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Revision 277 - (hide annotations) (download)
Mon Nov 26 17:03:45 2007 UTC (6 years, 8 months ago) by ph10
File size: 144764 byte(s)
Fix incorrect script bug in Unicode character table.

1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 ph10 263 Version 7.5 12-Nov-07
5     ---------------------
6    
7     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
8     values in parens when parsing an RE using the C++ wrapper."
9 ph10 264
10     2. Negative specials like \S did not work in character classes in UTF-8 mode.
11     Characters greater than 255 were excluded from the class instead of being
12     included.
13 ph10 265
14     3. The same bug as (2) above applied to negated POSIX classes such as
15     [:^space:].
16 ph10 267
17     4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18     defined or documented. It seems to have been a typo for PCRE_STATIC, so
19     I have changed it.
20 ph10 268
21     5. The construct (?&) was not diagnosed as a syntax error (it referenced the
22     first named subpattern) and a construct such as (?&a) would reference the
23     first named subpattern whose name started with "a" (in other words, the
24 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
25     expected" is now given for (?&) (a zero-length name), and this patch also
26     makes it give the same error for \k'' (previously it complained that that
27     was a reference to a non-existent subpattern).
28 ph10 269
29     6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
30     this is right because (?- can be followed by option settings as well as by
31     digits. I have, however, made the messages clearer.
32 ph10 270
33     7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34     than the number used in the conditional) now cause a compile-time error.
35     This is actually not compatible with Perl, which accepts such patterns, but
36     treats the conditional as always being FALSE (as PCRE used to), but it
37     seems to me that giving a diagnostic is better.
38 ph10 274
39     8. Change "alphameric" to the more common word "alphanumeric" in comments
40 ph10 275 and messages.
41    
42     9. Fix two occurrences of "backslash" in comments that should have been
43     "backspace".
44 ph10 276
45     10. Remove two redundant lines of code that can never be obeyed (their function
46     was moved elsewhere).
47 ph10 277
48     11. The program that makes PCRE's Unicode character property table had a bug
49     which caused it to generate incorrect table entries for sequences of
50     characters that have the same character type, but are in different scripts.
51     It amalgamated them into a single range, with the script of the first of
52     them. In other words, some characters were in the wrong script. There were
53     thirteen such cases, affecting characters in the following ranges:
54    
55     U+002b0 - U+002c1
56     U+0060c - U+0060d
57     U+0061e - U+00612
58     U+0064b - U+0065e
59     U+0074d - U+0076d
60     U+01800 - U+01805
61     U+01d00 - U+01d77
62     U+01d9b - U+01dbf
63     U+0200b - U+0200f
64     U+030fc - U+030fe
65     U+03260 - U+0327f
66     U+0fb46 - U+0fbb1
67     U+10450 - U+1049d
68 ph10 263
69    
70 ph10 260 Version 7.4 21-Sep-07
71 ph10 230 ---------------------
72    
73     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
74 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
75     LF". That isn't really right - the whole point of the change was to try to
76     help when there was an actual mention of one of the two characters. So now
77     the change happens only if \r or \n (or a literal CR or LF) character is
78 ph10 230 encountered.
79 ph10 231
80     2. The 32-bit options word was also used for 6 internal flags, but the numbers
81     of both had grown to the point where there were only 3 bits left.
82     Fortunately, there was spare space in the data structure, and so I have
83     moved the internal flags into a new 16-bit field to free up more option
84 ph10 230 bits.
85 ph10 231
86     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
87     but did not set the internal JCHANGED flag - either of these is enough to
88     control the way the "get" function works - but the PCRE_INFO_JCHANGED
89     facility is supposed to tell if (?J) was ever used, so now (?J) at the
90 ph10 230 start sets both bits.
91    
92 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
93     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
94 ph10 230
95 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
96    
97     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
98 ph10 233 compatibility, even though it is no longer used.
99 ph10 243
100     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
101 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
102 ph10 259 windows.h file is present (where different names are used). [This was
103 ph10 257 reversed later after testing - see 16 below.]
104 ph10 243
105     8. Changed all #include <config.h> to #include "config.h". There were also
106 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
107 ph10 243
108 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
109 ph10 243 sequence off the lines that it output.
110    
111     10. It was pointed out to me that arrays of string pointers cause lots of
112     relocations when a shared library is dynamically loaded. A technique of
113     using a single long string with a table of offsets can drastically reduce
114     these. I have refactored PCRE in four places to do this. The result is
115 ph10 240 dramatic:
116 ph10 243
117 ph10 240 Originally: 290
118     After changing UCP table: 187
119 ph10 243 After changing error message table: 43
120 ph10 240 After changing table of "verbs" 36
121     After changing table of Posix names 22
122 ph10 243
123 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
124 ph10 247
125 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
126 ph10 247 unicode-properties was also set.
127    
128 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
129 ph10 231
130 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
131     checked only for CRLF.
132 ph10 233
133 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
134    
135 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
136 ph10 253
137 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
138 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
139     entirely. This removes changes made in 7 above.
140 ph10 256
141 ph10 261 17. The CMake files have been updated, and there is now more information about
142     building with CMake in the NON-UNIX-USE document.
143 ph10 257
144 ph10 261
145 ph10 228 Version 7.3 28-Aug-07
146 ph10 157 ---------------------
147    
148 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
149     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
150     brackets there is not right, since it causes compilers to look for an
151     installed pcre.h, not the version that is in the source that is being
152     compiled (which of course may be different). I have changed it back to:
153 ph10 197
154 ph10 189 #include "pcre.h"
155 ph10 197
156     I have a vague recollection that the change was concerned with compiling in
157     different directories, but in the new build system, that is taken care of
158     by the VPATH setting the Makefile.
159    
160 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
161     when the subject happened to end in the byte 0x85 (e.g. if the last
162     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
163     characters but of course it shouldn't be taken as a newline when it is part
164     of another character. The bug was that, for an unlimited repeat of . in
165     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
166     characters when looking for a newline.
167 ph10 197
168     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
169    
170     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
171     in debug output.
172    
173 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
174     long printing in the pcrecpp unittest when running under MinGW.
175 ph10 189
176 ph10 197 6. ESC_K was left out of the EBCDIC table.
177 ph10 189
178 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
179     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
180     limit also applies to "virtual nesting" when a pattern is recursive, and in
181     this case 1000 isn't so big. I have been able to remove this limit at the
182     expense of backing off one optimization in certain circumstances. Normally,
183     when pcre_exec() would call its internal match() function recursively and
184     immediately return the result unconditionally, it uses a "tail recursion"
185     feature to save stack. However, when a subpattern that can match an empty
186     string has an unlimited repetition quantifier, it no longer makes this
187     optimization. That gives it a stack frame in which to save the data for
188     checking that an empty string has been matched. Previously this was taken
189     from the 1000-entry workspace that had been reserved. So now there is no
190     explicit limit, but more stack is used.
191 ph10 189
192 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
193     syntax that is required for Windows, and which was going wrong for the
194     pcreposix and pcrecpp parts of the library. These were overlooked when this
195     problem was solved for the main library.
196 ph10 197
197 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
198     the size of patterns that contain repeated groups with explicit upper
199     limits. As the maximum quantifier is 65535, the maximum group length was
200     set at 30,000 so that the product of these two numbers did not overflow a
201     32-bit integer. However, it turns out that people want to use groups that
202     are longer than 30,000 bytes (though not repeat them that many times).
203     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
204     made it possible to implement the integer overflow checks in a much more
205     dynamic way, which I have now done. The artificial limitation on group
206     length has been removed - we now have only the limit on the total length of
207     the compiled pattern, which depends on the LINK_SIZE setting.
208 ph10 208
209     10. Fixed a bug in the documentation for get/copy named substring when
210     duplicate names are permitted. If none of the named substrings are set, the
211     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
212     empty string.
213    
214     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
215     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
216     because the ] is interpreted as the first data character and the
217     terminating ] is not found. PCRE has been made compatible with Perl in this
218     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
219     cause memory overwriting.
220    
221 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
222     string has been matched (to stop an infinite loop). It was not recognizing
223 ph10 208 a conditional subpattern that could match an empty string if that
224 ph10 206 subpattern was within another subpattern. For example, it looped when
225 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
226 ph10 206 condition was not nested. This bug has been fixed.
227 ph10 208
228 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
229     past the start of the subject in the presence of bytes with the top bit
230     set, for example "\x8aBCD".
231 ph10 211
232 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
233     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
234 ph10 200
235 ph10 211 14. Optimized (?!) to (*FAIL).
236 ph10 202
237 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
238     This restricts code points to be within the range 0 to 0x10FFFF, excluding
239     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
240     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
241     does: it's just the validity check that is more restrictive.
242 ph10 220
243     16. Inserted checks for integer overflows during escape sequence (backslash)
244     processing, and also fixed erroneous offset values for syntax errors during
245     backslash processing.
246    
247 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
248 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
249    
250 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
251     caused an overrun.
252 ph10 220
253     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
254     something other than just ASCII characters) inside a group that had an
255     unlimited repeat caused a loop at compile time (while checking to see
256     whether the group could match an empty string).
257    
258 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
259     [\P{Any}] did so. (Error in the code for printing property names.)
260 ph10 210
261 ph10 220 21. An orphan \E inside a character class could cause a crash.
262    
263     22. A repeated capturing bracket such as (A)? could cause a wild memory
264 ph10 218 reference during compilation.
265 ph10 220
266     23. There are several functions in pcre_compile() that scan along a compiled
267     expression for various reasons (e.g. to see if it's fixed length for look
268 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
269 ph10 220 present in the pattern. These operators have additional parameters compared
270     with \d, etc, and these were not being taken into account when moving along
271 ph10 218 the compiled data. Specifically:
272 ph10 220
273     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
274     length.
275    
276     (b) An item such as \pL+ within a repeated group could cause crashes or
277 ph10 218 loops.
278 ph10 220
279 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
280 ph10 220 "reference to non-existent subpattern" error.
281    
282 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
283    
284 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
285 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
286 ph10 211
287 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
288 ph10 218
289 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
290 ph10 223 character were causing crashes (broken optimization).
291 ph10 227
292 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
293 ph10 227 \p or \P) caused a compile-time loop.
294    
295 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
296     break. For example, the unstudied pattern [\r\n]A does not match the string
297     "\r\nA" because change 7.0/46 below moves the current point on by two
298     characters after failing to match at the start. However, the pattern \nA
299 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
300     the same is true. There doesn't seem any very clean way out of this, but
301     what I have chosen to do makes the common cases work: PCRE now takes note
302     of whether there can be an explicit match for \r or \n anywhere in the
303     pattern, and if so, 7.0/46 no longer applies. As part of this change,
304     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
305     pattern has explicit CR or LF references.
306 ph10 222
307 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
308 ph10 223
309 ph10 227
310 ph10 189 Version 7.2 19-Jun-07
311     ---------------------
312    
313 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
314     which is apparently normally available under Windows.
315 ph10 159
316     2. Re-jig the pcregrep tests with different newline settings in an attempt
317     to make them independent of the local environment's newline setting.
318 ph10 157
319 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
320 ph10 165
321 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
322     was not 2, because the output contained actual offsets. The recent new
323 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
324     usable with all link sizes.
325    
326 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
327     stack recursion. This gives a massive performance boost under BSD, but just
328 ph10 165 a small improvement under Linux. However, it saves one field in the frame
329 ph10 164 in all cases.
330 ph10 172
331 ph10 166 6. Added more features from the forthcoming Perl 5.10:
332 ph10 172
333 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
334     recursion call. It refers to the nth most recently opened parentheses.
335 ph10 172
336 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
337 ph10 172 to be opened parentheses.
338    
339     (c) Conditions that refer to capturing parentheses can be specified
340 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
341 ph10 172
342 ph10 168 (d) \K resets the start of the current match so that everything before
343 ph10 172 is not part of it.
344    
345 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
346 ph10 172
347 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
348 ph10 172 reference syntax.
349 ph10 182
350 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
351 ph10 182 alternative starts with the same number.
352 ph10 172
353 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
354    
355 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
356     PCRE_INFO_JCHANGED.
357    
358     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
359     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
360 ph10 170 for detecting groups that can match an empty string.
361 ph10 159
362 ph10 172 9. A pattern with a very large number of alternatives (more than several
363     hundred) was running out of internal workspace during the pre-compile
364     phase, where pcre_compile() figures out how much memory will be needed. A
365     bit of new cunning has reduced the workspace needed for groups with
366     alternatives. The 1000-alternative test pattern now uses 12 bytes of
367     workspace instead of running out of the 4096 that are available.
368 ph10 182
369 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
370 ph10 172
371 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
372     The report of the bug said:
373 ph10 182
374 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
375     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
376 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
377 ph10 185
378 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
379 ph10 185 it matched the wrong number of bytes.
380 ph10 172
381 ph10 179
382 ph10 155 Version 7.1 24-Apr-07
383 ph10 98 ---------------------
384    
385 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
386 ph10 122 that is more "standard", making use of automake and other Autotools. There
387 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
388     on this.
389 ph10 111
390     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
391     for recursive directory scanning broke on some systems because the files
392     are not scanned in any specific order and on different systems the order
393     was different. A call to "sort" has been inserted into RunGrepTest for the
394     approprate test as a short-term fix. In the longer term there may be an
395 ph10 100 alternative.
396 ph10 111
397 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
398 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
399     people do their own conversions for various reasons). The problems
400     concerned the use of low-level troff macros .br and .in. I have therefore
401     removed all such uses from the man pages (some were redundant, some could
402 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
403     HTML has been updated to handle .nf/.fi and to complain if it encounters
404     .br or .in.
