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Revision 288 - (hide annotations) (download)
Wed Dec 19 12:21:45 2007 UTC (7 years, 4 months ago) by ph10
File size: 146380 byte(s)
Fix C++ GlobalReplace() double-counting bug.

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 286
10 ph10 264 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 286
14     3. The same bug as (2) above applied to negated POSIX classes such as
15 ph10 265 [:^space:].
16 ph10 286
17 ph10 267 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 ph10 286 I have changed it.
21 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
22 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
23     first named subpattern whose name started with "a" (in other words, the
24 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
25     expected" is now given for (?&) (a zero-length name), and this patch also
26     makes it give the same error for \k'' (previously it complained that that
27     was a reference to a non-existent subpattern).
28 ph10 286
29 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
30 ph10 286 this is right because (?- can be followed by option settings as well as by
31 ph10 269 digits. I have, however, made the messages clearer.
32 ph10 286
33 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34     than the number used in the conditional) now cause a compile-time error.
35     This is actually not compatible with Perl, which accepts such patterns, but
36     treats the conditional as always being FALSE (as PCRE used to), but it
37     seems to me that giving a diagnostic is better.
38 ph10 286
39 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
40 ph10 275 and messages.
41 ph10 286
42     9. Fix two occurrences of "backslash" in comments that should have been
43     "backspace".
45     10. Remove two redundant lines of code that can never be obeyed (their function
46     was moved elsewhere).
48     11. The program that makes PCRE's Unicode character property table had a bug
49     which caused it to generate incorrect table entries for sequences of
50 ph10 277 characters that have the same character type, but are in different scripts.
51 ph10 286 It amalgamated them into a single range, with the script of the first of
52 ph10 277 them. In other words, some characters were in the wrong script. There were
53     thirteen such cases, affecting characters in the following ranges:
54 ph10 286
55 ph10 277 U+002b0 - U+002c1
56     U+0060c - U+0060d
57 ph10 286 U+0061e - U+00612
58 ph10 277 U+0064b - U+0065e
59     U+0074d - U+0076d
60     U+01800 - U+01805
61     U+01d00 - U+01d77
62     U+01d9b - U+01dbf
63     U+0200b - U+0200f
64     U+030fc - U+030fe
65     U+03260 - U+0327f
66     U+0fb46 - U+0fbb1
67     U+10450 - U+1049d
68 ph10 286
69 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
70     compatible with GNU grep in that, if there was more than one match in a
71     line, it showed only the first of them. It now behaves in the same way as
72     GNU grep.
73 ph10 286
74     13. If the -o and -v options were combined for pcregrep, it printed a blank
75     line for every non-matching line. GNU grep prints nothing, and pcregrep now
76     does the same. The return code can be used to tell if there were any
77     non-matching lines.
79 ph10 282 14. The pattern (?=something)(?R) was not being diagnosed as a potentially
80     infinitely looping recursion. The bug was that positive lookaheads were not
81 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
82     and both kinds of lookbehind were skipped).
84     15. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
85 ph10 284 inclusion of <windows.h> to before rather than after the definition of
86     INVALID_FILE_ATTRIBUTES (patch from David Byron).
87 ph10 263
88 ph10 286 16. Specifying a possessive quantifier with a specific limit for a Unicode
89     character property caused pcre_compile() to compile bad code, which led at
90     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
91     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
92     caused the error; without that there was no problem.
93 ph10 263
94 ph10 286 17. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
96 ph10 287 18. Added --enable-pcretest-libreadline.
97 ph10 286
98 ph10 288 19. In pcrecpp.cc, the variable 'count' was incremented twice in
99     RE::GlobalReplace(). As a result, the number of replacements returned was
100     double what it should be. I have removed one of the increments.
101 ph10 287
102 ph10 288
103 ph10 260 Version 7.4 21-Sep-07
104 ph10 230 ---------------------
106     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
107 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
108     LF". That isn't really right - the whole point of the change was to try to
109     help when there was an actual mention of one of the two characters. So now
110     the change happens only if \r or \n (or a literal CR or LF) character is
111 ph10 230 encountered.
112 ph10 231
113     2. The 32-bit options word was also used for 6 internal flags, but the numbers
114     of both had grown to the point where there were only 3 bits left.
115     Fortunately, there was spare space in the data structure, and so I have
116     moved the internal flags into a new 16-bit field to free up more option
117 ph10 230 bits.
118 ph10 231
119     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
120     but did not set the internal JCHANGED flag - either of these is enough to
121     control the way the "get" function works - but the PCRE_INFO_JCHANGED
122     facility is supposed to tell if (?J) was ever used, so now (?J) at the
123 ph10 230 start sets both bits.
125 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
126     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
127 ph10 230
128 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
130     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
131 ph10 233 compatibility, even though it is no longer used.
132 ph10 243
133     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
134 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
135 ph10 259 windows.h file is present (where different names are used). [This was
136 ph10 257 reversed later after testing - see 16 below.]
137 ph10 243
138     8. Changed all #include <config.h> to #include "config.h". There were also
139 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
140 ph10 243
141 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
142 ph10 243 sequence off the lines that it output.
144     10. It was pointed out to me that arrays of string pointers cause lots of
145     relocations when a shared library is dynamically loaded. A technique of
146     using a single long string with a table of offsets can drastically reduce
147     these. I have refactored PCRE in four places to do this. The result is
148 ph10 240 dramatic:
149 ph10 243
150 ph10 240 Originally: 290
151     After changing UCP table: 187
152 ph10 243 After changing error message table: 43
153 ph10 240 After changing table of "verbs" 36
154     After changing table of Posix names 22
155 ph10 243
156 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
157 ph10 247
158 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
159 ph10 247 unicode-properties was also set.
161 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
162 ph10 231
163 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
164     checked only for CRLF.
165 ph10 233
166 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
168 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
169 ph10 253
170 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
171 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
172     entirely. This removes changes made in 7 above.
173 ph10 256
174 ph10 261 17. The CMake files have been updated, and there is now more information about
175     building with CMake in the NON-UNIX-USE document.
176 ph10 257
177 ph10 261
178 ph10 228 Version 7.3 28-Aug-07
179 ph10 157 ---------------------
181 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
182     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
183     brackets there is not right, since it causes compilers to look for an
184     installed pcre.h, not the version that is in the source that is being
185     compiled (which of course may be different). I have changed it back to:
186 ph10 197
187 ph10 189 #include "pcre.h"
188 ph10 197
189     I have a vague recollection that the change was concerned with compiling in
190     different directories, but in the new build system, that is taken care of
191     by the VPATH setting the Makefile.
193 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
194     when the subject happened to end in the byte 0x85 (e.g. if the last
195     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
196     characters but of course it shouldn't be taken as a newline when it is part
197     of another character. The bug was that, for an unlimited repeat of . in
198     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
199     characters when looking for a newline.
200 ph10 197
201     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
203     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
204     in debug output.
206 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
207     long printing in the pcrecpp unittest when running under MinGW.
208 ph10 189
209 ph10 197 6. ESC_K was left out of the EBCDIC table.
210 ph10 189
211 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
212     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
213     limit also applies to "virtual nesting" when a pattern is recursive, and in
214     this case 1000 isn't so big. I have been able to remove this limit at the
215     expense of backing off one optimization in certain circumstances. Normally,
216     when pcre_exec() would call its internal match() function recursively and
217     immediately return the result unconditionally, it uses a "tail recursion"
218     feature to save stack. However, when a subpattern that can match an empty
219     string has an unlimited repetition quantifier, it no longer makes this
220     optimization. That gives it a stack frame in which to save the data for
221     checking that an empty string has been matched. Previously this was taken
222     from the 1000-entry workspace that had been reserved. So now there is no
223     explicit limit, but more stack is used.
224 ph10 189
225 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
226     syntax that is required for Windows, and which was going wrong for the
227     pcreposix and pcrecpp parts of the library. These were overlooked when this
228     problem was solved for the main library.
229 ph10 197
230 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
231     the size of patterns that contain repeated groups with explicit upper
232     limits. As the maximum quantifier is 65535, the maximum group length was
233     set at 30,000 so that the product of these two numbers did not overflow a
234     32-bit integer. However, it turns out that people want to use groups that
235     are longer than 30,000 bytes (though not repeat them that many times).
236     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
237     made it possible to implement the integer overflow checks in a much more
238     dynamic way, which I have now done. The artificial limitation on group
239     length has been removed - we now have only the limit on the total length of
240     the compiled pattern, which depends on the LINK_SIZE setting.
241 ph10 208
242     10. Fixed a bug in the documentation for get/copy named substring when
243     duplicate names are permitted. If none of the named substrings are set, the
244     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
245     empty string.
247     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
248     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
249     because the ] is interpreted as the first data character and the
250     terminating ] is not found. PCRE has been made compatible with Perl in this
251     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
252     cause memory overwriting.
254 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
255     string has been matched (to stop an infinite loop). It was not recognizing
256 ph10 208 a conditional subpattern that could match an empty string if that
257 ph10 206 subpattern was within another subpattern. For example, it looped when
258 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
259 ph10 206 condition was not nested. This bug has been fixed.
260 ph10 208
261 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
262     past the start of the subject in the presence of bytes with the top bit
263     set, for example "\x8aBCD".
264 ph10 211
265 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
266     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
267 ph10 200
268 ph10 211 14. Optimized (?!) to (*FAIL).
269 ph10 202
270 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
271     This restricts code points to be within the range 0 to 0x10FFFF, excluding
272     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
273     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
274     does: it's just the validity check that is more restrictive.
275 ph10 220
276     16. Inserted checks for integer overflows during escape sequence (backslash)
277     processing, and also fixed erroneous offset values for syntax errors during
278     backslash processing.
280 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
281 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
283 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
284     caused an overrun.
285 ph10 220
286     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
287     something other than just ASCII characters) inside a group that had an
288     unlimited repeat caused a loop at compile time (while checking to see
289     whether the group could match an empty string).
291 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
292     [\P{Any}] did so. (Error in the code for printing property names.)
293 ph10 210
294 ph10 220 21. An orphan \E inside a character class could cause a crash.
296     22. A repeated capturing bracket such as (A)? could cause a wild memory
297 ph10 218 reference during compilation.
298 ph10 220
299     23. There are several functions in pcre_compile() that scan along a compiled
300     expression for various reasons (e.g. to see if it's fixed length for look
301 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
302 ph10 220 present in the pattern. These operators have additional parameters compared
303     with \d, etc, and these were not being taken into account when moving along
304 ph10 218 the compiled data. Specifically:
305 ph10 220
306     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
307     length.
309     (b) An item such as \pL+ within a repeated group could cause crashes or
310 ph10 218 loops.
311 ph10 220
312 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
313 ph10 220 "reference to non-existent subpattern" error.
315 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
317 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
318 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
319 ph10 211
320 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
321 ph10 218
322 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
323 ph10 223 character were causing crashes (broken optimization).
324 ph10 227
325 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
326 ph10 227 \p or \P) caused a compile-time loop.
328 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
329     break. For example, the unstudied pattern [\r\n]A does not match the string
330     "\r\nA" because change 7.0/46 below moves the current point on by two
331     characters after failing to match at the start. However, the pattern \nA
332 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
333     the same is true. There doesn't seem any very clean way out of this, but
334     what I have chosen to do makes the common cases work: PCRE now takes note
335     of whether there can be an explicit match for \r or \n anywhere in the
336     pattern, and if so, 7.0/46 no longer applies. As part of this change,
337     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
338     pattern has explicit CR or LF references.
339 ph10 222
340 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
341 ph10 223
342 ph10 227
343 ph10 189 Version 7.2 19-Jun-07
344     ---------------------
346 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
347     which is apparently normally available under Windows.
348 ph10 159
349     2. Re-jig the pcregrep tests with different newline settings in an attempt
350     to make them independent of the local environment's newline setting.
351 ph10 157
352 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
353 ph10 165
354 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
355     was not 2, because the output contained actual offsets. The recent new
356 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
357     usable with all link sizes.
359 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
360     stack recursion. This gives a massive performance boost under BSD, but just
361 ph10 165 a small improvement under Linux. However, it saves one field in the frame
362 ph10 164 in all cases.
363 ph10 172
364 ph10 166 6. Added more features from the forthcoming Perl 5.10:
365 ph10 172
366 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
367     recursion call. It refers to the nth most recently opened parentheses.
368 ph10 172
369 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
370 ph10 172 to be opened parentheses.
372     (c) Conditions that refer to capturing parentheses can be specified
373 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
374 ph10 172
375 ph10 168 (d) \K resets the start of the current match so that everything before
376 ph10 172 is not part of it.
378 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
379 ph10 172
380 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
381 ph10 172 reference syntax.
382 ph10 182
383 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
384 ph10 182 alternative starts with the same number.
