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Revision 279 - (hide annotations) (download)
Tue Dec 4 20:01:43 2007 UTC (7 years, 4 months ago) by ph10
File size: 145280 byte(s)
Fix -o bugs in pcregrep.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 263 Version 7.5 12-Nov-07
5     ---------------------
7     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
8     values in parens when parsing an RE using the C++ wrapper."
9 ph10 264
10     2. Negative specials like \S did not work in character classes in UTF-8 mode.
11     Characters greater than 255 were excluded from the class instead of being
12     included.
13 ph10 265
14     3. The same bug as (2) above applied to negated POSIX classes such as
15     [:^space:].
16 ph10 267
17     4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18     defined or documented. It seems to have been a typo for PCRE_STATIC, so
19     I have changed it.
20 ph10 268
21     5. The construct (?&) was not diagnosed as a syntax error (it referenced the
22     first named subpattern) and a construct such as (?&a) would reference the
23     first named subpattern whose name started with "a" (in other words, the
24 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
25     expected" is now given for (?&) (a zero-length name), and this patch also
26     makes it give the same error for \k'' (previously it complained that that
27     was a reference to a non-existent subpattern).
28 ph10 269
29     6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
30     this is right because (?- can be followed by option settings as well as by
31     digits. I have, however, made the messages clearer.
32 ph10 270
33     7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34     than the number used in the conditional) now cause a compile-time error.
35     This is actually not compatible with Perl, which accepts such patterns, but
36     treats the conditional as always being FALSE (as PCRE used to), but it
37     seems to me that giving a diagnostic is better.
38 ph10 274
39     8. Change "alphameric" to the more common word "alphanumeric" in comments
40 ph10 275 and messages.
42     9. Fix two occurrences of "backslash" in comments that should have been
43     "backspace".
44 ph10 276
45     10. Remove two redundant lines of code that can never be obeyed (their function
46     was moved elsewhere).
47 ph10 277
48     11. The program that makes PCRE's Unicode character property table had a bug
49     which caused it to generate incorrect table entries for sequences of
50     characters that have the same character type, but are in different scripts.
51     It amalgamated them into a single range, with the script of the first of
52     them. In other words, some characters were in the wrong script. There were
53     thirteen such cases, affecting characters in the following ranges:
55     U+002b0 - U+002c1
56     U+0060c - U+0060d
57     U+0061e - U+00612
58     U+0064b - U+0065e
59     U+0074d - U+0076d
60     U+01800 - U+01805
61     U+01d00 - U+01d77
62     U+01d9b - U+01dbf
63     U+0200b - U+0200f
64     U+030fc - U+030fe
65     U+03260 - U+0327f
66     U+0fb46 - U+0fbb1
67     U+10450 - U+1049d
68 ph10 279
69     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.
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.
78 ph10 263
80 ph10 260 Version 7.4 21-Sep-07
81 ph10 230 ---------------------
83     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
84 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
85     LF". That isn't really right - the whole point of the change was to try to
86     help when there was an actual mention of one of the two characters. So now
87     the change happens only if \r or \n (or a literal CR or LF) character is
88 ph10 230 encountered.
89 ph10 231
90     2. The 32-bit options word was also used for 6 internal flags, but the numbers
91     of both had grown to the point where there were only 3 bits left.
92     Fortunately, there was spare space in the data structure, and so I have
93     moved the internal flags into a new 16-bit field to free up more option
94 ph10 230 bits.
95 ph10 231
96     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
97     but did not set the internal JCHANGED flag - either of these is enough to
98     control the way the "get" function works - but the PCRE_INFO_JCHANGED
99     facility is supposed to tell if (?J) was ever used, so now (?J) at the
100 ph10 230 start sets both bits.
102 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
103     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
104 ph10 230
105 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
107     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
108 ph10 233 compatibility, even though it is no longer used.
109 ph10 243
110     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
111 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
112 ph10 259 windows.h file is present (where different names are used). [This was
113 ph10 257 reversed later after testing - see 16 below.]
114 ph10 243
115     8. Changed all #include <config.h> to #include "config.h". There were also
116 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
117 ph10 243
118 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
119 ph10 243 sequence off the lines that it output.
121     10. It was pointed out to me that arrays of string pointers cause lots of
122     relocations when a shared library is dynamically loaded. A technique of
123     using a single long string with a table of offsets can drastically reduce
124     these. I have refactored PCRE in four places to do this. The result is
125 ph10 240 dramatic:
126 ph10 243
127 ph10 240 Originally: 290
128     After changing UCP table: 187
129 ph10 243 After changing error message table: 43
130 ph10 240 After changing table of "verbs" 36
131     After changing table of Posix names 22
132 ph10 243
133 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
134 ph10 247
135 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
136 ph10 247 unicode-properties was also set.
138 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
139 ph10 231
140 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
141     checked only for CRLF.
142 ph10 233
143 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
145 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
146 ph10 253
147 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
148 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
149     entirely. This removes changes made in 7 above.
150 ph10 256
151 ph10 261 17. The CMake files have been updated, and there is now more information about
152     building with CMake in the NON-UNIX-USE document.
153 ph10 257
154 ph10 261
155 ph10 228 Version 7.3 28-Aug-07
156 ph10 157 ---------------------
158 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
159     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
160     brackets there is not right, since it causes compilers to look for an
161     installed pcre.h, not the version that is in the source that is being
162     compiled (which of course may be different). I have changed it back to:
163 ph10 197
164 ph10 189 #include "pcre.h"
165 ph10 197
166     I have a vague recollection that the change was concerned with compiling in
167     different directories, but in the new build system, that is taken care of
168     by the VPATH setting the Makefile.
170 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
171     when the subject happened to end in the byte 0x85 (e.g. if the last
172     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
173     characters but of course it shouldn't be taken as a newline when it is part
174     of another character. The bug was that, for an unlimited repeat of . in
175     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
176     characters when looking for a newline.
177 ph10 197
178     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
180     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
181     in debug output.
183 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
184     long printing in the pcrecpp unittest when running under MinGW.
185 ph10 189
186 ph10 197 6. ESC_K was left out of the EBCDIC table.
187 ph10 189
188 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
189     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
190     limit also applies to "virtual nesting" when a pattern is recursive, and in
191     this case 1000 isn't so big. I have been able to remove this limit at the
192     expense of backing off one optimization in certain circumstances. Normally,
193     when pcre_exec() would call its internal match() function recursively and
194     immediately return the result unconditionally, it uses a "tail recursion"
195     feature to save stack. However, when a subpattern that can match an empty
196     string has an unlimited repetition quantifier, it no longer makes this
197     optimization. That gives it a stack frame in which to save the data for
198     checking that an empty string has been matched. Previously this was taken
199     from the 1000-entry workspace that had been reserved. So now there is no
200     explicit limit, but more stack is used.
201 ph10 189
202 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
203     syntax that is required for Windows, and which was going wrong for the
204     pcreposix and pcrecpp parts of the library. These were overlooked when this
205     problem was solved for the main library.
206 ph10 197
207 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
208     the size of patterns that contain repeated groups with explicit upper
209     limits. As the maximum quantifier is 65535, the maximum group length was
210     set at 30,000 so that the product of these two numbers did not overflow a
211     32-bit integer. However, it turns out that people want to use groups that
212     are longer than 30,000 bytes (though not repeat them that many times).
213     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
214     made it possible to implement the integer overflow checks in a much more
215     dynamic way, which I have now done. The artificial limitation on group
216     length has been removed - we now have only the limit on the total length of
217     the compiled pattern, which depends on the LINK_SIZE setting.
218 ph10 208
219     10. Fixed a bug in the documentation for get/copy named substring when
220     duplicate names are permitted. If none of the named substrings are set, the
221     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
222     empty string.
224     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
225     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
226     because the ] is interpreted as the first data character and the
227     terminating ] is not found. PCRE has been made compatible with Perl in this
228     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
229     cause memory overwriting.
231 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
232     string has been matched (to stop an infinite loop). It was not recognizing
233 ph10 208 a conditional subpattern that could match an empty string if that
234 ph10 206 subpattern was within another subpattern. For example, it looped when
235 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
236 ph10 206 condition was not nested. This bug has been fixed.
237 ph10 208
238 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
239     past the start of the subject in the presence of bytes with the top bit
240     set, for example "\x8aBCD".
241 ph10 211
242 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
243     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
244 ph10 200
245 ph10 211 14. Optimized (?!) to (*FAIL).
246 ph10 202
247 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
248     This restricts code points to be within the range 0 to 0x10FFFF, excluding
249     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
250     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
251     does: it's just the validity check that is more restrictive.
252 ph10 220
253     16. Inserted checks for integer overflows during escape sequence (backslash)
254     processing, and also fixed erroneous offset values for syntax errors during
255     backslash processing.
257 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
258 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
260 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
261     caused an overrun.
262 ph10 220
263     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
264     something other than just ASCII characters) inside a group that had an
265     unlimited repeat caused a loop at compile time (while checking to see
266     whether the group could match an empty string).
268 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
269     [\P{Any}] did so. (Error in the code for printing property names.)
270 ph10 210
271 ph10 220 21. An orphan \E inside a character class could cause a crash.
273     22. A repeated capturing bracket such as (A)? could cause a wild memory
274 ph10 218 reference during compilation.
275 ph10 220
276     23. There are several functions in pcre_compile() that scan along a compiled
277     expression for various reasons (e.g. to see if it's fixed length for look
278 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
279 ph10 220 present in the pattern. These operators have additional parameters compared
280     with \d, etc, and these were not being taken into account when moving along
281 ph10 218 the compiled data. Specifically:
282 ph10 220
283     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
284     length.
286     (b) An item such as \pL+ within a repeated group could cause crashes or
287 ph10 218 loops.
288 ph10 220
289 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
290 ph10 220 "reference to non-existent subpattern" error.
292 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
294 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
295 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
296 ph10 211
297 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
298 ph10 218
299 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
300 ph10 223 character were causing crashes (broken optimization).
301 ph10 227
302 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
303 ph10 227 \p or \P) caused a compile-time loop.
305 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
306     break. For example, the unstudied pattern [\r\n]A does not match the string
307     "\r\nA" because change 7.0/46 below moves the current point on by two
308     characters after failing to match at the start. However, the pattern \nA
309 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
310     the same is true. There doesn't seem any very clean way out of this, but
311     what I have chosen to do makes the common cases work: PCRE now takes note
312     of whether there can be an explicit match for \r or \n anywhere in the
313     pattern, and if so, 7.0/46 no longer applies. As part of this change,
314     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
315     pattern has explicit CR or LF references.
316 ph10 222
317 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
318 ph10 223
319 ph10 227
320 ph10 189 Version 7.2 19-Jun-07
321     ---------------------
323 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
324     which is apparently normally available under Windows.
325 ph10 159
326     2. Re-jig the pcregrep tests with different newline settings in an attempt
327     to make them independent of the local environment's newline setting.
328 ph10 157
329 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
330 ph10 165
331 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
332     was not 2, because the output contained actual offsets. The recent new
333 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
334     usable with all link sizes.
336 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
337     stack recursion. This gives a massive performance boost under BSD, but just
338 ph10 165 a small improvement under Linux. However, it saves one field in the frame
339 ph10 164 in all cases.
340 ph10 172
341 ph10 166 6. Added more features from the forthcoming Perl 5.10:
342 ph10 172
343 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
344     recursion call. It refers to the nth most recently opened parentheses.