405 ph10 111
406 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
407 ph10 123 arranged for config.h to be included in the distribution, with the name
408 ph10 111 config.h.generic, for the benefit of those who have to compile without
409     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
410    
411     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
412     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
413 ph10 127 makevp.bat for the current PCRE, using the additional files
414 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
415 ph10 111
416     6. A Windows user reported a minor discrepancy with test 2, which turned out
417     to be caused by a trailing space on an input line that had got lost in his
418 ph10 102 copy. The trailing space was an accident, so I've just removed it.
419 ph10 111
420 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
421 ph10 111 that is needed.
422    
423 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
424     as "const" (a) because they are and (b) because it helps the PHP
425     maintainers who have recently made a script to detect big data structures
426 ph10 111 in the php code that should be moved to the .rodata section. I remembered
427     to update Builducptable as well, so it won't revert if ucptable.h is ever
428 ph10 105 re-created.
429 ph10 111
430     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
431 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
432 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
433     support is not required. This saves 1.5-2K of code, which is important in
434 ph10 107 some applications.
435 ph10 111
436 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
437 ph10 111 so as not to refer to the tables, even though these functions will never be
438     called when UTF-8 support is disabled. Otherwise there are problems with a
439     shared library.
440    
441 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
442    
443     (a) It was defining its arguments as char * instead of void *.
444    
445 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
446     a long time ago when I wrote it, but is no longer the case.
447    
448 ph10 118 The emulated memove() is provided for those environments that have neither
449 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
450 ph10 118 is clearly not the case, as these two bugs were recently reported.
451 ph10 123
452 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
453 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
454     pages, and it removes trailing spaces from listed files. It also creates
455     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
456     case, it wraps all the #defines with #ifndefs. This script should be run
457 ph10 111 before "make dist".
458 ph10 123
459 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
460     with Unicode property support.
461 ph10 123
462     (a) For a maximizing quantifier, if the two different cases of the
463     character were of different lengths in their UTF-8 codings (there are
464     some cases like this - I found 11), and the matching function had to
465 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
466     were both the same length.
467 ph10 123
468     (b) When PCRE was configured to use the heap rather than the stack for
469     recursion during matching, it was not correctly preserving the data for
470     the other case of a UTF-8 character when checking ahead for a match
471     while processing a minimizing repeat. If the check also involved
472 ph10 115 matching a wide character, but failed, corruption could cause an
473     erroneous result when trying to check for a repeat of the original
474     character.
475 ph10 123
476 ph10 116 13. Some tidying changes to the testing mechanism:
477 ph10 98
478 ph10 116 (a) The RunTest script now detects the internal link size and whether there
479     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
480 ph10 123 values substituted by "configure". (The RunGrepTest script already did
481     this for UTF-8.) The configure.ac script no longer substitutes the
482     relevant variables.
483    
484 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
485     with length and offset values. This means that the output is different
486     for different internal link sizes. Test 2 is skipped for link sizes
487     other than 2 because of this, bypassing the problem. Unfortunately,
488     there was also a test in test 3 (the locale tests) that used /B and
489 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
490     I have added a new /Z option to pcretest that replaces the length and
491     offset values with spaces. This is now used to make test 3 independent
492 ph10 122 of link size. (Test 2 will be tidied up later.)
493 ph10 123
494     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
495 ph10 122 segmentation fault instead of returning the appropriate error message.
496 ph10 134
497 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
498 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
499     This doesn't seem right; it now treats the CRLF combination as the line
500     ending, and so does not match in that case. It's only a pattern such as ^$
501     that would hit this one: something like ^ABC$ would have failed after \r
502     and then tried again after \r\n.
503    
504 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
505 ph10 134 in an attempt to make files that differ only in their line terminators
506     compare equal. This works on Linux.
507 ph10 142
508 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
509     as it exited. This is now fixed, thanks to valgrind.
510 ph10 142
511 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
512 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
513     was because its rules for how to advance for /g after matching an empty
514 ph10 143 string at the end of a line did not allow for this case. They now check for
515     it specially.
516 ph10 150
517     20. pcretest is supposed to handle patterns and data of any length, by
518     extending its buffers when necessary. It was getting this wrong when the
519 ph10 147 buffer for a data line had to be extended.
520 ph10 150
521 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
522 ph10 150 CRLF as a newline sequence.
523 ph10 152
524 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
525 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
526     I have nevertheless tidied it up.
527 ph10 111
528 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
529 ph10 123
530 ph10 153 24. Added a man page for pcre-config.
531 ph10 152
532 ph10 153
533 nigel 93 Version 7.0 19-Dec-06
534     ---------------------
535    
536     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
537     moving to gcc 4.1.1.
538    
539     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
540     sys/time.h, which is documented as needed for this function. It doesn't
541     seem to matter on Linux, but it showed up on some releases of OS X.
542    
543     3. It seems that there are systems where bytes whose values are greater than
544     127 match isprint() in the "C" locale. The "C" locale should be the
545     default when a C program starts up. In most systems, only ASCII printing
546     characters match isprint(). This difference caused the output from pcretest
547     to vary, making some of the tests fail. I have changed pcretest so that:
548    
549     (a) When it is outputting text in the compiled version of a pattern, bytes
550     other than 32-126 are always shown as hex escapes.
551    
552     (b) When it is outputting text that is a matched part of a subject string,
553     it does the same, unless a different locale has been set for the match
554     (using the /L modifier). In this case, it uses isprint() to decide.
555    
556     4. Fixed a major bug that caused incorrect computation of the amount of memory
557     required for a compiled pattern when options that changed within the
558     pattern affected the logic of the preliminary scan that determines the
559     length. The relevant options are -x, and -i in UTF-8 mode. The result was
560     that the computed length was too small. The symptoms of this bug were
561     either the PCRE error "internal error: code overflow" from pcre_compile(),
562     or a glibc crash with a message such as "pcretest: free(): invalid next
563     size (fast)". Examples of patterns that provoked this bug (shown in
564     pcretest format) are:
565    
566     /(?-x: )/x
567     /(?x)(?-x: \s*#\s*)/
568     /((?i)[\x{c0}])/8
569     /(?i:[\x{c0}])/8
570    
571     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
572     is now done differently.
573    
574     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
575     wrapper classes; (b) implement a new function in the C++ scanner that is
576     more efficient than the old way of doing things because it avoids levels of
577     recursion in the regex matching; (c) add a paragraph to the documentation
578     for the FullMatch() function.
579    
580     6. The escape sequence \n was being treated as whatever was defined as
581     "newline". Not only was this contrary to the documentation, which states
582     that \n is character 10 (hex 0A), but it also went horribly wrong when
583     "newline" was defined as CRLF. This has been fixed.
584    
585     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
586     was being set to -1 for the "end of line" case (supposedly a value that no
587     character can have). Though this value is never used (the check for end of
588     line is "zero bytes in current character"), it caused compiler complaints.
589     I've changed it to 0xffffffff.
590    
591     8. In pcre_version.c, the version string was being built by a sequence of
592     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
593     string (as it is for production releases) called a macro with an empty
594     argument. The C standard says the result of this is undefined. The gcc
595     compiler treats it as an empty string (which was what was wanted) but it is
596     reported that Visual C gives an error. The source has been hacked around to
597     avoid this problem.
598    
599     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
600     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
601     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
602     of them did).
603    
604     10. Originally, pcretest opened its input and output without "b"; then I was
605     told that "b" was needed in some environments, so it was added for release
606     5.0 to both the input and output. (It makes no difference on Unix-like
607     systems.) Later I was told that it is wrong for the input on Windows. I've
608     now abstracted the modes into two macros, to make it easier to fiddle with
609     them, and removed "b" from the input mode under Windows.
610    
611     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
612    
613     12. Added -help and --help to pcretest as an official way of being reminded
614     of the options.
615    
616     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
617     and pcrecpp.cc because they annoy compilers at high warning levels.
618    
619     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
620    
621     15. Fixed an occurrence of == in configure.ac that should have been = (shell
622     scripts are not C programs :-) and which was not noticed because it works
623     on Linux.
624    
625     16. pcretest is supposed to handle any length of pattern and data line (as one
626     line or as a continued sequence of lines) by extending its input buffer if
627     necessary. This feature was broken for very long pattern lines, leading to
628     a string of junk being passed to pcre_compile() if the pattern was longer
629     than about 50K.
630    
631     17. I have done a major re-factoring of the way pcre_compile() computes the
632     amount of memory needed for a compiled pattern. Previously, there was code
633     that made a preliminary scan of the pattern in order to do this. That was
634     OK when PCRE was new, but as the facilities have expanded, it has become
635     harder and harder to keep it in step with the real compile phase, and there
636     have been a number of bugs (see for example, 4 above). I have now found a
637     cunning way of running the real compile function in a "fake" mode that
638     enables it to compute how much memory it would need, while actually only
639     ever using a few hundred bytes of working memory and without too many
640     tests of the mode. This should make future maintenance and development
641     easier. A side effect of this work is that the limit of 200 on the nesting
642     depth of parentheses has been removed (though this was never a serious
643     limitation, I suspect). However, there is a downside: pcre_compile() now
644     runs more slowly than before (30% or more, depending on the pattern). I
645     hope this isn't a big issue. There is no effect on runtime performance.
646    
647     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
648     newline (only possible for the last line of a file) and it was a
649     pattern that set a locale (followed by /Lsomething), pcretest crashed.
650    
651     19. Added additional timing features to pcretest. (1) The -tm option now times
652     matching only, not compiling. (2) Both -t and -tm can be followed, as a
653     separate command line item, by a number that specifies the number of
654     repeats to use when timing. The default is 50000; this gives better
655     precision, but takes uncomfortably long for very large patterns.
656    
657     20. Extended pcre_study() to be more clever in cases where a branch of a
658     subpattern has no definite first character. For example, (a*|b*)[cd] would
659     previously give no result from pcre_study(). Now it recognizes that the
660     first character must be a, b, c, or d.
661    
662     21. There was an incorrect error "recursive call could loop indefinitely" if
663     a subpattern (or the entire pattern) that was being tested for matching an
664     empty string contained only one non-empty item after a nested subpattern.
665     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
666     incorrectly, because the \d was being skipped in the check.
667    
668     22. The pcretest program now has a new pattern option /B and a command line
669     option -b, which is equivalent to adding /B to every pattern. This causes
670     it to show the compiled bytecode, without the additional information that
671     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
672     is the same as /B/I).
673    
674     23. A new optimization is now able automatically to treat some sequences such
675     as a*b as a*+b. More specifically, if something simple (such as a character
676     or a simple class like \d) has an unlimited quantifier, and is followed by
677     something that cannot possibly match the quantified thing, the quantifier
678     is automatically "possessified".
679    
680     24. A recursive reference to a subpattern whose number was greater than 39
681     went wrong under certain circumstances in UTF-8 mode. This bug could also
682     have affected the operation of pcre_study().
683    
684     25. Realized that a little bit of performance could be had by replacing
685     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
686    
687     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
688    
689     27. Possessive quantifiers such as a++ were previously implemented by turning
690     them into atomic groups such as ($>a+). Now they have their own opcodes,
691     which improves performance. This includes the automatically created ones
692     from 23 above.
693    
694     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
695     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
696     the first matched character to be a colon. This applied both to named and
697     numbered groups.
698    
699     29. The ucpinternal.h header file was missing its idempotency #ifdef.
700    
701     30. I was sent a "project" file called libpcre.a.dev which I understand makes
702     building PCRE on Windows easier, so I have included it in the distribution.
703    
704     31. There is now a check in pcretest against a ridiculously large number being
705     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
706     loop, the loop is abandoned.
707    
708     32. Forward references to subpatterns in conditions such as (?(2)...) where
709     subpattern 2 is defined later cause pcre_compile() to search forwards in
710     the pattern for the relevant set of parentheses. This search went wrong
711     when there were unescaped parentheses in a character class, parentheses
712     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
713    
714     33. "Subroutine" calls and backreferences were previously restricted to
715     referencing subpatterns earlier in the regex. This restriction has now
716     been removed.
717    
718     34. Added a number of extra features that are going to be in Perl 5.10. On the
719     whole, these are just syntactic alternatives for features that PCRE had
720     previously implemented using the Python syntax or my own invention. The
721     other formats are all retained for compatibility.
722    
723     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
724     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
725     also .NET compatible.
726    
727     (b) A recursion or subroutine call to a named group can now be defined as
728     (?&name) as well as (?P>name).
729    
730     (c) A backreference to a named group can now be defined as \k<name> or
731     \k'name' as well as (?P=name). The new forms, as well as being in Perl
732     5.10, are also .NET compatible.
733    
734     (d) A conditional reference to a named group can now use the syntax
735     (?(<name>) or (?('name') as well as (?(name).
736    
737     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
738     groups (named and numbered) that are never evaluated inline, but can be
739     called as "subroutines" from elsewhere. In effect, the DEFINE condition
740     is always false. There may be only one alternative in such a group.
741    
742     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
743     as the simple (?(R). The condition is true only if the most recent
744     recursion is that of the given number or name. It does not search out
745     through the entire recursion stack.
746    
747     (g) The escape \gN or \g{N} has been added, where N is a positive or
748     negative number, specifying an absolute or relative reference.
749    
750     35. Tidied to get rid of some further signed/unsigned compiler warnings and
751     some "unreachable code" warnings.