385 ph10 172
386 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
388 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
391     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
392     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
393 ph10 170 for detecting groups that can match an empty string.
394 ph10 159
395 ph10 172 9. A pattern with a very large number of alternatives (more than several
396     hundred) was running out of internal workspace during the pre-compile
397     phase, where pcre_compile() figures out how much memory will be needed. A
398     bit of new cunning has reduced the workspace needed for groups with
399     alternatives. The 1000-alternative test pattern now uses 12 bytes of
400     workspace instead of running out of the 4096 that are available.
401 ph10 182
402 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
403 ph10 172
404 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
405     The report of the bug said:
406 ph10 182
407 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
408     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
409 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
410 ph10 185
411 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
412 ph10 185 it matched the wrong number of bytes.
413 ph10 172
414 ph10 179
415 ph10 155 Version 7.1 24-Apr-07
416 ph10 98 ---------------------
418 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
419 ph10 122 that is more "standard", making use of automake and other Autotools. There
420 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
421     on this.
422 ph10 111
423     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
424     for recursive directory scanning broke on some systems because the files
425     are not scanned in any specific order and on different systems the order
426     was different. A call to "sort" has been inserted into RunGrepTest for the
427     approprate test as a short-term fix. In the longer term there may be an
428 ph10 100 alternative.
429 ph10 111
430 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
431 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
432     people do their own conversions for various reasons). The problems
433     concerned the use of low-level troff macros .br and .in. I have therefore
434     removed all such uses from the man pages (some were redundant, some could
435 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
436     HTML has been updated to handle .nf/.fi and to complain if it encounters
437     .br or .in.
438 ph10 111
439 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
440 ph10 123 arranged for config.h to be included in the distribution, with the name
441 ph10 111 config.h.generic, for the benefit of those who have to compile without
442     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
444     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
445     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
446 ph10 127 makevp.bat for the current PCRE, using the additional files
447 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
448 ph10 111
449     6. A Windows user reported a minor discrepancy with test 2, which turned out
450     to be caused by a trailing space on an input line that had got lost in his
451 ph10 102 copy. The trailing space was an accident, so I've just removed it.
452 ph10 111
453 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
454 ph10 111 that is needed.
456 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
457     as "const" (a) because they are and (b) because it helps the PHP
458     maintainers who have recently made a script to detect big data structures
459 ph10 111 in the php code that should be moved to the .rodata section. I remembered
460     to update Builducptable as well, so it won't revert if ucptable.h is ever
461 ph10 105 re-created.
462 ph10 111
463     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
464 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
465 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
466     support is not required. This saves 1.5-2K of code, which is important in
467 ph10 107 some applications.
468 ph10 111
469 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
470 ph10 111 so as not to refer to the tables, even though these functions will never be
471     called when UTF-8 support is disabled. Otherwise there are problems with a
472     shared library.
474 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
476     (a) It was defining its arguments as char * instead of void *.
478 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
479     a long time ago when I wrote it, but is no longer the case.
481 ph10 118 The emulated memove() is provided for those environments that have neither
482 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
483 ph10 118 is clearly not the case, as these two bugs were recently reported.
484 ph10 123
485 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
486 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
487     pages, and it removes trailing spaces from listed files. It also creates
488     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
489     case, it wraps all the #defines with #ifndefs. This script should be run
490 ph10 111 before "make dist".
491 ph10 123
492 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
493     with Unicode property support.
494 ph10 123
495     (a) For a maximizing quantifier, if the two different cases of the
496     character were of different lengths in their UTF-8 codings (there are
497     some cases like this - I found 11), and the matching function had to
498 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
499     were both the same length.
500 ph10 123
501     (b) When PCRE was configured to use the heap rather than the stack for
502     recursion during matching, it was not correctly preserving the data for
503     the other case of a UTF-8 character when checking ahead for a match
504     while processing a minimizing repeat. If the check also involved
505 ph10 115 matching a wide character, but failed, corruption could cause an
506     erroneous result when trying to check for a repeat of the original
507     character.
508 ph10 123
509 ph10 116 13. Some tidying changes to the testing mechanism:
510 ph10 98
511 ph10 116 (a) The RunTest script now detects the internal link size and whether there
512     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
513 ph10 123 values substituted by "configure". (The RunGrepTest script already did
514     this for UTF-8.) The configure.ac script no longer substitutes the
515     relevant variables.
517 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
518     with length and offset values. This means that the output is different
519     for different internal link sizes. Test 2 is skipped for link sizes
520     other than 2 because of this, bypassing the problem. Unfortunately,
521     there was also a test in test 3 (the locale tests) that used /B and
522 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
523     I have added a new /Z option to pcretest that replaces the length and
524     offset values with spaces. This is now used to make test 3 independent
525 ph10 122 of link size. (Test 2 will be tidied up later.)
526 ph10 123
527     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
528 ph10 122 segmentation fault instead of returning the appropriate error message.
529 ph10 134
530 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
531 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
532     This doesn't seem right; it now treats the CRLF combination as the line
533     ending, and so does not match in that case. It's only a pattern such as ^$
534     that would hit this one: something like ^ABC$ would have failed after \r
535     and then tried again after \r\n.
537 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
538 ph10 134 in an attempt to make files that differ only in their line terminators
539     compare equal. This works on Linux.
540 ph10 142
541 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
542     as it exited. This is now fixed, thanks to valgrind.
543 ph10 142
544 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
545 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
546     was because its rules for how to advance for /g after matching an empty
547 ph10 143 string at the end of a line did not allow for this case. They now check for
548     it specially.
549 ph10 150
550     20. pcretest is supposed to handle patterns and data of any length, by
551     extending its buffers when necessary. It was getting this wrong when the
552 ph10 147 buffer for a data line had to be extended.
553 ph10 150
554 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
555 ph10 150 CRLF as a newline sequence.
556 ph10 152
557 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
558 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
559     I have nevertheless tidied it up.
560 ph10 111
561 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
562 ph10 123
563 ph10 153 24. Added a man page for pcre-config.
564 ph10 152
565 ph10 153
566 nigel 93 Version 7.0 19-Dec-06
567     ---------------------
569     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
570     moving to gcc 4.1.1.
572     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
573     sys/time.h, which is documented as needed for this function. It doesn't
574     seem to matter on Linux, but it showed up on some releases of OS X.
576     3. It seems that there are systems where bytes whose values are greater than
577     127 match isprint() in the "C" locale. The "C" locale should be the
578     default when a C program starts up. In most systems, only ASCII printing
579     characters match isprint(). This difference caused the output from pcretest
580     to vary, making some of the tests fail. I have changed pcretest so that:
582     (a) When it is outputting text in the compiled version of a pattern, bytes
583     other than 32-126 are always shown as hex escapes.
585     (b) When it is outputting text that is a matched part of a subject string,
586     it does the same, unless a different locale has been set for the match
587     (using the /L modifier). In this case, it uses isprint() to decide.
589     4. Fixed a major bug that caused incorrect computation of the amount of memory
590     required for a compiled pattern when options that changed within the
591     pattern affected the logic of the preliminary scan that determines the
592     length. The relevant options are -x, and -i in UTF-8 mode. The result was
593     that the computed length was too small. The symptoms of this bug were
594     either the PCRE error "internal error: code overflow" from pcre_compile(),
595     or a glibc crash with a message such as "pcretest: free(): invalid next
596     size (fast)". Examples of patterns that provoked this bug (shown in
597     pcretest format) are:
599     /(?-x: )/x
600     /(?x)(?-x: \s*#\s*)/
601     /((?i)[\x{c0}])/8
602     /(?i:[\x{c0}])/8
604     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
605     is now done differently.
607     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
608     wrapper classes; (b) implement a new function in the C++ scanner that is
609     more efficient than the old way of doing things because it avoids levels of
610     recursion in the regex matching; (c) add a paragraph to the documentation
611     for the FullMatch() function.
613     6. The escape sequence \n was being treated as whatever was defined as
614     "newline". Not only was this contrary to the documentation, which states
615     that \n is character 10 (hex 0A), but it also went horribly wrong when
616     "newline" was defined as CRLF. This has been fixed.
618     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
619     was being set to -1 for the "end of line" case (supposedly a value that no
620     character can have). Though this value is never used (the check for end of
621     line is "zero bytes in current character"), it caused compiler complaints.
622     I've changed it to 0xffffffff.
624     8. In pcre_version.c, the version string was being built by a sequence of
625     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
626     string (as it is for production releases) called a macro with an empty
627     argument. The C standard says the result of this is undefined. The gcc
628     compiler treats it as an empty string (which was what was wanted) but it is
629     reported that Visual C gives an error. The source has been hacked around to
630     avoid this problem.
632     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
633     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
634     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
635     of them did).
637     10. Originally, pcretest opened its input and output without "b"; then I was
638     told that "b" was needed in some environments, so it was added for release
639     5.0 to both the input and output. (It makes no difference on Unix-like
640     systems.) Later I was told that it is wrong for the input on Windows. I've
641     now abstracted the modes into two macros, to make it easier to fiddle with
642     them, and removed "b" from the input mode under Windows.
644     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
646     12. Added -help and --help to pcretest as an official way of being reminded
647     of the options.
649     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
650     and pcrecpp.cc because they annoy compilers at high warning levels.
652     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
654     15. Fixed an occurrence of == in configure.ac that should have been = (shell
655     scripts are not C programs :-) and which was not noticed because it works
656     on Linux.
658     16. pcretest is supposed to handle any length of pattern and data line (as one
659     line or as a continued sequence of lines) by extending its input buffer if
660     necessary. This feature was broken for very long pattern lines, leading to
661     a string of junk being passed to pcre_compile() if the pattern was longer
662     than about 50K.
664     17. I have done a major re-factoring of the way pcre_compile() computes the
665     amount of memory needed for a compiled pattern. Previously, there was code
666     that made a preliminary scan of the pattern in order to do this. That was
667     OK when PCRE was new, but as the facilities have expanded, it has become
668     harder and harder to keep it in step with the real compile phase, and there
669     have been a number of bugs (see for example, 4 above). I have now found a
670     cunning way of running the real compile function in a "fake" mode that
671     enables it to compute how much memory it would need, while actually only
672     ever using a few hundred bytes of working memory and without too many
673     tests of the mode. This should make future maintenance and development
674     easier. A side effect of this work is that the limit of 200 on the nesting
675     depth of parentheses has been removed (though this was never a serious
676     limitation, I suspect). However, there is a downside: pcre_compile() now
677     runs more slowly than before (30% or more, depending on the pattern). I
678     hope this isn't a big issue. There is no effect on runtime performance.
680     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
681     newline (only possible for the last line of a file) and it was a
682     pattern that set a locale (followed by /Lsomething), pcretest crashed.
684     19. Added additional timing features to pcretest. (1) The -tm option now times
685     matching only, not compiling. (2) Both -t and -tm can be followed, as a
686     separate command line item, by a number that specifies the number of
687     repeats to use when timing. The default is 50000; this gives better
688     precision, but takes uncomfortably long for very large patterns.
690     20. Extended pcre_study() to be more clever in cases where a branch of a
691     subpattern has no definite first character. For example, (a*|b*)[cd] would
692     previously give no result from pcre_study(). Now it recognizes that the
693     first character must be a, b, c, or d.
695     21. There was an incorrect error "recursive call could loop indefinitely" if
696     a subpattern (or the entire pattern) that was being tested for matching an
697     empty string contained only one non-empty item after a nested subpattern.
698     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
699     incorrectly, because the \d was being skipped in the check.
701     22. The pcretest program now has a new pattern option /B and a command line
702     option -b, which is equivalent to adding /B to every pattern. This causes
703     it to show the compiled bytecode, without the additional information that
704     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
705     is the same as /B/I).
707     23. A new optimization is now able automatically to treat some sequences such
708     as a*b as a*+b. More specifically, if something simple (such as a character
709     or a simple class like \d) has an unlimited quantifier, and is followed by
710     something that cannot possibly match the quantified thing, the quantifier
711     is automatically "possessified".
713     24. A recursive reference to a subpattern whose number was greater than 39
714     went wrong under certain circumstances in UTF-8 mode. This bug could also
715     have affected the operation of pcre_study().
717     25. Realized that a little bit of performance could be had by replacing
718     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
720     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
722     27. Possessive quantifiers such as a++ were previously implemented by turning
723     them into atomic groups such as ($>a+). Now they have their own opcodes,
724     which improves performance. This includes the automatically created ones
725     from 23 above.
727     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
728     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
729     the first matched character to be a colon. This applied both to named and
730     numbered groups.
732     29. The ucpinternal.h header file was missing its idempotency #ifdef.
734     30. I was sent a "project" file called libpcre.a.dev which I understand makes
735     building PCRE on Windows easier, so I have included it in the distribution.