345 ph10 172
346 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
347 ph10 172 to be opened parentheses.
349     (c) Conditions that refer to capturing parentheses can be specified
350 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
351 ph10 172
352 ph10 168 (d) \K resets the start of the current match so that everything before
353 ph10 172 is not part of it.
355 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
356 ph10 172
357 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
358 ph10 172 reference syntax.
359 ph10 182
360 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
361 ph10 182 alternative starts with the same number.
362 ph10 172
363 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
365 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
368     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
369     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
370 ph10 170 for detecting groups that can match an empty string.
371 ph10 159
372 ph10 172 9. A pattern with a very large number of alternatives (more than several
373     hundred) was running out of internal workspace during the pre-compile
374     phase, where pcre_compile() figures out how much memory will be needed. A
375     bit of new cunning has reduced the workspace needed for groups with
376     alternatives. The 1000-alternative test pattern now uses 12 bytes of
377     workspace instead of running out of the 4096 that are available.
378 ph10 182
379 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
380 ph10 172
381 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
382     The report of the bug said:
383 ph10 182
384 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
385     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
386 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
387 ph10 185
388 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
389 ph10 185 it matched the wrong number of bytes.
390 ph10 172
391 ph10 179
392 ph10 155 Version 7.1 24-Apr-07
393 ph10 98 ---------------------
395 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
396 ph10 122 that is more "standard", making use of automake and other Autotools. There
397 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
398     on this.
399 ph10 111
400     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
401     for recursive directory scanning broke on some systems because the files
402     are not scanned in any specific order and on different systems the order
403     was different. A call to "sort" has been inserted into RunGrepTest for the
404     approprate test as a short-term fix. In the longer term there may be an
405 ph10 100 alternative.
406 ph10 111
407 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
408 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
409     people do their own conversions for various reasons). The problems
410     concerned the use of low-level troff macros .br and .in. I have therefore
411     removed all such uses from the man pages (some were redundant, some could
412 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
413     HTML has been updated to handle .nf/.fi and to complain if it encounters
414     .br or .in.
415 ph10 111
416 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
417 ph10 123 arranged for config.h to be included in the distribution, with the name
418 ph10 111 config.h.generic, for the benefit of those who have to compile without
419     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
421     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
422     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
423 ph10 127 makevp.bat for the current PCRE, using the additional files
424 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
425 ph10 111
426     6. A Windows user reported a minor discrepancy with test 2, which turned out
427     to be caused by a trailing space on an input line that had got lost in his
428 ph10 102 copy. The trailing space was an accident, so I've just removed it.
429 ph10 111
430 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
431 ph10 111 that is needed.
433 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
434     as "const" (a) because they are and (b) because it helps the PHP
435     maintainers who have recently made a script to detect big data structures
436 ph10 111 in the php code that should be moved to the .rodata section. I remembered
437     to update Builducptable as well, so it won't revert if ucptable.h is ever
438 ph10 105 re-created.
439 ph10 111
440     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
441 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
442 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
443     support is not required. This saves 1.5-2K of code, which is important in
444 ph10 107 some applications.
445 ph10 111
446 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
447 ph10 111 so as not to refer to the tables, even though these functions will never be
448     called when UTF-8 support is disabled. Otherwise there are problems with a
449     shared library.
451 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
453     (a) It was defining its arguments as char * instead of void *.
455 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
456     a long time ago when I wrote it, but is no longer the case.
458 ph10 118 The emulated memove() is provided for those environments that have neither
459 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
460 ph10 118 is clearly not the case, as these two bugs were recently reported.
461 ph10 123
462 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
463 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
464     pages, and it removes trailing spaces from listed files. It also creates
465     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
466     case, it wraps all the #defines with #ifndefs. This script should be run
467 ph10 111 before "make dist".
468 ph10 123
469 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
470     with Unicode property support.
471 ph10 123
472     (a) For a maximizing quantifier, if the two different cases of the
473     character were of different lengths in their UTF-8 codings (there are
474     some cases like this - I found 11), and the matching function had to
475 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
476     were both the same length.
477 ph10 123
478     (b) When PCRE was configured to use the heap rather than the stack for
479     recursion during matching, it was not correctly preserving the data for
480     the other case of a UTF-8 character when checking ahead for a match
481     while processing a minimizing repeat. If the check also involved
482 ph10 115 matching a wide character, but failed, corruption could cause an
483     erroneous result when trying to check for a repeat of the original
484     character.
485 ph10 123
486 ph10 116 13. Some tidying changes to the testing mechanism:
487 ph10 98
488 ph10 116 (a) The RunTest script now detects the internal link size and whether there
489     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
490 ph10 123 values substituted by "configure". (The RunGrepTest script already did
491     this for UTF-8.) The configure.ac script no longer substitutes the
492     relevant variables.
494 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
495     with length and offset values. This means that the output is different
496     for different internal link sizes. Test 2 is skipped for link sizes
497     other than 2 because of this, bypassing the problem. Unfortunately,
498     there was also a test in test 3 (the locale tests) that used /B and
499 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
500     I have added a new /Z option to pcretest that replaces the length and
501     offset values with spaces. This is now used to make test 3 independent
502 ph10 122 of link size. (Test 2 will be tidied up later.)
503 ph10 123
504     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
505 ph10 122 segmentation fault instead of returning the appropriate error message.
506 ph10 134
507 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
508 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
509     This doesn't seem right; it now treats the CRLF combination as the line
510     ending, and so does not match in that case. It's only a pattern such as ^$
511     that would hit this one: something like ^ABC$ would have failed after \r
512     and then tried again after \r\n.
514 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
515 ph10 134 in an attempt to make files that differ only in their line terminators
516     compare equal. This works on Linux.
517 ph10 142
518 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
519     as it exited. This is now fixed, thanks to valgrind.
520 ph10 142
521 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
522 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
523     was because its rules for how to advance for /g after matching an empty
524 ph10 143 string at the end of a line did not allow for this case. They now check for
525     it specially.
526 ph10 150
527     20. pcretest is supposed to handle patterns and data of any length, by
528     extending its buffers when necessary. It was getting this wrong when the
529 ph10 147 buffer for a data line had to be extended.
530 ph10 150
531 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
532 ph10 150 CRLF as a newline sequence.
533 ph10 152
534 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
535 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
536     I have nevertheless tidied it up.
537 ph10 111
538 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
539 ph10 123
540 ph10 153 24. Added a man page for pcre-config.
541 ph10 152
542 ph10 153
543 nigel 93 Version 7.0 19-Dec-06
544     ---------------------
546     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
547     moving to gcc 4.1.1.
549     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
550     sys/time.h, which is documented as needed for this function. It doesn't
551     seem to matter on Linux, but it showed up on some releases of OS X.
553     3. It seems that there are systems where bytes whose values are greater than
554     127 match isprint() in the "C" locale. The "C" locale should be the
555     default when a C program starts up. In most systems, only ASCII printing
556     characters match isprint(). This difference caused the output from pcretest
557     to vary, making some of the tests fail. I have changed pcretest so that:
559     (a) When it is outputting text in the compiled version of a pattern, bytes
560     other than 32-126 are always shown as hex escapes.
562     (b) When it is outputting text that is a matched part of a subject string,
563     it does the same, unless a different locale has been set for the match
564     (using the /L modifier). In this case, it uses isprint() to decide.
566     4. Fixed a major bug that caused incorrect computation of the amount of memory
567     required for a compiled pattern when options that changed within the
568     pattern affected the logic of the preliminary scan that determines the
569     length. The relevant options are -x, and -i in UTF-8 mode. The result was
570     that the computed length was too small. The symptoms of this bug were
571     either the PCRE error "internal error: code overflow" from pcre_compile(),
572     or a glibc crash with a message such as "pcretest: free(): invalid next
573     size (fast)". Examples of patterns that provoked this bug (shown in
574     pcretest format) are:
576     /(?-x: )/x
577     /(?x)(?-x: \s*#\s*)/
578     /((?i)[\x{c0}])/8
579     /(?i:[\x{c0}])/8
581     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
582     is now done differently.
584     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
585     wrapper classes; (b) implement a new function in the C++ scanner that is
586     more efficient than the old way of doing things because it avoids levels of
587     recursion in the regex matching; (c) add a paragraph to the documentation
588     for the FullMatch() function.
590     6. The escape sequence \n was being treated as whatever was defined as
591     "newline". Not only was this contrary to the documentation, which states
592     that \n is character 10 (hex 0A), but it also went horribly wrong when
593     "newline" was defined as CRLF. This has been fixed.
595     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
596     was being set to -1 for the "end of line" case (supposedly a value that no
597     character can have). Though this value is never used (the check for end of
598     line is "zero bytes in current character"), it caused compiler complaints.
599     I've changed it to 0xffffffff.
601     8. In pcre_version.c, the version string was being built by a sequence of
602     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
603     string (as it is for production releases) called a macro with an empty
604     argument. The C standard says the result of this is undefined. The gcc
605     compiler treats it as an empty string (which was what was wanted) but it is
606     reported that Visual C gives an error. The source has been hacked around to
607     avoid this problem.
609     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
610     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
611     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
612     of them did).
614     10. Originally, pcretest opened its input and output without "b"; then I was
615     told that "b" was needed in some environments, so it was added for release
616     5.0 to both the input and output. (It makes no difference on Unix-like
617     systems.) Later I was told that it is wrong for the input on Windows. I've
618     now abstracted the modes into two macros, to make it easier to fiddle with
619     them, and removed "b" from the input mode under Windows.
621     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
623     12. Added -help and --help to pcretest as an official way of being reminded
624     of the options.
626     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
627     and pcrecpp.cc because they annoy compilers at high warning levels.
629     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
631     15. Fixed an occurrence of == in configure.ac that should have been = (shell
632     scripts are not C programs :-) and which was not noticed because it works
633     on Linux.
635     16. pcretest is supposed to handle any length of pattern and data line (as one
636     line or as a continued sequence of lines) by extending its input buffer if
637     necessary. This feature was broken for very long pattern lines, leading to
638     a string of junk being passed to pcre_compile() if the pattern was longer
639     than about 50K.
641     17. I have done a major re-factoring of the way pcre_compile() computes the
642     amount of memory needed for a compiled pattern. Previously, there was code
643     that made a preliminary scan of the pattern in order to do this. That was
644     OK when PCRE was new, but as the facilities have expanded, it has become
645     harder and harder to keep it in step with the real compile phase, and there
646     have been a number of bugs (see for example, 4 above). I have now found a
647     cunning way of running the real compile function in a "fake" mode that
648     enables it to compute how much memory it would need, while actually only
649     ever using a few hundred bytes of working memory and without too many
650     tests of the mode. This should make future maintenance and development
651     easier. A side effect of this work is that the limit of 200 on the nesting
652     depth of parentheses has been removed (though this was never a serious
653     limitation, I suspect). However, there is a downside: pcre_compile() now
654     runs more slowly than before (30% or more, depending on the pattern). I
655     hope this isn't a big issue. There is no effect on runtime performance.
657     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
658     newline (only possible for the last line of a file) and it was a
659     pattern that set a locale (followed by /Lsomething), pcretest crashed.
661     19. Added additional timing features to pcretest. (1) The -tm option now times
662     matching only, not compiling. (2) Both -t and -tm can be followed, as a
663     separate command line item, by a number that specifies the number of
664     repeats to use when timing. The default is 50000; this gives better
665     precision, but takes uncomfortably long for very large patterns.