752    
753     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
754     things, this adds five new scripts.
755    
756     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
757     There were also incompatibilities regarding the handling of \Q..\E inside
758     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
759     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
760    
761     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
762     matches an empty string, and forcibly breaks the loop. There were bugs in
763     this code in non-simple cases. For a pattern such as ^(a()*)* matched
764     against aaaa the result was just "a" rather than "aaaa", for example. Two
765     separate and independent bugs (that affected different cases) have been
766     fixed.
767    
768     39. Refactored the code to abolish the use of different opcodes for small
769     capturing bracket numbers. This is a tidy that I avoided doing when I
770     removed the limit on the number of capturing brackets for 3.5 back in 2001.
771     The new approach is not only tidier, it makes it possible to reduce the
772     memory needed to fix the previous bug (38).
773    
774     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
775     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
776     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
777     mode.
778    
779     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
780     report.
781    
782     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
783     copy construction and assignment in the C++ wrapper.
784    
785     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
786     couple of bugs that could have given wrong results in the "--newline=crlf"
787     case.
788    
789     44. Added a number of casts and did some reorganization of signed/unsigned int
790     variables following suggestions from Dair Grant. Also renamed the variable
791     "this" as "item" because it is a C++ keyword.
792    
793     45. Arranged for dftables to add
794    
795     #include "pcre_internal.h"
796    
797     to pcre_chartables.c because without it, gcc 4.x may remove the array
798     definition from the final binary if PCRE is built into a static library and
799     dead code stripping is activated.
800    
801     46. For an unanchored pattern, if a match attempt fails at the start of a
802     newline sequence, and the newline setting is CRLF or ANY, and the next two
803     characters are CRLF, advance by two characters instead of one.
804    
805    
806 nigel 91 Version 6.7 04-Jul-06
807     ---------------------
808    
809     1. In order to handle tests when input lines are enormously long, pcretest has
810     been re-factored so that it automatically extends its buffers when
811     necessary. The code is crude, but this _is_ just a test program. The
812     default size has been increased from 32K to 50K.
813    
814     2. The code in pcre_study() was using the value of the re argument before
815     testing it for NULL. (Of course, in any sensible call of the function, it
816     won't be NULL.)
817    
818     3. The memmove() emulation function in pcre_internal.h, which is used on
819     systems that lack both memmove() and bcopy() - that is, hardly ever -
820     was missing a "static" storage class specifier.
821    
822     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
823     containing an extended class (one that cannot be represented by a bitmap
824     because it contains high-valued characters or Unicode property items, e.g.
825     [\pZ]). Almost always one would set UTF-8 mode when processing such a
826     pattern, but PCRE should not loop if you do not (it no longer does).
827     [Detail: two cases were found: (a) a repeated subpattern containing an
828     extended class; (b) a recursive reference to a subpattern that followed a
829     previous extended class. It wasn't skipping over the extended class
830     correctly when UTF-8 mode was not set.]
831    
832     5. A negated single-character class was not being recognized as fixed-length
833     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
834     compile error "lookbehind assertion is not fixed length".
835    
836     6. The RunPerlTest auxiliary script was showing an unexpected difference
837     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
838     write a Perl script that can interpret lines of an input file either as
839     byte characters or as UTF-8, which is what "perltest" was being required to
840     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
841     can't do is switch easily at run time between having the "use utf8;" pragma
842     or not. In the end, I fudged it by using the RunPerlTest script to insert
843     "use utf8;" explicitly for the UTF-8 tests.
844    
845     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
846     the end of the subject string, contrary to the documentation and to what
847     Perl does. This was true of both matching functions. Now it matches only at
848     the start of the subject and immediately after *internal* newlines.
849    
850     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
851     a pointer to an int instead of a pointer to an unsigned long int. This
852     caused problems on 64-bit systems.
853    
854     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
855     instance of the 'standard' template library not being so standard".
856    
857     10. There was no check on the number of named subpatterns nor the maximum
858     length of a subpattern name. The product of these values is used to compute
859     the size of the memory block for a compiled pattern. By supplying a very
860     long subpattern name and a large number of named subpatterns, the size
861     computation could be caused to overflow. This is now prevented by limiting
862     the length of names to 32 characters, and the number of named subpatterns
863     to 10,000.
864    
865     11. Subpatterns that are repeated with specific counts have to be replicated in
866     the compiled pattern. The size of memory for this was computed from the
867     length of the subpattern and the repeat count. The latter is limited to
868     65535, but there was no limit on the former, meaning that integer overflow
869     could in principle occur. The compiled length of a repeated subpattern is
870     now limited to 30,000 bytes in order to prevent this.
871    
872     12. Added the optional facility to have named substrings with the same name.
873    
874     13. Added the ability to use a named substring as a condition, using the
875     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
876     are numbers (not recommended). Forward references are permitted.
877    
878     14. Added forward references in named backreferences (if you see what I mean).
879    
880     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
881     pattern could run off the end of the subject. For example, the pattern
882     "(?s)(.{1,5})"8 did this with the subject "ab".
883    
884     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
885     PCRE_CASELESS was set when matching characters that were quantified with ?
886     or *.
887    
888     17. A character class other than a single negated character that had a minimum
889     but no maximum quantifier - for example [ab]{6,} - was not handled
890     correctly by pce_dfa_exec(). It would match only one character.
891    
892     18. A valid (though odd) pattern that looked like a POSIX character
893     class but used an invalid character after [ (for example [[,abc,]]) caused
894     pcre_compile() to give the error "Failed: internal error: code overflow" or
895     in some cases to crash with a glibc free() error. This could even happen if
896     the pattern terminated after [[ but there just happened to be a sequence of
897     letters, a binary zero, and a closing ] in the memory that followed.
898    
899     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
900     over the years. Originally (before any Unicode support), just the bottom 8
901     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
902     output from "man perlunicode" includes this:
903    
904     The regular expression compiler produces polymorphic opcodes. That
905     is, the pattern adapts to the data and automatically switches to
906     the Unicode character scheme when presented with Unicode data--or
907     instead uses a traditional byte scheme when presented with byte
908     data.
909    
910     Sadly, a wide octal escape does not cause a switch, and in a string with
911     no other multibyte characters, these octal escapes are treated as before.
912     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
913     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
914     Unicode string.
915    
916     I have not perpetrated such confusion in PCRE. Up till now, it took just
917     the bottom 8 bits, as in old Perl. I have now made octal escapes with
918     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
919     translate to the appropriate multibyte character.
920    
921     29. Applied some refactoring to reduce the number of warnings from Microsoft
922     and Borland compilers. This has included removing the fudge introduced
923     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
924     a warning about an unused variable.
925    
926     21. PCRE has not included VT (character 0x0b) in the set of whitespace
927     characters since release 4.0, because Perl (from release 5.004) does not.
928     [Or at least, is documented not to: some releases seem to be in conflict
929     with the documentation.] However, when a pattern was studied with
930     pcre_study() and all its branches started with \s, PCRE still included VT
931     as a possible starting character. Of course, this did no harm; it just
932     caused an unnecessary match attempt.
933    
934     22. Removed a now-redundant internal flag bit that recorded the fact that case
935     dependency changed within the pattern. This was once needed for "required
936     byte" processing, but is no longer used. This recovers a now-scarce options
937     bit. Also moved the least significant internal flag bit to the most-
938     significant bit of the word, which was not previously used (hangover from
939     the days when it was an int rather than a uint) to free up another bit for
940     the future.
941    
942     23. Added support for CRLF line endings as well as CR and LF. As well as the
943     default being selectable at build time, it can now be changed at runtime
944     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
945     specify that it is scanning data with non-default line endings.
946    
947     24. Changed the definition of CXXLINK to make it agree with the definition of
948     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
949    
950     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
951     recursions. This makes a big different to stack usage for some patterns.
952    
953     26. If a subpattern containing a named recursion or subroutine reference such
954     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
955     the space required for the compiled pattern went wrong and gave too small a
956     value. Depending on the environment, this could lead to "Failed: internal
957     error: code overflow at offset 49" or "glibc detected double free or
958     corruption" errors.
959    
960     27. Applied patches from Google (a) to support the new newline modes and (b) to
961     advance over multibyte UTF-8 characters in GlobalReplace.
962    
963     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
964     difference for some implementation of PCRE in some Windows version.
965    
966     29. Added some extra testing facilities to pcretest:
967    
968     \q<number> in a data line sets the "match limit" value
969     \Q<number> in a data line sets the "match recursion limt" value
970     -S <number> sets the stack size, where <number> is in megabytes
971    
972     The -S option isn't available for Windows.
973    
974    
975 nigel 89 Version 6.6 06-Feb-06
976     ---------------------
977    
978     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
979     in pcreposix.h. I have copied the definition from pcre.h.
980    
981     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
982     because pcre.h is no longer a built file.
983    
984     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
985     not normally included in the compiled code.
986    
987    
988 nigel 87 Version 6.5 01-Feb-06
989     ---------------------
990    
991     1. When using the partial match feature with pcre_dfa_exec(), it was not
992     anchoring the second and subsequent partial matches at the new starting
993     point. This could lead to incorrect results. For example, with the pattern
994     /1234/, partially matching against "123" and then "a4" gave a match.
995    
996     2. Changes to pcregrep:
997    
998     (a) All non-match returns from pcre_exec() were being treated as failures
999     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1000     error message is output. Some extra information is given for the
1001     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1002     probably the only errors that are likely to be caused by users (by
1003     specifying a regex that has nested indefinite repeats, for instance).
1004     If there are more than 20 of these errors, pcregrep is abandoned.
1005    
1006     (b) A binary zero was treated as data while matching, but terminated the
1007     output line if it was written out. This has been fixed: binary zeroes
1008     are now no different to any other data bytes.
1009    
1010     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1011     used to set a locale for matching. The --locale=xxxx long option has
1012     been added (no short equivalent) to specify a locale explicitly on the
1013     pcregrep command, overriding the environment variables.
1014    
1015     (d) When -B was used with -n, some line numbers in the output were one less
1016     than they should have been.
1017    
1018     (e) Added the -o (--only-matching) option.
1019    
1020     (f) If -A or -C was used with -c (count only), some lines of context were
1021     accidentally printed for the final match.
1022    
1023     (g) Added the -H (--with-filename) option.
1024    
1025     (h) The combination of options -rh failed to suppress file names for files
1026     that were found from directory arguments.
1027    
1028     (i) Added the -D (--devices) and -d (--directories) options.
1029    
1030     (j) Added the -F (--fixed-strings) option.
1031    
1032     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1033    
1034     (l) Added the --colo(u)r option.
1035    
1036     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1037     is not present by default.
1038    
1039     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1040     items such as (?R) or (?1), when the recursion could match a number of
1041     alternatives. If it matched one of the alternatives, but subsequently,
1042     outside the recursion, there was a failure, the code tried to back up into
1043     the recursion. However, because of the way PCRE is implemented, this is not
1044     possible, and the result was an incorrect result from the match.
1045    
1046     In order to prevent this happening, the specification of recursion has
1047     been changed so that all such subpatterns are automatically treated as
1048     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1049    
1050     4. I had overlooked the fact that, in some locales, there are characters for
1051     which isalpha() is true but neither isupper() nor islower() are true. In
1052     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1053     and ordfeminine) are like this. This affected the treatment of \w and \W
1054     when they appeared in character classes, but not when they appeared outside
1055     a character class. The bit map for "word" characters is now created
1056     separately from the results of isalnum() instead of just taking it from the
1057     upper, lower, and digit maps. (Plus the underscore character, of course.)
1058    
1059     5. The above bug also affected the handling of POSIX character classes such as
1060     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1061     permanent tables. Instead, the bit maps for such a class were previously
1062     created as the appropriate unions of the upper, lower, and digit bitmaps.
1063     Now they are created by subtraction from the [[:word:]] class, which has
1064     its own bitmap.
1065    
1066     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1067     It is created by subtracting the vertical space characters (\x09, \x0a,
1068     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1069     subtraction was done in the overall bitmap for a character class, meaning
1070     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1071     be recognized. This bug has been fixed.
1072    
1073     7. Patches from the folks at Google:
1074    
1075     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1076     real life, but is still worth protecting against".
1077    
1078     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1079     regular expressions".
1080    
1081     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1082     have it.
1083    
1084     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1085     "configure" and the latter not, in order to fix a problem somebody had
1086     with compiling the Arg class on HP-UX.
1087    
1088     (e) Improve the error-handling of the C++ wrapper a little bit.
1089    
1090     (f) New tests for checking recursion limiting.
1091    
1092     8. The pcre_memmove() function, which is used only if the environment does not
1093     have a standard memmove() function (and is therefore rarely compiled),
1094     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1095     returning a result (though PCRE never actually uses the result).
1096    
1097     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1098     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1099     returned instead of calling malloc() with an overflowing number that would
1100     most likely cause subsequent chaos.
1101    
1102     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1103    
1104     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1105     with this option is matched, the nmatch and pmatch options of regexec() are
1106     ignored.
1107    
1108     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1109     provided in case anyone wants to the the POSIX interface with UTF-8
1110     strings.
1111    
1112     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1113     C++ linking (needed for some HP-UX environments).
1114    
1115     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1116     (unused parameter) and in the pcre_printint() function (omitted "default"
1117     switch label when the default is to do nothing).
1118    
1119     15. Added some code to make it possible, when PCRE is compiled as a C++
1120     library, to replace subject pointers for pcre_exec() with a smart pointer
1121     class, thus making it possible to process discontinuous strings.
