
95 ph10 243
96 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
97 ph10 247
98 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
99 ph10 247 unicode-properties was also set.
100    
101 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
102 ph10 231
103 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
104     checked only for CRLF.
105 ph10 233
106 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
107    
108 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
109 ph10 253
110 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
111 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
112     entirely. This removes changes made in 7 above.
113 ph10 256
114 ph10 261 17. The CMake files have been updated, and there is now more information about
115     building with CMake in the NON-UNIX-USE document.
116 ph10 257
117 ph10 261
118 ph10 228 Version 7.3 28-Aug-07
119 ph10 157 ---------------------
120    
121 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
122     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
123     brackets there is not right, since it causes compilers to look for an
124     installed pcre.h, not the version that is in the source that is being
125     compiled (which of course may be different). I have changed it back to:
126 ph10 197
127 ph10 189 #include "pcre.h"
128 ph10 197
129     I have a vague recollection that the change was concerned with compiling in
130     different directories, but in the new build system, that is taken care of
131     by the VPATH setting the Makefile.
132    
133 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
134     when the subject happened to end in the byte 0x85 (e.g. if the last
135     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
136     characters but of course it shouldn't be taken as a newline when it is part
137     of another character. The bug was that, for an unlimited repeat of . in
138     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
139     characters when looking for a newline.
140 ph10 197
141     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
142    
143     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
144     in debug output.
145    
146 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
147     long printing in the pcrecpp unittest when running under MinGW.
148 ph10 189
149 ph10 197 6. ESC_K was left out of the EBCDIC table.
150 ph10 189
151 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
152     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
153     limit also applies to "virtual nesting" when a pattern is recursive, and in
154     this case 1000 isn't so big. I have been able to remove this limit at the
155     expense of backing off one optimization in certain circumstances. Normally,
156     when pcre_exec() would call its internal match() function recursively and
157     immediately return the result unconditionally, it uses a "tail recursion"
158     feature to save stack. However, when a subpattern that can match an empty
159     string has an unlimited repetition quantifier, it no longer makes this
160     optimization. That gives it a stack frame in which to save the data for
161     checking that an empty string has been matched. Previously this was taken
162     from the 1000-entry workspace that had been reserved. So now there is no
163     explicit limit, but more stack is used.
164 ph10 189
165 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
166     syntax that is required for Windows, and which was going wrong for the
167     pcreposix and pcrecpp parts of the library. These were overlooked when this
168     problem was solved for the main library.
169 ph10 197
170 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
171     the size of patterns that contain repeated groups with explicit upper
172     limits. As the maximum quantifier is 65535, the maximum group length was
173     set at 30,000 so that the product of these two numbers did not overflow a
174     32-bit integer. However, it turns out that people want to use groups that
175     are longer than 30,000 bytes (though not repeat them that many times).
176     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
177     made it possible to implement the integer overflow checks in a much more
178     dynamic way, which I have now done. The artificial limitation on group
179     length has been removed - we now have only the limit on the total length of
180     the compiled pattern, which depends on the LINK_SIZE setting.
181 ph10 208
182     10. Fixed a bug in the documentation for get/copy named substring when
183     duplicate names are permitted. If none of the named substrings are set, the
184     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
185     empty string.
186    
187     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
188     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
189     because the ] is interpreted as the first data character and the
190     terminating ] is not found. PCRE has been made compatible with Perl in this
191     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
192     cause memory overwriting.
193    
194 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
195     string has been matched (to stop an infinite loop). It was not recognizing
196 ph10 208 a conditional subpattern that could match an empty string if that
197 ph10 206 subpattern was within another subpattern. For example, it looped when
198 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
199 ph10 206 condition was not nested. This bug has been fixed.
200 ph10 208
201 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
202     past the start of the subject in the presence of bytes with the top bit
203     set, for example "\x8aBCD".
204 ph10 211
205 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
206     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
207 ph10 200
208 ph10 211 14. Optimized (?!) to (*FAIL).
209 ph10 202
210 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
211     This restricts code points to be within the range 0 to 0x10FFFF, excluding
212     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
213     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
214     does: it's just the validity check that is more restrictive.
215 ph10 220
216     16. Inserted checks for integer overflows during escape sequence (backslash)
217     processing, and also fixed erroneous offset values for syntax errors during
218     backslash processing.
219    
220 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
221 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
222    
223 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
224     caused an overrun.
225 ph10 220
226     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
227     something other than just ASCII characters) inside a group that had an
228     unlimited repeat caused a loop at compile time (while checking to see
229     whether the group could match an empty string).
230    
231 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
232     [\P{Any}] did so. (Error in the code for printing property names.)
233 ph10 210
234 ph10 220 21. An orphan \E inside a character class could cause a crash.
235    
236     22. A repeated capturing bracket such as (A)? could cause a wild memory
237 ph10 218 reference during compilation.
238 ph10 220
239     23. There are several functions in pcre_compile() that scan along a compiled
240     expression for various reasons (e.g. to see if it's fixed length for look
241 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
242 ph10 220 present in the pattern. These operators have additional parameters compared
243     with \d, etc, and these were not being taken into account when moving along
244 ph10 218 the compiled data. Specifically:
245 ph10 220
246     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
247     length.
248    
249     (b) An item such as \pL+ within a repeated group could cause crashes or
250 ph10 218 loops.
251 ph10 220
252 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
253 ph10 220 "reference to non-existent subpattern" error.
254    
255 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
256    
257 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
258 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
259 ph10 211
260 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
261 ph10 218
262 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
263 ph10 223 character were causing crashes (broken optimization).
264 ph10 227
265 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
266 ph10 227 \p or \P) caused a compile-time loop.
267    
268 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
269     break. For example, the unstudied pattern [\r\n]A does not match the string
270     "\r\nA" because change 7.0/46 below moves the current point on by two
271     characters after failing to match at the start. However, the pattern \nA
272 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
273     the same is true. There doesn't seem any very clean way out of this, but
274     what I have chosen to do makes the common cases work: PCRE now takes note
275     of whether there can be an explicit match for \r or \n anywhere in the
276     pattern, and if so, 7.0/46 no longer applies. As part of this change,
277     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
278     pattern has explicit CR or LF references.
279 ph10 222
280 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
281 ph10 223
282 ph10 227
283 ph10 189 Version 7.2 19-Jun-07
284     ---------------------
285    
286 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
287     which is apparently normally available under Windows.
288 ph10 159
289     2. Re-jig the pcregrep tests with different newline settings in an attempt
290     to make them independent of the local environment's newline setting.
291 ph10 157
292 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
293 ph10 165
294 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
295     was not 2, because the output contained actual offsets. The recent new
296 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
297     usable with all link sizes.
298    
299 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
300     stack recursion. This gives a massive performance boost under BSD, but just
301 ph10 165 a small improvement under Linux. However, it saves one field in the frame
302 ph10 164 in all cases.
303 ph10 172
304 ph10 166 6. Added more features from the forthcoming Perl 5.10:
305 ph10 172
306 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
307     recursion call. It refers to the nth most recently opened parentheses.
308 ph10 172
309 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
310 ph10 172 to be opened parentheses.
311    
312     (c) Conditions that refer to capturing parentheses can be specified
313 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
314 ph10 172
315 ph10 168 (d) \K resets the start of the current match so that everything before
316 ph10 172 is not part of it.
317    
318 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
319 ph10 172
320 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
321 ph10 172 reference syntax.
322 ph10 182
323 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
324 ph10 182 alternative starts with the same number.
325 ph10 172
326 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
327    
328 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
329     PCRE_INFO_JCHANGED.
330    
331     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
332     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
333 ph10 170 for detecting groups that can match an empty string.
334 ph10 159
335 ph10 172 9. A pattern with a very large number of alternatives (more than several
336     hundred) was running out of internal workspace during the pre-compile
337     phase, where pcre_compile() figures out how much memory will be needed. A
338     bit of new cunning has reduced the workspace needed for groups with
339     alternatives. The 1000-alternative test pattern now uses 12 bytes of
340     workspace instead of running out of the 4096 that are available.
341 ph10 182
342 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
343 ph10 172
344 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
345     The report of the bug said:
346 ph10 182
347 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
348     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
349 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
350 ph10 185
351 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
352 ph10 185 it matched the wrong number of bytes.
353 ph10 172
354 ph10 179
355 ph10 155 Version 7.1 24-Apr-07
356 ph10 98 ---------------------
357    
358 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
359 ph10 122 that is more "standard", making use of automake and other Autotools. There
360 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
361     on this.
362 ph10 111
363     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
364     for recursive directory scanning broke on some systems because the files
365     are not scanned in any specific order and on different systems the order
366     was different. A call to "sort" has been inserted into RunGrepTest for the
367     approprate test as a short-term fix. In the longer term there may be an
368 ph10 100 alternative.
369 ph10 111
370 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
371 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
372     people do their own conversions for various reasons). The problems
373     concerned the use of low-level troff macros .br and .in. I have therefore
374     removed all such uses from the man pages (some were redundant, some could
375 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
376     HTML has been updated to handle .nf/.fi and to complain if it encounters
377     .br or .in.
378 ph10 111
379 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
380 ph10 123 arranged for config.h to be included in the distribution, with the name
381 ph10 111 config.h.generic, for the benefit of those who have to compile without
382     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
383    
384     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
385     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
386 ph10 127 makevp.bat for the current PCRE, using the additional files
387 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
388 ph10 111
389     6. A Windows user reported a minor discrepancy with test 2, which turned out
390     to be caused by a trailing space on an input line that had got lost in his
391 ph10 102 copy. The trailing space was an accident, so I've just removed it.
392 ph10 111
393 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
394 ph10 111 that is needed.
395    
396 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
397     as "const" (a) because they are and (b) because it helps the PHP
398     maintainers who have recently made a script to detect big data structures
399 ph10 111 in the php code that should be moved to the .rodata section. I remembered
400     to update Builducptable as well, so it won't revert if ucptable.h is ever
401 ph10 105 re-created.
402 ph10 111
403     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
404 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
405 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
406     support is not required. This saves 1.5-2K of code, which is important in
407 ph10 107 some applications.
408 ph10 111
409 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
410 ph10 111 so as not to refer to the tables, even though these functions will never be
411     called when UTF-8 support is disabled. Otherwise there are problems with a
412     shared library.
413    
414 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
415    
416     (a) It was defining its arguments as char * instead of void *.
417    
418 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
419     a long time ago when I wrote it, but is no longer the case.
420    
421 ph10 118 The emulated memove() is provided for those environments that have neither
422 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
423 ph10 118 is clearly not the case, as these two bugs were recently reported.
424 ph10 123
425 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
426 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
427     pages, and it removes trailing spaces from listed files. It also creates
428     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
429     case, it wraps all the #defines with #ifndefs. This script should be run
430 ph10 111 before "make dist".
431 ph10 123
432 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
433     with Unicode property support.
434 ph10 123
435     (a) For a maximizing quantifier, if the two different cases of the
436     character were of different lengths in their UTF-8 codings (there are
437     some cases like this - I found 11), and the matching function had to
438 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
439     were both the same length.
440 ph10 123
441     (b) When PCRE was configured to use the heap rather than the stack for
442     recursion during matching, it was not correctly preserving the data for
443     the other case of a UTF-8 character when checking ahead for a match
444     while processing a minimizing repeat. If the check also involved
445 ph10 115 matching a wide character, but failed, corruption could cause an
446     erroneous result when trying to check for a repeat of the original
447     character.
448 ph10 123
449 ph10 116 13. Some tidying changes to the testing mechanism:
450 ph10 98
451 ph10 116 (a) The RunTest script now detects the internal link size and whether there
452     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
453 ph10 123 values substituted by "configure". (The RunGrepTest script already did
454     this for UTF-8.) The configure.ac script no longer substitutes the
455     relevant variables.
456    
457 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
458     with length and offset values. This means that the output is different
459     for different internal link sizes. Test 2 is skipped for link sizes
460     other than 2 because of this, bypassing the problem. Unfortunately,
461     there was also a test in test 3 (the locale tests) that used /B and
462 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
463     I have added a new /Z option to pcretest that replaces the length and
464     offset values with spaces. This is now used to make test 3 independent
465 ph10 122 of link size. (Test 2 will be tidied up later.)
466 ph10 123
467     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
468 ph10 122 segmentation fault instead of returning the appropriate error message.
469 ph10 134
470 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
471 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
472     This doesn't seem right; it now treats the CRLF combination as the line
473     ending, and so does not match in that case. It's only a pattern such as ^$
474     that would hit this one: something like ^ABC$ would have failed after \r
475     and then tried again after \r\n.
476    
477 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
478 ph10 134 in an attempt to make files that differ only in their line terminators
479     compare equal. This works on Linux.
480 ph10 142
481 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
482     as it exited. This is now fixed, thanks to valgrind.
483 ph10 142
484 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
485 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
486     was because its rules for how to advance for /g after matching an empty
487 ph10 143 string at the end of a line did not allow for this case. They now check for
488     it specially.
