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Revision 272 - (hide annotations) (download)
Sat Nov 17 16:53:53 2007 UTC (7 years, 5 months ago) by ph10
File size: 143672 byte(s)
Generalize wording for (?&) error as it also applies to \k'' and other cases.

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


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