1122    
1123     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1124     much the same function. They were added by different people who were trying
1125     to make PCRE easy to compile on non-Unix systems. It has been suggested
1126     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1127     for compiling on Windows systems. I have therefore replaced it with
1128     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1129     defaults to "extern" for C or "extern C" for C++, which works fine on
1130     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1131     SCOPE with something explicit in config.h. In addition:
1132    
1133     (a) pcreposix.h still had just "extern" instead of either of these macros;
1134     I have replaced it with PCRE_DATA_SCOPE.
1135    
1136     (b) Functions such as _pcre_xclass(), which are internal to the library,
1137     but external in the C sense, all had PCRE_EXPORT in their definitions.
1138     This is apparently wrong for the Windows case, so I have removed it.
1139     (It makes no difference on Unix-like systems.)
1140    
1141     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1142     of recursive calls to match(). This is different to MATCH_LIMIT because
1143     that limits the total number of calls to match(), not all of which increase
1144     the depth of recursion. Limiting the recursion depth limits the amount of
1145     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1146     when PCRE is compiled, and changed at run time. A patch from Google adds
1147     this functionality to the C++ interface.
1148    
1149     18. Changes to the handling of Unicode character properties:
1150    
1151     (a) Updated the table to Unicode 4.1.0.
1152    
1153     (b) Recognize characters that are not in the table as "Cn" (undefined).
1154    
1155     (c) I revised the way the table is implemented to a much improved format
1156     which includes recognition of ranges. It now supports the ranges that
1157     are defined in UnicodeData.txt, and it also amalgamates other
1158     characters into ranges. This has reduced the number of entries in the
1159     table from around 16,000 to around 3,000, thus reducing its size
1160     considerably. I realized I did not need to use a tree structure after
1161     all - a binary chop search is just as efficient. Having reduced the
1162     number of entries, I extended their size from 6 bytes to 8 bytes to
1163     allow for more data.
1164    
1165     (d) Added support for Unicode script names via properties such as \p{Han}.
1166    
1167     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1168     matching that character.
1169    
1170     20. When matching a repeated Unicode property with a minimum greater than zero,
1171     (for example \pL{2,}), PCRE could look past the end of the subject if it
1172     reached it while seeking the minimum number of characters. This could
1173     happen only if some of the characters were more than one byte long, because
1174     there is a check for at least the minimum number of bytes.
1175    
1176     21. Refactored the implementation of \p and \P so as to be more general, to
1177     allow for more different types of property in future. This has changed the
1178     compiled form incompatibly. Anybody with saved compiled patterns that use
1179     \p or \P will have to recompile them.
1180    
1181     22. Added "Any" and "L&" to the supported property types.
1182    
1183     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1184     but give a compile time error if the value is greater than 0xff.
1185    
1186     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1187     accidentally not being installed or uninstalled.
1188    
1189     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1190     made were to insert the current release number. This seemed silly, because
1191     it made things harder for people building PCRE on systems that don't run
1192     "configure". I have turned pcre.h into a distributed file, no longer built
1193     by "configure", with the version identification directly included. There is
1194     no longer a pcre.h.in file.
1195    
1196     However, this change necessitated a change to the pcre-config script as
1197     well. It is built from pcre-config.in, and one of the substitutions was the
1198     release number. I have updated configure.ac so that ./configure now finds
1199     the release number by grepping pcre.h.
1200    
1201     26. Added the ability to run the tests under valgrind.
1202    
1203    
1204 nigel 85 Version 6.4 05-Sep-05
1205     ---------------------
1206    
1207     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1208     "--" to be printed when multiple files were scanned, even when none of the
1209     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1210     consider it to be a bug, and have restored the previous behaviour.
1211    
1212     2. A couple of code tidies to get rid of compiler warnings.
1213    
1214     3. The pcretest program used to cheat by referring to symbols in the library
1215     whose names begin with _pcre_. These are internal symbols that are not
1216     really supposed to be visible externally, and in some environments it is
1217     possible to suppress them. The cheating is now confined to including
1218     certain files from the library's source, which is a bit cleaner.
1219    
1220     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1221     file's purpose clearer.
1222    
1223     5. Reorganized pcre_ucp_findchar().
1224    
1225    
1226 nigel 83 Version 6.3 15-Aug-05
1227     ---------------------
1228    
1229     1. The file libpcre.pc.in did not have general read permission in the tarball.
1230    
1231     2. There were some problems when building without C++ support:
1232    
1233     (a) If C++ support was not built, "make install" and "make test" still
1234     tried to test it.
1235    
1236     (b) There were problems when the value of CXX was explicitly set. Some
1237     changes have been made to try to fix these, and ...
1238    
1239     (c) --disable-cpp can now be used to explicitly disable C++ support.
1240    
1241     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1242     backslash in a target when C++ was disabled. This confuses some
1243     versions of "make", apparently. Using an intermediate variable solves
1244     this. (Same for CPP_LOBJ.)
1245    
1246     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1247     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1248     necessary on certain architectures.
1249    
1250     4. Added a setting of -export-symbols-regex to the link command to remove
1251     those symbols that are exported in the C sense, but actually are local
1252     within the library, and not documented. Their names all begin with
1253     "_pcre_". This is not a perfect job, because (a) we have to except some
1254     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1255     available (and never for static libraries). I have made a note to try to
1256     find a way round (a) in the future.
1257    
1258    
1259 nigel 81 Version 6.2 01-Aug-05
1260     ---------------------
1261    
1262     1. There was no test for integer overflow of quantifier values. A construction
1263     such as {1111111111111111} would give undefined results. What is worse, if
1264     a minimum quantifier for a parenthesized subpattern overflowed and became
1265     negative, the calculation of the memory size went wrong. This could have
1266     led to memory overwriting.
1267    
1268     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1269    
1270     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1271     operating environments where this matters.
1272    
1273     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1274     PCRE options from within the C++ wrapper.
1275    
1276     5. Named capturing subpatterns were not being correctly counted when a pattern
1277     was compiled. This caused two problems: (a) If there were more than 100
1278     such subpatterns, the calculation of the memory needed for the whole
1279     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1280     back references of the form \12, where the number was greater than 9, were
1281     not recognized as back references, even though there were sufficient
1282     previous subpatterns.
1283    
1284     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1285     versions of gcc, e.g. 2.95.4.
1286    
1287    
1288 nigel 79 Version 6.1 21-Jun-05
1289     ---------------------
1290    
1291     1. There was one reference to the variable "posix" in pcretest.c that was not
1292     surrounded by "#if !defined NOPOSIX".
1293    
1294     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1295     the cross-check on the old pcre_info() function, for the benefit of the
1296     cut-down version of PCRE that is currently imported into Exim.
1297    
1298     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1299     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1300     patterns that start (?i) but I don't think that matters. The use of (?i) is
1301     just an example; this all applies to the other options as well.
1302    
1303     4. Since libtool seems to echo the compile commands it is issuing, the output
1304     from "make" can be reduced a bit by putting "@" in front of each libtool
1305     compile command.
1306    
1307     5. Patch from the folks at Google for configure.in to be a bit more thorough
1308     in checking for a suitable C++ installation before trying to compile the
1309     C++ stuff. This should fix a reported problem when a compiler was present,
1310     but no suitable headers.
1311    
1312     6. The man pages all had just "PCRE" as their title. I have changed them to
1313     be the relevant file name. I have also arranged that these names are
1314     retained in the file doc/pcre.txt, which is a concatenation in text format
1315     of all the man pages except the little individual ones for each function.
1316    
1317     7. The NON-UNIX-USE file had not been updated for the different set of source
1318     files that come with release 6. I also added a few comments about the C++
1319     wrapper.
1320    
1321    
1322 nigel 77 Version 6.0 07-Jun-05
1323     ---------------------
1324    
1325     1. Some minor internal re-organization to help with my DFA experiments.
1326    
1327     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1328     didn't matter for the library itself when fully configured, but did matter
1329     when compiling without UCP support, or within Exim, where the ucp files are
1330     not imported.
1331    
1332     3. Refactoring of the library code to split up the various functions into
1333     different source modules. The addition of the new DFA matching code (see
1334     below) to a single monolithic source would have made it really too
1335     unwieldy, quite apart from causing all the code to be include in a
1336     statically linked application, when only some functions are used. This is
1337     relevant even without the DFA addition now that patterns can be compiled in
1338     one application and matched in another.
1339    
1340     The downside of splitting up is that there have to be some external
1341     functions and data tables that are used internally in different modules of
1342     the library but which are not part of the API. These have all had their
1343     names changed to start with "_pcre_" so that they are unlikely to clash
1344     with other external names.
1345    
1346     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1347     a different (DFA) algorithm. Although it is slower than the original
1348     function, it does have some advantages for certain types of matching
1349     problem.
1350    
1351     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1352     including restarting after a partial match.
1353    
1354     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1355     defined when compiling for Windows was sent to me. I have put it into the
1356     code, though I have no means of testing or verifying it.
1357    
1358     7. Added the pcre_refcount() auxiliary function.
1359    
1360     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1361     match before or at the first newline in the subject string. In pcretest,
1362     the /f option on a pattern can be used to set this.
1363    
1364     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1365     would behave wrongly. This has been present in PCRE since release 4.0.
1366    
1367     10. A number of changes to the pcregrep command:
1368    
1369     (a) Refactored how -x works; insert ^(...)$ instead of setting
1370     PCRE_ANCHORED and checking the length, in preparation for adding
1371     something similar for -w.
1372    
1373     (b) Added the -w (match as a word) option.
1374    
1375     (c) Refactored the way lines are read and buffered so as to have more
1376     than one at a time available.
1377    
1378     (d) Implemented a pcregrep test script.
1379    
1380     (e) Added the -M (multiline match) option. This allows patterns to match
1381     over several lines of the subject. The buffering ensures that at least
1382     8K, or the rest of the document (whichever is the shorter) is available
1383     for matching (and similarly the previous 8K for lookbehind assertions).
1384    
1385     (f) Changed the --help output so that it now says
1386    
1387     -w, --word-regex(p)
1388    
1389     instead of two lines, one with "regex" and the other with "regexp"
1390     because that confused at least one person since the short forms are the
1391     same. (This required a bit of code, as the output is generated
1392     automatically from a table. It wasn't just a text change.)
1393    
1394     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1395     option but starts with a hyphen. Could be a pattern or a path name
1396     starting with a hyphen, for instance.
1397    
1398     (h) "-" can be given as a file name to represent stdin.
1399    
1400     (i) When file names are being printed, "(standard input)" is used for
1401     the standard input, for compatibility with GNU grep. Previously
1402     "<stdin>" was used.
1403    
1404     (j) The option --label=xxx can be used to supply a name to be used for
1405     stdin when file names are being printed. There is no short form.
1406    
1407     (k) Re-factored the options decoding logic because we are going to add
1408     two more options that take data. Such options can now be given in four
1409     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1410    
1411     (l) Added the -A, -B, and -C options for requesting that lines of context
1412     around matches be printed.
1413    
1414     (m) Added the -L option to print the names of files that do not contain
1415     any matching lines, that is, the complement of -l.
1416    
1417     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1418     continue to scan other files.
1419    
1420     (o) The -s option was incorrectly implemented. For compatibility with other
1421     greps, it now suppresses the error message for a non-existent or non-
1422     accessible file (but not the return code). There is a new option called
1423     -q that suppresses the output of matching lines, which was what -s was
1424     previously doing.
1425    
1426     (p) Added --include and --exclude options to specify files for inclusion
1427     and exclusion when recursing.
1428    
1429     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1430     Hopefully, it now does.
1431    
1432     12. Missing cast in pcre_study().
1433    
1434     13. Added an "uninstall" target to the makefile.
1435    
1436     14. Replaced "extern" in the function prototypes in Makefile.in with
1437     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1438     world, but is set differently for Windows.
1439    
1440     15. Added a second compiling function called pcre_compile2(). The only
1441     difference is that it has an extra argument, which is a pointer to an
1442     integer error code. When there is a compile-time failure, this is set
1443     non-zero, in addition to the error test pointer being set to point to an
1444     error message. The new argument may be NULL if no error number is required
1445     (but then you may as well call pcre_compile(), which is now just a
1446     wrapper). This facility is provided because some applications need a
1447     numeric error indication, but it has also enabled me to tidy up the way
1448     compile-time errors are handled in the POSIX wrapper.
1449    
1450     16. Added VPATH=.libs to the makefile; this should help when building with one
1451     prefix path and installing with another. (Or so I'm told by someone who
1452     knows more about this stuff than I do.)
1453    
1454     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1455     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1456     match everything, including newlines. This is not POSIX-compatible, but
1457     somebody wanted the feature. From pcretest it can be activated by using
1458     both the P and the s flags.
1459    
1460     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1461    
1462     19. libpcre.pc was being incorrectly installed as executable.
1463    
1464     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1465     it now also looks for '\r' so that it will work unmodified on Windows.
1466    
1467     21. Added Google's contributed C++ wrapper to the distribution.
1468    
1469     22. Added some untidy missing memory free() calls in pcretest, to keep
1470     Electric Fence happy when testing.
1471    
1472    
1473    
1474 nigel 75 Version 5.0 13-Sep-04
1475     ---------------------
1476    
1477     1. Internal change: literal characters are no longer packed up into items
1478     containing multiple characters in a single byte-string. Each character
1479     is now matched using a separate opcode. However, there may be more than one
1480     byte in the character in UTF-8 mode.
