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Revision 276 - (hide annotations) (download)
Wed Nov 21 15:39:20 2007 UTC (7 years, 5 months ago) by ph10
File size: 143980 byte(s)
Remove two redunant, never-reachable lines of code whose function had been 

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


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