737     31. There is now a check in pcretest against a ridiculously large number being
738     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
739     loop, the loop is abandoned.
741     32. Forward references to subpatterns in conditions such as (?(2)...) where
742     subpattern 2 is defined later cause pcre_compile() to search forwards in
743     the pattern for the relevant set of parentheses. This search went wrong
744     when there were unescaped parentheses in a character class, parentheses
745     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
747     33. "Subroutine" calls and backreferences were previously restricted to
748     referencing subpatterns earlier in the regex. This restriction has now
749     been removed.
751     34. Added a number of extra features that are going to be in Perl 5.10. On the
752     whole, these are just syntactic alternatives for features that PCRE had
753     previously implemented using the Python syntax or my own invention. The
754     other formats are all retained for compatibility.
756     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
757     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
758     also .NET compatible.
760     (b) A recursion or subroutine call to a named group can now be defined as
761     (?&name) as well as (?P>name).
763     (c) A backreference to a named group can now be defined as \k<name> or
764     \k'name' as well as (?P=name). The new forms, as well as being in Perl
765     5.10, are also .NET compatible.
767     (d) A conditional reference to a named group can now use the syntax
768     (?(<name>) or (?('name') as well as (?(name).
770     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
771     groups (named and numbered) that are never evaluated inline, but can be
772     called as "subroutines" from elsewhere. In effect, the DEFINE condition
773     is always false. There may be only one alternative in such a group.
775     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
776     as the simple (?(R). The condition is true only if the most recent
777     recursion is that of the given number or name. It does not search out
778     through the entire recursion stack.
780     (g) The escape \gN or \g{N} has been added, where N is a positive or
781     negative number, specifying an absolute or relative reference.
783     35. Tidied to get rid of some further signed/unsigned compiler warnings and
784     some "unreachable code" warnings.
786     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
787     things, this adds five new scripts.
789     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
790     There were also incompatibilities regarding the handling of \Q..\E inside
791     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
792     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
794     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
795     matches an empty string, and forcibly breaks the loop. There were bugs in
796     this code in non-simple cases. For a pattern such as ^(a()*)* matched
797     against aaaa the result was just "a" rather than "aaaa", for example. Two
798     separate and independent bugs (that affected different cases) have been
799     fixed.
801     39. Refactored the code to abolish the use of different opcodes for small
802     capturing bracket numbers. This is a tidy that I avoided doing when I
803     removed the limit on the number of capturing brackets for 3.5 back in 2001.
804     The new approach is not only tidier, it makes it possible to reduce the
805     memory needed to fix the previous bug (38).
807     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
808     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
809     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
810     mode.
812     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
813     report.
815     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
816     copy construction and assignment in the C++ wrapper.
818     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
819     couple of bugs that could have given wrong results in the "--newline=crlf"
820     case.
822     44. Added a number of casts and did some reorganization of signed/unsigned int
823     variables following suggestions from Dair Grant. Also renamed the variable
824     "this" as "item" because it is a C++ keyword.
826     45. Arranged for dftables to add
828     #include "pcre_internal.h"
830     to pcre_chartables.c because without it, gcc 4.x may remove the array
831     definition from the final binary if PCRE is built into a static library and
832     dead code stripping is activated.
834     46. For an unanchored pattern, if a match attempt fails at the start of a
835     newline sequence, and the newline setting is CRLF or ANY, and the next two
836     characters are CRLF, advance by two characters instead of one.
839 nigel 91 Version 6.7 04-Jul-06
840     ---------------------
842     1. In order to handle tests when input lines are enormously long, pcretest has
843     been re-factored so that it automatically extends its buffers when
844     necessary. The code is crude, but this _is_ just a test program. The
845     default size has been increased from 32K to 50K.
847     2. The code in pcre_study() was using the value of the re argument before
848     testing it for NULL. (Of course, in any sensible call of the function, it
849     won't be NULL.)
851     3. The memmove() emulation function in pcre_internal.h, which is used on
852     systems that lack both memmove() and bcopy() - that is, hardly ever -
853     was missing a "static" storage class specifier.
855     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
856     containing an extended class (one that cannot be represented by a bitmap
857     because it contains high-valued characters or Unicode property items, e.g.
858     [\pZ]). Almost always one would set UTF-8 mode when processing such a
859     pattern, but PCRE should not loop if you do not (it no longer does).
860     [Detail: two cases were found: (a) a repeated subpattern containing an
861     extended class; (b) a recursive reference to a subpattern that followed a
862     previous extended class. It wasn't skipping over the extended class
863     correctly when UTF-8 mode was not set.]
865     5. A negated single-character class was not being recognized as fixed-length
866     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
867     compile error "lookbehind assertion is not fixed length".
869     6. The RunPerlTest auxiliary script was showing an unexpected difference
870     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
871     write a Perl script that can interpret lines of an input file either as
872     byte characters or as UTF-8, which is what "perltest" was being required to
873     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
874     can't do is switch easily at run time between having the "use utf8;" pragma
875     or not. In the end, I fudged it by using the RunPerlTest script to insert
876     "use utf8;" explicitly for the UTF-8 tests.
878     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
879     the end of the subject string, contrary to the documentation and to what
880     Perl does. This was true of both matching functions. Now it matches only at
881     the start of the subject and immediately after *internal* newlines.
883     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
884     a pointer to an int instead of a pointer to an unsigned long int. This
885     caused problems on 64-bit systems.
887     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
888     instance of the 'standard' template library not being so standard".
890     10. There was no check on the number of named subpatterns nor the maximum
891     length of a subpattern name. The product of these values is used to compute
892     the size of the memory block for a compiled pattern. By supplying a very
893     long subpattern name and a large number of named subpatterns, the size
894     computation could be caused to overflow. This is now prevented by limiting
895     the length of names to 32 characters, and the number of named subpatterns
896     to 10,000.
898     11. Subpatterns that are repeated with specific counts have to be replicated in
899     the compiled pattern. The size of memory for this was computed from the
900     length of the subpattern and the repeat count. The latter is limited to
901     65535, but there was no limit on the former, meaning that integer overflow
902     could in principle occur. The compiled length of a repeated subpattern is
903     now limited to 30,000 bytes in order to prevent this.
905     12. Added the optional facility to have named substrings with the same name.
907     13. Added the ability to use a named substring as a condition, using the
908     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
909     are numbers (not recommended). Forward references are permitted.
911     14. Added forward references in named backreferences (if you see what I mean).
913     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
914     pattern could run off the end of the subject. For example, the pattern
915     "(?s)(.{1,5})"8 did this with the subject "ab".
917     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
918     PCRE_CASELESS was set when matching characters that were quantified with ?
919     or *.
921     17. A character class other than a single negated character that had a minimum
922     but no maximum quantifier - for example [ab]{6,} - was not handled
923     correctly by pce_dfa_exec(). It would match only one character.
925     18. A valid (though odd) pattern that looked like a POSIX character
926     class but used an invalid character after [ (for example [[,abc,]]) caused
927     pcre_compile() to give the error "Failed: internal error: code overflow" or
928     in some cases to crash with a glibc free() error. This could even happen if
929     the pattern terminated after [[ but there just happened to be a sequence of
930     letters, a binary zero, and a closing ] in the memory that followed.
932     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
933     over the years. Originally (before any Unicode support), just the bottom 8
934     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
935     output from "man perlunicode" includes this:
937     The regular expression compiler produces polymorphic opcodes. That
938     is, the pattern adapts to the data and automatically switches to
939     the Unicode character scheme when presented with Unicode data--or
940     instead uses a traditional byte scheme when presented with byte
941     data.
943     Sadly, a wide octal escape does not cause a switch, and in a string with
944     no other multibyte characters, these octal escapes are treated as before.
945     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
946     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
947     Unicode string.
949     I have not perpetrated such confusion in PCRE. Up till now, it took just
950     the bottom 8 bits, as in old Perl. I have now made octal escapes with
951     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
952     translate to the appropriate multibyte character.
954     29. Applied some refactoring to reduce the number of warnings from Microsoft
955     and Borland compilers. This has included removing the fudge introduced
956     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
957     a warning about an unused variable.
959     21. PCRE has not included VT (character 0x0b) in the set of whitespace
960     characters since release 4.0, because Perl (from release 5.004) does not.
961     [Or at least, is documented not to: some releases seem to be in conflict
962     with the documentation.] However, when a pattern was studied with
963     pcre_study() and all its branches started with \s, PCRE still included VT
964     as a possible starting character. Of course, this did no harm; it just
965     caused an unnecessary match attempt.
967     22. Removed a now-redundant internal flag bit that recorded the fact that case
968     dependency changed within the pattern. This was once needed for "required
969     byte" processing, but is no longer used. This recovers a now-scarce options
970     bit. Also moved the least significant internal flag bit to the most-
971     significant bit of the word, which was not previously used (hangover from
972     the days when it was an int rather than a uint) to free up another bit for
973     the future.
975     23. Added support for CRLF line endings as well as CR and LF. As well as the
976     default being selectable at build time, it can now be changed at runtime
977     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
978     specify that it is scanning data with non-default line endings.
980     24. Changed the definition of CXXLINK to make it agree with the definition of
981     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
983     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
984     recursions. This makes a big different to stack usage for some patterns.
986     26. If a subpattern containing a named recursion or subroutine reference such
987     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
988     the space required for the compiled pattern went wrong and gave too small a
989     value. Depending on the environment, this could lead to "Failed: internal
990     error: code overflow at offset 49" or "glibc detected double free or
991     corruption" errors.
993     27. Applied patches from Google (a) to support the new newline modes and (b) to
994     advance over multibyte UTF-8 characters in GlobalReplace.
996     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
997     difference for some implementation of PCRE in some Windows version.
999     29. Added some extra testing facilities to pcretest:
1001     \q<number> in a data line sets the "match limit" value
1002     \Q<number> in a data line sets the "match recursion limt" value
1003     -S <number> sets the stack size, where <number> is in megabytes
1005     The -S option isn't available for Windows.
1008 nigel 89 Version 6.6 06-Feb-06
1009     ---------------------
1011     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1012     in pcreposix.h. I have copied the definition from pcre.h.
1014     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1015     because pcre.h is no longer a built file.
1017     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1018     not normally included in the compiled code.
1021 nigel 87 Version 6.5 01-Feb-06
1022     ---------------------
1024     1. When using the partial match feature with pcre_dfa_exec(), it was not
1025     anchoring the second and subsequent partial matches at the new starting
1026     point. This could lead to incorrect results. For example, with the pattern
1027     /1234/, partially matching against "123" and then "a4" gave a match.
1029     2. Changes to pcregrep:
1031     (a) All non-match returns from pcre_exec() were being treated as failures
1032     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1033     error message is output. Some extra information is given for the
1035     probably the only errors that are likely to be caused by users (by
1036     specifying a regex that has nested indefinite repeats, for instance).
1037     If there are more than 20 of these errors, pcregrep is abandoned.
1039     (b) A binary zero was treated as data while matching, but terminated the
1040     output line if it was written out. This has been fixed: binary zeroes
1041     are now no different to any other data bytes.
1043     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1044     used to set a locale for matching. The --locale=xxxx long option has
1045     been added (no short equivalent) to specify a locale explicitly on the
1046     pcregrep command, overriding the environment variables.
1048     (d) When -B was used with -n, some line numbers in the output were one less
1049     than they should have been.
1051     (e) Added the -o (--only-matching) option.
1053     (f) If -A or -C was used with -c (count only), some lines of context were
1054     accidentally printed for the final match.
1056     (g) Added the -H (--with-filename) option.
1058     (h) The combination of options -rh failed to suppress file names for files
1059     that were found from directory arguments.
1061     (i) Added the -D (--devices) and -d (--directories) options.
1063     (j) Added the -F (--fixed-strings) option.
1065     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1067     (l) Added the --colo(u)r option.
1069     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1070     is not present by default.
1072     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1073     items such as (?R) or (?1), when the recursion could match a number of
1074     alternatives. If it matched one of the alternatives, but subsequently,
1075     outside the recursion, there was a failure, the code tried to back up into
1076     the recursion. However, because of the way PCRE is implemented, this is not
1077     possible, and the result was an incorrect result from the match.
1079     In order to prevent this happening, the specification of recursion has
1080     been changed so that all such subpatterns are automatically treated as
1081     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1083     4. I had overlooked the fact that, in some locales, there are characters for
1084     which isalpha() is true but neither isupper() nor islower() are true. In
1085     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1086     and ordfeminine) are like this. This affected the treatment of \w and \W
1087     when they appeared in character classes, but not when they appeared outside
1088     a character class. The bit map for "word" characters is now created
1089     separately from the results of isalnum() instead of just taking it from the
1090     upper, lower, and digit maps. (Plus the underscore character, of course.)