1481    
1482     2. The pcre_callout_block structure has two new fields: pattern_position and
1483     next_item_length. These contain the offset in the pattern to the next match
1484     item, and its length, respectively.
1485    
1486     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1487     insertion of callouts before each pattern item. Added the /C option to
1488     pcretest to make use of this.
1489    
1490     4. On the advice of a Windows user, the lines
1491    
1492     #if defined(_WIN32) || defined(WIN32)
1493     _setmode( _fileno( stdout ), 0x8000 );
1494     #endif /* defined(_WIN32) || defined(WIN32) */
1495    
1496     have been added to the source of pcretest. This apparently does useful
1497     magic in relation to line terminators.
1498    
1499     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1500     for the benefit of those environments where the "b" makes a difference.
1501    
1502     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1503     to know about it. I have put a hack into configure.in that adds in code
1504     to set GCC=yes if CC=icc. This seems to end up at a point in the
1505     generated configure script that is early enough to affect the setting of
1506     compiler options, which is what is needed, but I have no means of testing
1507     whether it really works. (The user who reported this had patched the
1508     generated configure script, which of course I cannot do.)
1509    
1510     LATER: After change 22 below (new libtool files), the configure script
1511     seems to know about icc (and also ecc). Therefore, I have commented out
1512     this hack in configure.in.
1513    
1514     7. Added support for pkg-config (2 patches were sent in).
1515    
1516     8. Negated POSIX character classes that used a combination of internal tables
1517     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1518     [[:^ascii]]. Typically, they would match almost any characters. The other
1519     POSIX classes were not broken in this way.
1520    
1521     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1522     to find the match, as PCRE was deluded into thinking that the match had to
1523     start at the start point or following a newline. The same bug applied to
1524     patterns with negative forward assertions or any backward assertions
1525     preceding ".*" at the start, unless the pattern required a fixed first
1526     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1527    
1528     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1529     starting at the last subject character, bytes beyond the end of the subject
1530     string were read.
1531    
1532     11. Renamed the variable "class" as "classbits" to make life easier for C++
1533     users. (Previously there was a macro definition, but it apparently wasn't
1534     enough.)
1535    
1536     12. Added the new field "tables" to the extra data so that tables can be passed
1537     in at exec time, or the internal tables can be re-selected. This allows
1538     a compiled regex to be saved and re-used at a later time by a different
1539     program that might have everything at different addresses.
1540    
1541     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1542     -R library as well as a -L library.
1543    
1544     14. The debugging options of pcretest (-d on the command line or D on a
1545     pattern) showed incorrect output for anything following an extended class
1546     that contained multibyte characters and which was followed by a quantifier.
1547    
1548     15. Added optional support for general category Unicode character properties
1549     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1550     support. It adds about 90K to the size of the library. The meanings of the
1551     inbuilt class escapes such as \d and \s have NOT been changed.
1552    
1553     16. Updated pcredemo.c to include calls to free() to release the memory for the
1554     compiled pattern.
1555    
1556     17. The generated file chartables.c was being created in the source directory
1557     instead of in the building directory. This caused the build to fail if the
1558     source directory was different from the building directory, and was
1559     read-only.
1560    
1561     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1562     file. No doubt somebody will tell me if they don't make sense... Also added
1563     Dan Mooney's comments about building on OpenVMS.
1564    
1565     19. Added support for partial matching via the PCRE_PARTIAL option for
1566     pcre_exec() and the \P data escape in pcretest.
1567    
1568     20. Extended pcretest with 3 new pattern features:
1569    
1570     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1571     write the compiled pattern to the file whose name is "rest-of-line".
1572     This is a straight binary dump of the data, with the saved pointer to
1573     the character tables forced to be NULL. The study data, if any, is
1574     written too. After writing, pcretest reads a new pattern.
1575    
1576     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1577     compiled pattern from the given file. There must not be any
1578     occurrences of "<" in the file name (pretty unlikely); if there are,
1579     pcretest will instead treat the initial "<" as a pattern delimiter.
1580     After reading in the pattern, pcretest goes on to read data lines as
1581     usual.
1582    
1583     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1584     and 16-bit fields in a compiled pattern, to simulate a pattern that
1585     was compiled on a host of opposite endianness.
1586    
1587     21. The pcre-exec() function can now cope with patterns that were compiled on
1588     hosts of opposite endianness, with this restriction:
1589    
1590     As for any compiled expression that is saved and used later, the tables
1591     pointer field cannot be preserved; the extra_data field in the arguments
1592     to pcre_exec() should be used to pass in a tables address if a value
1593     other than the default internal tables were used at compile time.
1594    
1595     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1596     now diagnosed as an error. Previously, most of the time, a negative number
1597     would have been treated as zero, but if in addition "ovector" was passed as
1598     NULL, a crash could occur.
1599    
1600     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1601     new versions from the libtool 1.5 distribution (the last one is a copy of
1602     a file called libtool.m4). This seems to have fixed the need to patch
1603     "configure" to support Darwin 1.3 (which I used to do). However, I still
1604     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1605     workstation).
1606    
1607     24. Changed the PCRE licence to be the more standard "BSD" licence.
1608    
1609    
1610 nigel 73 Version 4.5 01-Dec-03
1611     ---------------------
1612    
1613     1. There has been some re-arrangement of the code for the match() function so
1614     that it can be compiled in a version that does not call itself recursively.
1615     Instead, it keeps those local variables that need separate instances for
1616     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1617     needs to "recurse". Keeping track of where control must go is done by means
1618     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1619     hide most of the details from the main code, and operates only if
1620     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1621     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1622     operating.
1623    
1624     To make it easier for callers to provide specially tailored get/free
1625     functions for this usage, two new functions, pcre_stack_malloc, and
1626     pcre_stack_free, are used. They are always called in strict stacking order,
1627     and the size of block requested is always the same.
1628    
1629     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1630     PCRE has been compiled to use the stack or the heap for recursion. The
1631     -C option of pcretest uses this to show which version is compiled.
1632    
1633     A new data escape \S, is added to pcretest; it causes the amounts of store
1634     obtained and freed by both kinds of malloc/free at match time to be added
1635     to the output.
1636    
1637     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1638     what's available on my current Linux desktop machine.
1639    
1640     3. When matching a UTF-8 string, the test for a valid string at the start has
1641     been extended. If start_offset is not zero, PCRE now checks that it points
1642     to a byte that is the start of a UTF-8 character. If not, it returns
1643     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1644     this is necessary because there may be backward assertions in the pattern.
1645     When matching the same subject several times, it may save resources to use
1646     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1647    
1648     4. The code for checking the validity of UTF-8 strings has been tightened so
1649     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1650     containing "overlong sequences".
1651    
1652     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1653     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1654     should have been "&", but it just so happened that all the cases this let
1655     through by mistake were picked up later in the function.
1656    
1657     6. I had used a variable called "isblank" - this is a C99 function, causing
1658     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1659    
1660     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1661     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1662     so the version is shown; (c) stop "make test" echoing "./RunTest".
1663    
1664     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1665    
1666     9. The prototype for memmove() for systems that don't have it was using
1667     size_t, but the inclusion of the header that defines size_t was later. I've
1668     moved the #includes for the C headers earlier to avoid this.
1669    
1670     10. Added some adjustments to the code to make it easier to compiler on certain
1671     special systems:
1672    
1673     (a) Some "const" qualifiers were missing.
1674     (b) Added the macro EXPORT before all exported functions; by default this
1675     is defined to be empty.
1676     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1677     that it reads its output file name as an argument instead of writing
1678     to the standard output and assuming this can be redirected.
1679    
1680     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1681     class containing characters with values greater than 255, PCRE compilation
1682     went into a loop.
1683    
1684     12. A recursive reference to a subpattern that was within another subpattern
1685     that had a minimum quantifier of zero caused PCRE to crash. For example,
1686     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1687     recursion. If the recursively-called subpattern itself had a zero repeat,
1688     that was OK.
1689    
1690     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1691     buffer into which it was copied (for escape processing) was still set at
1692     1024, so long lines caused crashes.
1693    
1694     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1695     "internal error: code overflow...". This applied to any character class
1696     that was followed by a possessive quantifier.
1697    
1698     15. Modified the Makefile to add libpcre.la as a prerequisite for
1699     libpcreposix.la because I was told this is needed for a parallel build to
1700     work.
1701    
1702     16. If a pattern that contained .* following optional items at the start was
1703     studied, the wrong optimizing data was generated, leading to matching
1704     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1705     matching string must start with a or b or c. The correct conclusion for
1706     this pattern is that a match can start with any character.
1707    
1708    
1709 nigel 71 Version 4.4 13-Aug-03
1710     ---------------------
1711    
1712     1. In UTF-8 mode, a character class containing characters with values between
1713     127 and 255 was not handled correctly if the compiled pattern was studied.
1714     In fixing this, I have also improved the studying algorithm for such
1715     classes (slightly).
1716    
1717     2. Three internal functions had redundant arguments passed to them. Removal
1718     might give a very teeny performance improvement.
1719    
1720     3. Documentation bug: the value of the capture_top field in a callout is *one
1721     more than* the number of the hightest numbered captured substring.
1722    
1723     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1724     in incorrectly linking with a previously installed version. They now link
1725     explicitly with libpcre.la.
1726    
1727     5. configure.in no longer needs to recognize Cygwin specially.
1728    
1729     6. A problem in pcre.in for Windows platforms is fixed.
1730    
1731     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1732     pcretest, it used to include the size of the study block as part of its
1733     output. Unfortunately, the structure contains a field that has a different
1734     size on different hardware architectures. This meant that the tests that
1735     showed this size failed. As the block is currently always of a fixed size,
1736     this information isn't actually particularly useful in pcretest output, so
1737     I have just removed it.
1738    
1739     8. Three pre-processor statements accidentally did not start in column 1.
1740     Sadly, there are *still* compilers around that complain, even though
1741     standard C has not required this for well over a decade. Sigh.
1742    
1743     9. In pcretest, the code for checking callouts passed small integers in the
1744     callout_data field, which is a void * field. However, some picky compilers
1745     complained about the casts involved for this on 64-bit systems. Now
1746     pcretest passes the address of the small integer instead, which should get
1747     rid of the warnings.
1748    
1749     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1750     both compile and run time, and gives an error if an invalid UTF-8 sequence
1751     is found. There is a option for disabling this check in cases where the
1752     string is known to be correct and/or the maximum performance is wanted.
1753    
1754     11. In response to a bug report, I changed one line in Makefile.in from
1755    
1756     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1757     to
1758     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1759    
1760     to look similar to other lines, but I have no way of telling whether this
1761     is the right thing to do, as I do not use Windows. No doubt I'll get told
1762     if it's wrong...
1763    
1764    
1765 nigel 69 Version 4.3 21-May-03
1766     ---------------------
1767    
1768     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1769     Makefile.
1770    
1771     2. Some refactoring to improve the quality of the code:
1772    
1773     (i) The utf8_table... variables are now declared "const".
1774    
1775     (ii) The code for \cx, which used the "case flipping" table to upper case
1776     lower case letters, now just substracts 32. This is ASCII-specific,
1777     but the whole concept of \cx is ASCII-specific, so it seems
1778     reasonable.
1779    
1780     (iii) PCRE was using its character types table to recognize decimal and
1781     hexadecimal digits in the pattern. This is silly, because it handles
1782     only 0-9, a-f, and A-F, but the character types table is locale-
1783     specific, which means strange things might happen. A private
1784     table is now used for this - though it costs 256 bytes, a table is
1785     much faster than multiple explicit tests. Of course, the standard
1786     character types table is still used for matching digits in subject
1787     strings against \d.
1788    
1789     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1790     ending in _t are). So I've renamed it as ESC_tee.
1791    
1792     3. The first argument for regexec() in the POSIX wrapper should have been
1793     defined as "const".
1794    
1795     4. Changed pcretest to use malloc() for its buffers so that they can be
1796     Electric Fenced for debugging.
1797    
1798     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1799     to read one or more bytes before the start of the subject string. Often this
1800     had no effect on PCRE's behaviour, but in some circumstances it could
1801     provoke a segmentation fault.
1802    
1803     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1804     to try to read one or more bytes before the start of the subject string.
1805    
1806     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1807     UTF-8 support could misbehave in various ways if the subject string
1808     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1809     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1810     back over UTF-8 characters.)
1811    
1812    
1813 nigel 67 Version 4.2 14-Apr-03
1814     ---------------------
1815    
1816     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1817    
1818     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1819     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1820     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1821     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1822     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1823     and BUILD_EXEEXT
1824     Note: automatic setting of the BUILD variables is not yet working
1825     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1826     compile-time but not at link-time
1827     [LINK]: use for linking executables only
1828     make different versions for Windows and non-Windows
1829     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1830     libraries
1831     [LINK_FOR_BUILD]: new variable
1832     [OBJEXT]: use throughout
1833     [EXEEXT]: use throughout
1834     <winshared>: new target
1835     <wininstall>: new target
1836     <dftables.o>: use native compiler
1837     <dftables>: use native linker
1838     <install>: handle Windows platform correctly
1839     <clean>: ditto
1840     <check>: ditto
1841     copy DLL to top builddir before testing
1842    
1843     As part of these changes, -no-undefined was removed again. This was reported
1844     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1845     in any case.
1846    
1847     3. Some tidies to get rid of compiler warnings:
1848    
1849     . In the match_data structure, match_limit was an unsigned long int, whereas
1850     match_call_count was an int. I've made them both unsigned long ints.
1851    
1852     . In pcretest the fact that a const uschar * doesn't automatically cast to
1853     a void * provoked a warning.