667     20. Extended pcre_study() to be more clever in cases where a branch of a
668     subpattern has no definite first character. For example, (a*|b*)[cd] would
669     previously give no result from pcre_study(). Now it recognizes that the
670     first character must be a, b, c, or d.
672     21. There was an incorrect error "recursive call could loop indefinitely" if
673     a subpattern (or the entire pattern) that was being tested for matching an
674     empty string contained only one non-empty item after a nested subpattern.
675     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
676     incorrectly, because the \d was being skipped in the check.
678     22. The pcretest program now has a new pattern option /B and a command line
679     option -b, which is equivalent to adding /B to every pattern. This causes
680     it to show the compiled bytecode, without the additional information that
681     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
682     is the same as /B/I).
684     23. A new optimization is now able automatically to treat some sequences such
685     as a*b as a*+b. More specifically, if something simple (such as a character
686     or a simple class like \d) has an unlimited quantifier, and is followed by
687     something that cannot possibly match the quantified thing, the quantifier
688     is automatically "possessified".
690     24. A recursive reference to a subpattern whose number was greater than 39
691     went wrong under certain circumstances in UTF-8 mode. This bug could also
692     have affected the operation of pcre_study().
694     25. Realized that a little bit of performance could be had by replacing
695     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
697     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
699     27. Possessive quantifiers such as a++ were previously implemented by turning
700     them into atomic groups such as ($>a+). Now they have their own opcodes,
701     which improves performance. This includes the automatically created ones
702     from 23 above.
704     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
705     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
706     the first matched character to be a colon. This applied both to named and
707     numbered groups.
709     29. The ucpinternal.h header file was missing its idempotency #ifdef.
711     30. I was sent a "project" file called libpcre.a.dev which I understand makes
712     building PCRE on Windows easier, so I have included it in the distribution.
714     31. There is now a check in pcretest against a ridiculously large number being
715     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
716     loop, the loop is abandoned.
718     32. Forward references to subpatterns in conditions such as (?(2)...) where
719     subpattern 2 is defined later cause pcre_compile() to search forwards in
720     the pattern for the relevant set of parentheses. This search went wrong
721     when there were unescaped parentheses in a character class, parentheses
722     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
724     33. "Subroutine" calls and backreferences were previously restricted to
725     referencing subpatterns earlier in the regex. This restriction has now
726     been removed.
728     34. Added a number of extra features that are going to be in Perl 5.10. On the
729     whole, these are just syntactic alternatives for features that PCRE had
730     previously implemented using the Python syntax or my own invention. The
731     other formats are all retained for compatibility.
733     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
734     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
735     also .NET compatible.
737     (b) A recursion or subroutine call to a named group can now be defined as
738     (?&name) as well as (?P>name).
740     (c) A backreference to a named group can now be defined as \k<name> or
741     \k'name' as well as (?P=name). The new forms, as well as being in Perl
742     5.10, are also .NET compatible.
744     (d) A conditional reference to a named group can now use the syntax
745     (?(<name>) or (?('name') as well as (?(name).
747     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
748     groups (named and numbered) that are never evaluated inline, but can be
749     called as "subroutines" from elsewhere. In effect, the DEFINE condition
750     is always false. There may be only one alternative in such a group.
752     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
753     as the simple (?(R). The condition is true only if the most recent
754     recursion is that of the given number or name. It does not search out
755     through the entire recursion stack.
757     (g) The escape \gN or \g{N} has been added, where N is a positive or
758     negative number, specifying an absolute or relative reference.
760     35. Tidied to get rid of some further signed/unsigned compiler warnings and
761     some "unreachable code" warnings.
763     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
764     things, this adds five new scripts.
766     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
767     There were also incompatibilities regarding the handling of \Q..\E inside
768     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
769     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
771     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
772     matches an empty string, and forcibly breaks the loop. There were bugs in
773     this code in non-simple cases. For a pattern such as ^(a()*)* matched
774     against aaaa the result was just "a" rather than "aaaa", for example. Two
775     separate and independent bugs (that affected different cases) have been
776     fixed.
778     39. Refactored the code to abolish the use of different opcodes for small
779     capturing bracket numbers. This is a tidy that I avoided doing when I
780     removed the limit on the number of capturing brackets for 3.5 back in 2001.
781     The new approach is not only tidier, it makes it possible to reduce the
782     memory needed to fix the previous bug (38).
784     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
785     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
786     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
787     mode.
789     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
790     report.
792     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
793     copy construction and assignment in the C++ wrapper.
795     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
796     couple of bugs that could have given wrong results in the "--newline=crlf"
797     case.
799     44. Added a number of casts and did some reorganization of signed/unsigned int
800     variables following suggestions from Dair Grant. Also renamed the variable
801     "this" as "item" because it is a C++ keyword.
803     45. Arranged for dftables to add
805     #include "pcre_internal.h"
807     to pcre_chartables.c because without it, gcc 4.x may remove the array
808     definition from the final binary if PCRE is built into a static library and
809     dead code stripping is activated.
811     46. For an unanchored pattern, if a match attempt fails at the start of a
812     newline sequence, and the newline setting is CRLF or ANY, and the next two
813     characters are CRLF, advance by two characters instead of one.
816 nigel 91 Version 6.7 04-Jul-06
817     ---------------------
819     1. In order to handle tests when input lines are enormously long, pcretest has
820     been re-factored so that it automatically extends its buffers when
821     necessary. The code is crude, but this _is_ just a test program. The
822     default size has been increased from 32K to 50K.
824     2. The code in pcre_study() was using the value of the re argument before
825     testing it for NULL. (Of course, in any sensible call of the function, it
826     won't be NULL.)
828     3. The memmove() emulation function in pcre_internal.h, which is used on
829     systems that lack both memmove() and bcopy() - that is, hardly ever -
830     was missing a "static" storage class specifier.
832     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
833     containing an extended class (one that cannot be represented by a bitmap
834     because it contains high-valued characters or Unicode property items, e.g.
835     [\pZ]). Almost always one would set UTF-8 mode when processing such a
836     pattern, but PCRE should not loop if you do not (it no longer does).
837     [Detail: two cases were found: (a) a repeated subpattern containing an
838     extended class; (b) a recursive reference to a subpattern that followed a
839     previous extended class. It wasn't skipping over the extended class
840     correctly when UTF-8 mode was not set.]
842     5. A negated single-character class was not being recognized as fixed-length
843     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
844     compile error "lookbehind assertion is not fixed length".
846     6. The RunPerlTest auxiliary script was showing an unexpected difference
847     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
848     write a Perl script that can interpret lines of an input file either as
849     byte characters or as UTF-8, which is what "perltest" was being required to
850     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
851     can't do is switch easily at run time between having the "use utf8;" pragma
852     or not. In the end, I fudged it by using the RunPerlTest script to insert
853     "use utf8;" explicitly for the UTF-8 tests.
855     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
856     the end of the subject string, contrary to the documentation and to what
857     Perl does. This was true of both matching functions. Now it matches only at
858     the start of the subject and immediately after *internal* newlines.
860     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
861     a pointer to an int instead of a pointer to an unsigned long int. This
862     caused problems on 64-bit systems.
864     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
865     instance of the 'standard' template library not being so standard".
867     10. There was no check on the number of named subpatterns nor the maximum
868     length of a subpattern name. The product of these values is used to compute
869     the size of the memory block for a compiled pattern. By supplying a very
870     long subpattern name and a large number of named subpatterns, the size
871     computation could be caused to overflow. This is now prevented by limiting
872     the length of names to 32 characters, and the number of named subpatterns
873     to 10,000.
875     11. Subpatterns that are repeated with specific counts have to be replicated in
876     the compiled pattern. The size of memory for this was computed from the
877     length of the subpattern and the repeat count. The latter is limited to
878     65535, but there was no limit on the former, meaning that integer overflow
879     could in principle occur. The compiled length of a repeated subpattern is
880     now limited to 30,000 bytes in order to prevent this.
882     12. Added the optional facility to have named substrings with the same name.
884     13. Added the ability to use a named substring as a condition, using the
885     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
886     are numbers (not recommended). Forward references are permitted.
888     14. Added forward references in named backreferences (if you see what I mean).
890     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
891     pattern could run off the end of the subject. For example, the pattern
892     "(?s)(.{1,5})"8 did this with the subject "ab".
894     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
895     PCRE_CASELESS was set when matching characters that were quantified with ?
896     or *.
898     17. A character class other than a single negated character that had a minimum
899     but no maximum quantifier - for example [ab]{6,} - was not handled
900     correctly by pce_dfa_exec(). It would match only one character.
902     18. A valid (though odd) pattern that looked like a POSIX character
903     class but used an invalid character after [ (for example [[,abc,]]) caused
904     pcre_compile() to give the error "Failed: internal error: code overflow" or
905     in some cases to crash with a glibc free() error. This could even happen if
906     the pattern terminated after [[ but there just happened to be a sequence of
907     letters, a binary zero, and a closing ] in the memory that followed.
909     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
910     over the years. Originally (before any Unicode support), just the bottom 8
911     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
912     output from "man perlunicode" includes this:
914     The regular expression compiler produces polymorphic opcodes. That
915     is, the pattern adapts to the data and automatically switches to
916     the Unicode character scheme when presented with Unicode data--or
917     instead uses a traditional byte scheme when presented with byte
918     data.
920     Sadly, a wide octal escape does not cause a switch, and in a string with
921     no other multibyte characters, these octal escapes are treated as before.
922     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
923     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
924     Unicode string.
926     I have not perpetrated such confusion in PCRE. Up till now, it took just
927     the bottom 8 bits, as in old Perl. I have now made octal escapes with
928     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
929     translate to the appropriate multibyte character.
931     29. Applied some refactoring to reduce the number of warnings from Microsoft
932     and Borland compilers. This has included removing the fudge introduced
933     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
934     a warning about an unused variable.
936     21. PCRE has not included VT (character 0x0b) in the set of whitespace
937     characters since release 4.0, because Perl (from release 5.004) does not.
938     [Or at least, is documented not to: some releases seem to be in conflict
939     with the documentation.] However, when a pattern was studied with
940     pcre_study() and all its branches started with \s, PCRE still included VT
941     as a possible starting character. Of course, this did no harm; it just
942     caused an unnecessary match attempt.
944     22. Removed a now-redundant internal flag bit that recorded the fact that case
945     dependency changed within the pattern. This was once needed for "required
946     byte" processing, but is no longer used. This recovers a now-scarce options
947     bit. Also moved the least significant internal flag bit to the most-
948     significant bit of the word, which was not previously used (hangover from
949     the days when it was an int rather than a uint) to free up another bit for
950     the future.
952     23. Added support for CRLF line endings as well as CR and LF. As well as the
953     default being selectable at build time, it can now be changed at runtime
954     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
955     specify that it is scanning data with non-default line endings.
957     24. Changed the definition of CXXLINK to make it agree with the definition of
958     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
960     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
961     recursions. This makes a big different to stack usage for some patterns.
963     26. If a subpattern containing a named recursion or subroutine reference such
964     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
965     the space required for the compiled pattern went wrong and gave too small a
966     value. Depending on the environment, this could lead to "Failed: internal
967     error: code overflow at offset 49" or "glibc detected double free or
968     corruption" errors.