1092     5. The above bug also affected the handling of POSIX character classes such as
1093     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1094     permanent tables. Instead, the bit maps for such a class were previously
1095     created as the appropriate unions of the upper, lower, and digit bitmaps.
1096     Now they are created by subtraction from the [[:word:]] class, which has
1097     its own bitmap.
1099     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1100     It is created by subtracting the vertical space characters (\x09, \x0a,
1101     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1102     subtraction was done in the overall bitmap for a character class, meaning
1103     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1104     be recognized. This bug has been fixed.
1106     7. Patches from the folks at Google:
1108     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1109     real life, but is still worth protecting against".
1111     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1112     regular expressions".
1114     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1115     have it.
1117     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1118     "configure" and the latter not, in order to fix a problem somebody had
1119     with compiling the Arg class on HP-UX.
1121     (e) Improve the error-handling of the C++ wrapper a little bit.
1123     (f) New tests for checking recursion limiting.
1125     8. The pcre_memmove() function, which is used only if the environment does not
1126     have a standard memmove() function (and is therefore rarely compiled),
1127     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1128     returning a result (though PCRE never actually uses the result).
1130     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1131     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1132     returned instead of calling malloc() with an overflowing number that would
1133     most likely cause subsequent chaos.
1135     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1137     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1138     with this option is matched, the nmatch and pmatch options of regexec() are
1139     ignored.
1141     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1142     provided in case anyone wants to the the POSIX interface with UTF-8
1143     strings.
1145     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1146     C++ linking (needed for some HP-UX environments).
1148     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1149     (unused parameter) and in the pcre_printint() function (omitted "default"
1150     switch label when the default is to do nothing).
1152     15. Added some code to make it possible, when PCRE is compiled as a C++
1153     library, to replace subject pointers for pcre_exec() with a smart pointer
1154     class, thus making it possible to process discontinuous strings.
1156     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1157     much the same function. They were added by different people who were trying
1158     to make PCRE easy to compile on non-Unix systems. It has been suggested
1159     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1160     for compiling on Windows systems. I have therefore replaced it with
1161     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1162     defaults to "extern" for C or "extern C" for C++, which works fine on
1163     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1164     SCOPE with something explicit in config.h. In addition:
1166     (a) pcreposix.h still had just "extern" instead of either of these macros;
1167     I have replaced it with PCRE_DATA_SCOPE.
1169     (b) Functions such as _pcre_xclass(), which are internal to the library,
1170     but external in the C sense, all had PCRE_EXPORT in their definitions.
1171     This is apparently wrong for the Windows case, so I have removed it.
1172     (It makes no difference on Unix-like systems.)
1174     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1175     of recursive calls to match(). This is different to MATCH_LIMIT because
1176     that limits the total number of calls to match(), not all of which increase
1177     the depth of recursion. Limiting the recursion depth limits the amount of
1178     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1179     when PCRE is compiled, and changed at run time. A patch from Google adds
1180     this functionality to the C++ interface.
1182     18. Changes to the handling of Unicode character properties:
1184     (a) Updated the table to Unicode 4.1.0.
1186     (b) Recognize characters that are not in the table as "Cn" (undefined).
1188     (c) I revised the way the table is implemented to a much improved format
1189     which includes recognition of ranges. It now supports the ranges that
1190     are defined in UnicodeData.txt, and it also amalgamates other
1191     characters into ranges. This has reduced the number of entries in the
1192     table from around 16,000 to around 3,000, thus reducing its size
1193     considerably. I realized I did not need to use a tree structure after
1194     all - a binary chop search is just as efficient. Having reduced the
1195     number of entries, I extended their size from 6 bytes to 8 bytes to
1196     allow for more data.
1198     (d) Added support for Unicode script names via properties such as \p{Han}.
1200     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1201     matching that character.
1203     20. When matching a repeated Unicode property with a minimum greater than zero,
1204     (for example \pL{2,}), PCRE could look past the end of the subject if it
1205     reached it while seeking the minimum number of characters. This could
1206     happen only if some of the characters were more than one byte long, because
1207     there is a check for at least the minimum number of bytes.
1209     21. Refactored the implementation of \p and \P so as to be more general, to
1210     allow for more different types of property in future. This has changed the
1211     compiled form incompatibly. Anybody with saved compiled patterns that use
1212     \p or \P will have to recompile them.
1214     22. Added "Any" and "L&" to the supported property types.
1216     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1217     but give a compile time error if the value is greater than 0xff.
1219     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1220     accidentally not being installed or uninstalled.
1222     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1223     made were to insert the current release number. This seemed silly, because
1224     it made things harder for people building PCRE on systems that don't run
1225     "configure". I have turned pcre.h into a distributed file, no longer built
1226     by "configure", with the version identification directly included. There is
1227     no longer a pcre.h.in file.
1229     However, this change necessitated a change to the pcre-config script as
1230     well. It is built from pcre-config.in, and one of the substitutions was the
1231     release number. I have updated configure.ac so that ./configure now finds
1232     the release number by grepping pcre.h.
1234     26. Added the ability to run the tests under valgrind.
1237 nigel 85 Version 6.4 05-Sep-05
1238     ---------------------
1240     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1241     "--" to be printed when multiple files were scanned, even when none of the
1242     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1243     consider it to be a bug, and have restored the previous behaviour.
1245     2. A couple of code tidies to get rid of compiler warnings.
1247     3. The pcretest program used to cheat by referring to symbols in the library
1248     whose names begin with _pcre_. These are internal symbols that are not
1249     really supposed to be visible externally, and in some environments it is
1250     possible to suppress them. The cheating is now confined to including
1251     certain files from the library's source, which is a bit cleaner.
1253     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1254     file's purpose clearer.
1256     5. Reorganized pcre_ucp_findchar().
1259 nigel 83 Version 6.3 15-Aug-05
1260     ---------------------
1262     1. The file libpcre.pc.in did not have general read permission in the tarball.
1264     2. There were some problems when building without C++ support:
1266     (a) If C++ support was not built, "make install" and "make test" still
1267     tried to test it.
1269     (b) There were problems when the value of CXX was explicitly set. Some
1270     changes have been made to try to fix these, and ...
1272     (c) --disable-cpp can now be used to explicitly disable C++ support.
1274     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1275     backslash in a target when C++ was disabled. This confuses some
1276     versions of "make", apparently. Using an intermediate variable solves
1277     this. (Same for CPP_LOBJ.)
1279     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1280     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1281     necessary on certain architectures.
1283     4. Added a setting of -export-symbols-regex to the link command to remove
1284     those symbols that are exported in the C sense, but actually are local
1285     within the library, and not documented. Their names all begin with
1286     "_pcre_". This is not a perfect job, because (a) we have to except some
1287     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1288     available (and never for static libraries). I have made a note to try to
1289     find a way round (a) in the future.
1292 nigel 81 Version 6.2 01-Aug-05
1293     ---------------------
1295     1. There was no test for integer overflow of quantifier values. A construction
1296     such as {1111111111111111} would give undefined results. What is worse, if
1297     a minimum quantifier for a parenthesized subpattern overflowed and became
1298     negative, the calculation of the memory size went wrong. This could have
1299     led to memory overwriting.
1301     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1303     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1304     operating environments where this matters.
1306     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1307     PCRE options from within the C++ wrapper.
1309     5. Named capturing subpatterns were not being correctly counted when a pattern
1310     was compiled. This caused two problems: (a) If there were more than 100
1311     such subpatterns, the calculation of the memory needed for the whole
1312     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1313     back references of the form \12, where the number was greater than 9, were
1314     not recognized as back references, even though there were sufficient
1315     previous subpatterns.
1317     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1318     versions of gcc, e.g. 2.95.4.
1321 nigel 79 Version 6.1 21-Jun-05
1322     ---------------------
1324     1. There was one reference to the variable "posix" in pcretest.c that was not
1325     surrounded by "#if !defined NOPOSIX".
1327     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1328     the cross-check on the old pcre_info() function, for the benefit of the
1329     cut-down version of PCRE that is currently imported into Exim.
1331     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1332     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1333     patterns that start (?i) but I don't think that matters. The use of (?i) is
1334     just an example; this all applies to the other options as well.
1336     4. Since libtool seems to echo the compile commands it is issuing, the output
1337     from "make" can be reduced a bit by putting "@" in front of each libtool
1338     compile command.
1340     5. Patch from the folks at Google for configure.in to be a bit more thorough
1341     in checking for a suitable C++ installation before trying to compile the
1342     C++ stuff. This should fix a reported problem when a compiler was present,
1343     but no suitable headers.
1345     6. The man pages all had just "PCRE" as their title. I have changed them to
1346     be the relevant file name. I have also arranged that these names are
1347     retained in the file doc/pcre.txt, which is a concatenation in text format
1348     of all the man pages except the little individual ones for each function.
1350     7. The NON-UNIX-USE file had not been updated for the different set of source
1351     files that come with release 6. I also added a few comments about the C++
1352     wrapper.
1355 nigel 77 Version 6.0 07-Jun-05
1356     ---------------------
1358     1. Some minor internal re-organization to help with my DFA experiments.
1360     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1361     didn't matter for the library itself when fully configured, but did matter
1362     when compiling without UCP support, or within Exim, where the ucp files are
1363     not imported.
1365     3. Refactoring of the library code to split up the various functions into
1366     different source modules. The addition of the new DFA matching code (see
1367     below) to a single monolithic source would have made it really too
1368     unwieldy, quite apart from causing all the code to be include in a
1369     statically linked application, when only some functions are used. This is
1370     relevant even without the DFA addition now that patterns can be compiled in
1371     one application and matched in another.
1373     The downside of splitting up is that there have to be some external
1374     functions and data tables that are used internally in different modules of
1375     the library but which are not part of the API. These have all had their
1376     names changed to start with "_pcre_" so that they are unlikely to clash
1377     with other external names.
1379     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1380     a different (DFA) algorithm. Although it is slower than the original
1381     function, it does have some advantages for certain types of matching
1382     problem.
1384     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1385     including restarting after a partial match.
1387     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1388     defined when compiling for Windows was sent to me. I have put it into the
1389     code, though I have no means of testing or verifying it.
1391     7. Added the pcre_refcount() auxiliary function.
1393     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1394     match before or at the first newline in the subject string. In pcretest,
1395     the /f option on a pattern can be used to set this.
1397     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1398     would behave wrongly. This has been present in PCRE since release 4.0.
1400     10. A number of changes to the pcregrep command:
1402     (a) Refactored how -x works; insert ^(...)$ instead of setting
1403     PCRE_ANCHORED and checking the length, in preparation for adding
1404     something similar for -w.
1406     (b) Added the -w (match as a word) option.
1408     (c) Refactored the way lines are read and buffered so as to have more
1409     than one at a time available.
1411     (d) Implemented a pcregrep test script.
1413     (e) Added the -M (multiline match) option. This allows patterns to match
1414     over several lines of the subject. The buffering ensures that at least
1415     8K, or the rest of the document (whichever is the shorter) is available
1416     for matching (and similarly the previous 8K for lookbehind assertions).
1418     (f) Changed the --help output so that it now says
1420     -w, --word-regex(p)
1422     instead of two lines, one with "regex" and the other with "regexp"
1423     because that confused at least one person since the short forms are the
1424     same. (This required a bit of code, as the output is generated
1425     automatically from a table. It wasn't just a text change.)
1427     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1428     option but starts with a hyphen. Could be a pattern or a path name
1429     starting with a hyphen, for instance.
1431     (h) "-" can be given as a file name to represent stdin.
1433     (i) When file names are being printed, "(standard input)" is used for
1434     the standard input, for compatibility with GNU grep. Previously
1435     "<stdin>" was used.
1437     (j) The option --label=xxx can be used to supply a name to be used for
1438     stdin when file names are being printed. There is no short form.
1440     (k) Re-factored the options decoding logic because we are going to add
1441     two more options that take data. Such options can now be given in four
1442     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1444     (l) Added the -A, -B, and -C options for requesting that lines of context
1445     around matches be printed.
1447     (m) Added the -L option to print the names of files that do not contain
1448     any matching lines, that is, the complement of -l.
1450     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1451     continue to scan other files.
1453     (o) The -s option was incorrectly implemented. For compatibility with other
1454     greps, it now suppresses the error message for a non-existent or non-
1455     accessible file (but not the return code). There is a new option called
1456     -q that suppresses the output of matching lines, which was what -s was
1457     previously doing.
1459     (p) Added --include and --exclude options to specify files for inclusion
1460     and exclusion when recursing.
1462     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1463     Hopefully, it now does.
1465     12. Missing cast in pcre_study().
1467     13. Added an "uninstall" target to the makefile.