1854    
1855     . Turning on some more compiler warnings threw up some "shadow" variables
1856     and a few more missing casts.
1857    
1858     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1859     option, a class that contained a single character with a value between 128
1860     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1861    
1862     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1863     option, a class that contained several characters, but with at least one
1864     whose value was between 128 and 255 caused PCRE to crash.
1865    
1866    
1867 nigel 65 Version 4.1 12-Mar-03
1868     ---------------------
1869 nigel 63
1870 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1871     needed, and a string in dftables.c that was longer than standard compilers are
1872     required to support.
1873    
1874     2. Compiling with Sun's compiler found a few more places where the code could
1875     be tidied up in order to avoid warnings.
1876    
1877     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1878     first of these names is deprecated in the latest Autoconf in favour of the name
1879     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1880     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1881     analogy I have changed it to CFLAGS_FOR_BUILD.
1882    
1883     4. Added -no-undefined to the linking command in the Makefile, because this is
1884     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1885     linking step for the pcreposix library.
1886    
1887     5. PCRE was failing to diagnose the case of two named groups with the same
1888     name.
1889    
1890     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1891     literal character that is needed in the subject for a match, and scans along to
1892     ensure that it is present before embarking on the full matching process. This
1893     saves time in cases of nested unlimited repeats that are never going to match.
1894     Problem: the scan can take a lot of time if the subject is very long (e.g.
1895     megabytes), thus penalizing straightforward matches. It is now done only if the
1896     amount of subject to be scanned is less than 1000 bytes.
1897    
1898     7. A lesser problem with the same optimization is that it was recording the
1899     first character of an anchored pattern as "needed", thus provoking a search
1900     right along the subject, even when the first match of the pattern was going to
1901     fail. The "needed" character is now not set for anchored patterns, unless it
1902     follows something in the pattern that is of non-fixed length. Thus, it still
1903     fulfils its original purpose of finding quick non-matches in cases of nested
1904     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1905    
1906    
1907     Version 4.0 17-Feb-03
1908     ---------------------
1909    
1910 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1911     extended to the end of string, PCRE compiled incorrect data. This could lead to
1912     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1913    
1914     2. Moved to autoconf 2.53 and libtool 1.4.2.
1915    
1916     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1917     the special perltest8 script is no longer needed - all the tests can be run
1918     from a single perltest script.
1919    
1920     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1921     by \s. It has now been removed in PCRE. This means it isn't recognized as
1922     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1923     class [:space:] *does* include VT, thereby creating a mess.
1924    
1925     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1926     space and tab.
1927    
1928     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1929     its new features into the main test script, reducing the number of scripts.
1930    
1931     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1932     were backward compatible, and made the (?i) apply to the whole pattern, as if
1933     /i were given. Now it behaves more logically, and applies the option setting
1934     only to what follows. PCRE has been changed to follow suit. However, if it
1935     finds options settings right at the start of the pattern, it extracts them into
1936     the global options, as before. Thus, they show up in the info data.
1937    
1938     8. Added support for the \Q...\E escape sequence. Characters in between are
1939     treated as literals. This is slightly different from Perl in that $ and @ are
1940     also handled as literals inside the quotes. In Perl, they will cause variable
1941     interpolation. Note the following examples:
1942    
1943     Pattern PCRE matches Perl matches
1944    
1945     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1946     \Qabc\$xyz\E abc\$xyz abc\$xyz
1947     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1948    
1949     For compatibility with Perl, \Q...\E sequences are recognized inside character
1950     classes as well as outside them.
1951    
1952     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1953     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1954     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1955     signed/unsigned warnings.
1956    
1957     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1958     option for pcretest, so I've replaced it by a simple function that does just
1959     that job.
1960    
1961     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1962     "pcregrep -".
1963    
1964     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1965     Java package. This provides some syntactic sugar for simple cases of what my
1966     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1967     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1968     item, you can use this simplified notation. Note that only makes sense with
1969     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1970     greediness, whatever the setting of the PCRE_UNGREEDY option.
1971    
1972     13. A change of greediness default within a pattern was not taking effect at
1973     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1974     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1975     was abstracted outside.
1976    
1977     14. PCRE now supports the \G assertion. It is true when the current matching
1978     position is at the start point of the match. This differs from \A when the
1979     starting offset is non-zero. Used with the /g option of pcretest (or similar
1980     code), it works in the same way as it does for Perl's /g option. If all
1981     alternatives of a regex begin with \G, the expression is anchored to the start
1982     match position, and the "anchored" flag is set in the compiled expression.
1983    
1984     15. Some bugs concerning the handling of certain option changes within patterns
1985     have been fixed. These applied to options other than (?ims). For example,
1986     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1987     been the other way round. Some of this was related to change 7 above.
1988    
1989     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1990     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1991     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1992     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1993    
1994     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1995     mode. Unlike ".", it always matches newline, whatever the setting of
1996     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1997     assertions. Perl allows it, but it doesn't (in general) work because it can't
1998     calculate the length of the lookbehind. At least, that's the case for Perl
1999     5.8.0 - I've been told they are going to document that it doesn't work in
2000     future.
2001    
2002     18. Added an error diagnosis for escapes that PCRE does not support: these are
2003     \L, \l, \N, \P, \p, \U, \u, and \X.
2004    
2005     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2006     reading past the end of the pattern in cases such as /[abcd/.
2007    
2008     20. PCRE was getting more memory than necessary for patterns with classes that
2009     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2010    
2011     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2012     compiling PCRE for use with Virtual Pascal.
2013    
2014     22. Small fix to the Makefile to make it work properly if the build is done
2015     outside the source tree.
2016    
2017     23. Added a new extension: a condition to go with recursion. If a conditional
2018     subpattern starts with (?(R) the "true" branch is used if recursion has
2019     happened, whereas the "false" branch is used only at the top level.
2020    
2021     24. When there was a very long string of literal characters (over 255 bytes
2022     without UTF support, over 250 bytes with UTF support), the computation of how
2023     much memory was required could be incorrect, leading to segfaults or other
2024     strange effects.
2025    
2026     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2027     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2028     there was a subsequent back reference to those brackets. This meant that, for
2029     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2030     possible to check for precisely this case. All we can do is abandon the
2031     optimization if .* occurs inside capturing brackets when there are any back
2032     references whatsoever. (See below for a better fix that came later.)
2033    
2034     26. The handling of the optimization for finding the first character of a
2035     non-anchored pattern, and for finding a character that is required later in the
2036     match were failing in some cases. This didn't break the matching; it just
2037     failed to optimize when it could. The way this is done has been re-implemented.
2038    
2039     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2040    
2041     28. Added a new feature that provides some of the functionality that Perl
2042     provides with (?{...}). The facility is termed a "callout". The way it is done
2043     in PCRE is for the caller to provide an optional function, by setting
2044     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2045     global variable. By default it is unset, which disables all calling out. To get
2046     the function called, the regex must include (?C) at appropriate points. This
2047     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2048     This provides a means of identifying different callout points. When PCRE
2049     reaches such a point in the regex, if pcre_callout has been set, the external
2050     function is called. It is provided with data in a structure called
2051     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2052     matching continues; if it returns a non-zero value, the match at the current
2053     point fails. However, backtracking will occur if possible. [This was changed
2054     later and other features added - see item 49 below.]
2055    
2056     29. pcretest is upgraded to test the callout functionality. It provides a
2057     callout function that displays information. By default, it shows the start of
2058     the match and the current position in the text. There are some new data escapes
2059     to vary what happens:
2060    
2061     \C+ in addition, show current contents of captured substrings
2062     \C- do not supply a callout function
2063     \C!n return 1 when callout number n is reached
2064     \C!n!m return 1 when callout number n is reached for the mth time
2065    
2066     30. If pcregrep was called with the -l option and just a single file name, it
2067     output "<stdin>" if a match was found, instead of the file name.
2068    
2069     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2070     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2071     pcre_exec(). This saves a malloc/free per call. The default value of
2072     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2073     when configuring.
2074    
2075     32. The default maximum size of a compiled pattern is 64K. There have been a
2076     few cases of people hitting this limit. The code now uses macros to handle the
2077     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2078     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2079     configuring. Tests 2 and 5 work only with 2-byte links because they output
2080     debugging information about compiled patterns.
2081    
2082     33. Internal code re-arrangements:
2083    
2084     (a) Moved the debugging function for printing out a compiled regex into
2085     its own source file (printint.c) and used #include to pull it into
2086     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2087     separate copies.
2088    
2089     (b) Defined the list of op-code names for debugging as a macro in
2090     internal.h so that it is next to the definition of the opcodes.
2091    
2092     (c) Defined a table of op-code lengths for simpler skipping along compiled
2093     code. This is again a macro in internal.h so that it is next to the
2094     definition of the opcodes.
2095    
2096     34. Added support for recursive calls to individual subpatterns, along the
2097     lines of Robin Houston's patch (but implemented somewhat differently).
2098    
2099     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2100     allow it to read and process whole directories in Win32. This code was
2101     contributed by Lionel Fourquaux; it has not been tested by me.
2102    
2103     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2104     used to name a group. Names consist of alphanumerics and underscores, and must
2105     be unique. Back references use the syntax (?P=name) and recursive calls use
2106     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2107     numbers. The function pcre_fullinfo() can be used after compilation to extract
2108     a name/number map. There are three relevant calls:
2109    
2110     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2111     PCRE_INFO_NAMECOUNT yields the number of entries
2112     PCRE_INFO_NAMETABLE yields a pointer to the map.
2113    
2114     The map is a vector of fixed-size entries. The size of each entry depends on
2115     the length of the longest name used. The first two bytes of each entry are the
2116     group number, most significant byte first. There follows the corresponding
2117     name, zero terminated. The names are in alphabetical order.
2118    
2119     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2120     case instead of 255. Making it the same both with and without UTF-8 support
2121     means that the same test output works with both.
2122    
2123     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2124     calling malloc() with a zero argument.
2125    
2126     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2127     optimization. I've improved things by keeping a bitmap of backreferences with
2128     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2129     fact referenced, the optimization can be applied. It is unlikely that a
2130     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2131     the match to follow \n) will appear inside brackets with a number greater than
2132     31, but if it does, any back reference > 31 suppresses the optimization.
2133    
2134     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2135     of disabling numbered capturing parentheses. Any opening parenthesis that is
2136     not followed by ? behaves as if it were followed by ?: but named parentheses
2137     can still be used for capturing (and they will acquire numbers in the usual
2138     way).
2139    
2140     41. Redesigned the return codes from the match() function into yes/no/error so
2141     that errors can be passed back from deep inside the nested calls. A malloc
2142     failure while inside a recursive subpattern call now causes the
2143     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2144    
2145     42. It is now possible to set a limit on the number of times the match()
2146     function is called in a call to pcre_exec(). This facility makes it possible to
2147     limit the amount of recursion and backtracking, though not in a directly
2148     obvious way, because the match() function is used in a number of different
2149     circumstances. The count starts from zero for each position in the subject
2150     string (for non-anchored patterns). The default limit is, for compatibility, a
2151     large number, namely 10 000 000. You can change this in two ways:
2152    
2153     (a) When configuring PCRE before making, you can use --with-match-limit=n
2154     to set a default value for the compiled library.
2155    
2156     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2157     a different value is set. See 45 below.
2158    
2159     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2160    
2161     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2162     of things that can be changed at compile time. The first argument specifies
2163     what is wanted and the second points to where the information is to be placed.
2164     The current list of available information is:
2165    
2166     PCRE_CONFIG_UTF8
2167    
2168     The output is an integer that is set to one if UTF-8 support is available;
2169     otherwise it is set to zero.
2170    
2171     PCRE_CONFIG_NEWLINE
2172    
2173     The output is an integer that it set to the value of the code that is used for
2174     newline. It is either LF (10) or CR (13).
2175    
2176     PCRE_CONFIG_LINK_SIZE
2177    
2178     The output is an integer that contains the number of bytes used for internal
2179     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2180    
2181     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2182    
2183     The output is an integer that contains the threshold above which the POSIX
2184     interface uses malloc() for output vectors. See item 31 above.
2185    
2186     PCRE_CONFIG_MATCH_LIMIT
2187    
2188     The output is an unsigned integer that contains the default limit of the number
2189     of match() calls in a pcre_exec() execution. See 42 above.
2190    
2191     44. pcretest has been upgraded by the addition of the -C option. This causes it
2192     to extract all the available output from the new pcre_config() function, and to
2193     output it. The program then exits immediately.
2194    
2195     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2196     order to support additional features. One way would have been to define
2197     pcre_exec2() (for example) with extra arguments, but this would not have been
2198     extensible, and would also have required all calls to the original function to
2199     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2200     is used for passing in "extra" data from pcre_study().
2201    
2202     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2203     contains the following fields:
2204    
2205     flags a bitmap indicating which of the following fields are set
2206     study_data opaque data from pcre_study()
2207     match_limit a way of specifying a limit on match() calls for a specific
2208     call to pcre_exec()
2209     callout_data data for callouts (see 49 below)
2210    
2211     The flag bits are also defined in pcre.h, and are
2212    
2213     PCRE_EXTRA_STUDY_DATA
2214     PCRE_EXTRA_MATCH_LIMIT
2215     PCRE_EXTRA_CALLOUT_DATA
2216    
2217     The pcre_study() function now returns one of these new pcre_extra blocks, with
2218     the actual study data pointed to by the study_data field, and the
2219     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2220     before. That is, this change is entirely upwards-compatible and requires no
2221     change to existing code.
