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Revision 264 - (hide annotations) (download)
Tue Nov 13 11:07:16 2007 UTC (7 years, 1 month ago) by ph10
File size: 142292 byte(s)
Fix [\S] etc. bug in UTF-8 mode with characters > 255.

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

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