1469     14. Replaced "extern" in the function prototypes in Makefile.in with
1470     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1471     world, but is set differently for Windows.
1473     15. Added a second compiling function called pcre_compile2(). The only
1474     difference is that it has an extra argument, which is a pointer to an
1475     integer error code. When there is a compile-time failure, this is set
1476     non-zero, in addition to the error test pointer being set to point to an
1477     error message. The new argument may be NULL if no error number is required
1478     (but then you may as well call pcre_compile(), which is now just a
1479     wrapper). This facility is provided because some applications need a
1480     numeric error indication, but it has also enabled me to tidy up the way
1481     compile-time errors are handled in the POSIX wrapper.
1483     16. Added VPATH=.libs to the makefile; this should help when building with one
1484     prefix path and installing with another. (Or so I'm told by someone who
1485     knows more about this stuff than I do.)
1487     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1488     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1489     match everything, including newlines. This is not POSIX-compatible, but
1490     somebody wanted the feature. From pcretest it can be activated by using
1491     both the P and the s flags.
1493     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1495     19. libpcre.pc was being incorrectly installed as executable.
1497     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1498     it now also looks for '\r' so that it will work unmodified on Windows.
1500     21. Added Google's contributed C++ wrapper to the distribution.
1502     22. Added some untidy missing memory free() calls in pcretest, to keep
1503     Electric Fence happy when testing.
1507 nigel 75 Version 5.0 13-Sep-04
1508     ---------------------
1510     1. Internal change: literal characters are no longer packed up into items
1511     containing multiple characters in a single byte-string. Each character
1512     is now matched using a separate opcode. However, there may be more than one
1513     byte in the character in UTF-8 mode.
1515     2. The pcre_callout_block structure has two new fields: pattern_position and
1516     next_item_length. These contain the offset in the pattern to the next match
1517     item, and its length, respectively.
1519     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1520     insertion of callouts before each pattern item. Added the /C option to
1521     pcretest to make use of this.
1523     4. On the advice of a Windows user, the lines
1525     #if defined(_WIN32) || defined(WIN32)
1526     _setmode( _fileno( stdout ), 0x8000 );
1527     #endif /* defined(_WIN32) || defined(WIN32) */
1529     have been added to the source of pcretest. This apparently does useful
1530     magic in relation to line terminators.
1532     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1533     for the benefit of those environments where the "b" makes a difference.
1535     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1536     to know about it. I have put a hack into configure.in that adds in code
1537     to set GCC=yes if CC=icc. This seems to end up at a point in the
1538     generated configure script that is early enough to affect the setting of
1539     compiler options, which is what is needed, but I have no means of testing
1540     whether it really works. (The user who reported this had patched the
1541     generated configure script, which of course I cannot do.)
1543     LATER: After change 22 below (new libtool files), the configure script
1544     seems to know about icc (and also ecc). Therefore, I have commented out
1545     this hack in configure.in.
1547     7. Added support for pkg-config (2 patches were sent in).
1549     8. Negated POSIX character classes that used a combination of internal tables
1550     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1551     [[:^ascii]]. Typically, they would match almost any characters. The other
1552     POSIX classes were not broken in this way.
1554     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1555     to find the match, as PCRE was deluded into thinking that the match had to
1556     start at the start point or following a newline. The same bug applied to
1557     patterns with negative forward assertions or any backward assertions
1558     preceding ".*" at the start, unless the pattern required a fixed first
1559     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1561     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1562     starting at the last subject character, bytes beyond the end of the subject
1563     string were read.
1565     11. Renamed the variable "class" as "classbits" to make life easier for C++
1566     users. (Previously there was a macro definition, but it apparently wasn't
1567     enough.)
1569     12. Added the new field "tables" to the extra data so that tables can be passed
1570     in at exec time, or the internal tables can be re-selected. This allows
1571     a compiled regex to be saved and re-used at a later time by a different
1572     program that might have everything at different addresses.
1574     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1575     -R library as well as a -L library.
1577     14. The debugging options of pcretest (-d on the command line or D on a
1578     pattern) showed incorrect output for anything following an extended class
1579     that contained multibyte characters and which was followed by a quantifier.
1581     15. Added optional support for general category Unicode character properties
1582     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1583     support. It adds about 90K to the size of the library. The meanings of the
1584     inbuilt class escapes such as \d and \s have NOT been changed.
1586     16. Updated pcredemo.c to include calls to free() to release the memory for the
1587     compiled pattern.
1589     17. The generated file chartables.c was being created in the source directory
1590     instead of in the building directory. This caused the build to fail if the
1591     source directory was different from the building directory, and was
1592     read-only.
1594     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1595     file. No doubt somebody will tell me if they don't make sense... Also added
1596     Dan Mooney's comments about building on OpenVMS.
1598     19. Added support for partial matching via the PCRE_PARTIAL option for
1599     pcre_exec() and the \P data escape in pcretest.
1601     20. Extended pcretest with 3 new pattern features:
1603     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1604     write the compiled pattern to the file whose name is "rest-of-line".
1605     This is a straight binary dump of the data, with the saved pointer to
1606     the character tables forced to be NULL. The study data, if any, is
1607     written too. After writing, pcretest reads a new pattern.
1609     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1610     compiled pattern from the given file. There must not be any
1611     occurrences of "<" in the file name (pretty unlikely); if there are,
1612     pcretest will instead treat the initial "<" as a pattern delimiter.
1613     After reading in the pattern, pcretest goes on to read data lines as
1614     usual.
1616     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1617     and 16-bit fields in a compiled pattern, to simulate a pattern that
1618     was compiled on a host of opposite endianness.
1620     21. The pcre-exec() function can now cope with patterns that were compiled on
1621     hosts of opposite endianness, with this restriction:
1623     As for any compiled expression that is saved and used later, the tables
1624     pointer field cannot be preserved; the extra_data field in the arguments
1625     to pcre_exec() should be used to pass in a tables address if a value
1626     other than the default internal tables were used at compile time.
1628     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1629     now diagnosed as an error. Previously, most of the time, a negative number
1630     would have been treated as zero, but if in addition "ovector" was passed as
1631     NULL, a crash could occur.
1633     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1634     new versions from the libtool 1.5 distribution (the last one is a copy of
1635     a file called libtool.m4). This seems to have fixed the need to patch
1636     "configure" to support Darwin 1.3 (which I used to do). However, I still
1637     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1638     workstation).
1640     24. Changed the PCRE licence to be the more standard "BSD" licence.
1643 nigel 73 Version 4.5 01-Dec-03
1644     ---------------------
1646     1. There has been some re-arrangement of the code for the match() function so
1647     that it can be compiled in a version that does not call itself recursively.
1648     Instead, it keeps those local variables that need separate instances for
1649     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1650     needs to "recurse". Keeping track of where control must go is done by means
1651     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1652     hide most of the details from the main code, and operates only if
1653     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1654     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1655     operating.
1657     To make it easier for callers to provide specially tailored get/free
1658     functions for this usage, two new functions, pcre_stack_malloc, and
1659     pcre_stack_free, are used. They are always called in strict stacking order,
1660     and the size of block requested is always the same.
1662     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1663     PCRE has been compiled to use the stack or the heap for recursion. The
1664     -C option of pcretest uses this to show which version is compiled.
1666     A new data escape \S, is added to pcretest; it causes the amounts of store
1667     obtained and freed by both kinds of malloc/free at match time to be added
1668     to the output.
1670     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1671     what's available on my current Linux desktop machine.
1673     3. When matching a UTF-8 string, the test for a valid string at the start has
1674     been extended. If start_offset is not zero, PCRE now checks that it points
1675     to a byte that is the start of a UTF-8 character. If not, it returns
1676     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1677     this is necessary because there may be backward assertions in the pattern.
1678     When matching the same subject several times, it may save resources to use
1679     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1681     4. The code for checking the validity of UTF-8 strings has been tightened so
1682     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1683     containing "overlong sequences".
1685     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1686     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1687     should have been "&", but it just so happened that all the cases this let
1688     through by mistake were picked up later in the function.
1690     6. I had used a variable called "isblank" - this is a C99 function, causing
1691     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1693     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1694     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1695     so the version is shown; (c) stop "make test" echoing "./RunTest".
1697     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1699     9. The prototype for memmove() for systems that don't have it was using
1700     size_t, but the inclusion of the header that defines size_t was later. I've
1701     moved the #includes for the C headers earlier to avoid this.
1703     10. Added some adjustments to the code to make it easier to compiler on certain
1704     special systems:
1706     (a) Some "const" qualifiers were missing.
1707     (b) Added the macro EXPORT before all exported functions; by default this
1708     is defined to be empty.
1709     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1710     that it reads its output file name as an argument instead of writing
1711     to the standard output and assuming this can be redirected.
1713     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1714     class containing characters with values greater than 255, PCRE compilation
1715     went into a loop.
1717     12. A recursive reference to a subpattern that was within another subpattern
1718     that had a minimum quantifier of zero caused PCRE to crash. For example,
1719     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1720     recursion. If the recursively-called subpattern itself had a zero repeat,
1721     that was OK.
1723     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1724     buffer into which it was copied (for escape processing) was still set at
1725     1024, so long lines caused crashes.
1727     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1728     "internal error: code overflow...". This applied to any character class
1729     that was followed by a possessive quantifier.
1731     15. Modified the Makefile to add libpcre.la as a prerequisite for
1732     libpcreposix.la because I was told this is needed for a parallel build to
1733     work.
1735     16. If a pattern that contained .* following optional items at the start was
1736     studied, the wrong optimizing data was generated, leading to matching
1737     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1738     matching string must start with a or b or c. The correct conclusion for
1739     this pattern is that a match can start with any character.
1742 nigel 71 Version 4.4 13-Aug-03
1743     ---------------------
1745     1. In UTF-8 mode, a character class containing characters with values between
1746     127 and 255 was not handled correctly if the compiled pattern was studied.
1747     In fixing this, I have also improved the studying algorithm for such
1748     classes (slightly).
1750     2. Three internal functions had redundant arguments passed to them. Removal
1751     might give a very teeny performance improvement.
1753     3. Documentation bug: the value of the capture_top field in a callout is *one
1754     more than* the number of the hightest numbered captured substring.
1756     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1757     in incorrectly linking with a previously installed version. They now link
1758     explicitly with libpcre.la.
1760     5. configure.in no longer needs to recognize Cygwin specially.
1762     6. A problem in pcre.in for Windows platforms is fixed.
1764     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1765     pcretest, it used to include the size of the study block as part of its
1766     output. Unfortunately, the structure contains a field that has a different
1767     size on different hardware architectures. This meant that the tests that
1768     showed this size failed. As the block is currently always of a fixed size,
1769     this information isn't actually particularly useful in pcretest output, so
1770     I have just removed it.
1772     8. Three pre-processor statements accidentally did not start in column 1.
1773     Sadly, there are *still* compilers around that complain, even though
1774     standard C has not required this for well over a decade. Sigh.
1776     9. In pcretest, the code for checking callouts passed small integers in the
1777     callout_data field, which is a void * field. However, some picky compilers
1778     complained about the casts involved for this on 64-bit systems. Now
1779     pcretest passes the address of the small integer instead, which should get
1780     rid of the warnings.
1782     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1783     both compile and run time, and gives an error if an invalid UTF-8 sequence
1784     is found. There is a option for disabling this check in cases where the
1785     string is known to be correct and/or the maximum performance is wanted.
1787     11. In response to a bug report, I changed one line in Makefile.in from
1789     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1790     to
1791     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1793     to look similar to other lines, but I have no way of telling whether this
1794     is the right thing to do, as I do not use Windows. No doubt I'll get told
1795     if it's wrong...
1798 nigel 69 Version 4.3 21-May-03
1799     ---------------------
1801     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1802     Makefile.
1804     2. Some refactoring to improve the quality of the code:
1806     (i) The utf8_table... variables are now declared "const".
1808     (ii) The code for \cx, which used the "case flipping" table to upper case
1809     lower case letters, now just substracts 32. This is ASCII-specific,
1810     but the whole concept of \cx is ASCII-specific, so it seems
1811     reasonable.
1813     (iii) PCRE was using its character types table to recognize decimal and
1814     hexadecimal digits in the pattern. This is silly, because it handles
1815     only 0-9, a-f, and A-F, but the character types table is locale-
1816     specific, which means strange things might happen. A private
1817     table is now used for this - though it costs 256 bytes, a table is
1818     much faster than multiple explicit tests. Of course, the standard
1819     character types table is still used for matching digits in subject
1820     strings against \d.
1822     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1823     ending in _t are). So I've renamed it as ESC_tee.
1825     3. The first argument for regexec() in the POSIX wrapper should have been
1826     defined as "const".