489 ph10 150
490     20. pcretest is supposed to handle patterns and data of any length, by
491     extending its buffers when necessary. It was getting this wrong when the
492 ph10 147 buffer for a data line had to be extended.
493 ph10 150
494 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
495 ph10 150 CRLF as a newline sequence.
496 ph10 152
497 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
498 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
499     I have nevertheless tidied it up.
500 ph10 111
501 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
502 ph10 123
503 ph10 153 24. Added a man page for pcre-config.
504 ph10 152
505 ph10 153
506 nigel 93 Version 7.0 19-Dec-06
507     ---------------------
508    
509     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
510     moving to gcc 4.1.1.
511    
512     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
513     sys/time.h, which is documented as needed for this function. It doesn't
514     seem to matter on Linux, but it showed up on some releases of OS X.
515    
516     3. It seems that there are systems where bytes whose values are greater than
517     127 match isprint() in the "C" locale. The "C" locale should be the
518     default when a C program starts up. In most systems, only ASCII printing
519     characters match isprint(). This difference caused the output from pcretest
520     to vary, making some of the tests fail. I have changed pcretest so that:
521    
522     (a) When it is outputting text in the compiled version of a pattern, bytes
523     other than 32-126 are always shown as hex escapes.
524    
525     (b) When it is outputting text that is a matched part of a subject string,
526     it does the same, unless a different locale has been set for the match
527     (using the /L modifier). In this case, it uses isprint() to decide.
528    
529     4. Fixed a major bug that caused incorrect computation of the amount of memory
530     required for a compiled pattern when options that changed within the
531     pattern affected the logic of the preliminary scan that determines the
532     length. The relevant options are -x, and -i in UTF-8 mode. The result was
533     that the computed length was too small. The symptoms of this bug were
534     either the PCRE error "internal error: code overflow" from pcre_compile(),
535     or a glibc crash with a message such as "pcretest: free(): invalid next
536     size (fast)". Examples of patterns that provoked this bug (shown in
537     pcretest format) are:
538    
539     /(?-x: )/x
540     /(?x)(?-x: \s*#\s*)/
541     /((?i)[\x{c0}])/8
542     /(?i:[\x{c0}])/8
543    
544     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
545     is now done differently.
546    
547     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
548     wrapper classes; (b) implement a new function in the C++ scanner that is
549     more efficient than the old way of doing things because it avoids levels of
550     recursion in the regex matching; (c) add a paragraph to the documentation
551     for the FullMatch() function.
552    
553     6. The escape sequence \n was being treated as whatever was defined as
554     "newline". Not only was this contrary to the documentation, which states
555     that \n is character 10 (hex 0A), but it also went horribly wrong when
556     "newline" was defined as CRLF. This has been fixed.
557    
558     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
559     was being set to -1 for the "end of line" case (supposedly a value that no
560     character can have). Though this value is never used (the check for end of
561     line is "zero bytes in current character"), it caused compiler complaints.
562     I've changed it to 0xffffffff.
563    
564     8. In pcre_version.c, the version string was being built by a sequence of
565     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
566     string (as it is for production releases) called a macro with an empty
567     argument. The C standard says the result of this is undefined. The gcc
568     compiler treats it as an empty string (which was what was wanted) but it is
569     reported that Visual C gives an error. The source has been hacked around to
570     avoid this problem.
571    
572     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
573     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
574     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
575     of them did).
576    
577     10. Originally, pcretest opened its input and output without "b"; then I was
578     told that "b" was needed in some environments, so it was added for release
579     5.0 to both the input and output. (It makes no difference on Unix-like
580     systems.) Later I was told that it is wrong for the input on Windows. I've
581     now abstracted the modes into two macros, to make it easier to fiddle with
582     them, and removed "b" from the input mode under Windows.
583    
584     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
585    
586     12. Added -help and --help to pcretest as an official way of being reminded
587     of the options.
588    
589     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
590     and pcrecpp.cc because they annoy compilers at high warning levels.
591    
592     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
593    
594     15. Fixed an occurrence of == in configure.ac that should have been = (shell
595     scripts are not C programs :-) and which was not noticed because it works
596     on Linux.
597    
598     16. pcretest is supposed to handle any length of pattern and data line (as one
599     line or as a continued sequence of lines) by extending its input buffer if
600     necessary. This feature was broken for very long pattern lines, leading to
601     a string of junk being passed to pcre_compile() if the pattern was longer
602     than about 50K.
603    
604     17. I have done a major re-factoring of the way pcre_compile() computes the
605     amount of memory needed for a compiled pattern. Previously, there was code
606     that made a preliminary scan of the pattern in order to do this. That was
607     OK when PCRE was new, but as the facilities have expanded, it has become
608     harder and harder to keep it in step with the real compile phase, and there
609     have been a number of bugs (see for example, 4 above). I have now found a
610     cunning way of running the real compile function in a "fake" mode that
611     enables it to compute how much memory it would need, while actually only
612     ever using a few hundred bytes of working memory and without too many
613     tests of the mode. This should make future maintenance and development
614     easier. A side effect of this work is that the limit of 200 on the nesting
615     depth of parentheses has been removed (though this was never a serious
616     limitation, I suspect). However, there is a downside: pcre_compile() now
617     runs more slowly than before (30% or more, depending on the pattern). I
618     hope this isn't a big issue. There is no effect on runtime performance.
619    
620     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
621     newline (only possible for the last line of a file) and it was a
622     pattern that set a locale (followed by /Lsomething), pcretest crashed.
623    
624     19. Added additional timing features to pcretest. (1) The -tm option now times
625     matching only, not compiling. (2) Both -t and -tm can be followed, as a
626     separate command line item, by a number that specifies the number of
627     repeats to use when timing. The default is 50000; this gives better
628     precision, but takes uncomfortably long for very large patterns.
629    
630     20. Extended pcre_study() to be more clever in cases where a branch of a
631     subpattern has no definite first character. For example, (a*|b*)[cd] would
632     previously give no result from pcre_study(). Now it recognizes that the
633     first character must be a, b, c, or d.
634    
635     21. There was an incorrect error "recursive call could loop indefinitely" if
636     a subpattern (or the entire pattern) that was being tested for matching an
637     empty string contained only one non-empty item after a nested subpattern.
638     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
639     incorrectly, because the \d was being skipped in the check.
640    
641     22. The pcretest program now has a new pattern option /B and a command line
642     option -b, which is equivalent to adding /B to every pattern. This causes
643     it to show the compiled bytecode, without the additional information that
644     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
645     is the same as /B/I).
646    
647     23. A new optimization is now able automatically to treat some sequences such
648     as a*b as a*+b. More specifically, if something simple (such as a character
649     or a simple class like \d) has an unlimited quantifier, and is followed by
650     something that cannot possibly match the quantified thing, the quantifier
651     is automatically "possessified".
652    
653     24. A recursive reference to a subpattern whose number was greater than 39
654     went wrong under certain circumstances in UTF-8 mode. This bug could also
655     have affected the operation of pcre_study().
656    
657     25. Realized that a little bit of performance could be had by replacing
658     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
659    
660     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
661    
662     27. Possessive quantifiers such as a++ were previously implemented by turning
663     them into atomic groups such as ($>a+). Now they have their own opcodes,
664     which improves performance. This includes the automatically created ones
665     from 23 above.
666    
667     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
668     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
669     the first matched character to be a colon. This applied both to named and
670     numbered groups.
671    
672     29. The ucpinternal.h header file was missing its idempotency #ifdef.
673    
674     30. I was sent a "project" file called libpcre.a.dev which I understand makes
675     building PCRE on Windows easier, so I have included it in the distribution.
676    
677     31. There is now a check in pcretest against a ridiculously large number being
678     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
679     loop, the loop is abandoned.
680    
681     32. Forward references to subpatterns in conditions such as (?(2)...) where
682     subpattern 2 is defined later cause pcre_compile() to search forwards in
683     the pattern for the relevant set of parentheses. This search went wrong
684     when there were unescaped parentheses in a character class, parentheses
685     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
686    
687     33. "Subroutine" calls and backreferences were previously restricted to
688     referencing subpatterns earlier in the regex. This restriction has now
689     been removed.
690    
691     34. Added a number of extra features that are going to be in Perl 5.10. On the
692     whole, these are just syntactic alternatives for features that PCRE had
693     previously implemented using the Python syntax or my own invention. The
694     other formats are all retained for compatibility.
695    
696     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
697     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
698     also .NET compatible.
699    
700     (b) A recursion or subroutine call to a named group can now be defined as
701     (?&name) as well as (?P>name).
702    
703     (c) A backreference to a named group can now be defined as \k<name> or
704     \k'name' as well as (?P=name). The new forms, as well as being in Perl
705     5.10, are also .NET compatible.
706    
707     (d) A conditional reference to a named group can now use the syntax
708     (?(<name>) or (?('name') as well as (?(name).
709    
710     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
711     groups (named and numbered) that are never evaluated inline, but can be
712     called as "subroutines" from elsewhere. In effect, the DEFINE condition
713     is always false. There may be only one alternative in such a group.
714    
715     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
716     as the simple (?(R). The condition is true only if the most recent
717     recursion is that of the given number or name. It does not search out
718     through the entire recursion stack.
719    
720     (g) The escape \gN or \g{N} has been added, where N is a positive or
721     negative number, specifying an absolute or relative reference.
722    
723     35. Tidied to get rid of some further signed/unsigned compiler warnings and
724     some "unreachable code" warnings.
725    
726     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
727     things, this adds five new scripts.
728    
729     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
730     There were also incompatibilities regarding the handling of \Q..\E inside
731     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
732     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
733    
734     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
735     matches an empty string, and forcibly breaks the loop. There were bugs in
736     this code in non-simple cases. For a pattern such as ^(a()*)* matched
737     against aaaa the result was just "a" rather than "aaaa", for example. Two
738     separate and independent bugs (that affected different cases) have been
739     fixed.
740    
741     39. Refactored the code to abolish the use of different opcodes for small
742     capturing bracket numbers. This is a tidy that I avoided doing when I
743     removed the limit on the number of capturing brackets for 3.5 back in 2001.
744     The new approach is not only tidier, it makes it possible to reduce the
745     memory needed to fix the previous bug (38).
746    
747     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
748     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
749     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
750     mode.
751    
752     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
753     report.
754    
755     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
756     copy construction and assignment in the C++ wrapper.
757    
758     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
759     couple of bugs that could have given wrong results in the "--newline=crlf"
760     case.
761    
762     44. Added a number of casts and did some reorganization of signed/unsigned int
763     variables following suggestions from Dair Grant. Also renamed the variable
764     "this" as "item" because it is a C++ keyword.
765    
766     45. Arranged for dftables to add
767    
768     #include "pcre_internal.h"
769    
770     to pcre_chartables.c because without it, gcc 4.x may remove the array
771     definition from the final binary if PCRE is built into a static library and
772     dead code stripping is activated.
773    
774     46. For an unanchored pattern, if a match attempt fails at the start of a
775     newline sequence, and the newline setting is CRLF or ANY, and the next two
776     characters are CRLF, advance by two characters instead of one.
777    
778    
779 nigel 91 Version 6.7 04-Jul-06
780     ---------------------
781    
782     1. In order to handle tests when input lines are enormously long, pcretest has
783     been re-factored so that it automatically extends its buffers when
784     necessary. The code is crude, but this _is_ just a test program. The
785     default size has been increased from 32K to 50K.
786    
787     2. The code in pcre_study() was using the value of the re argument before
788     testing it for NULL. (Of course, in any sensible call of the function, it
789     won't be NULL.)
790    
791     3. The memmove() emulation function in pcre_internal.h, which is used on
792     systems that lack both memmove() and bcopy() - that is, hardly ever -
793     was missing a "static" storage class specifier.
794    
795     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
796     containing an extended class (one that cannot be represented by a bitmap
797     because it contains high-valued characters or Unicode property items, e.g.
798     [\pZ]). Almost always one would set UTF-8 mode when processing such a
799     pattern, but PCRE should not loop if you do not (it no longer does).
800     [Detail: two cases were found: (a) a repeated subpattern containing an
801     extended class; (b) a recursive reference to a subpattern that followed a
802     previous extended class. It wasn't skipping over the extended class
803     correctly when UTF-8 mode was not set.]
804    
805     5. A negated single-character class was not being recognized as fixed-length
806     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
807     compile error "lookbehind assertion is not fixed length".
808    
809     6. The RunPerlTest auxiliary script was showing an unexpected difference
810     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
811     write a Perl script that can interpret lines of an input file either as
812     byte characters or as UTF-8, which is what "perltest" was being required to
813     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
814     can't do is switch easily at run time between having the "use utf8;" pragma
815     or not. In the end, I fudged it by using the RunPerlTest script to insert
816     "use utf8;" explicitly for the UTF-8 tests.