970     27. Applied patches from Google (a) to support the new newline modes and (b) to
971     advance over multibyte UTF-8 characters in GlobalReplace.
973     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
974     difference for some implementation of PCRE in some Windows version.
976     29. Added some extra testing facilities to pcretest:
978     \q<number> in a data line sets the "match limit" value
979     \Q<number> in a data line sets the "match recursion limt" value
980     -S <number> sets the stack size, where <number> is in megabytes
982     The -S option isn't available for Windows.
985 nigel 89 Version 6.6 06-Feb-06
986     ---------------------
988     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
989     in pcreposix.h. I have copied the definition from pcre.h.
991     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
992     because pcre.h is no longer a built file.
994     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
995     not normally included in the compiled code.
998 nigel 87 Version 6.5 01-Feb-06
999     ---------------------
1001     1. When using the partial match feature with pcre_dfa_exec(), it was not
1002     anchoring the second and subsequent partial matches at the new starting
1003     point. This could lead to incorrect results. For example, with the pattern
1004     /1234/, partially matching against "123" and then "a4" gave a match.
1006     2. Changes to pcregrep:
1008     (a) All non-match returns from pcre_exec() were being treated as failures
1009     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1010     error message is output. Some extra information is given for the
1012     probably the only errors that are likely to be caused by users (by
1013     specifying a regex that has nested indefinite repeats, for instance).
1014     If there are more than 20 of these errors, pcregrep is abandoned.
1016     (b) A binary zero was treated as data while matching, but terminated the
1017     output line if it was written out. This has been fixed: binary zeroes
1018     are now no different to any other data bytes.
1020     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1021     used to set a locale for matching. The --locale=xxxx long option has
1022     been added (no short equivalent) to specify a locale explicitly on the
1023     pcregrep command, overriding the environment variables.
1025     (d) When -B was used with -n, some line numbers in the output were one less
1026     than they should have been.
1028     (e) Added the -o (--only-matching) option.
1030     (f) If -A or -C was used with -c (count only), some lines of context were
1031     accidentally printed for the final match.
1033     (g) Added the -H (--with-filename) option.
1035     (h) The combination of options -rh failed to suppress file names for files
1036     that were found from directory arguments.
1038     (i) Added the -D (--devices) and -d (--directories) options.
1040     (j) Added the -F (--fixed-strings) option.
1042     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1044     (l) Added the --colo(u)r option.
1046     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1047     is not present by default.
1049     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1050     items such as (?R) or (?1), when the recursion could match a number of
1051     alternatives. If it matched one of the alternatives, but subsequently,
1052     outside the recursion, there was a failure, the code tried to back up into
1053     the recursion. However, because of the way PCRE is implemented, this is not
1054     possible, and the result was an incorrect result from the match.
1056     In order to prevent this happening, the specification of recursion has
1057     been changed so that all such subpatterns are automatically treated as
1058     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1060     4. I had overlooked the fact that, in some locales, there are characters for
1061     which isalpha() is true but neither isupper() nor islower() are true. In
1062     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1063     and ordfeminine) are like this. This affected the treatment of \w and \W
1064     when they appeared in character classes, but not when they appeared outside
1065     a character class. The bit map for "word" characters is now created
1066     separately from the results of isalnum() instead of just taking it from the
1067     upper, lower, and digit maps. (Plus the underscore character, of course.)
1069     5. The above bug also affected the handling of POSIX character classes such as
1070     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1071     permanent tables. Instead, the bit maps for such a class were previously
1072     created as the appropriate unions of the upper, lower, and digit bitmaps.
1073     Now they are created by subtraction from the [[:word:]] class, which has
1074     its own bitmap.
1076     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1077     It is created by subtracting the vertical space characters (\x09, \x0a,
1078     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1079     subtraction was done in the overall bitmap for a character class, meaning
1080     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1081     be recognized. This bug has been fixed.
1083     7. Patches from the folks at Google:
1085     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1086     real life, but is still worth protecting against".
1088     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1089     regular expressions".
1091     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1092     have it.
1094     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1095     "configure" and the latter not, in order to fix a problem somebody had
1096     with compiling the Arg class on HP-UX.
1098     (e) Improve the error-handling of the C++ wrapper a little bit.
1100     (f) New tests for checking recursion limiting.
1102     8. The pcre_memmove() function, which is used only if the environment does not
1103     have a standard memmove() function (and is therefore rarely compiled),
1104     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1105     returning a result (though PCRE never actually uses the result).
1107     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1108     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1109     returned instead of calling malloc() with an overflowing number that would
1110     most likely cause subsequent chaos.
1112     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1114     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1115     with this option is matched, the nmatch and pmatch options of regexec() are
1116     ignored.
1118     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1119     provided in case anyone wants to the the POSIX interface with UTF-8
1120     strings.
1122     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1123     C++ linking (needed for some HP-UX environments).
1125     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1126     (unused parameter) and in the pcre_printint() function (omitted "default"
1127     switch label when the default is to do nothing).
1129     15. Added some code to make it possible, when PCRE is compiled as a C++
1130     library, to replace subject pointers for pcre_exec() with a smart pointer
1131     class, thus making it possible to process discontinuous strings.
1133     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1134     much the same function. They were added by different people who were trying
1135     to make PCRE easy to compile on non-Unix systems. It has been suggested
1136     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1137     for compiling on Windows systems. I have therefore replaced it with
1138     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1139     defaults to "extern" for C or "extern C" for C++, which works fine on
1140     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1141     SCOPE with something explicit in config.h. In addition:
1143     (a) pcreposix.h still had just "extern" instead of either of these macros;
1144     I have replaced it with PCRE_DATA_SCOPE.
1146     (b) Functions such as _pcre_xclass(), which are internal to the library,
1147     but external in the C sense, all had PCRE_EXPORT in their definitions.
1148     This is apparently wrong for the Windows case, so I have removed it.
1149     (It makes no difference on Unix-like systems.)
1151     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1152     of recursive calls to match(). This is different to MATCH_LIMIT because
1153     that limits the total number of calls to match(), not all of which increase
1154     the depth of recursion. Limiting the recursion depth limits the amount of
1155     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1156     when PCRE is compiled, and changed at run time. A patch from Google adds
1157     this functionality to the C++ interface.
1159     18. Changes to the handling of Unicode character properties:
1161     (a) Updated the table to Unicode 4.1.0.
1163     (b) Recognize characters that are not in the table as "Cn" (undefined).
1165     (c) I revised the way the table is implemented to a much improved format
1166     which includes recognition of ranges. It now supports the ranges that
1167     are defined in UnicodeData.txt, and it also amalgamates other
1168     characters into ranges. This has reduced the number of entries in the
1169     table from around 16,000 to around 3,000, thus reducing its size
1170     considerably. I realized I did not need to use a tree structure after
1171     all - a binary chop search is just as efficient. Having reduced the
1172     number of entries, I extended their size from 6 bytes to 8 bytes to
1173     allow for more data.
1175     (d) Added support for Unicode script names via properties such as \p{Han}.
1177     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1178     matching that character.
1180     20. When matching a repeated Unicode property with a minimum greater than zero,
1181     (for example \pL{2,}), PCRE could look past the end of the subject if it
1182     reached it while seeking the minimum number of characters. This could
1183     happen only if some of the characters were more than one byte long, because
1184     there is a check for at least the minimum number of bytes.
1186     21. Refactored the implementation of \p and \P so as to be more general, to
1187     allow for more different types of property in future. This has changed the
1188     compiled form incompatibly. Anybody with saved compiled patterns that use
1189     \p or \P will have to recompile them.
1191     22. Added "Any" and "L&" to the supported property types.
1193     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1194     but give a compile time error if the value is greater than 0xff.
1196     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1197     accidentally not being installed or uninstalled.
1199     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1200     made were to insert the current release number. This seemed silly, because
1201     it made things harder for people building PCRE on systems that don't run
1202     "configure". I have turned pcre.h into a distributed file, no longer built
1203     by "configure", with the version identification directly included. There is
1204     no longer a pcre.h.in file.
1206     However, this change necessitated a change to the pcre-config script as
1207     well. It is built from pcre-config.in, and one of the substitutions was the
1208     release number. I have updated configure.ac so that ./configure now finds
1209     the release number by grepping pcre.h.
1211     26. Added the ability to run the tests under valgrind.
1214 nigel 85 Version 6.4 05-Sep-05
1215     ---------------------
1217     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1218     "--" to be printed when multiple files were scanned, even when none of the
1219     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1220     consider it to be a bug, and have restored the previous behaviour.
1222     2. A couple of code tidies to get rid of compiler warnings.
1224     3. The pcretest program used to cheat by referring to symbols in the library
1225     whose names begin with _pcre_. These are internal symbols that are not
1226     really supposed to be visible externally, and in some environments it is
1227     possible to suppress them. The cheating is now confined to including
1228     certain files from the library's source, which is a bit cleaner.
1230     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1231     file's purpose clearer.
1233     5. Reorganized pcre_ucp_findchar().
1236 nigel 83 Version 6.3 15-Aug-05
1237     ---------------------
1239     1. The file libpcre.pc.in did not have general read permission in the tarball.
1241     2. There were some problems when building without C++ support:
1243     (a) If C++ support was not built, "make install" and "make test" still
1244     tried to test it.
1246     (b) There were problems when the value of CXX was explicitly set. Some
1247     changes have been made to try to fix these, and ...
1249     (c) --disable-cpp can now be used to explicitly disable C++ support.
1251     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1252     backslash in a target when C++ was disabled. This confuses some
1253     versions of "make", apparently. Using an intermediate variable solves
1254     this. (Same for CPP_LOBJ.)
1256     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1257     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1258     necessary on certain architectures.
1260     4. Added a setting of -export-symbols-regex to the link command to remove
1261     those symbols that are exported in the C sense, but actually are local
1262     within the library, and not documented. Their names all begin with
1263     "_pcre_". This is not a perfect job, because (a) we have to except some
1264     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1265     available (and never for static libraries). I have made a note to try to
1266     find a way round (a) in the future.
1269 nigel 81 Version 6.2 01-Aug-05
1270     ---------------------
1272     1. There was no test for integer overflow of quantifier values. A construction
1273     such as {1111111111111111} would give undefined results. What is worse, if
1274     a minimum quantifier for a parenthesized subpattern overflowed and became
1275     negative, the calculation of the memory size went wrong. This could have
1276     led to memory overwriting.
1278     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1280     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1281     operating environments where this matters.
1283     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1284     PCRE options from within the C++ wrapper.
1286     5. Named capturing subpatterns were not being correctly counted when a pattern
1287     was compiled. This caused two problems: (a) If there were more than 100
1288     such subpatterns, the calculation of the memory needed for the whole
1289     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1290     back references of the form \12, where the number was greater than 9, were
1291     not recognized as back references, even though there were sufficient
1292     previous subpatterns.
1294     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1295     versions of gcc, e.g. 2.95.4.
1298 nigel 79 Version 6.1 21-Jun-05
1299     ---------------------
1301     1. There was one reference to the variable "posix" in pcretest.c that was not
1302     surrounded by "#if !defined NOPOSIX".
1304     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1305     the cross-check on the old pcre_info() function, for the benefit of the
1306     cut-down version of PCRE that is currently imported into Exim.
1308     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1309     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1310     patterns that start (?i) but I don't think that matters. The use of (?i) is
1311     just an example; this all applies to the other options as well.