1828     4. Changed pcretest to use malloc() for its buffers so that they can be
1829     Electric Fenced for debugging.
1831     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1832     to read one or more bytes before the start of the subject string. Often this
1833     had no effect on PCRE's behaviour, but in some circumstances it could
1834     provoke a segmentation fault.
1836     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1837     to try to read one or more bytes before the start of the subject string.
1839     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1840     UTF-8 support could misbehave in various ways if the subject string
1841     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1842     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1843     back over UTF-8 characters.)
1846 nigel 67 Version 4.2 14-Apr-03
1847     ---------------------
1849     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1851     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1852     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1853     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1854     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1855     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1856     and BUILD_EXEEXT
1857     Note: automatic setting of the BUILD variables is not yet working
1858     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1859     compile-time but not at link-time
1860     [LINK]: use for linking executables only
1861     make different versions for Windows and non-Windows
1862     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1863     libraries
1864     [LINK_FOR_BUILD]: new variable
1865     [OBJEXT]: use throughout
1866     [EXEEXT]: use throughout
1867     <winshared>: new target
1868     <wininstall>: new target
1869     <dftables.o>: use native compiler
1870     <dftables>: use native linker
1871     <install>: handle Windows platform correctly
1872     <clean>: ditto
1873     <check>: ditto
1874     copy DLL to top builddir before testing
1876     As part of these changes, -no-undefined was removed again. This was reported
1877     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1878     in any case.
1880     3. Some tidies to get rid of compiler warnings:
1882     . In the match_data structure, match_limit was an unsigned long int, whereas
1883     match_call_count was an int. I've made them both unsigned long ints.
1885     . In pcretest the fact that a const uschar * doesn't automatically cast to
1886     a void * provoked a warning.
1888     . Turning on some more compiler warnings threw up some "shadow" variables
1889     and a few more missing casts.
1891     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1892     option, a class that contained a single character with a value between 128
1893     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1895     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1896     option, a class that contained several characters, but with at least one
1897     whose value was between 128 and 255 caused PCRE to crash.
1900 nigel 65 Version 4.1 12-Mar-03
1901     ---------------------
1902 nigel 63
1903 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1904     needed, and a string in dftables.c that was longer than standard compilers are
1905     required to support.
1907     2. Compiling with Sun's compiler found a few more places where the code could
1908     be tidied up in order to avoid warnings.
1910     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1911     first of these names is deprecated in the latest Autoconf in favour of the name
1912     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1913     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1914     analogy I have changed it to CFLAGS_FOR_BUILD.
1916     4. Added -no-undefined to the linking command in the Makefile, because this is
1917     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1918     linking step for the pcreposix library.
1920     5. PCRE was failing to diagnose the case of two named groups with the same
1921     name.
1923     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1924     literal character that is needed in the subject for a match, and scans along to
1925     ensure that it is present before embarking on the full matching process. This
1926     saves time in cases of nested unlimited repeats that are never going to match.
1927     Problem: the scan can take a lot of time if the subject is very long (e.g.
1928     megabytes), thus penalizing straightforward matches. It is now done only if the
1929     amount of subject to be scanned is less than 1000 bytes.
1931     7. A lesser problem with the same optimization is that it was recording the
1932     first character of an anchored pattern as "needed", thus provoking a search
1933     right along the subject, even when the first match of the pattern was going to
1934     fail. The "needed" character is now not set for anchored patterns, unless it
1935     follows something in the pattern that is of non-fixed length. Thus, it still
1936     fulfils its original purpose of finding quick non-matches in cases of nested
1937     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1940     Version 4.0 17-Feb-03
1941     ---------------------
1943 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1944     extended to the end of string, PCRE compiled incorrect data. This could lead to
1945     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1947     2. Moved to autoconf 2.53 and libtool 1.4.2.
1949     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1950     the special perltest8 script is no longer needed - all the tests can be run
1951     from a single perltest script.
1953     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1954     by \s. It has now been removed in PCRE. This means it isn't recognized as
1955     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1956     class [:space:] *does* include VT, thereby creating a mess.
1958     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1959     space and tab.
1961     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1962     its new features into the main test script, reducing the number of scripts.
1964     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1965     were backward compatible, and made the (?i) apply to the whole pattern, as if
1966     /i were given. Now it behaves more logically, and applies the option setting
1967     only to what follows. PCRE has been changed to follow suit. However, if it
1968     finds options settings right at the start of the pattern, it extracts them into
1969     the global options, as before. Thus, they show up in the info data.
1971     8. Added support for the \Q...\E escape sequence. Characters in between are
1972     treated as literals. This is slightly different from Perl in that $ and @ are
1973     also handled as literals inside the quotes. In Perl, they will cause variable
1974     interpolation. Note the following examples:
1976     Pattern PCRE matches Perl matches
1978     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1979     \Qabc\$xyz\E abc\$xyz abc\$xyz
1980     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1982     For compatibility with Perl, \Q...\E sequences are recognized inside character
1983     classes as well as outside them.
1985     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1986     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1987     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1988     signed/unsigned warnings.
1990     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1991     option for pcretest, so I've replaced it by a simple function that does just
1992     that job.
1994     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1995     "pcregrep -".
1997     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1998     Java package. This provides some syntactic sugar for simple cases of what my
1999     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2000     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2001     item, you can use this simplified notation. Note that only makes sense with
2002     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2003     greediness, whatever the setting of the PCRE_UNGREEDY option.
2005     13. A change of greediness default within a pattern was not taking effect at
2006     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2007     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2008     was abstracted outside.
2010     14. PCRE now supports the \G assertion. It is true when the current matching
2011     position is at the start point of the match. This differs from \A when the
2012     starting offset is non-zero. Used with the /g option of pcretest (or similar
2013     code), it works in the same way as it does for Perl's /g option. If all
2014     alternatives of a regex begin with \G, the expression is anchored to the start
2015     match position, and the "anchored" flag is set in the compiled expression.
2017     15. Some bugs concerning the handling of certain option changes within patterns
2018     have been fixed. These applied to options other than (?ims). For example,
2019     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2020     been the other way round. Some of this was related to change 7 above.
2022     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2023     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2024     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2025     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2027     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2028     mode. Unlike ".", it always matches newline, whatever the setting of
2029     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2030     assertions. Perl allows it, but it doesn't (in general) work because it can't
2031     calculate the length of the lookbehind. At least, that's the case for Perl
2032     5.8.0 - I've been told they are going to document that it doesn't work in
2033     future.
2035     18. Added an error diagnosis for escapes that PCRE does not support: these are
2036     \L, \l, \N, \P, \p, \U, \u, and \X.
2038     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2039     reading past the end of the pattern in cases such as /[abcd/.
2041     20. PCRE was getting more memory than necessary for patterns with classes that
2042     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2044     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2045     compiling PCRE for use with Virtual Pascal.
2047     22. Small fix to the Makefile to make it work properly if the build is done
2048     outside the source tree.
2050     23. Added a new extension: a condition to go with recursion. If a conditional
2051     subpattern starts with (?(R) the "true" branch is used if recursion has
2052     happened, whereas the "false" branch is used only at the top level.
2054     24. When there was a very long string of literal characters (over 255 bytes
2055     without UTF support, over 250 bytes with UTF support), the computation of how
2056     much memory was required could be incorrect, leading to segfaults or other
2057     strange effects.
2059     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2060     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2061     there was a subsequent back reference to those brackets. This meant that, for
2062     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2063     possible to check for precisely this case. All we can do is abandon the
2064     optimization if .* occurs inside capturing brackets when there are any back
2065     references whatsoever. (See below for a better fix that came later.)
2067     26. The handling of the optimization for finding the first character of a
2068     non-anchored pattern, and for finding a character that is required later in the
2069     match were failing in some cases. This didn't break the matching; it just
2070     failed to optimize when it could. The way this is done has been re-implemented.
2072     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2074     28. Added a new feature that provides some of the functionality that Perl
2075     provides with (?{...}). The facility is termed a "callout". The way it is done
2076     in PCRE is for the caller to provide an optional function, by setting
2077     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2078     global variable. By default it is unset, which disables all calling out. To get
2079     the function called, the regex must include (?C) at appropriate points. This
2080     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2081     This provides a means of identifying different callout points. When PCRE
2082     reaches such a point in the regex, if pcre_callout has been set, the external
2083     function is called. It is provided with data in a structure called
2084     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2085     matching continues; if it returns a non-zero value, the match at the current
2086     point fails. However, backtracking will occur if possible. [This was changed
2087     later and other features added - see item 49 below.]
2089     29. pcretest is upgraded to test the callout functionality. It provides a
2090     callout function that displays information. By default, it shows the start of
2091     the match and the current position in the text. There are some new data escapes
2092     to vary what happens:
2094     \C+ in addition, show current contents of captured substrings
2095     \C- do not supply a callout function
2096     \C!n return 1 when callout number n is reached
2097     \C!n!m return 1 when callout number n is reached for the mth time
2099     30. If pcregrep was called with the -l option and just a single file name, it
2100     output "<stdin>" if a match was found, instead of the file name.
2102     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2103     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2104     pcre_exec(). This saves a malloc/free per call. The default value of
2105     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2106     when configuring.
2108     32. The default maximum size of a compiled pattern is 64K. There have been a
2109     few cases of people hitting this limit. The code now uses macros to handle the
2110     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2111     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2112     configuring. Tests 2 and 5 work only with 2-byte links because they output
2113     debugging information about compiled patterns.
2115     33. Internal code re-arrangements:
2117     (a) Moved the debugging function for printing out a compiled regex into
2118     its own source file (printint.c) and used #include to pull it into
2119     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2120     separate copies.
2122     (b) Defined the list of op-code names for debugging as a macro in
2123     internal.h so that it is next to the definition of the opcodes.
2125     (c) Defined a table of op-code lengths for simpler skipping along compiled
2126     code. This is again a macro in internal.h so that it is next to the
2127     definition of the opcodes.
2129     34. Added support for recursive calls to individual subpatterns, along the
2130     lines of Robin Houston's patch (but implemented somewhat differently).
2132     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2133     allow it to read and process whole directories in Win32. This code was
2134     contributed by Lionel Fourquaux; it has not been tested by me.
2136     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2137     used to name a group. Names consist of alphanumerics and underscores, and must
2138     be unique. Back references use the syntax (?P=name) and recursive calls use
2139     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2140     numbers. The function pcre_fullinfo() can be used after compilation to extract
2141     a name/number map. There are three relevant calls:
2143     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2144     PCRE_INFO_NAMECOUNT yields the number of entries
2145     PCRE_INFO_NAMETABLE yields a pointer to the map.
2147     The map is a vector of fixed-size entries. The size of each entry depends on
2148     the length of the longest name used. The first two bytes of each entry are the
2149     group number, most significant byte first. There follows the corresponding
2150     name, zero terminated. The names are in alphabetical order.
2152     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2153     case instead of 255. Making it the same both with and without UTF-8 support
2154     means that the same test output works with both.
2156     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2157     calling malloc() with a zero argument.
2159     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2160     optimization. I've improved things by keeping a bitmap of backreferences with
2161     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2162     fact referenced, the optimization can be applied. It is unlikely that a
2163     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2164     the match to follow \n) will appear inside brackets with a number greater than
2165     31, but if it does, any back reference > 31 suppresses the optimization.
2167     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2168     of disabling numbered capturing parentheses. Any opening parenthesis that is
2169     not followed by ? behaves as if it were followed by ?: but named parentheses
2170     can still be used for capturing (and they will acquire numbers in the usual
2171     way).
2173     41. Redesigned the return codes from the match() function into yes/no/error so
2174     that errors can be passed back from deep inside the nested calls. A malloc
2175     failure while inside a recursive subpattern call now causes the
2176     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2178     42. It is now possible to set a limit on the number of times the match()
2179     function is called in a call to pcre_exec(). This facility makes it possible to
2180     limit the amount of recursion and backtracking, though not in a directly
2181     obvious way, because the match() function is used in a number of different
2182     circumstances. The count starts from zero for each position in the subject
2183     string (for non-anchored patterns). The default limit is, for compatibility, a
2184     large number, namely 10 000 000. You can change this in two ways:
2186     (a) When configuring PCRE before making, you can use --with-match-limit=n
2187     to set a default value for the compiled library.
2189     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2190     a different value is set. See 45 below.
2192     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2194     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2195     of things that can be changed at compile time. The first argument specifies
2196     what is wanted and the second points to where the information is to be placed.
2197     The current list of available information is:
2201     The output is an integer that is set to one if UTF-8 support is available;
2202     otherwise it is set to zero.
2206     The output is an integer that it set to the value of the code that is used for
2207     newline. It is either LF (10) or CR (13).
2211     The output is an integer that contains the number of bytes used for internal
2212     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2216     The output is an integer that contains the threshold above which the POSIX
2217     interface uses malloc() for output vectors. See item 31 above.