2222    
2223     If you want to pass in additional data to pcre_exec(), you can either place it
2224     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2225     block.
2226    
2227     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2228     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2229     times with different match limits, until it finds the minimum value needed for
2230     pcre_exec() to complete. The value is then output. This can be instructive; for
2231     most simple matches the number is quite small, but for pathological cases it
2232     gets very large very quickly.
2233    
2234     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2235     returns the size of the data block pointed to by the study_data field in a
2236     pcre_extra block, that is, the value that was passed as the argument to
2237     pcre_malloc() when PCRE was getting memory in which to place the information
2238     created by pcre_study(). The fourth argument should point to a size_t variable.
2239     pcretest has been extended so that this information is shown after a successful
2240     pcre_study() call when information about the compiled regex is being displayed.
2241    
2242     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2243     because what follows is always an absolute path. (Later: it turns out that this
2244     is more than cosmetic for MinGW, because it doesn't like empty path
2245     components.)
2246    
2247     49. Some changes have been made to the callout feature (see 28 above):
2248    
2249     (i) A callout function now has three choices for what it returns:
2250    
2251     0 => success, carry on matching
2252     > 0 => failure at this point, but backtrack if possible
2253     < 0 => serious error, return this value from pcre_exec()
2254    
2255     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2256     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2257     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2258     use by callout functions. It will never be used by PCRE itself.
2259    
2260     (ii) The pcre_extra structure (see 45 above) has a void * field called
2261     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2262     pcre_callout_block structure has a field of the same name. The contents of
2263     the field passed in the pcre_extra structure are passed to the callout
2264     function in the corresponding field in the callout block. This makes it
2265     easier to use the same callout-containing regex from multiple threads. For
2266     testing, the pcretest program has a new data escape
2267    
2268     \C*n pass the number n (may be negative) as callout_data
2269    
2270     If the callout function in pcretest receives a non-zero value as
2271     callout_data, it returns that value.
2272    
2273     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2274     there were some redundant $(CFLAGS) in commands that are now specified as
2275     $(LINK), which already includes $(CFLAGS).
2276    
2277     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2278     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2279     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2280     one-byte characters throughout. Note that case-insensitive matching applies
2281     only to characters whose values are less than 256. PCRE doesn't support the
2282     notion of cases for higher-valued characters.
2283    
2284     (i) A character class whose characters are all within 0-255 is handled as
2285     a bit map, and the map is inverted for negative classes. Previously, a
2286     character > 255 always failed to match such a class; however it should
2287     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2288    
2289     (ii) A negated character class with a single character < 255 is coded as
2290     "not this character" (OP_NOT). This wasn't working properly when the test
2291     character was multibyte, either singly or repeated.
2292    
2293     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2294     mode, for example: \x{100}{2,3}.
2295    
2296     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2297     singly or repeated) now correctly test multibyte characters. However,
2298     PCRE doesn't recognize any characters with values greater than 255 as
2299     digits, spaces, or word characters. Such characters always match \D, \S,
2300     and \W, and never match \d, \s, or \w.
2301    
2302     (v) Classes may now contain characters and character ranges with values
2303     greater than 255. For example: [ab\x{100}-\x{400}].
2304    
2305     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2306     PCRE in UTF-8 mode.
2307    
2308     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2309     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2310     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2311     value.)
2312    
2313     53. The single man page has become too large. I have therefore split it up into
2314     a number of separate man pages. These also give rise to individual HTML pages;
2315     these are now put in a separate directory, and there is an index.html page that
2316     lists them all. Some hyperlinking between the pages has been installed.
2317    
2318     54. Added convenience functions for handling named capturing parentheses.
2319    
2320     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2321     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2322     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2323     are faulted.
2324    
2325     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2326     calling configure. These values are used when compiling the dftables.c program
2327     which is run to generate the source of the default character tables. They
2328     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2329     you will need to set these values.
2330    
2331     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2332    
2333    
2334     Version 3.9 02-Jan-02
2335 nigel 61 ---------------------
2336    
2337     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2338    
2339     2. If --disable-static was given, the building process failed when trying to
2340     build pcretest and pcregrep. (For some reason it was using libtool to compile
2341     them, which is not right, as they aren't part of the library.)
2342    
2343    
2344 nigel 59 Version 3.8 18-Dec-01
2345     ---------------------
2346    
2347     1. The experimental UTF-8 code was completely screwed up. It was packing the
2348     bytes in the wrong order. How dumb can you get?
2349    
2350    
2351 nigel 57 Version 3.7 29-Oct-01
2352     ---------------------
2353    
2354     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2355     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2356     this didn't happen under Solaris 8, where I normally test things.
2357    
2358 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2359     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2360     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2361     this fix an hour or so after the initial 3.7 release.)
2362 nigel 57
2363 nigel 59
2364 nigel 55 Version 3.6 23-Oct-01
2365     ---------------------
2366    
2367     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2368     offsets passed as NULL with zero offset count.
2369    
2370     2. The config.guess and config.sub files had not been updated when I moved to
2371     the latest autoconf.
2372    
2373    
2374 nigel 53 Version 3.5 15-Aug-01
2375     ---------------------
2376 nigel 5
2377 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2378     had been forgotten.
2379    
2380     2. By using declared but undefined structures, we can avoid using "void"
2381     definitions in pcre.h while keeping the internal definitions of the structures
2382     private.
2383    
2384     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2385     user point of view, this means that both static and shared libraries are built
2386     by default, but this can be individually controlled. More of the work of
2387     handling this static/shared cases is now inside libtool instead of PCRE's make
2388     file.
2389    
2390     4. The pcretest utility is now installed along with pcregrep because it is
2391     useful for users (to test regexs) and by doing this, it automatically gets
2392     relinked by libtool. The documentation has been turned into a man page, so
2393     there are now .1, .txt, and .html versions in /doc.
2394    
2395     5. Upgrades to pcregrep:
2396     (i) Added long-form option names like gnu grep.
2397     (ii) Added --help to list all options with an explanatory phrase.
2398     (iii) Added -r, --recursive to recurse into sub-directories.
2399     (iv) Added -f, --file to read patterns from a file.
2400    
2401     6. pcre_exec() was referring to its "code" argument before testing that
2402     argument for NULL (and giving an error if it was NULL).
2403    
2404     7. Upgraded Makefile.in to allow for compiling in a different directory from
2405     the source directory.
2406    
2407     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2408     options bits, the pointer it was passed was to an int instead of to an unsigned
2409     long int. This mattered only on 64-bit systems.
2410    
2411     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2412     generated) instead of pcre.in, which it its source. Also made the same change
2413     in several of the .c files.
2414    
2415     10. A new release of gcc defines printf() as a macro, which broke pcretest
2416     because it had an ifdef in the middle of a string argument for printf(). Fixed
2417     by using separate calls to printf().
2418    
2419     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2420     script, to force use of CR or LF instead of \n in the source. On non-Unix
2421     systems, the value can be set in config.h.
2422    
2423     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2424     absolute limit. Changed the text of the error message to make this clear, and
2425     likewise updated the man page.
2426    
2427     13. The limit of 99 on the number of capturing subpatterns has been removed.
2428     The new limit is 65535, which I hope will not be a "real" limit.
2429    
2430    
2431 nigel 51 Version 3.4 22-Aug-00
2432     ---------------------
2433    
2434     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2435    
2436     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2437    
2438    
2439 nigel 49 Version 3.3 01-Aug-00
2440     ---------------------
2441    
2442     1. If an octal character was given, but the value was greater than \377, it
2443     was not getting masked to the least significant bits, as documented. This could
2444     lead to crashes in some systems.
2445    
2446     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2447     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2448    
2449     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2450     These just pass their arguments on to (pcre_free)(), but they are provided
2451     because some uses of PCRE bind it to non-C systems that can call its functions,
2452     but cannot call free() or pcre_free() directly.
2453    
2454     4. Add "make test" as a synonym for "make check". Corrected some comments in
2455     the Makefile.
2456    
2457     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2458     Makefile.
2459    
2460     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2461     command called pgrep for grepping around the active processes.
2462    
2463     7. Added the beginnings of support for UTF-8 character strings.
2464    
2465     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2466     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2467     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2468     out for the ar command.)
2469    
2470    
2471 nigel 47 Version 3.2 12-May-00
2472     ---------------------
2473    
2474     This is purely a bug fixing release.
2475    
2476     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2477     of ZA. This was just one example of several cases that could provoke this bug,
2478     which was introduced by change 9 of version 2.00. The code for breaking
2479     infinite loops after an iteration that matches an empty string was't working
2480     correctly.
2481    
2482     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2483     when matched against abbab (for example). After matching an empty string, it
2484     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2485     caused it to match further down the string than it should.
2486    
2487     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2488     was there because it doesn't seem to be needed, and it causes trouble on some
2489     systems, as it is not a Standard C header. It has been removed.
2490    
2491     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2492     were reported on the Macintosh. The changes were from
2493    
2494     while ((c = *(++ptr)) != 0 && c != '\n');
2495     to
2496     while ((c = *(++ptr)) != 0 && c != '\n') ;
2497    
2498     Totally extraordinary, but if that's what it takes...
2499    
2500     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2501     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2502     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2503     assumes the way PCRE uses memmove() (always moving upwards).
2504    
2505     6. PCRE is being used in one environment where strchr() is not available. There
2506     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2507     faster code anyway.
2508    
2509    
2510 nigel 45 Version 3.1 09-Feb-00
2511     ---------------------
2512    
2513     The only change in this release is the fixing of some bugs in Makefile.in for
2514     the "install" target:
2515    
2516     (1) It was failing to install pcreposix.h.
2517    
2518     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2519    
2520    
2521 nigel 43 Version 3.0 01-Feb-00
2522     ---------------------
2523 nigel 41
2524     1. Add support for the /+ modifier to perltest (to output $` like it does in
2525     pcretest).
2526    
2527     2. Add support for the /g modifier to perltest.
2528    
2529     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2530     matches null strings.
2531    
2532     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2533     pattern. Perl treats empty patterns specially - it reuses the most recent
2534     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2535     effect.
2536    
2537     5. The POSIX interface was broken in that it was just handing over the POSIX
2538     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2539     required a bigger vector, with some working space on the end. This means that
2540     the POSIX wrapper now has to get and free some memory, and copy the results.
2541    
2542 nigel 43 6. Added some simple autoconf support, placing the test data and the
2543     documentation in separate directories, re-organizing some of the
2544     information files, and making it build pcre-config (a GNU standard). Also added
2545     libtool support for building PCRE as a shared library, which is now the
2546     default.
2547 nigel 41
2548 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2549     09 are not valid octal constants. Single digits will be used for minor values
2550     less than 10.
2551    
2552     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2553     existing programs that set these in the POSIX interface can use PCRE without
2554     modification.
2555    
2556     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2557     return all that pcre_info() returns, plus additional data. The pcre_info()
2558     function is retained for compatibility, but is considered to be obsolete.
2559    
2560     10. Added experimental recursion feature (?R) to handle one common case that
2561     Perl 5.6 will be able to do with (?p{...}).
2562    
2563     11. Added support for POSIX character classes like [:alpha:], which Perl is
2564     adopting.
2565    
2566    
2567 nigel 39 Version 2.08 31-Aug-99
2568     ----------------------
2569    
2570     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2571     trying to match at the startoffset position, but instead was moving forward to
2572     the next newline as if a previous match had failed.
2573    
2574     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2575     and could get into a loop if a null string was matched other than at the start
2576     of the subject.
2577    
2578     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2579     be distinguished at compile time, and for completeness also added PCRE_DATE.
2580    
2581     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2582     in GnuWin32 environments.
2583    
2584    
2585 nigel 37 Version 2.07 29-Jul-99
2586     ----------------------
2587    
2588     1. The documentation is now supplied in plain text form and HTML as well as in
2589     the form of man page sources.
2590    
2591     2. C++ compilers don't like assigning (void *) values to other pointer types.
2592     In particular this affects malloc(). Although there is no problem in Standard
2593     C, I've put in casts to keep C++ compilers happy.
2594    
2595     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2596     should be (const char *).
2597    
2598     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2599     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2600     However, I haven't made this a standard facility. The documentation doesn't
2601     mention it, and the Makefile doesn't support it.
2602    
2603     5. The Makefile now contains an "install" target, with editable destinations at
2604     the top of the file. The pcretest program is not installed.
2605    
2606     6. pgrep -V now gives the PCRE version number and date.
2607    
2608     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2609     causing the entire string to be ignored, instead of just the last character.
2610    
2611     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2612     non-matching string, it can take a very, very long time, even for strings of
2613     quite modest length, because of the nested recursion. PCRE now does better in
2614     some of these cases. It does this by remembering the last required literal
2615     character in the pattern, and pre-searching the subject to ensure it is present
2616     before running the real match. In other words, it applies a heuristic to detect
2617     some types of certain failure quickly, and in the above example, if presented
2618     with a string that has no trailing " it gives "no match" very quickly.
2619    
2620     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2621     other alternatives are tried instead.
2622    
2623    
2624 nigel 35 Version 2.06 09-Jun-99
2625     ----------------------
2626    
2627     1. Change pcretest's output for amount of store used to show just the code
2628     space, because the remainder (the data block) varies in size between 32-bit and
2629     64-bit systems.
2630    
2631     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2632     start matching at. This allows lookbehinds to work when searching for multiple
2633     occurrences in a string.