817    
818     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
819     the end of the subject string, contrary to the documentation and to what
820     Perl does. This was true of both matching functions. Now it matches only at
821     the start of the subject and immediately after *internal* newlines.
822    
823     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
824     a pointer to an int instead of a pointer to an unsigned long int. This
825     caused problems on 64-bit systems.
826    
827     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
828     instance of the 'standard' template library not being so standard".
829    
830     10. There was no check on the number of named subpatterns nor the maximum
831     length of a subpattern name. The product of these values is used to compute
832     the size of the memory block for a compiled pattern. By supplying a very
833     long subpattern name and a large number of named subpatterns, the size
834     computation could be caused to overflow. This is now prevented by limiting
835     the length of names to 32 characters, and the number of named subpatterns
836     to 10,000.
837    
838     11. Subpatterns that are repeated with specific counts have to be replicated in
839     the compiled pattern. The size of memory for this was computed from the
840     length of the subpattern and the repeat count. The latter is limited to
841     65535, but there was no limit on the former, meaning that integer overflow
842     could in principle occur. The compiled length of a repeated subpattern is
843     now limited to 30,000 bytes in order to prevent this.
844    
845     12. Added the optional facility to have named substrings with the same name.
846    
847     13. Added the ability to use a named substring as a condition, using the
848     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
849     are numbers (not recommended). Forward references are permitted.
850    
851     14. Added forward references in named backreferences (if you see what I mean).
852    
853     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
854     pattern could run off the end of the subject. For example, the pattern
855     "(?s)(.{1,5})"8 did this with the subject "ab".
856    
857     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
858     PCRE_CASELESS was set when matching characters that were quantified with ?
859     or *.
860    
861     17. A character class other than a single negated character that had a minimum
862     but no maximum quantifier - for example [ab]{6,} - was not handled
863     correctly by pce_dfa_exec(). It would match only one character.
864    
865     18. A valid (though odd) pattern that looked like a POSIX character
866     class but used an invalid character after [ (for example [[,abc,]]) caused
867     pcre_compile() to give the error "Failed: internal error: code overflow" or
868     in some cases to crash with a glibc free() error. This could even happen if
869     the pattern terminated after [[ but there just happened to be a sequence of
870     letters, a binary zero, and a closing ] in the memory that followed.
871    
872     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
873     over the years. Originally (before any Unicode support), just the bottom 8
874     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
875     output from "man perlunicode" includes this:
876    
877     The regular expression compiler produces polymorphic opcodes. That
878     is, the pattern adapts to the data and automatically switches to
879     the Unicode character scheme when presented with Unicode data--or
880     instead uses a traditional byte scheme when presented with byte
881     data.
882    
883     Sadly, a wide octal escape does not cause a switch, and in a string with
884     no other multibyte characters, these octal escapes are treated as before.
885     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
886     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
887     Unicode string.
888    
889     I have not perpetrated such confusion in PCRE. Up till now, it took just
890     the bottom 8 bits, as in old Perl. I have now made octal escapes with
891     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
892     translate to the appropriate multibyte character.
893    
894     29. Applied some refactoring to reduce the number of warnings from Microsoft
895     and Borland compilers. This has included removing the fudge introduced
896     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
897     a warning about an unused variable.
898    
899     21. PCRE has not included VT (character 0x0b) in the set of whitespace
900     characters since release 4.0, because Perl (from release 5.004) does not.
901     [Or at least, is documented not to: some releases seem to be in conflict
902     with the documentation.] However, when a pattern was studied with
903     pcre_study() and all its branches started with \s, PCRE still included VT
904     as a possible starting character. Of course, this did no harm; it just
905     caused an unnecessary match attempt.
906    
907     22. Removed a now-redundant internal flag bit that recorded the fact that case
908     dependency changed within the pattern. This was once needed for "required
909     byte" processing, but is no longer used. This recovers a now-scarce options
910     bit. Also moved the least significant internal flag bit to the most-
911     significant bit of the word, which was not previously used (hangover from
912     the days when it was an int rather than a uint) to free up another bit for
913     the future.
914    
915     23. Added support for CRLF line endings as well as CR and LF. As well as the
916     default being selectable at build time, it can now be changed at runtime
917     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
918     specify that it is scanning data with non-default line endings.
919    
920     24. Changed the definition of CXXLINK to make it agree with the definition of
921     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
922    
923     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
924     recursions. This makes a big different to stack usage for some patterns.
925    
926     26. If a subpattern containing a named recursion or subroutine reference such
927     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
928     the space required for the compiled pattern went wrong and gave too small a
929     value. Depending on the environment, this could lead to "Failed: internal
930     error: code overflow at offset 49" or "glibc detected double free or
931     corruption" errors.
932    
933     27. Applied patches from Google (a) to support the new newline modes and (b) to
934     advance over multibyte UTF-8 characters in GlobalReplace.
935    
936     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
937     difference for some implementation of PCRE in some Windows version.
938    
939     29. Added some extra testing facilities to pcretest:
940    
941     \q<number> in a data line sets the "match limit" value
942     \Q<number> in a data line sets the "match recursion limt" value
943     -S <number> sets the stack size, where <number> is in megabytes
944    
945     The -S option isn't available for Windows.
946    
947    
948 nigel 89 Version 6.6 06-Feb-06
949     ---------------------
950    
951     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
952     in pcreposix.h. I have copied the definition from pcre.h.
953    
954     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
955     because pcre.h is no longer a built file.
956    
957     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
958     not normally included in the compiled code.
959    
960    
961 nigel 87 Version 6.5 01-Feb-06
962     ---------------------
963    
964     1. When using the partial match feature with pcre_dfa_exec(), it was not
965     anchoring the second and subsequent partial matches at the new starting
966     point. This could lead to incorrect results. For example, with the pattern
967     /1234/, partially matching against "123" and then "a4" gave a match.
968    
969     2. Changes to pcregrep:
970    
971     (a) All non-match returns from pcre_exec() were being treated as failures
972     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
973     error message is output. Some extra information is given for the
974     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
975     probably the only errors that are likely to be caused by users (by
976     specifying a regex that has nested indefinite repeats, for instance).
977     If there are more than 20 of these errors, pcregrep is abandoned.
978    
979     (b) A binary zero was treated as data while matching, but terminated the
980     output line if it was written out. This has been fixed: binary zeroes
981     are now no different to any other data bytes.
982    
983     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
984     used to set a locale for matching. The --locale=xxxx long option has
985     been added (no short equivalent) to specify a locale explicitly on the
986     pcregrep command, overriding the environment variables.
987    
988     (d) When -B was used with -n, some line numbers in the output were one less
989     than they should have been.
990    
991     (e) Added the -o (--only-matching) option.
992    
993     (f) If -A or -C was used with -c (count only), some lines of context were
994     accidentally printed for the final match.
995    
996     (g) Added the -H (--with-filename) option.
997    
998     (h) The combination of options -rh failed to suppress file names for files
999     that were found from directory arguments.
1000    
1001     (i) Added the -D (--devices) and -d (--directories) options.
1002    
1003     (j) Added the -F (--fixed-strings) option.
1004    
1005     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1006    
1007     (l) Added the --colo(u)r option.
1008    
1009     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1010     is not present by default.
1011    
1012     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1013     items such as (?R) or (?1), when the recursion could match a number of
1014     alternatives. If it matched one of the alternatives, but subsequently,
1015     outside the recursion, there was a failure, the code tried to back up into
1016     the recursion. However, because of the way PCRE is implemented, this is not
1017     possible, and the result was an incorrect result from the match.
1018    
1019     In order to prevent this happening, the specification of recursion has
1020     been changed so that all such subpatterns are automatically treated as
1021     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1022    
1023     4. I had overlooked the fact that, in some locales, there are characters for
1024     which isalpha() is true but neither isupper() nor islower() are true. In
1025     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1026     and ordfeminine) are like this. This affected the treatment of \w and \W
1027     when they appeared in character classes, but not when they appeared outside
1028     a character class. The bit map for "word" characters is now created
1029     separately from the results of isalnum() instead of just taking it from the
1030     upper, lower, and digit maps. (Plus the underscore character, of course.)
1031    
1032     5. The above bug also affected the handling of POSIX character classes such as
1033     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1034     permanent tables. Instead, the bit maps for such a class were previously
1035     created as the appropriate unions of the upper, lower, and digit bitmaps.
1036     Now they are created by subtraction from the [[:word:]] class, which has
1037     its own bitmap.
1038    
1039     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1040     It is created by subtracting the vertical space characters (\x09, \x0a,
1041     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1042     subtraction was done in the overall bitmap for a character class, meaning
1043     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1044     be recognized. This bug has been fixed.
1045    
1046     7. Patches from the folks at Google:
1047    
1048     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1049     real life, but is still worth protecting against".
1050    
1051     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1052     regular expressions".
1053    
1054     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1055     have it.
1056    
1057     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1058     "configure" and the latter not, in order to fix a problem somebody had
1059     with compiling the Arg class on HP-UX.
1060    
1061     (e) Improve the error-handling of the C++ wrapper a little bit.
1062    
1063     (f) New tests for checking recursion limiting.
1064    
1065     8. The pcre_memmove() function, which is used only if the environment does not
1066     have a standard memmove() function (and is therefore rarely compiled),
1067     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1068     returning a result (though PCRE never actually uses the result).
1069    
1070     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1071     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1072     returned instead of calling malloc() with an overflowing number that would
1073     most likely cause subsequent chaos.
1074    
1075     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1076    
1077     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1078     with this option is matched, the nmatch and pmatch options of regexec() are
1079     ignored.
1080    
1081     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1082     provided in case anyone wants to the the POSIX interface with UTF-8
1083     strings.
1084    
1085     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1086     C++ linking (needed for some HP-UX environments).
1087    
1088     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1089     (unused parameter) and in the pcre_printint() function (omitted "default"
1090     switch label when the default is to do nothing).
1091    
1092     15. Added some code to make it possible, when PCRE is compiled as a C++
1093     library, to replace subject pointers for pcre_exec() with a smart pointer
1094     class, thus making it possible to process discontinuous strings.
1095    
1096     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1097     much the same function. They were added by different people who were trying
1098     to make PCRE easy to compile on non-Unix systems. It has been suggested
1099     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1100     for compiling on Windows systems. I have therefore replaced it with
1101     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1102     defaults to "extern" for C or "extern C" for C++, which works fine on
1103     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1104     SCOPE with something explicit in config.h. In addition:
1105    
1106     (a) pcreposix.h still had just "extern" instead of either of these macros;
1107     I have replaced it with PCRE_DATA_SCOPE.
1108    
1109     (b) Functions such as _pcre_xclass(), which are internal to the library,
1110     but external in the C sense, all had PCRE_EXPORT in their definitions.
1111     This is apparently wrong for the Windows case, so I have removed it.
1112     (It makes no difference on Unix-like systems.)
1113    
1114     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1115     of recursive calls to match(). This is different to MATCH_LIMIT because
1116     that limits the total number of calls to match(), not all of which increase
1117     the depth of recursion. Limiting the recursion depth limits the amount of
1118     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1119     when PCRE is compiled, and changed at run time. A patch from Google adds
1120     this functionality to the C++ interface.
1121    
1122     18. Changes to the handling of Unicode character properties:
1123    
1124     (a) Updated the table to Unicode 4.1.0.
1125    
1126     (b) Recognize characters that are not in the table as "Cn" (undefined).
1127    
1128     (c) I revised the way the table is implemented to a much improved format
1129     which includes recognition of ranges. It now supports the ranges that
1130     are defined in UnicodeData.txt, and it also amalgamates other
1131     characters into ranges. This has reduced the number of entries in the
1132     table from around 16,000 to around 3,000, thus reducing its size
1133     considerably. I realized I did not need to use a tree structure after
1134     all - a binary chop search is just as efficient. Having reduced the
1135     number of entries, I extended their size from 6 bytes to 8 bytes to
1136     allow for more data.
1137    
1138     (d) Added support for Unicode script names via properties such as \p{Han}.
1139    
1140     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1141     matching that character.
1142    
1143     20. When matching a repeated Unicode property with a minimum greater than zero,
1144     (for example \pL{2,}), PCRE could look past the end of the subject if it
1145     reached it while seeking the minimum number of characters. This could
1146     happen only if some of the characters were more than one byte long, because
1147     there is a check for at least the minimum number of bytes.
1148    
1149     21. Refactored the implementation of \p and \P so as to be more general, to
1150     allow for more different types of property in future. This has changed the
1151     compiled form incompatibly. Anybody with saved compiled patterns that use
1152     \p or \P will have to recompile them.
1153    
1154     22. Added "Any" and "L&" to the supported property types.
1155    
1156     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1157     but give a compile time error if the value is greater than 0xff.
1158    
1159     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1160     accidentally not being installed or uninstalled.
1161    
1162     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1163     made were to insert the current release number. This seemed silly, because
1164     it made things harder for people building PCRE on systems that don't run
1165     "configure". I have turned pcre.h into a distributed file, no longer built
1166     by "configure", with the version identification directly included. There is
1167     no longer a pcre.h.in file.