2221     The output is an unsigned integer that contains the default limit of the number
2222     of match() calls in a pcre_exec() execution. See 42 above.
2224     44. pcretest has been upgraded by the addition of the -C option. This causes it
2225     to extract all the available output from the new pcre_config() function, and to
2226     output it. The program then exits immediately.
2228     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2229     order to support additional features. One way would have been to define
2230     pcre_exec2() (for example) with extra arguments, but this would not have been
2231     extensible, and would also have required all calls to the original function to
2232     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2233     is used for passing in "extra" data from pcre_study().
2235     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2236     contains the following fields:
2238     flags a bitmap indicating which of the following fields are set
2239     study_data opaque data from pcre_study()
2240     match_limit a way of specifying a limit on match() calls for a specific
2241     call to pcre_exec()
2242     callout_data data for callouts (see 49 below)
2244     The flag bits are also defined in pcre.h, and are
2250     The pcre_study() function now returns one of these new pcre_extra blocks, with
2251     the actual study data pointed to by the study_data field, and the
2252     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2253     before. That is, this change is entirely upwards-compatible and requires no
2254     change to existing code.
2256     If you want to pass in additional data to pcre_exec(), you can either place it
2257     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2258     block.
2260     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2261     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2262     times with different match limits, until it finds the minimum value needed for
2263     pcre_exec() to complete. The value is then output. This can be instructive; for
2264     most simple matches the number is quite small, but for pathological cases it
2265     gets very large very quickly.
2267     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2268     returns the size of the data block pointed to by the study_data field in a
2269     pcre_extra block, that is, the value that was passed as the argument to
2270     pcre_malloc() when PCRE was getting memory in which to place the information
2271     created by pcre_study(). The fourth argument should point to a size_t variable.
2272     pcretest has been extended so that this information is shown after a successful
2273     pcre_study() call when information about the compiled regex is being displayed.
2275     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2276     because what follows is always an absolute path. (Later: it turns out that this
2277     is more than cosmetic for MinGW, because it doesn't like empty path
2278     components.)
2280     49. Some changes have been made to the callout feature (see 28 above):
2282     (i) A callout function now has three choices for what it returns:
2284     0 => success, carry on matching
2285     > 0 => failure at this point, but backtrack if possible
2286     < 0 => serious error, return this value from pcre_exec()
2288     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2289     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2290     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2291     use by callout functions. It will never be used by PCRE itself.
2293     (ii) The pcre_extra structure (see 45 above) has a void * field called
2294     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2295     pcre_callout_block structure has a field of the same name. The contents of
2296     the field passed in the pcre_extra structure are passed to the callout
2297     function in the corresponding field in the callout block. This makes it
2298     easier to use the same callout-containing regex from multiple threads. For
2299     testing, the pcretest program has a new data escape
2301     \C*n pass the number n (may be negative) as callout_data
2303     If the callout function in pcretest receives a non-zero value as
2304     callout_data, it returns that value.
2306     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2307     there were some redundant $(CFLAGS) in commands that are now specified as
2308     $(LINK), which already includes $(CFLAGS).
2310     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2311     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2312     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2313     one-byte characters throughout. Note that case-insensitive matching applies
2314     only to characters whose values are less than 256. PCRE doesn't support the
2315     notion of cases for higher-valued characters.
2317     (i) A character class whose characters are all within 0-255 is handled as
2318     a bit map, and the map is inverted for negative classes. Previously, a
2319     character > 255 always failed to match such a class; however it should
2320     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2322     (ii) A negated character class with a single character < 255 is coded as
2323     "not this character" (OP_NOT). This wasn't working properly when the test
2324     character was multibyte, either singly or repeated.
2326     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2327     mode, for example: \x{100}{2,3}.
2329     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2330     singly or repeated) now correctly test multibyte characters. However,
2331     PCRE doesn't recognize any characters with values greater than 255 as
2332     digits, spaces, or word characters. Such characters always match \D, \S,
2333     and \W, and never match \d, \s, or \w.
2335     (v) Classes may now contain characters and character ranges with values
2336     greater than 255. For example: [ab\x{100}-\x{400}].
2338     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2339     PCRE in UTF-8 mode.
2341     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2342     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2343     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2344     value.)
2346     53. The single man page has become too large. I have therefore split it up into
2347     a number of separate man pages. These also give rise to individual HTML pages;
2348     these are now put in a separate directory, and there is an index.html page that
2349     lists them all. Some hyperlinking between the pages has been installed.
2351     54. Added convenience functions for handling named capturing parentheses.
2353     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2354     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2355     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2356     are faulted.
2358     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2359     calling configure. These values are used when compiling the dftables.c program
2360     which is run to generate the source of the default character tables. They
2361     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2362     you will need to set these values.
2364     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2367     Version 3.9 02-Jan-02
2368 nigel 61 ---------------------
2370     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2372     2. If --disable-static was given, the building process failed when trying to
2373     build pcretest and pcregrep. (For some reason it was using libtool to compile
2374     them, which is not right, as they aren't part of the library.)
2377 nigel 59 Version 3.8 18-Dec-01
2378     ---------------------
2380     1. The experimental UTF-8 code was completely screwed up. It was packing the
2381     bytes in the wrong order. How dumb can you get?
2384 nigel 57 Version 3.7 29-Oct-01
2385     ---------------------
2387     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2388     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2389     this didn't happen under Solaris 8, where I normally test things.
2391 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2392     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2393     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2394     this fix an hour or so after the initial 3.7 release.)
2395 nigel 57
2396 nigel 59
2397 nigel 55 Version 3.6 23-Oct-01
2398     ---------------------
2400     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2401     offsets passed as NULL with zero offset count.
2403     2. The config.guess and config.sub files had not been updated when I moved to
2404     the latest autoconf.
2407 nigel 53 Version 3.5 15-Aug-01
2408     ---------------------
2409 nigel 5
2410 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2411     had been forgotten.
2413     2. By using declared but undefined structures, we can avoid using "void"
2414     definitions in pcre.h while keeping the internal definitions of the structures
2415     private.
2417     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2418     user point of view, this means that both static and shared libraries are built
2419     by default, but this can be individually controlled. More of the work of
2420     handling this static/shared cases is now inside libtool instead of PCRE's make
2421     file.
2423     4. The pcretest utility is now installed along with pcregrep because it is
2424     useful for users (to test regexs) and by doing this, it automatically gets
2425     relinked by libtool. The documentation has been turned into a man page, so
2426     there are now .1, .txt, and .html versions in /doc.
2428     5. Upgrades to pcregrep:
2429     (i) Added long-form option names like gnu grep.
2430     (ii) Added --help to list all options with an explanatory phrase.
2431     (iii) Added -r, --recursive to recurse into sub-directories.
2432     (iv) Added -f, --file to read patterns from a file.
2434     6. pcre_exec() was referring to its "code" argument before testing that
2435     argument for NULL (and giving an error if it was NULL).
2437     7. Upgraded Makefile.in to allow for compiling in a different directory from
2438     the source directory.
2440     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2441     options bits, the pointer it was passed was to an int instead of to an unsigned
2442     long int. This mattered only on 64-bit systems.
2444     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2445     generated) instead of pcre.in, which it its source. Also made the same change
2446     in several of the .c files.
2448     10. A new release of gcc defines printf() as a macro, which broke pcretest
2449     because it had an ifdef in the middle of a string argument for printf(). Fixed
2450     by using separate calls to printf().
2452     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2453     script, to force use of CR or LF instead of \n in the source. On non-Unix
2454     systems, the value can be set in config.h.
2456     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2457     absolute limit. Changed the text of the error message to make this clear, and
2458     likewise updated the man page.
2460     13. The limit of 99 on the number of capturing subpatterns has been removed.
2461     The new limit is 65535, which I hope will not be a "real" limit.
2464 nigel 51 Version 3.4 22-Aug-00
2465     ---------------------
2467     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2469     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2472 nigel 49 Version 3.3 01-Aug-00
2473     ---------------------
2475     1. If an octal character was given, but the value was greater than \377, it
2476     was not getting masked to the least significant bits, as documented. This could
2477     lead to crashes in some systems.
2479     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2480     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2482     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2483     These just pass their arguments on to (pcre_free)(), but they are provided
2484     because some uses of PCRE bind it to non-C systems that can call its functions,
2485     but cannot call free() or pcre_free() directly.
2487     4. Add "make test" as a synonym for "make check". Corrected some comments in
2488     the Makefile.
2490     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2491     Makefile.
2493     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2494     command called pgrep for grepping around the active processes.
2496     7. Added the beginnings of support for UTF-8 character strings.
2498     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2499     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2500     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2501     out for the ar command.)
2504 nigel 47 Version 3.2 12-May-00
2505     ---------------------
2507     This is purely a bug fixing release.
2509     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2510     of ZA. This was just one example of several cases that could provoke this bug,
2511     which was introduced by change 9 of version 2.00. The code for breaking
2512     infinite loops after an iteration that matches an empty string was't working
2513     correctly.
2515     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2516     when matched against abbab (for example). After matching an empty string, it
2517     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2518     caused it to match further down the string than it should.
2520     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2521     was there because it doesn't seem to be needed, and it causes trouble on some
2522     systems, as it is not a Standard C header. It has been removed.
2524     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2525     were reported on the Macintosh. The changes were from
2527     while ((c = *(++ptr)) != 0 && c != '\n');
2528     to
2529     while ((c = *(++ptr)) != 0 && c != '\n') ;
2531     Totally extraordinary, but if that's what it takes...
2533     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2534     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2535     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2536     assumes the way PCRE uses memmove() (always moving upwards).
2538     6. PCRE is being used in one environment where strchr() is not available. There
2539     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2540     faster code anyway.
2543 nigel 45 Version 3.1 09-Feb-00
2544     ---------------------
2546     The only change in this release is the fixing of some bugs in Makefile.in for
2547     the "install" target:
2549     (1) It was failing to install pcreposix.h.
2551     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2554 nigel 43 Version 3.0 01-Feb-00
2555     ---------------------
2556 nigel 41
2557     1. Add support for the /+ modifier to perltest (to output $` like it does in
2558     pcretest).
2560     2. Add support for the /g modifier to perltest.
2562     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2563     matches null strings.
2565     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2566     pattern. Perl treats empty patterns specially - it reuses the most recent
2567     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2568     effect.
2570     5. The POSIX interface was broken in that it was just handing over the POSIX
2571     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2572     required a bigger vector, with some working space on the end. This means that
2573     the POSIX wrapper now has to get and free some memory, and copy the results.
2575 nigel 43 6. Added some simple autoconf support, placing the test data and the
2576     documentation in separate directories, re-organizing some of the
2577     information files, and making it build pcre-config (a GNU standard). Also added
2578     libtool support for building PCRE as a shared library, which is now the
2579     default.
2580 nigel 41
2581 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2582     09 are not valid octal constants. Single digits will be used for minor values
2583     less than 10.
2585     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2586     existing programs that set these in the POSIX interface can use PCRE without
2587     modification.
2589     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2590     return all that pcre_info() returns, plus additional data. The pcre_info()
2591     function is retained for compatibility, but is considered to be obsolete.
2593     10. Added experimental recursion feature (?R) to handle one common case that
2594     Perl 5.6 will be able to do with (?p{...}).
2596     11. Added support for POSIX character classes like [:alpha:], which Perl is
2597     adopting.
2600 nigel 39 Version 2.08 31-Aug-99
2601     ----------------------
2603     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2604     trying to match at the startoffset position, but instead was moving forward to
2605     the next newline as if a previous match had failed.
2607     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2608     and could get into a loop if a null string was matched other than at the start
2609     of the subject.
2611     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2612     be distinguished at compile time, and for completeness also added PCRE_DATE.
2614     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2615     in GnuWin32 environments.
2618 nigel 37 Version 2.07 29-Jul-99
2619     ----------------------
2621     1. The documentation is now supplied in plain text form and HTML as well as in
2622     the form of man page sources.
2624     2. C++ compilers don't like assigning (void *) values to other pointer types.
2625     In particular this affects malloc(). Although there is no problem in Standard
2626     C, I've put in casts to keep C++ compilers happy.
2628     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2629     should be (const char *).
2631     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2632     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2633     However, I haven't made this a standard facility. The documentation doesn't
2634     mention it, and the Makefile doesn't support it.
2636     5. The Makefile now contains an "install" target, with editable destinations at
2637     the top of the file. The pcretest program is not installed.
2639     6. pgrep -V now gives the PCRE version number and date.
2641     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2642     causing the entire string to be ignored, instead of just the last character.