1313     4. Since libtool seems to echo the compile commands it is issuing, the output
1314     from "make" can be reduced a bit by putting "@" in front of each libtool
1315     compile command.
1317     5. Patch from the folks at Google for configure.in to be a bit more thorough
1318     in checking for a suitable C++ installation before trying to compile the
1319     C++ stuff. This should fix a reported problem when a compiler was present,
1320     but no suitable headers.
1322     6. The man pages all had just "PCRE" as their title. I have changed them to
1323     be the relevant file name. I have also arranged that these names are
1324     retained in the file doc/pcre.txt, which is a concatenation in text format
1325     of all the man pages except the little individual ones for each function.
1327     7. The NON-UNIX-USE file had not been updated for the different set of source
1328     files that come with release 6. I also added a few comments about the C++
1329     wrapper.
1332 nigel 77 Version 6.0 07-Jun-05
1333     ---------------------
1335     1. Some minor internal re-organization to help with my DFA experiments.
1337     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1338     didn't matter for the library itself when fully configured, but did matter
1339     when compiling without UCP support, or within Exim, where the ucp files are
1340     not imported.
1342     3. Refactoring of the library code to split up the various functions into
1343     different source modules. The addition of the new DFA matching code (see
1344     below) to a single monolithic source would have made it really too
1345     unwieldy, quite apart from causing all the code to be include in a
1346     statically linked application, when only some functions are used. This is
1347     relevant even without the DFA addition now that patterns can be compiled in
1348     one application and matched in another.
1350     The downside of splitting up is that there have to be some external
1351     functions and data tables that are used internally in different modules of
1352     the library but which are not part of the API. These have all had their
1353     names changed to start with "_pcre_" so that they are unlikely to clash
1354     with other external names.
1356     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1357     a different (DFA) algorithm. Although it is slower than the original
1358     function, it does have some advantages for certain types of matching
1359     problem.
1361     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1362     including restarting after a partial match.
1364     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1365     defined when compiling for Windows was sent to me. I have put it into the
1366     code, though I have no means of testing or verifying it.
1368     7. Added the pcre_refcount() auxiliary function.
1370     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1371     match before or at the first newline in the subject string. In pcretest,
1372     the /f option on a pattern can be used to set this.
1374     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1375     would behave wrongly. This has been present in PCRE since release 4.0.
1377     10. A number of changes to the pcregrep command:
1379     (a) Refactored how -x works; insert ^(...)$ instead of setting
1380     PCRE_ANCHORED and checking the length, in preparation for adding
1381     something similar for -w.
1383     (b) Added the -w (match as a word) option.
1385     (c) Refactored the way lines are read and buffered so as to have more
1386     than one at a time available.
1388     (d) Implemented a pcregrep test script.
1390     (e) Added the -M (multiline match) option. This allows patterns to match
1391     over several lines of the subject. The buffering ensures that at least
1392     8K, or the rest of the document (whichever is the shorter) is available
1393     for matching (and similarly the previous 8K for lookbehind assertions).
1395     (f) Changed the --help output so that it now says
1397     -w, --word-regex(p)
1399     instead of two lines, one with "regex" and the other with "regexp"
1400     because that confused at least one person since the short forms are the
1401     same. (This required a bit of code, as the output is generated
1402     automatically from a table. It wasn't just a text change.)
1404     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1405     option but starts with a hyphen. Could be a pattern or a path name
1406     starting with a hyphen, for instance.
1408     (h) "-" can be given as a file name to represent stdin.
1410     (i) When file names are being printed, "(standard input)" is used for
1411     the standard input, for compatibility with GNU grep. Previously
1412     "<stdin>" was used.
1414     (j) The option --label=xxx can be used to supply a name to be used for
1415     stdin when file names are being printed. There is no short form.
1417     (k) Re-factored the options decoding logic because we are going to add
1418     two more options that take data. Such options can now be given in four
1419     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1421     (l) Added the -A, -B, and -C options for requesting that lines of context
1422     around matches be printed.
1424     (m) Added the -L option to print the names of files that do not contain
1425     any matching lines, that is, the complement of -l.
1427     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1428     continue to scan other files.
1430     (o) The -s option was incorrectly implemented. For compatibility with other
1431     greps, it now suppresses the error message for a non-existent or non-
1432     accessible file (but not the return code). There is a new option called
1433     -q that suppresses the output of matching lines, which was what -s was
1434     previously doing.
1436     (p) Added --include and --exclude options to specify files for inclusion
1437     and exclusion when recursing.
1439     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1440     Hopefully, it now does.
1442     12. Missing cast in pcre_study().
1444     13. Added an "uninstall" target to the makefile.
1446     14. Replaced "extern" in the function prototypes in Makefile.in with
1447     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1448     world, but is set differently for Windows.
1450     15. Added a second compiling function called pcre_compile2(). The only
1451     difference is that it has an extra argument, which is a pointer to an
1452     integer error code. When there is a compile-time failure, this is set
1453     non-zero, in addition to the error test pointer being set to point to an
1454     error message. The new argument may be NULL if no error number is required
1455     (but then you may as well call pcre_compile(), which is now just a
1456     wrapper). This facility is provided because some applications need a
1457     numeric error indication, but it has also enabled me to tidy up the way
1458     compile-time errors are handled in the POSIX wrapper.
1460     16. Added VPATH=.libs to the makefile; this should help when building with one
1461     prefix path and installing with another. (Or so I'm told by someone who
1462     knows more about this stuff than I do.)
1464     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1465     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1466     match everything, including newlines. This is not POSIX-compatible, but
1467     somebody wanted the feature. From pcretest it can be activated by using
1468     both the P and the s flags.
1470     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1472     19. libpcre.pc was being incorrectly installed as executable.
1474     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1475     it now also looks for '\r' so that it will work unmodified on Windows.
1477     21. Added Google's contributed C++ wrapper to the distribution.
1479     22. Added some untidy missing memory free() calls in pcretest, to keep
1480     Electric Fence happy when testing.
1484 nigel 75 Version 5.0 13-Sep-04
1485     ---------------------
1487     1. Internal change: literal characters are no longer packed up into items
1488     containing multiple characters in a single byte-string. Each character
1489     is now matched using a separate opcode. However, there may be more than one
1490     byte in the character in UTF-8 mode.
1492     2. The pcre_callout_block structure has two new fields: pattern_position and
1493     next_item_length. These contain the offset in the pattern to the next match
1494     item, and its length, respectively.
1496     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1497     insertion of callouts before each pattern item. Added the /C option to
1498     pcretest to make use of this.
1500     4. On the advice of a Windows user, the lines
1502     #if defined(_WIN32) || defined(WIN32)
1503     _setmode( _fileno( stdout ), 0x8000 );
1504     #endif /* defined(_WIN32) || defined(WIN32) */
1506     have been added to the source of pcretest. This apparently does useful
1507     magic in relation to line terminators.
1509     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1510     for the benefit of those environments where the "b" makes a difference.
1512     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1513     to know about it. I have put a hack into configure.in that adds in code
1514     to set GCC=yes if CC=icc. This seems to end up at a point in the
1515     generated configure script that is early enough to affect the setting of
1516     compiler options, which is what is needed, but I have no means of testing
1517     whether it really works. (The user who reported this had patched the
1518     generated configure script, which of course I cannot do.)
1520     LATER: After change 22 below (new libtool files), the configure script
1521     seems to know about icc (and also ecc). Therefore, I have commented out
1522     this hack in configure.in.
1524     7. Added support for pkg-config (2 patches were sent in).
1526     8. Negated POSIX character classes that used a combination of internal tables
1527     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1528     [[:^ascii]]. Typically, they would match almost any characters. The other
1529     POSIX classes were not broken in this way.
1531     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1532     to find the match, as PCRE was deluded into thinking that the match had to
1533     start at the start point or following a newline. The same bug applied to
1534     patterns with negative forward assertions or any backward assertions
1535     preceding ".*" at the start, unless the pattern required a fixed first
1536     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1538     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1539     starting at the last subject character, bytes beyond the end of the subject
1540     string were read.
1542     11. Renamed the variable "class" as "classbits" to make life easier for C++
1543     users. (Previously there was a macro definition, but it apparently wasn't
1544     enough.)
1546     12. Added the new field "tables" to the extra data so that tables can be passed
1547     in at exec time, or the internal tables can be re-selected. This allows
1548     a compiled regex to be saved and re-used at a later time by a different
1549     program that might have everything at different addresses.
1551     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1552     -R library as well as a -L library.
1554     14. The debugging options of pcretest (-d on the command line or D on a
1555     pattern) showed incorrect output for anything following an extended class
1556     that contained multibyte characters and which was followed by a quantifier.
1558     15. Added optional support for general category Unicode character properties
1559     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1560     support. It adds about 90K to the size of the library. The meanings of the
1561     inbuilt class escapes such as \d and \s have NOT been changed.
1563     16. Updated pcredemo.c to include calls to free() to release the memory for the
1564     compiled pattern.
1566     17. The generated file chartables.c was being created in the source directory
1567     instead of in the building directory. This caused the build to fail if the
1568     source directory was different from the building directory, and was
1569     read-only.
1571     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1572     file. No doubt somebody will tell me if they don't make sense... Also added
1573     Dan Mooney's comments about building on OpenVMS.
1575     19. Added support for partial matching via the PCRE_PARTIAL option for
1576     pcre_exec() and the \P data escape in pcretest.
1578     20. Extended pcretest with 3 new pattern features:
1580     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1581     write the compiled pattern to the file whose name is "rest-of-line".
1582     This is a straight binary dump of the data, with the saved pointer to
1583     the character tables forced to be NULL. The study data, if any, is
1584     written too. After writing, pcretest reads a new pattern.
1586     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1587     compiled pattern from the given file. There must not be any
1588     occurrences of "<" in the file name (pretty unlikely); if there are,
1589     pcretest will instead treat the initial "<" as a pattern delimiter.
1590     After reading in the pattern, pcretest goes on to read data lines as
1591     usual.
1593     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1594     and 16-bit fields in a compiled pattern, to simulate a pattern that
1595     was compiled on a host of opposite endianness.
1597     21. The pcre-exec() function can now cope with patterns that were compiled on
1598     hosts of opposite endianness, with this restriction:
1600     As for any compiled expression that is saved and used later, the tables
1601     pointer field cannot be preserved; the extra_data field in the arguments
1602     to pcre_exec() should be used to pass in a tables address if a value
1603     other than the default internal tables were used at compile time.
1605     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1606     now diagnosed as an error. Previously, most of the time, a negative number
1607     would have been treated as zero, but if in addition "ovector" was passed as
1608     NULL, a crash could occur.
1610     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1611     new versions from the libtool 1.5 distribution (the last one is a copy of
1612     a file called libtool.m4). This seems to have fixed the need to patch
1613     "configure" to support Darwin 1.3 (which I used to do). However, I still
1614     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1615     workstation).
1617     24. Changed the PCRE licence to be the more standard "BSD" licence.
1620 nigel 73 Version 4.5 01-Dec-03
1621     ---------------------
1623     1. There has been some re-arrangement of the code for the match() function so
1624     that it can be compiled in a version that does not call itself recursively.
1625     Instead, it keeps those local variables that need separate instances for
1626     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1627     needs to "recurse". Keeping track of where control must go is done by means
1628     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1629     hide most of the details from the main code, and operates only if
1630     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1631     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1632     operating.