1168    
1169     However, this change necessitated a change to the pcre-config script as
1170     well. It is built from pcre-config.in, and one of the substitutions was the
1171     release number. I have updated configure.ac so that ./configure now finds
1172     the release number by grepping pcre.h.
1173    
1174     26. Added the ability to run the tests under valgrind.
1175    
1176    
1177 nigel 85 Version 6.4 05-Sep-05
1178     ---------------------
1179    
1180     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1181     "--" to be printed when multiple files were scanned, even when none of the
1182     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1183     consider it to be a bug, and have restored the previous behaviour.
1184    
1185     2. A couple of code tidies to get rid of compiler warnings.
1186    
1187     3. The pcretest program used to cheat by referring to symbols in the library
1188     whose names begin with _pcre_. These are internal symbols that are not
1189     really supposed to be visible externally, and in some environments it is
1190     possible to suppress them. The cheating is now confined to including
1191     certain files from the library's source, which is a bit cleaner.
1192    
1193     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1194     file's purpose clearer.
1195    
1196     5. Reorganized pcre_ucp_findchar().
1197    
1198    
1199 nigel 83 Version 6.3 15-Aug-05
1200     ---------------------
1201    
1202     1. The file libpcre.pc.in did not have general read permission in the tarball.
1203    
1204     2. There were some problems when building without C++ support:
1205    
1206     (a) If C++ support was not built, "make install" and "make test" still
1207     tried to test it.
1208    
1209     (b) There were problems when the value of CXX was explicitly set. Some
1210     changes have been made to try to fix these, and ...
1211    
1212     (c) --disable-cpp can now be used to explicitly disable C++ support.
1213    
1214     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1215     backslash in a target when C++ was disabled. This confuses some
1216     versions of "make", apparently. Using an intermediate variable solves
1217     this. (Same for CPP_LOBJ.)
1218    
1219     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1220     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1221     necessary on certain architectures.
1222    
1223     4. Added a setting of -export-symbols-regex to the link command to remove
1224     those symbols that are exported in the C sense, but actually are local
1225     within the library, and not documented. Their names all begin with
1226     "_pcre_". This is not a perfect job, because (a) we have to except some
1227     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1228     available (and never for static libraries). I have made a note to try to
1229     find a way round (a) in the future.
1230    
1231    
1232 nigel 81 Version 6.2 01-Aug-05
1233     ---------------------
1234    
1235     1. There was no test for integer overflow of quantifier values. A construction
1236     such as {1111111111111111} would give undefined results. What is worse, if
1237     a minimum quantifier for a parenthesized subpattern overflowed and became
1238     negative, the calculation of the memory size went wrong. This could have
1239     led to memory overwriting.
1240    
1241     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1242    
1243     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1244     operating environments where this matters.
1245    
1246     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1247     PCRE options from within the C++ wrapper.
1248    
1249     5. Named capturing subpatterns were not being correctly counted when a pattern
1250     was compiled. This caused two problems: (a) If there were more than 100
1251     such subpatterns, the calculation of the memory needed for the whole
1252     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1253     back references of the form \12, where the number was greater than 9, were
1254     not recognized as back references, even though there were sufficient
1255     previous subpatterns.
1256    
1257     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1258     versions of gcc, e.g. 2.95.4.
1259    
1260    
1261 nigel 79 Version 6.1 21-Jun-05
1262     ---------------------
1263    
1264     1. There was one reference to the variable "posix" in pcretest.c that was not
1265     surrounded by "#if !defined NOPOSIX".
1266    
1267     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1268     the cross-check on the old pcre_info() function, for the benefit of the
1269     cut-down version of PCRE that is currently imported into Exim.
1270    
1271     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1272     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1273     patterns that start (?i) but I don't think that matters. The use of (?i) is
1274     just an example; this all applies to the other options as well.
1275    
1276     4. Since libtool seems to echo the compile commands it is issuing, the output
1277     from "make" can be reduced a bit by putting "@" in front of each libtool
1278     compile command.
1279    
1280     5. Patch from the folks at Google for configure.in to be a bit more thorough
1281     in checking for a suitable C++ installation before trying to compile the
1282     C++ stuff. This should fix a reported problem when a compiler was present,
1283     but no suitable headers.
1284    
1285     6. The man pages all had just "PCRE" as their title. I have changed them to
1286     be the relevant file name. I have also arranged that these names are
1287     retained in the file doc/pcre.txt, which is a concatenation in text format
1288     of all the man pages except the little individual ones for each function.
1289    
1290     7. The NON-UNIX-USE file had not been updated for the different set of source
1291     files that come with release 6. I also added a few comments about the C++
1292     wrapper.
1293    
1294    
1295 nigel 77 Version 6.0 07-Jun-05
1296     ---------------------
1297    
1298     1. Some minor internal re-organization to help with my DFA experiments.
1299    
1300     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1301     didn't matter for the library itself when fully configured, but did matter
1302     when compiling without UCP support, or within Exim, where the ucp files are
1303     not imported.
1304    
1305     3. Refactoring of the library code to split up the various functions into
1306     different source modules. The addition of the new DFA matching code (see
1307     below) to a single monolithic source would have made it really too
1308     unwieldy, quite apart from causing all the code to be include in a
1309     statically linked application, when only some functions are used. This is
1310     relevant even without the DFA addition now that patterns can be compiled in
1311     one application and matched in another.
1312    
1313     The downside of splitting up is that there have to be some external
1314     functions and data tables that are used internally in different modules of
1315     the library but which are not part of the API. These have all had their
1316     names changed to start with "_pcre_" so that they are unlikely to clash
1317     with other external names.
1318    
1319     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1320     a different (DFA) algorithm. Although it is slower than the original
1321     function, it does have some advantages for certain types of matching
1322     problem.
1323    
1324     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1325     including restarting after a partial match.
1326    
1327     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1328     defined when compiling for Windows was sent to me. I have put it into the
1329     code, though I have no means of testing or verifying it.
1330    
1331     7. Added the pcre_refcount() auxiliary function.
1332    
1333     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1334     match before or at the first newline in the subject string. In pcretest,
1335     the /f option on a pattern can be used to set this.
1336    
1337     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1338     would behave wrongly. This has been present in PCRE since release 4.0.
1339    
1340     10. A number of changes to the pcregrep command:
1341    
1342     (a) Refactored how -x works; insert ^(...)$ instead of setting
1343     PCRE_ANCHORED and checking the length, in preparation for adding
1344     something similar for -w.
1345    
1346     (b) Added the -w (match as a word) option.
1347    
1348     (c) Refactored the way lines are read and buffered so as to have more
1349     than one at a time available.
1350    
1351     (d) Implemented a pcregrep test script.
1352    
1353     (e) Added the -M (multiline match) option. This allows patterns to match
1354     over several lines of the subject. The buffering ensures that at least
1355     8K, or the rest of the document (whichever is the shorter) is available
1356     for matching (and similarly the previous 8K for lookbehind assertions).
1357    
1358     (f) Changed the --help output so that it now says
1359    
1360     -w, --word-regex(p)
1361    
1362     instead of two lines, one with "regex" and the other with "regexp"
1363     because that confused at least one person since the short forms are the
1364     same. (This required a bit of code, as the output is generated
1365     automatically from a table. It wasn't just a text change.)
1366    
1367     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1368     option but starts with a hyphen. Could be a pattern or a path name
1369     starting with a hyphen, for instance.
1370    
1371     (h) "-" can be given as a file name to represent stdin.
1372    
1373     (i) When file names are being printed, "(standard input)" is used for
1374     the standard input, for compatibility with GNU grep. Previously
1375     "<stdin>" was used.
1376    
1377     (j) The option --label=xxx can be used to supply a name to be used for
1378     stdin when file names are being printed. There is no short form.
1379    
1380     (k) Re-factored the options decoding logic because we are going to add
1381     two more options that take data. Such options can now be given in four
1382     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1383    
1384     (l) Added the -A, -B, and -C options for requesting that lines of context
1385     around matches be printed.
1386    
1387     (m) Added the -L option to print the names of files that do not contain
1388     any matching lines, that is, the complement of -l.
1389    
1390     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1391     continue to scan other files.
1392    
1393     (o) The -s option was incorrectly implemented. For compatibility with other
1394     greps, it now suppresses the error message for a non-existent or non-
1395     accessible file (but not the return code). There is a new option called
1396     -q that suppresses the output of matching lines, which was what -s was
1397     previously doing.
1398    
1399     (p) Added --include and --exclude options to specify files for inclusion
1400     and exclusion when recursing.
1401    
1402     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1403     Hopefully, it now does.
1404    
1405     12. Missing cast in pcre_study().
1406    
1407     13. Added an "uninstall" target to the makefile.
1408    
1409     14. Replaced "extern" in the function prototypes in Makefile.in with
1410     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1411     world, but is set differently for Windows.
1412    
1413     15. Added a second compiling function called pcre_compile2(). The only
1414     difference is that it has an extra argument, which is a pointer to an
1415     integer error code. When there is a compile-time failure, this is set
1416     non-zero, in addition to the error test pointer being set to point to an
1417     error message. The new argument may be NULL if no error number is required
1418     (but then you may as well call pcre_compile(), which is now just a
1419     wrapper). This facility is provided because some applications need a
1420     numeric error indication, but it has also enabled me to tidy up the way
1421     compile-time errors are handled in the POSIX wrapper.
1422    
1423     16. Added VPATH=.libs to the makefile; this should help when building with one
1424     prefix path and installing with another. (Or so I'm told by someone who
1425     knows more about this stuff than I do.)
1426    
1427     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1428     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1429     match everything, including newlines. This is not POSIX-compatible, but
1430     somebody wanted the feature. From pcretest it can be activated by using
1431     both the P and the s flags.
1432    
1433     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1434    
1435     19. libpcre.pc was being incorrectly installed as executable.
1436    
1437     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1438     it now also looks for '\r' so that it will work unmodified on Windows.
1439    
1440     21. Added Google's contributed C++ wrapper to the distribution.
1441    
1442     22. Added some untidy missing memory free() calls in pcretest, to keep
1443     Electric Fence happy when testing.
1444    
1445    
1446    
1447 nigel 75 Version 5.0 13-Sep-04
1448     ---------------------
1449    
1450     1. Internal change: literal characters are no longer packed up into items
1451     containing multiple characters in a single byte-string. Each character
1452     is now matched using a separate opcode. However, there may be more than one
1453     byte in the character in UTF-8 mode.
1454    
1455     2. The pcre_callout_block structure has two new fields: pattern_position and
1456     next_item_length. These contain the offset in the pattern to the next match
1457     item, and its length, respectively.
1458    
1459     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1460     insertion of callouts before each pattern item. Added the /C option to
1461     pcretest to make use of this.
1462    
1463     4. On the advice of a Windows user, the lines
1464    
1465     #if defined(_WIN32) || defined(WIN32)
1466     _setmode( _fileno( stdout ), 0x8000 );
1467     #endif /* defined(_WIN32) || defined(WIN32) */
1468    
1469     have been added to the source of pcretest. This apparently does useful
1470     magic in relation to line terminators.
1471    
1472     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1473     for the benefit of those environments where the "b" makes a difference.
1474    
1475     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1476     to know about it. I have put a hack into configure.in that adds in code
1477     to set GCC=yes if CC=icc. This seems to end up at a point in the
1478     generated configure script that is early enough to affect the setting of
1479     compiler options, which is what is needed, but I have no means of testing
1480     whether it really works. (The user who reported this had patched the
1481     generated configure script, which of course I cannot do.)
1482    
1483     LATER: After change 22 below (new libtool files), the configure script
1484     seems to know about icc (and also ecc). Therefore, I have commented out
1485     this hack in configure.in.
1486    
1487     7. Added support for pkg-config (2 patches were sent in).
1488    
1489     8. Negated POSIX character classes that used a combination of internal tables
1490     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1491     [[:^ascii]]. Typically, they would match almost any characters. The other
1492     POSIX classes were not broken in this way.
1493    
1494     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1495     to find the match, as PCRE was deluded into thinking that the match had to
1496     start at the start point or following a newline. The same bug applied to
1497     patterns with negative forward assertions or any backward assertions
1498     preceding ".*" at the start, unless the pattern required a fixed first
1499     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1500    
1501     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1502     starting at the last subject character, bytes beyond the end of the subject
1503     string were read.
1504    
1505     11. Renamed the variable "class" as "classbits" to make life easier for C++
1506     users. (Previously there was a macro definition, but it apparently wasn't
1507     enough.)
1508    
1509     12. Added the new field "tables" to the extra data so that tables can be passed
1510     in at exec time, or the internal tables can be re-selected. This allows
1511     a compiled regex to be saved and re-used at a later time by a different
1512     program that might have everything at different addresses.
1513    
1514     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1515     -R library as well as a -L library.