2634    
2635     3. Added additional options to pcretest for testing multiple occurrences:
2636    
2637     /+ outputs the rest of the string that follows a match
2638     /g loops for multiple occurrences, using the new startoffset argument
2639     /G loops for multiple occurrences by passing an incremented pointer
2640    
2641     4. PCRE wasn't doing the "first character" optimization for patterns starting
2642     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2643     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2644     the letter 'x'. On long subject strings, this gives a significant speed-up.
2645    
2646    
2647 nigel 33 Version 2.05 21-Apr-99
2648     ----------------------
2649    
2650     1. Changed the type of magic_number from int to long int so that it works
2651     properly on 16-bit systems.
2652    
2653     2. Fixed a bug which caused patterns starting with .* not to work correctly
2654     when the subject string contained newline characters. PCRE was assuming
2655     anchoring for such patterns in all cases, which is not correct because .* will
2656     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2657     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2658     must be retried after every newline in the subject.
2659    
2660    
2661 nigel 31 Version 2.04 18-Feb-99
2662     ----------------------
2663    
2664     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2665     computation of the store needed to hold the pattern was incorrect (too large).
2666     If such patterns were nested a few deep, this could multiply and become a real
2667     problem.
2668    
2669     2. Added /M option to pcretest to show the memory requirement of a specific
2670     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2671    
2672     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2673     compiled in such a way that the backtracking after subsequent failure was
2674     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2675     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2676    
2677    
2678 nigel 29 Version 2.03 02-Feb-99
2679     ----------------------
2680    
2681     1. Fixed typo and small mistake in man page.
2682    
2683 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2684     LICENCE file containing the conditions.
2685 nigel 29
2686     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2687     Perl, that is the internal \ allows the delimiter to be included in the
2688     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2689     the final delimiter, add \ to the end of the pattern (to test the error).
2690    
2691     4. Added the convenience functions for extracting substrings after a successful
2692     match. Updated pcretest to make it able to test these functions.
2693    
2694    
2695 nigel 27 Version 2.02 14-Jan-99
2696     ----------------------
2697    
2698     1. Initialized the working variables associated with each extraction so that
2699     their saving and restoring doesn't refer to uninitialized store.
2700    
2701     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2702     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2703     fix the problem.
2704    
2705     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2706     calls, and wasn't printing the correct value for compiling calls. Increased the
2707     default value of LOOPREPEAT, and the number of significant figures in the
2708     times.
2709    
2710     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2711    
2712     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2713     a building problem on Windows NT with a FAT file system.
2714    
2715    
2716 nigel 25 Version 2.01 21-Oct-98
2717     ----------------------
2718    
2719     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2720     to character tables built by pcre_maketables() in the current locale. If NULL
2721     is passed, the default tables are used.
2722    
2723    
2724 nigel 23 Version 2.00 24-Sep-98
2725 nigel 21 ----------------------
2726    
2727 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2728     it any more.
2729    
2730     2. Allow quantification of (?>) groups, and make it work correctly.
2731    
2732     3. The first character computation wasn't working for (?>) groups.
2733    
2734     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2735     end of the subject) and add 5.005's \z, which really does match only at the
2736     very end of the subject.
2737    
2738     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2739    
2740     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2741     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2742     localized options. All options to pcre_study() were also removed.
2743    
2744     7. Add other new features from 5.005:
2745    
2746     $(?<= positive lookbehind
2747     $(?<! negative lookbehind
2748     (?imsx-imsx) added the unsetting capability
2749     such a setting is global if at outer level; local otherwise
2750     (?imsx-imsx:) non-capturing groups with option setting
2751     (?(cond)re|re) conditional pattern matching
2752    
2753     A backreference to itself in a repeated group matches the previous
2754     captured string.
2755    
2756     8. General tidying up of studying (both automatic and via "study")
2757     consequential on the addition of new assertions.
2758    
2759     9. As in 5.005, unlimited repeated groups that could match an empty substring
2760     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2761     runtime if any iteration does actually match an empty substring.
2762    
2763     10. Include the RunTest script in the distribution.
2764    
2765     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2766     discrepancies, some of which were old and were also with respect to 5.004. They
2767     have now been fixed.
2768    
2769    
2770     Version 1.09 28-Apr-98
2771     ----------------------
2772    
2773 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2774     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2775     program crashes, or just wrong answers. This did not apply to negated classes
2776     containing more than one character, or to minima other than one.
2777    
2778    
2779 nigel 19 Version 1.08 27-Mar-98
2780     ----------------------
2781    
2782     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2783    
2784     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2785     latter must appear before anything that relies on it in the pattern.
2786    
2787    
2788 nigel 17 Version 1.07 16-Feb-98
2789     ----------------------
2790    
2791     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2792     repeat of a potentially empty string).
2793    
2794    
2795 nigel 15 Version 1.06 23-Jan-98
2796     ----------------------
2797    
2798     1. Added Markus Oberhumer's little patches for C++.
2799    
2800     2. Literal strings longer than 255 characters were broken.
2801    
2802    
2803 nigel 13 Version 1.05 23-Dec-97
2804     ----------------------
2805    
2806     1. Negated character classes containing more than one character were failing if
2807     PCRE_CASELESS was set at run time.
2808    
2809    
2810 nigel 11 Version 1.04 19-Dec-97
2811     ----------------------
2812    
2813     1. Corrected the man page, where some "const" qualifiers had been omitted.
2814    
2815     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2816     input syntax.
2817    
2818     3. Fixed memory leak which occurred when a regex with back references was
2819     matched with an offsets vector that wasn't big enough. The temporary memory
2820     that is used in this case wasn't being freed if the match failed.
2821    
2822     4. Tidied pcretest to ensure it frees memory that it gets.
2823    
2824     5. Temporary memory was being obtained in the case where the passed offsets
2825     vector was exactly big enough.
2826    
2827     6. Corrected definition of offsetof() from change 5 below.
2828    
2829     7. I had screwed up change 6 below and broken the rules for the use of
2830     setjmp(). Now fixed.
2831    
2832    
2833 nigel 9 Version 1.03 18-Dec-97
2834     ----------------------
2835    
2836     1. A erroneous regex with a missing opening parenthesis was correctly
2837     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2838     on some systems.
2839    
2840     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2841     it was reported that one broken compiler failed on the former because "code" is
2842     also an independent variable.
2843    
2844     3. The erroneous regex a[]b caused an array overrun reference.
2845    
2846     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2847     fail on data ending with that character. (It was going on too far, and checking
2848     the next character, typically a binary zero.) This was specific to the
2849     optimized code for single-character negative classes.
2850    
2851     5. Added a contributed patch from the TIN world which does the following:
2852    
2853     + Add an undef for memmove, in case the the system defines a macro for it.
2854    
2855     + Add a definition of offsetof(), in case there isn't one. (I don't know
2856     the reason behind this - offsetof() is part of the ANSI standard - but
2857     it does no harm).
2858    
2859     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2860     most of the places where whitespace preceded '#'. I have given up and
2861     allowed the remaining 2 cases to be at the margin.
2862    
2863     + Rename some variables in pcre to eliminate shadowing. This seems very
2864     pedantic, but does no harm, of course.
2865    
2866     6. Moved the call to setjmp() into its own function, to get rid of warnings
2867     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2868    
2869     7. Constructs such as \d{8,} were compiling into the equivalent of
2870 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2871 nigel 9 outcome, but in this particular case used more store than had been allocated,
2872     which caused the bug to be discovered because it threw up an internal error.
2873    
2874     8. The debugging code in both pcre and pcretest for outputting the compiled
2875     form of a regex was going wrong in the case of back references followed by
2876     curly-bracketed repeats.
2877    
2878    
2879 nigel 7 Version 1.02 12-Dec-97
2880     ----------------------
2881    
2882     1. Typos in pcre.3 and comments in the source fixed.
2883    
2884     2. Applied a contributed patch to get rid of places where it used to remove
2885     'const' from variables, and fixed some signed/unsigned and uninitialized
2886     variable warnings.
2887    
2888     3. Added the "runtest" target to Makefile.
2889    
2890     4. Set default compiler flag to -O2 rather than just -O.
2891    
2892    
2893 nigel 5 Version 1.01 19-Nov-97
2894     ----------------------
2895    
2896     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2897     like /([ab]*)*/, that is, for classes with more than one character in them.
2898    
2899     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2900     as /((?>a*))*/ (a PCRE_EXTRA facility).
2901    
2902    
2903     Version 1.00 18-Nov-97
2904     ----------------------
2905    
2906     1. Added compile-time macros to support systems such as SunOS4 which don't have
2907     memmove() or strerror() but have other things that can be used instead.
2908    
2909     2. Arranged that "make clean" removes the executables.
2910    
2911    
2912 nigel 3 Version 0.99 27-Oct-97
2913     ----------------------
2914    
2915     1. Fixed bug in code for optimizing classes with only one character. It was
2916     initializing a 32-byte map regardless, which could cause it to run off the end
2917     of the memory it had got.
2918    
2919     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2920    
2921    
2922     Version 0.98 22-Oct-97
2923     ----------------------
2924    
2925     1. Fixed bug in code for handling temporary memory usage when there are more
2926     back references than supplied space in the ovector. This could cause segfaults.
2927    
2928    
2929     Version 0.97 21-Oct-97
2930     ----------------------
2931    
2932     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2933    
2934     2. Optimized negated single characters not to use a bit map.
2935    
2936     3. Brought error texts together as macro definitions; clarified some of them;
2937     fixed one that was wrong - it said "range out of order" when it meant "invalid
2938     escape sequence".
2939    
2940     4. Changed some char * arguments to const char *.
2941    
2942     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2943    
2944     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2945     pcretest.
2946    
2947    
2948     Version 0.96 16-Oct-97
2949     ----------------------
2950    
2951     1. Added a simple "pgrep" utility to the distribution.
2952    
2953     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2954     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2955     where "ddd" means "one or more decimal digits".
2956    
2957     3. Fixed serious bug. If a pattern had a back reference, but the call to
2958     pcre_exec() didn't supply a large enough ovector to record the related
2959     identifying subpattern, the match always failed. PCRE now remembers the number
2960     of the largest back reference, and gets some temporary memory in which to save
2961     the offsets during matching if necessary, in order to ensure that
2962     backreferences always work.
2963    
2964     4. Increased the compatibility with Perl in a number of ways:
2965    
2966     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2967     to request this handling. The option can be set at compile or exec time.
2968    
2969     (b) $ matches before a terminating newline by default; an option
2970     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2971     mode). The option can be set at compile or exec time.
2972    
2973     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2974     the same as Perl's. If the decimal number it represents is less than 10
2975     or there aren't that many previous left capturing parentheses, an octal
2976     escape is read. Inside a character class, it's always an octal escape,
2977     even if it is a single digit.
2978    
2979     (d) An escaped but undefined alphabetic character is taken as a literal,
2980     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2981     escapes.
2982    
2983     (e) {0} is now permitted. (The previous item is removed from the compiled
2984     pattern).
2985    
2986     5. Changed all the names of code files so that the basic parts are no longer
2987     than 10 characters, and abolished the teeny "globals.c" file.
2988    
2989     6. Changed the handling of character classes; they are now done with a 32-byte
2990     bit map always.
2991    
2992     7. Added the -d and /D options to pcretest to make it possible to look at the
2993     internals of compilation without having to recompile pcre.
2994    
2995    
2996     Version 0.95 23-Sep-97
2997     ----------------------
2998    
2999     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3000     \x20 at the start of a run of normal characters. These were being treated as
3001     real characters, instead of the source characters being re-checked.
3002    
3003    
3004     Version 0.94 18-Sep-97
3005     ----------------------
3006    
3007     1. The functions are now thread-safe, with the caveat that the global variables
3008     containing pointers to malloc() and free() or alternative functions are the
3009     same for all threads.
3010    
3011     2. Get pcre_study() to generate a bitmap of initial characters for non-
3012     anchored patterns when this is possible, and use it if passed to pcre_exec().
3013    
3014    
3015     Version 0.93 15-Sep-97
3016     ----------------------
3017    
3018     1. /(b)|(:+)/ was computing an incorrect first character.
3019    
3020     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3021     but not actually doing anything yet.
3022    
3023     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3024     as Perl does (e.g. [-az] or [az-]).
3025    
3026     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3027     all possible positions.
3028    
3029     5. Split up into different modules to avoid including unneeded functions in a
3030     compiled binary. However, compile and exec are still in one module. The "study"
3031     function is split off.
3032    
3033     6. The character tables are now in a separate module whose source is generated
3034     by an auxiliary program - but can then be edited by hand if required. There are
3035     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3036     toupper() in the code.
3037    
3038     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3039     make them global. Abolish the function for setting them, as the caller can now
3040     set them directly.
3041    
3042    
3043     Version 0.92 11-Sep-97
3044     ----------------------
3045    
3046     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3047     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3048    
3049     2. Caseless matching was not working in character classes if the characters in
3050     the pattern were in upper case.
3051    
3052     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3053    
3054     4. Make PCRE_ANCHORED public and accept as a compile option.
3055    
3056     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3057     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3058     pass them.
3059    
3060     6. Give an error if bad option bits passed at compile or run time.
3061    
3062     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3063     pcretest to cause it to pass that flag.
3064    
3065     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3066     options, and the first character, if set.
3067    
3068     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3069    
3070    
3071     Version 0.91 10-Sep-97
3072     ----------------------
3073    
3074     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3075     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3076    
3077     2. PCRE was looping on encountering an indefinitely repeated back reference to
3078     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3079     Perl does - treats the match as successful.
3080    
3081     ****

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