1634     To make it easier for callers to provide specially tailored get/free
1635     functions for this usage, two new functions, pcre_stack_malloc, and
1636     pcre_stack_free, are used. They are always called in strict stacking order,
1637     and the size of block requested is always the same.
1639     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1640     PCRE has been compiled to use the stack or the heap for recursion. The
1641     -C option of pcretest uses this to show which version is compiled.
1643     A new data escape \S, is added to pcretest; it causes the amounts of store
1644     obtained and freed by both kinds of malloc/free at match time to be added
1645     to the output.
1647     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1648     what's available on my current Linux desktop machine.
1650     3. When matching a UTF-8 string, the test for a valid string at the start has
1651     been extended. If start_offset is not zero, PCRE now checks that it points
1652     to a byte that is the start of a UTF-8 character. If not, it returns
1653     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1654     this is necessary because there may be backward assertions in the pattern.
1655     When matching the same subject several times, it may save resources to use
1656     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1658     4. The code for checking the validity of UTF-8 strings has been tightened so
1659     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1660     containing "overlong sequences".
1662     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1663     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1664     should have been "&", but it just so happened that all the cases this let
1665     through by mistake were picked up later in the function.
1667     6. I had used a variable called "isblank" - this is a C99 function, causing
1668     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1670     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1671     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1672     so the version is shown; (c) stop "make test" echoing "./RunTest".
1674     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1676     9. The prototype for memmove() for systems that don't have it was using
1677     size_t, but the inclusion of the header that defines size_t was later. I've
1678     moved the #includes for the C headers earlier to avoid this.
1680     10. Added some adjustments to the code to make it easier to compiler on certain
1681     special systems:
1683     (a) Some "const" qualifiers were missing.
1684     (b) Added the macro EXPORT before all exported functions; by default this
1685     is defined to be empty.
1686     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1687     that it reads its output file name as an argument instead of writing
1688     to the standard output and assuming this can be redirected.
1690     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1691     class containing characters with values greater than 255, PCRE compilation
1692     went into a loop.
1694     12. A recursive reference to a subpattern that was within another subpattern
1695     that had a minimum quantifier of zero caused PCRE to crash. For example,
1696     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1697     recursion. If the recursively-called subpattern itself had a zero repeat,
1698     that was OK.
1700     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1701     buffer into which it was copied (for escape processing) was still set at
1702     1024, so long lines caused crashes.
1704     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1705     "internal error: code overflow...". This applied to any character class
1706     that was followed by a possessive quantifier.
1708     15. Modified the Makefile to add libpcre.la as a prerequisite for
1709     libpcreposix.la because I was told this is needed for a parallel build to
1710     work.
1712     16. If a pattern that contained .* following optional items at the start was
1713     studied, the wrong optimizing data was generated, leading to matching
1714     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1715     matching string must start with a or b or c. The correct conclusion for
1716     this pattern is that a match can start with any character.
1719 nigel 71 Version 4.4 13-Aug-03
1720     ---------------------
1722     1. In UTF-8 mode, a character class containing characters with values between
1723     127 and 255 was not handled correctly if the compiled pattern was studied.
1724     In fixing this, I have also improved the studying algorithm for such
1725     classes (slightly).
1727     2. Three internal functions had redundant arguments passed to them. Removal
1728     might give a very teeny performance improvement.
1730     3. Documentation bug: the value of the capture_top field in a callout is *one
1731     more than* the number of the hightest numbered captured substring.
1733     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1734     in incorrectly linking with a previously installed version. They now link
1735     explicitly with libpcre.la.
1737     5. configure.in no longer needs to recognize Cygwin specially.
1739     6. A problem in pcre.in for Windows platforms is fixed.
1741     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1742     pcretest, it used to include the size of the study block as part of its
1743     output. Unfortunately, the structure contains a field that has a different
1744     size on different hardware architectures. This meant that the tests that
1745     showed this size failed. As the block is currently always of a fixed size,
1746     this information isn't actually particularly useful in pcretest output, so
1747     I have just removed it.
1749     8. Three pre-processor statements accidentally did not start in column 1.
1750     Sadly, there are *still* compilers around that complain, even though
1751     standard C has not required this for well over a decade. Sigh.
1753     9. In pcretest, the code for checking callouts passed small integers in the
1754     callout_data field, which is a void * field. However, some picky compilers
1755     complained about the casts involved for this on 64-bit systems. Now
1756     pcretest passes the address of the small integer instead, which should get
1757     rid of the warnings.
1759     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1760     both compile and run time, and gives an error if an invalid UTF-8 sequence
1761     is found. There is a option for disabling this check in cases where the
1762     string is known to be correct and/or the maximum performance is wanted.
1764     11. In response to a bug report, I changed one line in Makefile.in from
1766     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1767     to
1768     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1770     to look similar to other lines, but I have no way of telling whether this
1771     is the right thing to do, as I do not use Windows. No doubt I'll get told
1772     if it's wrong...
1775 nigel 69 Version 4.3 21-May-03
1776     ---------------------
1778     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1779     Makefile.
1781     2. Some refactoring to improve the quality of the code:
1783     (i) The utf8_table... variables are now declared "const".
1785     (ii) The code for \cx, which used the "case flipping" table to upper case
1786     lower case letters, now just substracts 32. This is ASCII-specific,
1787     but the whole concept of \cx is ASCII-specific, so it seems
1788     reasonable.
1790     (iii) PCRE was using its character types table to recognize decimal and
1791     hexadecimal digits in the pattern. This is silly, because it handles
1792     only 0-9, a-f, and A-F, but the character types table is locale-
1793     specific, which means strange things might happen. A private
1794     table is now used for this - though it costs 256 bytes, a table is
1795     much faster than multiple explicit tests. Of course, the standard
1796     character types table is still used for matching digits in subject
1797     strings against \d.
1799     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1800     ending in _t are). So I've renamed it as ESC_tee.
1802     3. The first argument for regexec() in the POSIX wrapper should have been
1803     defined as "const".
1805     4. Changed pcretest to use malloc() for its buffers so that they can be
1806     Electric Fenced for debugging.
1808     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1809     to read one or more bytes before the start of the subject string. Often this
1810     had no effect on PCRE's behaviour, but in some circumstances it could
1811     provoke a segmentation fault.
1813     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1814     to try to read one or more bytes before the start of the subject string.
1816     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1817     UTF-8 support could misbehave in various ways if the subject string
1818     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1819     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1820     back over UTF-8 characters.)
1823 nigel 67 Version 4.2 14-Apr-03
1824     ---------------------
1826     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1828     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1829     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1830     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1831     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1832     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1833     and BUILD_EXEEXT
1834     Note: automatic setting of the BUILD variables is not yet working
1835     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1836     compile-time but not at link-time
1837     [LINK]: use for linking executables only
1838     make different versions for Windows and non-Windows
1839     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1840     libraries
1841     [LINK_FOR_BUILD]: new variable
1842     [OBJEXT]: use throughout
1843     [EXEEXT]: use throughout
1844     <winshared>: new target
1845     <wininstall>: new target
1846     <dftables.o>: use native compiler
1847     <dftables>: use native linker
1848     <install>: handle Windows platform correctly
1849     <clean>: ditto
1850     <check>: ditto
1851     copy DLL to top builddir before testing
1853     As part of these changes, -no-undefined was removed again. This was reported
1854     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1855     in any case.
1857     3. Some tidies to get rid of compiler warnings:
1859     . In the match_data structure, match_limit was an unsigned long int, whereas
1860     match_call_count was an int. I've made them both unsigned long ints.
1862     . In pcretest the fact that a const uschar * doesn't automatically cast to
1863     a void * provoked a warning.
1865     . Turning on some more compiler warnings threw up some "shadow" variables
1866     and a few more missing casts.
1868     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1869     option, a class that contained a single character with a value between 128
1870     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1872     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1873     option, a class that contained several characters, but with at least one
1874     whose value was between 128 and 255 caused PCRE to crash.
1877 nigel 65 Version 4.1 12-Mar-03
1878     ---------------------
1879 nigel 63
1880 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1881     needed, and a string in dftables.c that was longer than standard compilers are
1882     required to support.
1884     2. Compiling with Sun's compiler found a few more places where the code could
1885     be tidied up in order to avoid warnings.
1887     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1888     first of these names is deprecated in the latest Autoconf in favour of the name
1889     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1890     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1891     analogy I have changed it to CFLAGS_FOR_BUILD.
1893     4. Added -no-undefined to the linking command in the Makefile, because this is
1894     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1895     linking step for the pcreposix library.
1897     5. PCRE was failing to diagnose the case of two named groups with the same
1898     name.
1900     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1901     literal character that is needed in the subject for a match, and scans along to
1902     ensure that it is present before embarking on the full matching process. This
1903     saves time in cases of nested unlimited repeats that are never going to match.
1904     Problem: the scan can take a lot of time if the subject is very long (e.g.
1905     megabytes), thus penalizing straightforward matches. It is now done only if the
1906     amount of subject to be scanned is less than 1000 bytes.
1908     7. A lesser problem with the same optimization is that it was recording the
1909     first character of an anchored pattern as "needed", thus provoking a search
1910     right along the subject, even when the first match of the pattern was going to
1911     fail. The "needed" character is now not set for anchored patterns, unless it
1912     follows something in the pattern that is of non-fixed length. Thus, it still
1913     fulfils its original purpose of finding quick non-matches in cases of nested
1914     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1917     Version 4.0 17-Feb-03
1918     ---------------------
1920 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1921     extended to the end of string, PCRE compiled incorrect data. This could lead to
1922     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1924     2. Moved to autoconf 2.53 and libtool 1.4.2.
1926     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1927     the special perltest8 script is no longer needed - all the tests can be run
1928     from a single perltest script.
1930     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1931     by \s. It has now been removed in PCRE. This means it isn't recognized as
1932     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1933     class [:space:] *does* include VT, thereby creating a mess.
1935     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1936     space and tab.
1938     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1939     its new features into the main test script, reducing the number of scripts.
1941     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1942     were backward compatible, and made the (?i) apply to the whole pattern, as if
1943     /i were given. Now it behaves more logically, and applies the option setting
1944     only to what follows. PCRE has been changed to follow suit. However, if it
1945     finds options settings right at the start of the pattern, it extracts them into
1946     the global options, as before. Thus, they show up in the info data.
1948     8. Added support for the \Q...\E escape sequence. Characters in between are
1949     treated as literals. This is slightly different from Perl in that $ and @ are
1950     also handled as literals inside the quotes. In Perl, they will cause variable
1951     interpolation. Note the following examples:
1953     Pattern PCRE matches Perl matches
1955     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1956     \Qabc\$xyz\E abc\$xyz abc\$xyz
1957     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1959     For compatibility with Perl, \Q...\E sequences are recognized inside character
1960     classes as well as outside them.
1962     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1963     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1964     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1965     signed/unsigned warnings.
1967     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1968     option for pcretest, so I've replaced it by a simple function that does just
1969     that job.
1971     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1972     "pcregrep -".
1974     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1975     Java package. This provides some syntactic sugar for simple cases of what my
1976     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1977     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1978     item, you can use this simplified notation. Note that only makes sense with
1979     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1980     greediness, whatever the setting of the PCRE_UNGREEDY option.
1982     13. A change of greediness default within a pattern was not taking effect at
1983     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1984     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1985     was abstracted outside.