1516    
1517     14. The debugging options of pcretest (-d on the command line or D on a
1518     pattern) showed incorrect output for anything following an extended class
1519     that contained multibyte characters and which was followed by a quantifier.
1520    
1521     15. Added optional support for general category Unicode character properties
1522     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1523     support. It adds about 90K to the size of the library. The meanings of the
1524     inbuilt class escapes such as \d and \s have NOT been changed.
1525    
1526     16. Updated pcredemo.c to include calls to free() to release the memory for the
1527     compiled pattern.
1528    
1529     17. The generated file chartables.c was being created in the source directory
1530     instead of in the building directory. This caused the build to fail if the
1531     source directory was different from the building directory, and was
1532     read-only.
1533    
1534     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1535     file. No doubt somebody will tell me if they don't make sense... Also added
1536     Dan Mooney's comments about building on OpenVMS.
1537    
1538     19. Added support for partial matching via the PCRE_PARTIAL option for
1539     pcre_exec() and the \P data escape in pcretest.
1540    
1541     20. Extended pcretest with 3 new pattern features:
1542    
1543     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1544     write the compiled pattern to the file whose name is "rest-of-line".
1545     This is a straight binary dump of the data, with the saved pointer to
1546     the character tables forced to be NULL. The study data, if any, is
1547     written too. After writing, pcretest reads a new pattern.
1548    
1549     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1550     compiled pattern from the given file. There must not be any
1551     occurrences of "<" in the file name (pretty unlikely); if there are,
1552     pcretest will instead treat the initial "<" as a pattern delimiter.
1553     After reading in the pattern, pcretest goes on to read data lines as
1554     usual.
1555    
1556     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1557     and 16-bit fields in a compiled pattern, to simulate a pattern that
1558     was compiled on a host of opposite endianness.
1559    
1560     21. The pcre-exec() function can now cope with patterns that were compiled on
1561     hosts of opposite endianness, with this restriction:
1562    
1563     As for any compiled expression that is saved and used later, the tables
1564     pointer field cannot be preserved; the extra_data field in the arguments
1565     to pcre_exec() should be used to pass in a tables address if a value
1566     other than the default internal tables were used at compile time.
1567    
1568     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1569     now diagnosed as an error. Previously, most of the time, a negative number
1570     would have been treated as zero, but if in addition "ovector" was passed as
1571     NULL, a crash could occur.
1572    
1573     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1574     new versions from the libtool 1.5 distribution (the last one is a copy of
1575     a file called libtool.m4). This seems to have fixed the need to patch
1576     "configure" to support Darwin 1.3 (which I used to do). However, I still
1577     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1578     workstation).
1579    
1580     24. Changed the PCRE licence to be the more standard "BSD" licence.
1581    
1582    
1583 nigel 73 Version 4.5 01-Dec-03
1584     ---------------------
1585    
1586     1. There has been some re-arrangement of the code for the match() function so
1587     that it can be compiled in a version that does not call itself recursively.
1588     Instead, it keeps those local variables that need separate instances for
1589     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1590     needs to "recurse". Keeping track of where control must go is done by means
1591     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1592     hide most of the details from the main code, and operates only if
1593     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1594     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1595     operating.
1596    
1597     To make it easier for callers to provide specially tailored get/free
1598     functions for this usage, two new functions, pcre_stack_malloc, and
1599     pcre_stack_free, are used. They are always called in strict stacking order,
1600     and the size of block requested is always the same.
1601    
1602     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1603     PCRE has been compiled to use the stack or the heap for recursion. The
1604     -C option of pcretest uses this to show which version is compiled.
1605    
1606     A new data escape \S, is added to pcretest; it causes the amounts of store
1607     obtained and freed by both kinds of malloc/free at match time to be added
1608     to the output.
1609    
1610     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1611     what's available on my current Linux desktop machine.
1612    
1613     3. When matching a UTF-8 string, the test for a valid string at the start has
1614     been extended. If start_offset is not zero, PCRE now checks that it points
1615     to a byte that is the start of a UTF-8 character. If not, it returns
1616     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1617     this is necessary because there may be backward assertions in the pattern.
1618     When matching the same subject several times, it may save resources to use
1619     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1620    
1621     4. The code for checking the validity of UTF-8 strings has been tightened so
1622     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1623     containing "overlong sequences".
1624    
1625     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1626     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1627     should have been "&", but it just so happened that all the cases this let
1628     through by mistake were picked up later in the function.
1629    
1630     6. I had used a variable called "isblank" - this is a C99 function, causing
1631     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1632    
1633     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1634     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1635     so the version is shown; (c) stop "make test" echoing "./RunTest".
1636    
1637     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1638    
1639     9. The prototype for memmove() for systems that don't have it was using
1640     size_t, but the inclusion of the header that defines size_t was later. I've
1641     moved the #includes for the C headers earlier to avoid this.
1642    
1643     10. Added some adjustments to the code to make it easier to compiler on certain
1644     special systems:
1645    
1646     (a) Some "const" qualifiers were missing.
1647     (b) Added the macro EXPORT before all exported functions; by default this
1648     is defined to be empty.
1649     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1650     that it reads its output file name as an argument instead of writing
1651     to the standard output and assuming this can be redirected.
1652    
1653     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1654     class containing characters with values greater than 255, PCRE compilation
1655     went into a loop.
1656    
1657     12. A recursive reference to a subpattern that was within another subpattern
1658     that had a minimum quantifier of zero caused PCRE to crash. For example,
1659     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1660     recursion. If the recursively-called subpattern itself had a zero repeat,
1661     that was OK.
1662    
1663     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1664     buffer into which it was copied (for escape processing) was still set at
1665     1024, so long lines caused crashes.
1666    
1667     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1668     "internal error: code overflow...". This applied to any character class
1669     that was followed by a possessive quantifier.
1670    
1671     15. Modified the Makefile to add libpcre.la as a prerequisite for
1672     libpcreposix.la because I was told this is needed for a parallel build to
1673     work.
1674    
1675     16. If a pattern that contained .* following optional items at the start was
1676     studied, the wrong optimizing data was generated, leading to matching
1677     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1678     matching string must start with a or b or c. The correct conclusion for
1679     this pattern is that a match can start with any character.
1680    
1681    
1682 nigel 71 Version 4.4 13-Aug-03
1683     ---------------------
1684    
1685     1. In UTF-8 mode, a character class containing characters with values between
1686     127 and 255 was not handled correctly if the compiled pattern was studied.
1687     In fixing this, I have also improved the studying algorithm for such
1688     classes (slightly).
1689    
1690     2. Three internal functions had redundant arguments passed to them. Removal
1691     might give a very teeny performance improvement.
1692    
1693     3. Documentation bug: the value of the capture_top field in a callout is *one
1694     more than* the number of the hightest numbered captured substring.
1695    
1696     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1697     in incorrectly linking with a previously installed version. They now link
1698     explicitly with libpcre.la.
1699    
1700     5. configure.in no longer needs to recognize Cygwin specially.
1701    
1702     6. A problem in pcre.in for Windows platforms is fixed.
1703    
1704     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1705     pcretest, it used to include the size of the study block as part of its
1706     output. Unfortunately, the structure contains a field that has a different
1707     size on different hardware architectures. This meant that the tests that
1708     showed this size failed. As the block is currently always of a fixed size,
1709     this information isn't actually particularly useful in pcretest output, so
1710     I have just removed it.
1711    
1712     8. Three pre-processor statements accidentally did not start in column 1.
1713     Sadly, there are *still* compilers around that complain, even though
1714     standard C has not required this for well over a decade. Sigh.
1715    
1716     9. In pcretest, the code for checking callouts passed small integers in the
1717     callout_data field, which is a void * field. However, some picky compilers
1718     complained about the casts involved for this on 64-bit systems. Now
1719     pcretest passes the address of the small integer instead, which should get
1720     rid of the warnings.
1721    
1722     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1723     both compile and run time, and gives an error if an invalid UTF-8 sequence
1724     is found. There is a option for disabling this check in cases where the
1725     string is known to be correct and/or the maximum performance is wanted.
1726    
1727     11. In response to a bug report, I changed one line in Makefile.in from
1728    
1729     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1730     to
1731     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1732    
1733     to look similar to other lines, but I have no way of telling whether this
1734     is the right thing to do, as I do not use Windows. No doubt I'll get told
1735     if it's wrong...
1736    
1737    
1738 nigel 69 Version 4.3 21-May-03
1739     ---------------------
1740    
1741     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1742     Makefile.
1743    
1744     2. Some refactoring to improve the quality of the code:
1745    
1746     (i) The utf8_table... variables are now declared "const".
1747    
1748     (ii) The code for \cx, which used the "case flipping" table to upper case
1749     lower case letters, now just substracts 32. This is ASCII-specific,
1750     but the whole concept of \cx is ASCII-specific, so it seems
1751     reasonable.
1752    
1753     (iii) PCRE was using its character types table to recognize decimal and
1754     hexadecimal digits in the pattern. This is silly, because it handles
1755     only 0-9, a-f, and A-F, but the character types table is locale-
1756     specific, which means strange things might happen. A private
1757     table is now used for this - though it costs 256 bytes, a table is
1758     much faster than multiple explicit tests. Of course, the standard
1759     character types table is still used for matching digits in subject
1760     strings against \d.
1761    
1762     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1763     ending in _t are). So I've renamed it as ESC_tee.
1764    
1765     3. The first argument for regexec() in the POSIX wrapper should have been
1766     defined as "const".
1767    
1768     4. Changed pcretest to use malloc() for its buffers so that they can be
1769     Electric Fenced for debugging.
1770    
1771     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1772     to read one or more bytes before the start of the subject string. Often this
1773     had no effect on PCRE's behaviour, but in some circumstances it could
1774     provoke a segmentation fault.
1775    
1776     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1777     to try to read one or more bytes before the start of the subject string.
1778    
1779     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1780     UTF-8 support could misbehave in various ways if the subject string
1781     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1782     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1783     back over UTF-8 characters.)
1784    
1785    
1786 nigel 67 Version 4.2 14-Apr-03
1787     ---------------------
1788    
1789     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1790    
1791     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1792     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1793     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1794     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1795     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1796     and BUILD_EXEEXT
1797     Note: automatic setting of the BUILD variables is not yet working
1798     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1799     compile-time but not at link-time
1800     [LINK]: use for linking executables only
1801     make different versions for Windows and non-Windows
1802     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1803     libraries
1804     [LINK_FOR_BUILD]: new variable
1805     [OBJEXT]: use throughout
1806     [EXEEXT]: use throughout
1807     <winshared>: new target
1808     <wininstall>: new target
1809     <dftables.o>: use native compiler
1810     <dftables>: use native linker
1811     <install>: handle Windows platform correctly
1812     <clean>: ditto
1813     <check>: ditto
1814     copy DLL to top builddir before testing
1815    
1816     As part of these changes, -no-undefined was removed again. This was reported
1817     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1818     in any case.
1819    
1820     3. Some tidies to get rid of compiler warnings:
1821    
1822     . In the match_data structure, match_limit was an unsigned long int, whereas
1823     match_call_count was an int. I've made them both unsigned long ints.
1824    
1825     . In pcretest the fact that a const uschar * doesn't automatically cast to
1826     a void * provoked a warning.
1827    
1828     . Turning on some more compiler warnings threw up some "shadow" variables
1829     and a few more missing casts.
1830    
1831     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1832     option, a class that contained a single character with a value between 128
1833     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1834    
1835     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1836     option, a class that contained several characters, but with at least one
1837     whose value was between 128 and 255 caused PCRE to crash.
1838    
1839    
1840 nigel 65 Version 4.1 12-Mar-03
1841     ---------------------
1842 nigel 63
1843 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1844     needed, and a string in dftables.c that was longer than standard compilers are
1845     required to support.
1846    
1847     2. Compiling with Sun's compiler found a few more places where the code could
1848     be tidied up in order to avoid warnings.
1849    
1850     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1851     first of these names is deprecated in the latest Autoconf in favour of the name
1852     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1853     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1854     analogy I have changed it to CFLAGS_FOR_BUILD.
1855    
1856     4. Added -no-undefined to the linking command in the Makefile, because this is
1857     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1858     linking step for the pcreposix library.
1859    
1860     5. PCRE was failing to diagnose the case of two named groups with the same
1861     name.
1862    
1863     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1864     literal character that is needed in the subject for a match, and scans along to
1865     ensure that it is present before embarking on the full matching process. This
1866     saves time in cases of nested unlimited repeats that are never going to match.
1867     Problem: the scan can take a lot of time if the subject is very long (e.g.
1868     megabytes), thus penalizing straightforward matches. It is now done only if the
1869     amount of subject to be scanned is less than 1000 bytes.
