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Revision 269 - (hide annotations) (download)
Fri Nov 16 16:22:24 2007 UTC (7 years, 5 months ago) by ph10
File size: 143055 byte(s)
Improve error messages for (?+-a) and (?-+a).

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


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