1987     14. PCRE now supports the \G assertion. It is true when the current matching
1988     position is at the start point of the match. This differs from \A when the
1989     starting offset is non-zero. Used with the /g option of pcretest (or similar
1990     code), it works in the same way as it does for Perl's /g option. If all
1991     alternatives of a regex begin with \G, the expression is anchored to the start
1992     match position, and the "anchored" flag is set in the compiled expression.
1994     15. Some bugs concerning the handling of certain option changes within patterns
1995     have been fixed. These applied to options other than (?ims). For example,
1996     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1997     been the other way round. Some of this was related to change 7 above.
1999     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2000     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2001     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2002     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2004     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2005     mode. Unlike ".", it always matches newline, whatever the setting of
2006     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2007     assertions. Perl allows it, but it doesn't (in general) work because it can't
2008     calculate the length of the lookbehind. At least, that's the case for Perl
2009     5.8.0 - I've been told they are going to document that it doesn't work in
2010     future.
2012     18. Added an error diagnosis for escapes that PCRE does not support: these are
2013     \L, \l, \N, \P, \p, \U, \u, and \X.
2015     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2016     reading past the end of the pattern in cases such as /[abcd/.
2018     20. PCRE was getting more memory than necessary for patterns with classes that
2019     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2021     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2022     compiling PCRE for use with Virtual Pascal.
2024     22. Small fix to the Makefile to make it work properly if the build is done
2025     outside the source tree.
2027     23. Added a new extension: a condition to go with recursion. If a conditional
2028     subpattern starts with (?(R) the "true" branch is used if recursion has
2029     happened, whereas the "false" branch is used only at the top level.
2031     24. When there was a very long string of literal characters (over 255 bytes
2032     without UTF support, over 250 bytes with UTF support), the computation of how
2033     much memory was required could be incorrect, leading to segfaults or other
2034     strange effects.
2036     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2037     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2038     there was a subsequent back reference to those brackets. This meant that, for
2039     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2040     possible to check for precisely this case. All we can do is abandon the
2041     optimization if .* occurs inside capturing brackets when there are any back
2042     references whatsoever. (See below for a better fix that came later.)
2044     26. The handling of the optimization for finding the first character of a
2045     non-anchored pattern, and for finding a character that is required later in the
2046     match were failing in some cases. This didn't break the matching; it just
2047     failed to optimize when it could. The way this is done has been re-implemented.
2049     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2051     28. Added a new feature that provides some of the functionality that Perl
2052     provides with (?{...}). The facility is termed a "callout". The way it is done
2053     in PCRE is for the caller to provide an optional function, by setting
2054     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2055     global variable. By default it is unset, which disables all calling out. To get
2056     the function called, the regex must include (?C) at appropriate points. This
2057     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2058     This provides a means of identifying different callout points. When PCRE
2059     reaches such a point in the regex, if pcre_callout has been set, the external
2060     function is called. It is provided with data in a structure called
2061     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2062     matching continues; if it returns a non-zero value, the match at the current
2063     point fails. However, backtracking will occur if possible. [This was changed
2064     later and other features added - see item 49 below.]
2066     29. pcretest is upgraded to test the callout functionality. It provides a
2067     callout function that displays information. By default, it shows the start of
2068     the match and the current position in the text. There are some new data escapes
2069     to vary what happens:
2071     \C+ in addition, show current contents of captured substrings
2072     \C- do not supply a callout function
2073     \C!n return 1 when callout number n is reached
2074     \C!n!m return 1 when callout number n is reached for the mth time
2076     30. If pcregrep was called with the -l option and just a single file name, it
2077     output "<stdin>" if a match was found, instead of the file name.
2079     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2080     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2081     pcre_exec(). This saves a malloc/free per call. The default value of
2082     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2083     when configuring.
2085     32. The default maximum size of a compiled pattern is 64K. There have been a
2086     few cases of people hitting this limit. The code now uses macros to handle the
2087     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2088     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2089     configuring. Tests 2 and 5 work only with 2-byte links because they output
2090     debugging information about compiled patterns.
2092     33. Internal code re-arrangements:
2094     (a) Moved the debugging function for printing out a compiled regex into
2095     its own source file (printint.c) and used #include to pull it into
2096     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2097     separate copies.
2099     (b) Defined the list of op-code names for debugging as a macro in
2100     internal.h so that it is next to the definition of the opcodes.
2102     (c) Defined a table of op-code lengths for simpler skipping along compiled
2103     code. This is again a macro in internal.h so that it is next to the
2104     definition of the opcodes.
2106     34. Added support for recursive calls to individual subpatterns, along the
2107     lines of Robin Houston's patch (but implemented somewhat differently).
2109     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2110     allow it to read and process whole directories in Win32. This code was
2111     contributed by Lionel Fourquaux; it has not been tested by me.
2113     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2114     used to name a group. Names consist of alphanumerics and underscores, and must
2115     be unique. Back references use the syntax (?P=name) and recursive calls use
2116     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2117     numbers. The function pcre_fullinfo() can be used after compilation to extract
2118     a name/number map. There are three relevant calls:
2120     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2121     PCRE_INFO_NAMECOUNT yields the number of entries
2122     PCRE_INFO_NAMETABLE yields a pointer to the map.
2124     The map is a vector of fixed-size entries. The size of each entry depends on
2125     the length of the longest name used. The first two bytes of each entry are the
2126     group number, most significant byte first. There follows the corresponding
2127     name, zero terminated. The names are in alphabetical order.
2129     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2130     case instead of 255. Making it the same both with and without UTF-8 support
2131     means that the same test output works with both.
2133     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2134     calling malloc() with a zero argument.
2136     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2137     optimization. I've improved things by keeping a bitmap of backreferences with
2138     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2139     fact referenced, the optimization can be applied. It is unlikely that a
2140     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2141     the match to follow \n) will appear inside brackets with a number greater than
2142     31, but if it does, any back reference > 31 suppresses the optimization.
2144     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2145     of disabling numbered capturing parentheses. Any opening parenthesis that is
2146     not followed by ? behaves as if it were followed by ?: but named parentheses
2147     can still be used for capturing (and they will acquire numbers in the usual
2148     way).
2150     41. Redesigned the return codes from the match() function into yes/no/error so
2151     that errors can be passed back from deep inside the nested calls. A malloc
2152     failure while inside a recursive subpattern call now causes the
2153     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2155     42. It is now possible to set a limit on the number of times the match()
2156     function is called in a call to pcre_exec(). This facility makes it possible to
2157     limit the amount of recursion and backtracking, though not in a directly
2158     obvious way, because the match() function is used in a number of different
2159     circumstances. The count starts from zero for each position in the subject
2160     string (for non-anchored patterns). The default limit is, for compatibility, a
2161     large number, namely 10 000 000. You can change this in two ways:
2163     (a) When configuring PCRE before making, you can use --with-match-limit=n
2164     to set a default value for the compiled library.
2166     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2167     a different value is set. See 45 below.
2169     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2171     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2172     of things that can be changed at compile time. The first argument specifies
2173     what is wanted and the second points to where the information is to be placed.
2174     The current list of available information is:
2178     The output is an integer that is set to one if UTF-8 support is available;
2179     otherwise it is set to zero.
2183     The output is an integer that it set to the value of the code that is used for
2184     newline. It is either LF (10) or CR (13).
2188     The output is an integer that contains the number of bytes used for internal
2189     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2193     The output is an integer that contains the threshold above which the POSIX
2194     interface uses malloc() for output vectors. See item 31 above.
2198     The output is an unsigned integer that contains the default limit of the number
2199     of match() calls in a pcre_exec() execution. See 42 above.
2201     44. pcretest has been upgraded by the addition of the -C option. This causes it
2202     to extract all the available output from the new pcre_config() function, and to
2203     output it. The program then exits immediately.
2205     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2206     order to support additional features. One way would have been to define
2207     pcre_exec2() (for example) with extra arguments, but this would not have been
2208     extensible, and would also have required all calls to the original function to
2209     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2210     is used for passing in "extra" data from pcre_study().
2212     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2213     contains the following fields:
2215     flags a bitmap indicating which of the following fields are set
2216     study_data opaque data from pcre_study()
2217     match_limit a way of specifying a limit on match() calls for a specific
2218     call to pcre_exec()
2219     callout_data data for callouts (see 49 below)
2221     The flag bits are also defined in pcre.h, and are
2227     The pcre_study() function now returns one of these new pcre_extra blocks, with
2228     the actual study data pointed to by the study_data field, and the
2229     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2230     before. That is, this change is entirely upwards-compatible and requires no
2231     change to existing code.
2233     If you want to pass in additional data to pcre_exec(), you can either place it
2234     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2235     block.
2237     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2238     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2239     times with different match limits, until it finds the minimum value needed for
2240     pcre_exec() to complete. The value is then output. This can be instructive; for
2241     most simple matches the number is quite small, but for pathological cases it
2242     gets very large very quickly.
2244     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2245     returns the size of the data block pointed to by the study_data field in a
2246     pcre_extra block, that is, the value that was passed as the argument to
2247     pcre_malloc() when PCRE was getting memory in which to place the information
2248     created by pcre_study(). The fourth argument should point to a size_t variable.
2249     pcretest has been extended so that this information is shown after a successful
2250     pcre_study() call when information about the compiled regex is being displayed.
2252     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2253     because what follows is always an absolute path. (Later: it turns out that this
2254     is more than cosmetic for MinGW, because it doesn't like empty path
2255     components.)
2257     49. Some changes have been made to the callout feature (see 28 above):
2259     (i) A callout function now has three choices for what it returns:
2261     0 => success, carry on matching
2262     > 0 => failure at this point, but backtrack if possible
2263     < 0 => serious error, return this value from pcre_exec()
2265     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2266     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2267     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2268     use by callout functions. It will never be used by PCRE itself.
2270     (ii) The pcre_extra structure (see 45 above) has a void * field called
2271     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2272     pcre_callout_block structure has a field of the same name. The contents of
2273     the field passed in the pcre_extra structure are passed to the callout
2274     function in the corresponding field in the callout block. This makes it
2275     easier to use the same callout-containing regex from multiple threads. For
2276     testing, the pcretest program has a new data escape
2278     \C*n pass the number n (may be negative) as callout_data
2280     If the callout function in pcretest receives a non-zero value as
2281     callout_data, it returns that value.
2283     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2284     there were some redundant $(CFLAGS) in commands that are now specified as
2285     $(LINK), which already includes $(CFLAGS).
2287     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2288     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2289     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2290     one-byte characters throughout. Note that case-insensitive matching applies
2291     only to characters whose values are less than 256. PCRE doesn't support the
2292     notion of cases for higher-valued characters.
2294     (i) A character class whose characters are all within 0-255 is handled as
2295     a bit map, and the map is inverted for negative classes. Previously, a
2296     character > 255 always failed to match such a class; however it should
2297     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2299     (ii) A negated character class with a single character < 255 is coded as
2300     "not this character" (OP_NOT). This wasn't working properly when the test
2301     character was multibyte, either singly or repeated.
2303     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2304     mode, for example: \x{100}{2,3}.
2306     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2307     singly or repeated) now correctly test multibyte characters. However,
2308     PCRE doesn't recognize any characters with values greater than 255 as
2309     digits, spaces, or word characters. Such characters always match \D, \S,
2310     and \W, and never match \d, \s, or \w.