1870    
1871     7. A lesser problem with the same optimization is that it was recording the
1872     first character of an anchored pattern as "needed", thus provoking a search
1873     right along the subject, even when the first match of the pattern was going to
1874     fail. The "needed" character is now not set for anchored patterns, unless it
1875     follows something in the pattern that is of non-fixed length. Thus, it still
1876     fulfils its original purpose of finding quick non-matches in cases of nested
1877     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1878    
1879    
1880     Version 4.0 17-Feb-03
1881     ---------------------
1882    
1883 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1884     extended to the end of string, PCRE compiled incorrect data. This could lead to
1885     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1886    
1887     2. Moved to autoconf 2.53 and libtool 1.4.2.
1888    
1889     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1890     the special perltest8 script is no longer needed - all the tests can be run
1891     from a single perltest script.
1892    
1893     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1894     by \s. It has now been removed in PCRE. This means it isn't recognized as
1895     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1896     class [:space:] *does* include VT, thereby creating a mess.
1897    
1898     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1899     space and tab.
1900    
1901     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1902     its new features into the main test script, reducing the number of scripts.
1903    
1904     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1905     were backward compatible, and made the (?i) apply to the whole pattern, as if
1906     /i were given. Now it behaves more logically, and applies the option setting
1907     only to what follows. PCRE has been changed to follow suit. However, if it
1908     finds options settings right at the start of the pattern, it extracts them into
1909     the global options, as before. Thus, they show up in the info data.
1910    
1911     8. Added support for the \Q...\E escape sequence. Characters in between are
1912     treated as literals. This is slightly different from Perl in that $ and @ are
1913     also handled as literals inside the quotes. In Perl, they will cause variable
1914     interpolation. Note the following examples:
1915    
1916     Pattern PCRE matches Perl matches
1917    
1918     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1919     \Qabc\$xyz\E abc\$xyz abc\$xyz
1920     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1921    
1922     For compatibility with Perl, \Q...\E sequences are recognized inside character
1923     classes as well as outside them.
1924    
1925     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1926     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1927     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1928     signed/unsigned warnings.
1929    
1930     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1931     option for pcretest, so I've replaced it by a simple function that does just
1932     that job.
1933    
1934     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1935     "pcregrep -".
1936    
1937     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1938     Java package. This provides some syntactic sugar for simple cases of what my
1939     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1940     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1941     item, you can use this simplified notation. Note that only makes sense with
1942     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1943     greediness, whatever the setting of the PCRE_UNGREEDY option.
1944    
1945     13. A change of greediness default within a pattern was not taking effect at
1946     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1947     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1948     was abstracted outside.
1949    
1950     14. PCRE now supports the \G assertion. It is true when the current matching
1951     position is at the start point of the match. This differs from \A when the
1952     starting offset is non-zero. Used with the /g option of pcretest (or similar
1953     code), it works in the same way as it does for Perl's /g option. If all
1954     alternatives of a regex begin with \G, the expression is anchored to the start
1955     match position, and the "anchored" flag is set in the compiled expression.
1956    
1957     15. Some bugs concerning the handling of certain option changes within patterns
1958     have been fixed. These applied to options other than (?ims). For example,
1959     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1960     been the other way round. Some of this was related to change 7 above.
1961    
1962     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1963     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1964     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1965     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1966    
1967     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1968     mode. Unlike ".", it always matches newline, whatever the setting of
1969     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1970     assertions. Perl allows it, but it doesn't (in general) work because it can't
1971     calculate the length of the lookbehind. At least, that's the case for Perl
1972     5.8.0 - I've been told they are going to document that it doesn't work in
1973     future.
1974    
1975     18. Added an error diagnosis for escapes that PCRE does not support: these are
1976     \L, \l, \N, \P, \p, \U, \u, and \X.
1977    
1978     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1979     reading past the end of the pattern in cases such as /[abcd/.
1980    
1981     20. PCRE was getting more memory than necessary for patterns with classes that
1982     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1983    
1984     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1985     compiling PCRE for use with Virtual Pascal.
1986    
1987     22. Small fix to the Makefile to make it work properly if the build is done
1988     outside the source tree.
1989    
1990     23. Added a new extension: a condition to go with recursion. If a conditional
1991     subpattern starts with (?(R) the "true" branch is used if recursion has
1992     happened, whereas the "false" branch is used only at the top level.
1993    
1994     24. When there was a very long string of literal characters (over 255 bytes
1995     without UTF support, over 250 bytes with UTF support), the computation of how
1996     much memory was required could be incorrect, leading to segfaults or other
1997     strange effects.
1998    
1999     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2000     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2001     there was a subsequent back reference to those brackets. This meant that, for
2002     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2003     possible to check for precisely this case. All we can do is abandon the
2004     optimization if .* occurs inside capturing brackets when there are any back
2005     references whatsoever. (See below for a better fix that came later.)
2006    
2007     26. The handling of the optimization for finding the first character of a
2008     non-anchored pattern, and for finding a character that is required later in the
2009     match were failing in some cases. This didn't break the matching; it just
2010     failed to optimize when it could. The way this is done has been re-implemented.
2011    
2012     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2013    
2014     28. Added a new feature that provides some of the functionality that Perl
2015     provides with (?{...}). The facility is termed a "callout". The way it is done
2016     in PCRE is for the caller to provide an optional function, by setting
2017     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2018     global variable. By default it is unset, which disables all calling out. To get
2019     the function called, the regex must include (?C) at appropriate points. This
2020     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2021     This provides a means of identifying different callout points. When PCRE
2022     reaches such a point in the regex, if pcre_callout has been set, the external
2023     function is called. It is provided with data in a structure called
2024     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2025     matching continues; if it returns a non-zero value, the match at the current
2026     point fails. However, backtracking will occur if possible. [This was changed
2027     later and other features added - see item 49 below.]
2028    
2029     29. pcretest is upgraded to test the callout functionality. It provides a
2030     callout function that displays information. By default, it shows the start of
2031     the match and the current position in the text. There are some new data escapes
2032     to vary what happens:
2033    
2034     \C+ in addition, show current contents of captured substrings
2035     \C- do not supply a callout function
2036     \C!n return 1 when callout number n is reached
2037     \C!n!m return 1 when callout number n is reached for the mth time
2038    
2039     30. If pcregrep was called with the -l option and just a single file name, it
2040     output "<stdin>" if a match was found, instead of the file name.
2041    
2042     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2043     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2044     pcre_exec(). This saves a malloc/free per call. The default value of
2045     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2046     when configuring.
2047    
2048     32. The default maximum size of a compiled pattern is 64K. There have been a
2049     few cases of people hitting this limit. The code now uses macros to handle the
2050     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2051     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2052     configuring. Tests 2 and 5 work only with 2-byte links because they output
2053     debugging information about compiled patterns.
2054    
2055     33. Internal code re-arrangements:
2056    
2057     (a) Moved the debugging function for printing out a compiled regex into
2058     its own source file (printint.c) and used #include to pull it into
2059     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2060     separate copies.
2061    
2062     (b) Defined the list of op-code names for debugging as a macro in
2063     internal.h so that it is next to the definition of the opcodes.
2064    
2065     (c) Defined a table of op-code lengths for simpler skipping along compiled
2066     code. This is again a macro in internal.h so that it is next to the
2067     definition of the opcodes.
2068    
2069     34. Added support for recursive calls to individual subpatterns, along the
2070     lines of Robin Houston's patch (but implemented somewhat differently).
2071    
2072     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2073     allow it to read and process whole directories in Win32. This code was
2074     contributed by Lionel Fourquaux; it has not been tested by me.
2075    
2076     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2077     used to name a group. Names consist of alphanumerics and underscores, and must
2078     be unique. Back references use the syntax (?P=name) and recursive calls use
2079     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2080     numbers. The function pcre_fullinfo() can be used after compilation to extract
2081     a name/number map. There are three relevant calls:
2082    
2083     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2084     PCRE_INFO_NAMECOUNT yields the number of entries
2085     PCRE_INFO_NAMETABLE yields a pointer to the map.
2086    
2087     The map is a vector of fixed-size entries. The size of each entry depends on
2088     the length of the longest name used. The first two bytes of each entry are the
2089     group number, most significant byte first. There follows the corresponding
2090     name, zero terminated. The names are in alphabetical order.
2091    
2092     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2093     case instead of 255. Making it the same both with and without UTF-8 support
2094     means that the same test output works with both.
2095    
2096     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2097     calling malloc() with a zero argument.
2098    
2099     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2100     optimization. I've improved things by keeping a bitmap of backreferences with
2101     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2102     fact referenced, the optimization can be applied. It is unlikely that a
2103     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2104     the match to follow \n) will appear inside brackets with a number greater than
2105     31, but if it does, any back reference > 31 suppresses the optimization.
2106    
2107     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2108     of disabling numbered capturing parentheses. Any opening parenthesis that is
2109     not followed by ? behaves as if it were followed by ?: but named parentheses
2110     can still be used for capturing (and they will acquire numbers in the usual
2111     way).
2112    
2113     41. Redesigned the return codes from the match() function into yes/no/error so
2114     that errors can be passed back from deep inside the nested calls. A malloc
2115     failure while inside a recursive subpattern call now causes the
2116     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2117    
2118     42. It is now possible to set a limit on the number of times the match()
2119     function is called in a call to pcre_exec(). This facility makes it possible to
2120     limit the amount of recursion and backtracking, though not in a directly
2121     obvious way, because the match() function is used in a number of different
2122     circumstances. The count starts from zero for each position in the subject
2123     string (for non-anchored patterns). The default limit is, for compatibility, a
2124     large number, namely 10 000 000. You can change this in two ways:
2125    
2126     (a) When configuring PCRE before making, you can use --with-match-limit=n
2127     to set a default value for the compiled library.
2128    
2129     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2130     a different value is set. See 45 below.
2131    
2132     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2133    
2134     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2135     of things that can be changed at compile time. The first argument specifies
2136     what is wanted and the second points to where the information is to be placed.
2137     The current list of available information is:
2138    
2139     PCRE_CONFIG_UTF8
2140    
2141     The output is an integer that is set to one if UTF-8 support is available;
2142     otherwise it is set to zero.
2143    
2144     PCRE_CONFIG_NEWLINE
2145    
2146     The output is an integer that it set to the value of the code that is used for
2147     newline. It is either LF (10) or CR (13).
2148    
2149     PCRE_CONFIG_LINK_SIZE
2150    
2151     The output is an integer that contains the number of bytes used for internal
2152     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2153    
2154     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2155    
2156     The output is an integer that contains the threshold above which the POSIX
2157     interface uses malloc() for output vectors. See item 31 above.
2158    
2159     PCRE_CONFIG_MATCH_LIMIT
2160    
2161     The output is an unsigned integer that contains the default limit of the number
2162     of match() calls in a pcre_exec() execution. See 42 above.
2163    
2164     44. pcretest has been upgraded by the addition of the -C option. This causes it
2165     to extract all the available output from the new pcre_config() function, and to
2166     output it. The program then exits immediately.
2167    
2168     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2169     order to support additional features. One way would have been to define
2170     pcre_exec2() (for example) with extra arguments, but this would not have been
2171     extensible, and would also have required all calls to the original function to
2172     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2173     is used for passing in "extra" data from pcre_study().
2174    
2175     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2176     contains the following fields:
2177    
2178     flags a bitmap indicating which of the following fields are set
2179     study_data opaque data from pcre_study()
2180     match_limit a way of specifying a limit on match() calls for a specific
2181     call to pcre_exec()
2182     callout_data data for callouts (see 49 below)
2183    
2184     The flag bits are also defined in pcre.h, and are
2185    
2186     PCRE_EXTRA_STUDY_DATA
2187     PCRE_EXTRA_MATCH_LIMIT
2188     PCRE_EXTRA_CALLOUT_DATA
2189    
2190     The pcre_study() function now returns one of these new pcre_extra blocks, with
2191     the actual study data pointed to by the study_data field, and the
2192     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2193     before. That is, this change is entirely upwards-compatible and requires no
2194     change to existing code.
2195    
2196     If you want to pass in additional data to pcre_exec(), you can either place it
2197     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2198     block.
2199    
2200     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2201     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2202     times with different match limits, until it finds the minimum value needed for
2203     pcre_exec() to complete. The value is then output. This can be instructive; for
2204     most simple matches the number is quite small, but for pathological cases it
2205     gets very large very quickly.
2206    
2207     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2208     returns the size of the data block pointed to by the study_data field in a
2209     pcre_extra block, that is, the value that was passed as the argument to
2210     pcre_malloc() when PCRE was getting memory in which to place the information
2211     created by pcre_study(). The fourth argument should point to a size_t variable.
2212     pcretest has been extended so that this information is shown after a successful
2213     pcre_study() call when information about the compiled regex is being displayed.
2214    
2215     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2216     because what follows is always an absolute path. (Later: it turns out that this
2217     is more than cosmetic for MinGW, because it doesn't like empty path
2218     components.)
2219    
2220     49. Some changes have been made to the callout feature (see 28 above):
2221    
2222     (i) A callout function now has three choices for what it returns:
2223    
2224     0 => success, carry on matching
2225     > 0 => failure at this point, but backtrack if possible
2226     < 0 => serious error, return this value from pcre_exec()
2227    
2228     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2229     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2230     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2231     use by callout functions. It will never be used by PCRE itself.