2644     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2645     non-matching string, it can take a very, very long time, even for strings of
2646     quite modest length, because of the nested recursion. PCRE now does better in
2647     some of these cases. It does this by remembering the last required literal
2648     character in the pattern, and pre-searching the subject to ensure it is present
2649     before running the real match. In other words, it applies a heuristic to detect
2650     some types of certain failure quickly, and in the above example, if presented
2651     with a string that has no trailing " it gives "no match" very quickly.
2653     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2654     other alternatives are tried instead.
2657 nigel 35 Version 2.06 09-Jun-99
2658     ----------------------
2660     1. Change pcretest's output for amount of store used to show just the code
2661     space, because the remainder (the data block) varies in size between 32-bit and
2662     64-bit systems.
2664     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2665     start matching at. This allows lookbehinds to work when searching for multiple
2666     occurrences in a string.
2668     3. Added additional options to pcretest for testing multiple occurrences:
2670     /+ outputs the rest of the string that follows a match
2671     /g loops for multiple occurrences, using the new startoffset argument
2672     /G loops for multiple occurrences by passing an incremented pointer
2674     4. PCRE wasn't doing the "first character" optimization for patterns starting
2675     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2676     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2677     the letter 'x'. On long subject strings, this gives a significant speed-up.
2680 nigel 33 Version 2.05 21-Apr-99
2681     ----------------------
2683     1. Changed the type of magic_number from int to long int so that it works
2684     properly on 16-bit systems.
2686     2. Fixed a bug which caused patterns starting with .* not to work correctly
2687     when the subject string contained newline characters. PCRE was assuming
2688     anchoring for such patterns in all cases, which is not correct because .* will
2689     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2690     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2691     must be retried after every newline in the subject.
2694 nigel 31 Version 2.04 18-Feb-99
2695     ----------------------
2697     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2698     computation of the store needed to hold the pattern was incorrect (too large).
2699     If such patterns were nested a few deep, this could multiply and become a real
2700     problem.
2702     2. Added /M option to pcretest to show the memory requirement of a specific
2703     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2705     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2706     compiled in such a way that the backtracking after subsequent failure was
2707     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2708     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2711 nigel 29 Version 2.03 02-Feb-99
2712     ----------------------
2714     1. Fixed typo and small mistake in man page.
2716 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2717     LICENCE file containing the conditions.
2718 nigel 29
2719     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2720     Perl, that is the internal \ allows the delimiter to be included in the
2721     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2722     the final delimiter, add \ to the end of the pattern (to test the error).
2724     4. Added the convenience functions for extracting substrings after a successful
2725     match. Updated pcretest to make it able to test these functions.
2728 nigel 27 Version 2.02 14-Jan-99
2729     ----------------------
2731     1. Initialized the working variables associated with each extraction so that
2732     their saving and restoring doesn't refer to uninitialized store.
2734     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2735     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2736     fix the problem.
2738     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2739     calls, and wasn't printing the correct value for compiling calls. Increased the
2740     default value of LOOPREPEAT, and the number of significant figures in the
2741     times.
2743     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2745     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2746     a building problem on Windows NT with a FAT file system.
2749 nigel 25 Version 2.01 21-Oct-98
2750     ----------------------
2752     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2753     to character tables built by pcre_maketables() in the current locale. If NULL
2754     is passed, the default tables are used.
2757 nigel 23 Version 2.00 24-Sep-98
2758 nigel 21 ----------------------
2760 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2761     it any more.
2763     2. Allow quantification of (?>) groups, and make it work correctly.
2765     3. The first character computation wasn't working for (?>) groups.
2767     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2768     end of the subject) and add 5.005's \z, which really does match only at the
2769     very end of the subject.
2771     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2773     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2774     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2775     localized options. All options to pcre_study() were also removed.
2777     7. Add other new features from 5.005:
2779     $(?<= positive lookbehind
2780     $(?<! negative lookbehind
2781     (?imsx-imsx) added the unsetting capability
2782     such a setting is global if at outer level; local otherwise
2783     (?imsx-imsx:) non-capturing groups with option setting
2784     (?(cond)re|re) conditional pattern matching
2786     A backreference to itself in a repeated group matches the previous
2787     captured string.
2789     8. General tidying up of studying (both automatic and via "study")
2790     consequential on the addition of new assertions.
2792     9. As in 5.005, unlimited repeated groups that could match an empty substring
2793     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2794     runtime if any iteration does actually match an empty substring.
2796     10. Include the RunTest script in the distribution.
2798     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2799     discrepancies, some of which were old and were also with respect to 5.004. They
2800     have now been fixed.
2803     Version 1.09 28-Apr-98
2804     ----------------------
2806 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2807     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2808     program crashes, or just wrong answers. This did not apply to negated classes
2809     containing more than one character, or to minima other than one.
2812 nigel 19 Version 1.08 27-Mar-98
2813     ----------------------
2815     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2817     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2818     latter must appear before anything that relies on it in the pattern.
2821 nigel 17 Version 1.07 16-Feb-98
2822     ----------------------
2824     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2825     repeat of a potentially empty string).
2828 nigel 15 Version 1.06 23-Jan-98
2829     ----------------------
2831     1. Added Markus Oberhumer's little patches for C++.
2833     2. Literal strings longer than 255 characters were broken.
2836 nigel 13 Version 1.05 23-Dec-97
2837     ----------------------
2839     1. Negated character classes containing more than one character were failing if
2840     PCRE_CASELESS was set at run time.
2843 nigel 11 Version 1.04 19-Dec-97
2844     ----------------------
2846     1. Corrected the man page, where some "const" qualifiers had been omitted.
2848     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2849     input syntax.
2851     3. Fixed memory leak which occurred when a regex with back references was
2852     matched with an offsets vector that wasn't big enough. The temporary memory
2853     that is used in this case wasn't being freed if the match failed.
2855     4. Tidied pcretest to ensure it frees memory that it gets.
2857     5. Temporary memory was being obtained in the case where the passed offsets
2858     vector was exactly big enough.
2860     6. Corrected definition of offsetof() from change 5 below.
2862     7. I had screwed up change 6 below and broken the rules for the use of
2863     setjmp(). Now fixed.
2866 nigel 9 Version 1.03 18-Dec-97
2867     ----------------------
2869     1. A erroneous regex with a missing opening parenthesis was correctly
2870     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2871     on some systems.
2873     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2874     it was reported that one broken compiler failed on the former because "code" is
2875     also an independent variable.
2877     3. The erroneous regex a[]b caused an array overrun reference.
2879     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2880     fail on data ending with that character. (It was going on too far, and checking
2881     the next character, typically a binary zero.) This was specific to the
2882     optimized code for single-character negative classes.
2884     5. Added a contributed patch from the TIN world which does the following:
2886     + Add an undef for memmove, in case the the system defines a macro for it.
2888     + Add a definition of offsetof(), in case there isn't one. (I don't know
2889     the reason behind this - offsetof() is part of the ANSI standard - but
2890     it does no harm).
2892     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2893     most of the places where whitespace preceded '#'. I have given up and
2894     allowed the remaining 2 cases to be at the margin.
2896     + Rename some variables in pcre to eliminate shadowing. This seems very
2897     pedantic, but does no harm, of course.
2899     6. Moved the call to setjmp() into its own function, to get rid of warnings
2900     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2902     7. Constructs such as \d{8,} were compiling into the equivalent of
2903 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2904 nigel 9 outcome, but in this particular case used more store than had been allocated,
2905     which caused the bug to be discovered because it threw up an internal error.
2907     8. The debugging code in both pcre and pcretest for outputting the compiled
2908     form of a regex was going wrong in the case of back references followed by
2909     curly-bracketed repeats.
2912 nigel 7 Version 1.02 12-Dec-97
2913     ----------------------
2915     1. Typos in pcre.3 and comments in the source fixed.
2917     2. Applied a contributed patch to get rid of places where it used to remove
2918     'const' from variables, and fixed some signed/unsigned and uninitialized
2919     variable warnings.
2921     3. Added the "runtest" target to Makefile.
2923     4. Set default compiler flag to -O2 rather than just -O.
2926 nigel 5 Version 1.01 19-Nov-97
2927     ----------------------
2929     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2930     like /([ab]*)*/, that is, for classes with more than one character in them.
2932     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2933     as /((?>a*))*/ (a PCRE_EXTRA facility).
2936     Version 1.00 18-Nov-97
2937     ----------------------
2939     1. Added compile-time macros to support systems such as SunOS4 which don't have
2940     memmove() or strerror() but have other things that can be used instead.
2942     2. Arranged that "make clean" removes the executables.
2945 nigel 3 Version 0.99 27-Oct-97
2946     ----------------------
2948     1. Fixed bug in code for optimizing classes with only one character. It was
2949     initializing a 32-byte map regardless, which could cause it to run off the end
2950     of the memory it had got.
2952     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2955     Version 0.98 22-Oct-97
2956     ----------------------
2958     1. Fixed bug in code for handling temporary memory usage when there are more
2959     back references than supplied space in the ovector. This could cause segfaults.
2962     Version 0.97 21-Oct-97
2963     ----------------------
2965     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2967     2. Optimized negated single characters not to use a bit map.
2969     3. Brought error texts together as macro definitions; clarified some of them;
2970     fixed one that was wrong - it said "range out of order" when it meant "invalid
2971     escape sequence".
2973     4. Changed some char * arguments to const char *.
2975     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2977     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2978     pcretest.
2981     Version 0.96 16-Oct-97
2982     ----------------------
2984     1. Added a simple "pgrep" utility to the distribution.
2986     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2987     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2988     where "ddd" means "one or more decimal digits".
2990     3. Fixed serious bug. If a pattern had a back reference, but the call to
2991     pcre_exec() didn't supply a large enough ovector to record the related
2992     identifying subpattern, the match always failed. PCRE now remembers the number
2993     of the largest back reference, and gets some temporary memory in which to save
2994     the offsets during matching if necessary, in order to ensure that
2995     backreferences always work.
2997     4. Increased the compatibility with Perl in a number of ways:
2999     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3000     to request this handling. The option can be set at compile or exec time.
3002     (b) $ matches before a terminating newline by default; an option
3003     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3004     mode). The option can be set at compile or exec time.
3006     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3007     the same as Perl's. If the decimal number it represents is less than 10
3008     or there aren't that many previous left capturing parentheses, an octal
3009     escape is read. Inside a character class, it's always an octal escape,
3010     even if it is a single digit.
3012     (d) An escaped but undefined alphabetic character is taken as a literal,
3013     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3014     escapes.
3016     (e) {0} is now permitted. (The previous item is removed from the compiled
3017     pattern).
3019     5. Changed all the names of code files so that the basic parts are no longer
3020     than 10 characters, and abolished the teeny "globals.c" file.
3022     6. Changed the handling of character classes; they are now done with a 32-byte
3023     bit map always.
3025     7. Added the -d and /D options to pcretest to make it possible to look at the
3026     internals of compilation without having to recompile pcre.
3029     Version 0.95 23-Sep-97
3030     ----------------------
3032     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3033     \x20 at the start of a run of normal characters. These were being treated as
3034     real characters, instead of the source characters being re-checked.
3037     Version 0.94 18-Sep-97
3038     ----------------------
3040     1. The functions are now thread-safe, with the caveat that the global variables
3041     containing pointers to malloc() and free() or alternative functions are the
3042     same for all threads.
3044     2. Get pcre_study() to generate a bitmap of initial characters for non-
3045     anchored patterns when this is possible, and use it if passed to pcre_exec().
3048     Version 0.93 15-Sep-97
3049     ----------------------
3051     1. /(b)|(:+)/ was computing an incorrect first character.
3053     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3054     but not actually doing anything yet.
3056     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3057     as Perl does (e.g. [-az] or [az-]).
3059     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3060     all possible positions.
3062     5. Split up into different modules to avoid including unneeded functions in a
3063     compiled binary. However, compile and exec are still in one module. The "study"
3064     function is split off.
3066     6. The character tables are now in a separate module whose source is generated
3067     by an auxiliary program - but can then be edited by hand if required. There are
3068     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3069     toupper() in the code.
3071     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3072     make them global. Abolish the function for setting them, as the caller can now
3073     set them directly.
3076     Version 0.92 11-Sep-97
3077     ----------------------
3079     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3080     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3082     2. Caseless matching was not working in character classes if the characters in
3083     the pattern were in upper case.
3085     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3087     4. Make PCRE_ANCHORED public and accept as a compile option.
3089     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3090     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3091     pass them.
3093     6. Give an error if bad option bits passed at compile or run time.
3095     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3096     pcretest to cause it to pass that flag.
3098     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3099     options, and the first character, if set.
3101     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3104     Version 0.91 10-Sep-97
3105     ----------------------
3107     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3108     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3110     2. PCRE was looping on encountering an indefinitely repeated back reference to
3111     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3112     Perl does - treats the match as successful.
3114     ****


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