2232    
2233     (ii) The pcre_extra structure (see 45 above) has a void * field called
2234     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2235     pcre_callout_block structure has a field of the same name. The contents of
2236     the field passed in the pcre_extra structure are passed to the callout
2237     function in the corresponding field in the callout block. This makes it
2238     easier to use the same callout-containing regex from multiple threads. For
2239     testing, the pcretest program has a new data escape
2240    
2241     \C*n pass the number n (may be negative) as callout_data
2242    
2243     If the callout function in pcretest receives a non-zero value as
2244     callout_data, it returns that value.
2245    
2246     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2247     there were some redundant $(CFLAGS) in commands that are now specified as
2248     $(LINK), which already includes $(CFLAGS).
2249    
2250     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2251     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2252     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2253     one-byte characters throughout. Note that case-insensitive matching applies
2254     only to characters whose values are less than 256. PCRE doesn't support the
2255     notion of cases for higher-valued characters.
2256    
2257     (i) A character class whose characters are all within 0-255 is handled as
2258     a bit map, and the map is inverted for negative classes. Previously, a
2259     character > 255 always failed to match such a class; however it should
2260     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2261    
2262     (ii) A negated character class with a single character < 255 is coded as
2263     "not this character" (OP_NOT). This wasn't working properly when the test
2264     character was multibyte, either singly or repeated.
2265    
2266     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2267     mode, for example: \x{100}{2,3}.
2268    
2269     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2270     singly or repeated) now correctly test multibyte characters. However,
2271     PCRE doesn't recognize any characters with values greater than 255 as
2272     digits, spaces, or word characters. Such characters always match \D, \S,
2273     and \W, and never match \d, \s, or \w.
2274    
2275     (v) Classes may now contain characters and character ranges with values
2276     greater than 255. For example: [ab\x{100}-\x{400}].
2277    
2278     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2279     PCRE in UTF-8 mode.
2280    
2281     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2282     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2283     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2284     value.)
2285    
2286     53. The single man page has become too large. I have therefore split it up into
2287     a number of separate man pages. These also give rise to individual HTML pages;
2288     these are now put in a separate directory, and there is an index.html page that
2289     lists them all. Some hyperlinking between the pages has been installed.
2290    
2291     54. Added convenience functions for handling named capturing parentheses.
2292    
2293     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2294     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2295     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2296     are faulted.
2297    
2298     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2299     calling configure. These values are used when compiling the dftables.c program
2300     which is run to generate the source of the default character tables. They
2301     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2302     you will need to set these values.
2303    
2304     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2305    
2306    
2307     Version 3.9 02-Jan-02
2308 nigel 61 ---------------------
2309    
2310     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2311    
2312     2. If --disable-static was given, the building process failed when trying to
2313     build pcretest and pcregrep. (For some reason it was using libtool to compile
2314     them, which is not right, as they aren't part of the library.)
2315    
2316    
2317 nigel 59 Version 3.8 18-Dec-01
2318     ---------------------
2319    
2320     1. The experimental UTF-8 code was completely screwed up. It was packing the
2321     bytes in the wrong order. How dumb can you get?
2322    
2323    
2324 nigel 57 Version 3.7 29-Oct-01
2325     ---------------------
2326    
2327     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2328     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2329     this didn't happen under Solaris 8, where I normally test things.
2330    
2331 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2332     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2333     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2334     this fix an hour or so after the initial 3.7 release.)
2335 nigel 57
2336 nigel 59
2337 nigel 55 Version 3.6 23-Oct-01
2338     ---------------------
2339    
2340     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2341     offsets passed as NULL with zero offset count.
2342    
2343     2. The config.guess and config.sub files had not been updated when I moved to
2344     the latest autoconf.
2345    
2346    
2347 nigel 53 Version 3.5 15-Aug-01
2348     ---------------------
2349 nigel 5
2350 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2351     had been forgotten.
2352    
2353     2. By using declared but undefined structures, we can avoid using "void"
2354     definitions in pcre.h while keeping the internal definitions of the structures
2355     private.
2356    
2357     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2358     user point of view, this means that both static and shared libraries are built
2359     by default, but this can be individually controlled. More of the work of
2360     handling this static/shared cases is now inside libtool instead of PCRE's make
2361     file.
2362    
2363     4. The pcretest utility is now installed along with pcregrep because it is
2364     useful for users (to test regexs) and by doing this, it automatically gets
2365     relinked by libtool. The documentation has been turned into a man page, so
2366     there are now .1, .txt, and .html versions in /doc.
2367    
2368     5. Upgrades to pcregrep:
2369     (i) Added long-form option names like gnu grep.
2370     (ii) Added --help to list all options with an explanatory phrase.
2371     (iii) Added -r, --recursive to recurse into sub-directories.
2372     (iv) Added -f, --file to read patterns from a file.
2373    
2374     6. pcre_exec() was referring to its "code" argument before testing that
2375     argument for NULL (and giving an error if it was NULL).
2376    
2377     7. Upgraded Makefile.in to allow for compiling in a different directory from
2378     the source directory.
2379    
2380     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2381     options bits, the pointer it was passed was to an int instead of to an unsigned
2382     long int. This mattered only on 64-bit systems.
2383    
2384     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2385     generated) instead of pcre.in, which it its source. Also made the same change
2386     in several of the .c files.
2387    
2388     10. A new release of gcc defines printf() as a macro, which broke pcretest
2389     because it had an ifdef in the middle of a string argument for printf(). Fixed
2390     by using separate calls to printf().
2391    
2392     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2393     script, to force use of CR or LF instead of \n in the source. On non-Unix
2394     systems, the value can be set in config.h.
2395    
2396     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2397     absolute limit. Changed the text of the error message to make this clear, and
2398     likewise updated the man page.
2399    
2400     13. The limit of 99 on the number of capturing subpatterns has been removed.
2401     The new limit is 65535, which I hope will not be a "real" limit.
2402    
2403    
2404 nigel 51 Version 3.4 22-Aug-00
2405     ---------------------
2406    
2407     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2408    
2409     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2410    
2411    
2412 nigel 49 Version 3.3 01-Aug-00
2413     ---------------------
2414    
2415     1. If an octal character was given, but the value was greater than \377, it
2416     was not getting masked to the least significant bits, as documented. This could
2417     lead to crashes in some systems.
2418    
2419     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2420     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2421    
2422     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2423     These just pass their arguments on to (pcre_free)(), but they are provided
2424     because some uses of PCRE bind it to non-C systems that can call its functions,
2425     but cannot call free() or pcre_free() directly.
2426    
2427     4. Add "make test" as a synonym for "make check". Corrected some comments in
2428     the Makefile.
2429    
2430     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2431     Makefile.
2432    
2433     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2434     command called pgrep for grepping around the active processes.
2435    
2436     7. Added the beginnings of support for UTF-8 character strings.
2437    
2438     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2439     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2440     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2441     out for the ar command.)
2442    
2443    
2444 nigel 47 Version 3.2 12-May-00
2445     ---------------------
2446    
2447     This is purely a bug fixing release.
2448    
2449     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2450     of ZA. This was just one example of several cases that could provoke this bug,
2451     which was introduced by change 9 of version 2.00. The code for breaking
2452     infinite loops after an iteration that matches an empty string was't working
2453     correctly.
2454    
2455     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2456     when matched against abbab (for example). After matching an empty string, it
2457     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2458     caused it to match further down the string than it should.
2459    
2460     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2461     was there because it doesn't seem to be needed, and it causes trouble on some
2462     systems, as it is not a Standard C header. It has been removed.
2463    
2464     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2465     were reported on the Macintosh. The changes were from
2466    
2467     while ((c = *(++ptr)) != 0 && c != '\n');
2468     to
2469     while ((c = *(++ptr)) != 0 && c != '\n') ;
2470    
2471     Totally extraordinary, but if that's what it takes...
2472    
2473     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2474     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2475     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2476     assumes the way PCRE uses memmove() (always moving upwards).
2477    
2478     6. PCRE is being used in one environment where strchr() is not available. There
2479     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2480     faster code anyway.
2481    
2482    
2483 nigel 45 Version 3.1 09-Feb-00
2484     ---------------------
2485    
2486     The only change in this release is the fixing of some bugs in Makefile.in for
2487     the "install" target:
2488    
2489     (1) It was failing to install pcreposix.h.
2490    
2491     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2492    
2493    
2494 nigel 43 Version 3.0 01-Feb-00
2495     ---------------------
2496 nigel 41
2497     1. Add support for the /+ modifier to perltest (to output $` like it does in
2498     pcretest).
2499    
2500     2. Add support for the /g modifier to perltest.
2501    
2502     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2503     matches null strings.
2504    
2505     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2506     pattern. Perl treats empty patterns specially - it reuses the most recent
2507     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2508     effect.
2509    
2510     5. The POSIX interface was broken in that it was just handing over the POSIX
2511     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2512     required a bigger vector, with some working space on the end. This means that
2513     the POSIX wrapper now has to get and free some memory, and copy the results.
2514    
2515 nigel 43 6. Added some simple autoconf support, placing the test data and the
2516     documentation in separate directories, re-organizing some of the
2517     information files, and making it build pcre-config (a GNU standard). Also added
2518     libtool support for building PCRE as a shared library, which is now the
2519     default.
2520 nigel 41
2521 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2522     09 are not valid octal constants. Single digits will be used for minor values
2523     less than 10.
2524    
2525     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2526     existing programs that set these in the POSIX interface can use PCRE without
2527     modification.
2528    
2529     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2530     return all that pcre_info() returns, plus additional data. The pcre_info()
2531     function is retained for compatibility, but is considered to be obsolete.
2532    
2533     10. Added experimental recursion feature (?R) to handle one common case that
2534     Perl 5.6 will be able to do with (?p{...}).
2535    
2536     11. Added support for POSIX character classes like [:alpha:], which Perl is
2537     adopting.
2538    
2539    
2540 nigel 39 Version 2.08 31-Aug-99
2541     ----------------------
2542    
2543     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2544     trying to match at the startoffset position, but instead was moving forward to
2545     the next newline as if a previous match had failed.
2546    
2547     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2548     and could get into a loop if a null string was matched other than at the start
2549     of the subject.
2550    
2551     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2552     be distinguished at compile time, and for completeness also added PCRE_DATE.
2553    
2554     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2555     in GnuWin32 environments.
2556    
2557    
2558 nigel 37 Version 2.07 29-Jul-99
2559     ----------------------
2560    
2561     1. The documentation is now supplied in plain text form and HTML as well as in
2562     the form of man page sources.
2563    
2564     2. C++ compilers don't like assigning (void *) values to other pointer types.
2565     In particular this affects malloc(). Although there is no problem in Standard
2566     C, I've put in casts to keep C++ compilers happy.
2567    
2568     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2569     should be (const char *).
2570    
2571     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2572     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2573     However, I haven't made this a standard facility. The documentation doesn't
2574     mention it, and the Makefile doesn't support it.
2575    
2576     5. The Makefile now contains an "install" target, with editable destinations at
2577     the top of the file. The pcretest program is not installed.
2578    
2579     6. pgrep -V now gives the PCRE version number and date.
2580    
2581     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2582     causing the entire string to be ignored, instead of just the last character.
2583    
2584     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2585     non-matching string, it can take a very, very long time, even for strings of
2586     quite modest length, because of the nested recursion. PCRE now does better in
2587     some of these cases. It does this by remembering the last required literal
2588     character in the pattern, and pre-searching the subject to ensure it is present
2589     before running the real match. In other words, it applies a heuristic to detect
2590     some types of certain failure quickly, and in the above example, if presented
2591     with a string that has no trailing " it gives "no match" very quickly.
2592    
2593     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2594     other alternatives are tried instead.
2595    
2596    
2597 nigel 35 Version 2.06 09-Jun-99
2598     ----------------------
2599    
2600     1. Change pcretest's output for amount of store used to show just the code
2601     space, because the remainder (the data block) varies in size between 32-bit and
2602     64-bit systems.
2603    
2604     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2605     start matching at. This allows lookbehinds to work when searching for multiple
2606     occurrences in a string.
2607    
2608     3. Added additional options to pcretest for testing multiple occurrences:
2609    
2610     /+ outputs the rest of the string that follows a match
2611     /g loops for multiple occurrences, using the new startoffset argument
2612     /G loops for multiple occurrences by passing an incremented pointer
2613    
2614     4. PCRE wasn't doing the "first character" optimization for patterns starting
2615     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2616     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2617     the letter 'x'. On long subject strings, this gives a significant speed-up.
2618    
2619    
2620 nigel 33 Version 2.05 21-Apr-99
2621     ----------------------
2622    
2623     1. Changed the type of magic_number from int to long int so that it works
2624     properly on 16-bit systems.
2625    
2626     2. Fixed a bug which caused patterns starting with .* not to work correctly
2627     when the subject string contained newline characters. PCRE was assuming
2628     anchoring for such patterns in all cases, which is not correct because .* will
2629     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2630     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2631     must be retried after every newline in the subject.
2632    
2633    
2634 nigel 31 Version 2.04 18-Feb-99
2635     ----------------------
2636    
2637     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2638     computation of the store needed to hold the pattern was incorrect (too large).
2639     If such patterns were nested a few deep, this could multiply and become a real
2640     problem.
2641    
2642     2. Added /M option to pcretest to show the memory requirement of a specific
2643     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2644    
2645     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2646     compiled in such a way that the backtracking after subsequent failure was
2647     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2648     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2649    
2650    
2651 nigel 29 Version 2.03 02-Feb-99
2652     ----------------------
2653    
2654     1. Fixed typo and small mistake in man page.
2655    
2656 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2657     LICENCE file containing the conditions.
2658 nigel 29
2659     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2660     Perl, that is the internal \ allows the delimiter to be included in the
2661     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2662     the final delimiter, add \ to the end of the pattern (to test the error).
2663    
2664     4. Added the convenience functions for extracting substrings after a successful
2665     match. Updated pcretest to make it able to test these functions.
2666    
2667    
2668 nigel 27 Version 2.02 14-Jan-99
2669     ----------------------
2670    
2671     1. Initialized the working variables associated with each extraction so that
2672     their saving and restoring doesn't refer to uninitialized store.
2673    
2674     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2675     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2676     fix the problem.
2677    
2678     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2679     calls, and wasn't printing the correct value for compiling calls. Increased the
2680     default value of LOOPREPEAT, and the number of significant figures in the
2681     times.
2682    
2683     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2684    
2685     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2686     a building problem on Windows NT with a FAT file system.
2687    
2688    
2689 nigel 25 Version 2.01 21-Oct-98
2690     ----------------------
2691    
2692     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2693     to character tables built by pcre_maketables() in the current locale. If NULL
2694     is passed, the default tables are used.
2695    
2696    
2697 nigel 23 Version 2.00 24-Sep-98
2698 nigel 21 ----------------------
2699    
2700 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2701     it any more.
2702    
2703     2. Allow quantification of (?>) groups, and make it work correctly.
2704    
2705     3. The first character computation wasn't working for (?>) groups.
2706    
2707     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2708     end of the subject) and add 5.005's \z, which really does match only at the
2709     very end of the subject.
2710    
2711     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2712    
2713     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2714     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2715     localized options. All options to pcre_study() were also removed.
2716    
2717     7. Add other new features from 5.005:
2718    
2719     $(?<= positive lookbehind
2720     $(?<! negative lookbehind
2721     (?imsx-imsx) added the unsetting capability
2722     such a setting is global if at outer level; local otherwise
2723     (?imsx-imsx:) non-capturing groups with option setting
2724     (?(cond)re|re) conditional pattern matching
2725    
2726     A backreference to itself in a repeated group matches the previous
2727     captured string.
2728    
2729     8. General tidying up of studying (both automatic and via "study")
2730     consequential on the addition of new assertions.
2731    
2732     9. As in 5.005, unlimited repeated groups that could match an empty substring
2733     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2734     runtime if any iteration does actually match an empty substring.
2735    
2736     10. Include the RunTest script in the distribution.
2737    
2738     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2739     discrepancies, some of which were old and were also with respect to 5.004. They
2740     have now been fixed.
2741    
2742    
2743     Version 1.09 28-Apr-98
2744     ----------------------
2745    
2746 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2747     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2748     program crashes, or just wrong answers. This did not apply to negated classes
2749     containing more than one character, or to minima other than one.
2750    
2751    
2752 nigel 19 Version 1.08 27-Mar-98
2753     ----------------------
2754    
2755     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2756    
2757     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2758     latter must appear before anything that relies on it in the pattern.
2759    
2760    
2761 nigel 17 Version 1.07 16-Feb-98
2762     ----------------------
2763    
2764     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2765     repeat of a potentially empty string).
2766    
2767    
2768 nigel 15 Version 1.06 23-Jan-98
2769     ----------------------
2770    
2771     1. Added Markus Oberhumer's little patches for C++.
2772    
2773     2. Literal strings longer than 255 characters were broken.
2774    
2775    
2776 nigel 13 Version 1.05 23-Dec-97
2777     ----------------------
2778    
2779     1. Negated character classes containing more than one character were failing if
2780     PCRE_CASELESS was set at run time.
2781    
2782    
2783 nigel 11 Version 1.04 19-Dec-97
2784     ----------------------
2785    
2786     1. Corrected the man page, where some "const" qualifiers had been omitted.
2787    
2788     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2789     input syntax.
2790    
2791     3. Fixed memory leak which occurred when a regex with back references was
2792     matched with an offsets vector that wasn't big enough. The temporary memory
2793     that is used in this case wasn't being freed if the match failed.
2794    
2795     4. Tidied pcretest to ensure it frees memory that it gets.
2796    
2797     5. Temporary memory was being obtained in the case where the passed offsets
2798     vector was exactly big enough.
2799    
2800     6. Corrected definition of offsetof() from change 5 below.
2801    
2802     7. I had screwed up change 6 below and broken the rules for the use of
2803     setjmp(). Now fixed.
2804    
2805    
2806 nigel 9 Version 1.03 18-Dec-97
2807     ----------------------
2808    
2809     1. A erroneous regex with a missing opening parenthesis was correctly
2810     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2811     on some systems.
2812    
2813     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2814     it was reported that one broken compiler failed on the former because "code" is
2815     also an independent variable.
2816    
2817     3. The erroneous regex a[]b caused an array overrun reference.
2818    
2819     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2820     fail on data ending with that character. (It was going on too far, and checking
2821     the next character, typically a binary zero.) This was specific to the
2822     optimized code for single-character negative classes.
2823    
2824     5. Added a contributed patch from the TIN world which does the following:
2825    
2826     + Add an undef for memmove, in case the the system defines a macro for it.
2827    
2828     + Add a definition of offsetof(), in case there isn't one. (I don't know
2829     the reason behind this - offsetof() is part of the ANSI standard - but
2830     it does no harm).
2831    
2832     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2833     most of the places where whitespace preceded '#'. I have given up and
2834     allowed the remaining 2 cases to be at the margin.
2835    
2836     + Rename some variables in pcre to eliminate shadowing. This seems very
2837     pedantic, but does no harm, of course.
2838    
2839     6. Moved the call to setjmp() into its own function, to get rid of warnings
2840     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2841    
2842     7. Constructs such as \d{8,} were compiling into the equivalent of
2843 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2844 nigel 9 outcome, but in this particular case used more store than had been allocated,
2845     which caused the bug to be discovered because it threw up an internal error.
2846    
2847     8. The debugging code in both pcre and pcretest for outputting the compiled
2848     form of a regex was going wrong in the case of back references followed by
2849     curly-bracketed repeats.
2850    
2851    
2852 nigel 7 Version 1.02 12-Dec-97
2853     ----------------------
2854    
2855     1. Typos in pcre.3 and comments in the source fixed.
2856    
2857     2. Applied a contributed patch to get rid of places where it used to remove
2858     'const' from variables, and fixed some signed/unsigned and uninitialized
2859     variable warnings.
2860    
2861     3. Added the "runtest" target to Makefile.
2862    
2863     4. Set default compiler flag to -O2 rather than just -O.
2864    
2865    
2866 nigel 5 Version 1.01 19-Nov-97
2867     ----------------------
2868    
2869     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2870     like /([ab]*)*/, that is, for classes with more than one character in them.
2871    
2872     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2873     as /((?>a*))*/ (a PCRE_EXTRA facility).
2874    
2875    
2876     Version 1.00 18-Nov-97
2877     ----------------------
2878    
2879     1. Added compile-time macros to support systems such as SunOS4 which don't have
2880     memmove() or strerror() but have other things that can be used instead.
2881    
2882     2. Arranged that "make clean" removes the executables.
2883    
2884    
2885 nigel 3 Version 0.99 27-Oct-97
2886     ----------------------
2887    
2888     1. Fixed bug in code for optimizing classes with only one character. It was
2889     initializing a 32-byte map regardless, which could cause it to run off the end
2890     of the memory it had got.
2891    
2892     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2893    
2894    
2895     Version 0.98 22-Oct-97
2896     ----------------------
2897    
2898     1. Fixed bug in code for handling temporary memory usage when there are more
2899     back references than supplied space in the ovector. This could cause segfaults.
2900    
2901    
2902     Version 0.97 21-Oct-97
2903     ----------------------
2904    
2905     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2906    
2907     2. Optimized negated single characters not to use a bit map.
2908    
2909     3. Brought error texts together as macro definitions; clarified some of them;
2910     fixed one that was wrong - it said "range out of order" when it meant "invalid
2911     escape sequence".
2912    
2913     4. Changed some char * arguments to const char *.
2914    
2915     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2916    
2917     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2918     pcretest.
2919    
2920    
2921     Version 0.96 16-Oct-97
2922     ----------------------
2923    
2924     1. Added a simple "pgrep" utility to the distribution.
2925    
2926     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2927     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2928     where "ddd" means "one or more decimal digits".
2929    
2930     3. Fixed serious bug. If a pattern had a back reference, but the call to
2931     pcre_exec() didn't supply a large enough ovector to record the related
2932     identifying subpattern, the match always failed. PCRE now remembers the number
2933     of the largest back reference, and gets some temporary memory in which to save
2934     the offsets during matching if necessary, in order to ensure that
2935     backreferences always work.
2936    
2937     4. Increased the compatibility with Perl in a number of ways:
2938    
2939     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2940     to request this handling. The option can be set at compile or exec time.
2941    
2942     (b) $ matches before a terminating newline by default; an option
2943     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2944     mode). The option can be set at compile or exec time.
2945    
2946     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2947     the same as Perl's. If the decimal number it represents is less than 10
2948     or there aren't that many previous left capturing parentheses, an octal
2949     escape is read. Inside a character class, it's always an octal escape,
2950     even if it is a single digit.
2951    
2952     (d) An escaped but undefined alphabetic character is taken as a literal,
2953     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2954     escapes.
2955    
2956     (e) {0} is now permitted. (The previous item is removed from the compiled
2957     pattern).
2958    
2959     5. Changed all the names of code files so that the basic parts are no longer
2960     than 10 characters, and abolished the teeny "globals.c" file.
2961    
2962     6. Changed the handling of character classes; they are now done with a 32-byte
2963     bit map always.
2964    
2965     7. Added the -d and /D options to pcretest to make it possible to look at the
2966     internals of compilation without having to recompile pcre.
2967    
2968    
2969     Version 0.95 23-Sep-97
2970     ----------------------
2971    
2972     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2973     \x20 at the start of a run of normal characters. These were being treated as
2974     real characters, instead of the source characters being re-checked.
2975    
2976    
2977     Version 0.94 18-Sep-97
2978     ----------------------
2979    
2980     1. The functions are now thread-safe, with the caveat that the global variables
2981     containing pointers to malloc() and free() or alternative functions are the
2982     same for all threads.
2983    
2984     2. Get pcre_study() to generate a bitmap of initial characters for non-
2985     anchored patterns when this is possible, and use it if passed to pcre_exec().
2986    
2987    
2988     Version 0.93 15-Sep-97
2989     ----------------------
2990    
2991     1. /(b)|(:+)/ was computing an incorrect first character.
2992    
2993     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2994     but not actually doing anything yet.
2995    
2996     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2997     as Perl does (e.g. [-az] or [az-]).
2998    
2999     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3000     all possible positions.
3001    
3002     5. Split up into different modules to avoid including unneeded functions in a
3003     compiled binary. However, compile and exec are still in one module. The "study"
3004     function is split off.
3005    
3006     6. The character tables are now in a separate module whose source is generated
3007     by an auxiliary program - but can then be edited by hand if required. There are
3008     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3009     toupper() in the code.
3010    
3011     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3012     make them global. Abolish the function for setting them, as the caller can now
3013     set them directly.
3014    
3015    
3016     Version 0.92 11-Sep-97
3017     ----------------------
3018    
3019     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3020     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3021    
3022     2. Caseless matching was not working in character classes if the characters in
3023     the pattern were in upper case.
3024    
3025     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3026    
3027     4. Make PCRE_ANCHORED public and accept as a compile option.
3028    
3029     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3030     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3031     pass them.
3032    
3033     6. Give an error if bad option bits passed at compile or run time.
3034    
3035     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3036     pcretest to cause it to pass that flag.
3037    
3038     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3039     options, and the first character, if set.
3040    
3041     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3042    
3043    
3044     Version 0.91 10-Sep-97
3045     ----------------------
3046    
3047     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3048     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3049    
3050     2. PCRE was looping on encountering an indefinitely repeated back reference to
3051     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3052     Perl does - treats the match as successful.
3053    
3054     ****

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