2312     (v) Classes may now contain characters and character ranges with values
2313     greater than 255. For example: [ab\x{100}-\x{400}].
2315     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2316     PCRE in UTF-8 mode.
2318     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2319     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2320     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2321     value.)
2323     53. The single man page has become too large. I have therefore split it up into
2324     a number of separate man pages. These also give rise to individual HTML pages;
2325     these are now put in a separate directory, and there is an index.html page that
2326     lists them all. Some hyperlinking between the pages has been installed.
2328     54. Added convenience functions for handling named capturing parentheses.
2330     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2331     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2332     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2333     are faulted.
2335     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2336     calling configure. These values are used when compiling the dftables.c program
2337     which is run to generate the source of the default character tables. They
2338     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2339     you will need to set these values.
2341     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2344     Version 3.9 02-Jan-02
2345 nigel 61 ---------------------
2347     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2349     2. If --disable-static was given, the building process failed when trying to
2350     build pcretest and pcregrep. (For some reason it was using libtool to compile
2351     them, which is not right, as they aren't part of the library.)
2354 nigel 59 Version 3.8 18-Dec-01
2355     ---------------------
2357     1. The experimental UTF-8 code was completely screwed up. It was packing the
2358     bytes in the wrong order. How dumb can you get?
2361 nigel 57 Version 3.7 29-Oct-01
2362     ---------------------
2364     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2365     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2366     this didn't happen under Solaris 8, where I normally test things.
2368 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2369     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2370     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2371     this fix an hour or so after the initial 3.7 release.)
2372 nigel 57
2373 nigel 59
2374 nigel 55 Version 3.6 23-Oct-01
2375     ---------------------
2377     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2378     offsets passed as NULL with zero offset count.
2380     2. The config.guess and config.sub files had not been updated when I moved to
2381     the latest autoconf.
2384 nigel 53 Version 3.5 15-Aug-01
2385     ---------------------
2386 nigel 5
2387 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2388     had been forgotten.
2390     2. By using declared but undefined structures, we can avoid using "void"
2391     definitions in pcre.h while keeping the internal definitions of the structures
2392     private.
2394     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2395     user point of view, this means that both static and shared libraries are built
2396     by default, but this can be individually controlled. More of the work of
2397     handling this static/shared cases is now inside libtool instead of PCRE's make
2398     file.
2400     4. The pcretest utility is now installed along with pcregrep because it is
2401     useful for users (to test regexs) and by doing this, it automatically gets
2402     relinked by libtool. The documentation has been turned into a man page, so
2403     there are now .1, .txt, and .html versions in /doc.
2405     5. Upgrades to pcregrep:
2406     (i) Added long-form option names like gnu grep.
2407     (ii) Added --help to list all options with an explanatory phrase.
2408     (iii) Added -r, --recursive to recurse into sub-directories.
2409     (iv) Added -f, --file to read patterns from a file.
2411     6. pcre_exec() was referring to its "code" argument before testing that
2412     argument for NULL (and giving an error if it was NULL).
2414     7. Upgraded Makefile.in to allow for compiling in a different directory from
2415     the source directory.
2417     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2418     options bits, the pointer it was passed was to an int instead of to an unsigned
2419     long int. This mattered only on 64-bit systems.
2421     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2422     generated) instead of pcre.in, which it its source. Also made the same change
2423     in several of the .c files.
2425     10. A new release of gcc defines printf() as a macro, which broke pcretest
2426     because it had an ifdef in the middle of a string argument for printf(). Fixed
2427     by using separate calls to printf().
2429     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2430     script, to force use of CR or LF instead of \n in the source. On non-Unix
2431     systems, the value can be set in config.h.
2433     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2434     absolute limit. Changed the text of the error message to make this clear, and
2435     likewise updated the man page.
2437     13. The limit of 99 on the number of capturing subpatterns has been removed.
2438     The new limit is 65535, which I hope will not be a "real" limit.
2441 nigel 51 Version 3.4 22-Aug-00
2442     ---------------------
2444     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2446     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2449 nigel 49 Version 3.3 01-Aug-00
2450     ---------------------
2452     1. If an octal character was given, but the value was greater than \377, it
2453     was not getting masked to the least significant bits, as documented. This could
2454     lead to crashes in some systems.
2456     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2457     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2459     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2460     These just pass their arguments on to (pcre_free)(), but they are provided
2461     because some uses of PCRE bind it to non-C systems that can call its functions,
2462     but cannot call free() or pcre_free() directly.
2464     4. Add "make test" as a synonym for "make check". Corrected some comments in
2465     the Makefile.
2467     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2468     Makefile.
2470     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2471     command called pgrep for grepping around the active processes.
2473     7. Added the beginnings of support for UTF-8 character strings.
2475     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2476     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2477     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2478     out for the ar command.)
2481 nigel 47 Version 3.2 12-May-00
2482     ---------------------
2484     This is purely a bug fixing release.
2486     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2487     of ZA. This was just one example of several cases that could provoke this bug,
2488     which was introduced by change 9 of version 2.00. The code for breaking
2489     infinite loops after an iteration that matches an empty string was't working
2490     correctly.
2492     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2493     when matched against abbab (for example). After matching an empty string, it
2494     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2495     caused it to match further down the string than it should.
2497     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2498     was there because it doesn't seem to be needed, and it causes trouble on some
2499     systems, as it is not a Standard C header. It has been removed.
2501     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2502     were reported on the Macintosh. The changes were from
2504     while ((c = *(++ptr)) != 0 && c != '\n');
2505     to
2506     while ((c = *(++ptr)) != 0 && c != '\n') ;
2508     Totally extraordinary, but if that's what it takes...
2510     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2511     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2512     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2513     assumes the way PCRE uses memmove() (always moving upwards).
2515     6. PCRE is being used in one environment where strchr() is not available. There
2516     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2517     faster code anyway.
2520 nigel 45 Version 3.1 09-Feb-00
2521     ---------------------
2523     The only change in this release is the fixing of some bugs in Makefile.in for
2524     the "install" target:
2526     (1) It was failing to install pcreposix.h.
2528     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2531 nigel 43 Version 3.0 01-Feb-00
2532     ---------------------
2533 nigel 41
2534     1. Add support for the /+ modifier to perltest (to output $` like it does in
2535     pcretest).
2537     2. Add support for the /g modifier to perltest.
2539     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2540     matches null strings.
2542     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2543     pattern. Perl treats empty patterns specially - it reuses the most recent
2544     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2545     effect.
2547     5. The POSIX interface was broken in that it was just handing over the POSIX
2548     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2549     required a bigger vector, with some working space on the end. This means that
2550     the POSIX wrapper now has to get and free some memory, and copy the results.
2552 nigel 43 6. Added some simple autoconf support, placing the test data and the
2553     documentation in separate directories, re-organizing some of the
2554     information files, and making it build pcre-config (a GNU standard). Also added
2555     libtool support for building PCRE as a shared library, which is now the
2556     default.
2557 nigel 41
2558 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2559     09 are not valid octal constants. Single digits will be used for minor values
2560     less than 10.
2562     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2563     existing programs that set these in the POSIX interface can use PCRE without
2564     modification.
2566     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2567     return all that pcre_info() returns, plus additional data. The pcre_info()
2568     function is retained for compatibility, but is considered to be obsolete.
2570     10. Added experimental recursion feature (?R) to handle one common case that
2571     Perl 5.6 will be able to do with (?p{...}).
2573     11. Added support for POSIX character classes like [:alpha:], which Perl is
2574     adopting.
2577 nigel 39 Version 2.08 31-Aug-99
2578     ----------------------
2580     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2581     trying to match at the startoffset position, but instead was moving forward to
2582     the next newline as if a previous match had failed.
2584     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2585     and could get into a loop if a null string was matched other than at the start
2586     of the subject.
2588     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2589     be distinguished at compile time, and for completeness also added PCRE_DATE.
2591     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2592     in GnuWin32 environments.
2595 nigel 37 Version 2.07 29-Jul-99
2596     ----------------------
2598     1. The documentation is now supplied in plain text form and HTML as well as in
2599     the form of man page sources.
2601     2. C++ compilers don't like assigning (void *) values to other pointer types.
2602     In particular this affects malloc(). Although there is no problem in Standard
2603     C, I've put in casts to keep C++ compilers happy.
2605     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2606     should be (const char *).
2608     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2609     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2610     However, I haven't made this a standard facility. The documentation doesn't
2611     mention it, and the Makefile doesn't support it.
2613     5. The Makefile now contains an "install" target, with editable destinations at
2614     the top of the file. The pcretest program is not installed.
2616     6. pgrep -V now gives the PCRE version number and date.
2618     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2619     causing the entire string to be ignored, instead of just the last character.
2621     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2622     non-matching string, it can take a very, very long time, even for strings of
2623     quite modest length, because of the nested recursion. PCRE now does better in
2624     some of these cases. It does this by remembering the last required literal
2625     character in the pattern, and pre-searching the subject to ensure it is present
2626     before running the real match. In other words, it applies a heuristic to detect
2627     some types of certain failure quickly, and in the above example, if presented
2628     with a string that has no trailing " it gives "no match" very quickly.
2630     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2631     other alternatives are tried instead.
2634 nigel 35 Version 2.06 09-Jun-99
2635     ----------------------
2637     1. Change pcretest's output for amount of store used to show just the code
2638     space, because the remainder (the data block) varies in size between 32-bit and
2639     64-bit systems.
2641     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2642     start matching at. This allows lookbehinds to work when searching for multiple
2643     occurrences in a string.
2645     3. Added additional options to pcretest for testing multiple occurrences:
2647     /+ outputs the rest of the string that follows a match
2648     /g loops for multiple occurrences, using the new startoffset argument
2649     /G loops for multiple occurrences by passing an incremented pointer
2651     4. PCRE wasn't doing the "first character" optimization for patterns starting
2652     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2653     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2654     the letter 'x'. On long subject strings, this gives a significant speed-up.
2657 nigel 33 Version 2.05 21-Apr-99
2658     ----------------------
2660     1. Changed the type of magic_number from int to long int so that it works
2661     properly on 16-bit systems.
2663     2. Fixed a bug which caused patterns starting with .* not to work correctly
2664     when the subject string contained newline characters. PCRE was assuming
2665     anchoring for such patterns in all cases, which is not correct because .* will
2666     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2667     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2668     must be retried after every newline in the subject.
2671 nigel 31 Version 2.04 18-Feb-99
2672     ----------------------
2674     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2675     computation of the store needed to hold the pattern was incorrect (too large).
2676     If such patterns were nested a few deep, this could multiply and become a real
2677     problem.
2679     2. Added /M option to pcretest to show the memory requirement of a specific
2680     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2682     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2683     compiled in such a way that the backtracking after subsequent failure was
2684     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2685     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2688 nigel 29 Version 2.03 02-Feb-99
2689     ----------------------
2691     1. Fixed typo and small mistake in man page.
2693 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2694     LICENCE file containing the conditions.
2695 nigel 29
2696     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2697     Perl, that is the internal \ allows the delimiter to be included in the
2698     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2699     the final delimiter, add \ to the end of the pattern (to test the error).
2701     4. Added the convenience functions for extracting substrings after a successful
2702     match. Updated pcretest to make it able to test these functions.
2705 nigel 27 Version 2.02 14-Jan-99
2706     ----------------------
2708     1. Initialized the working variables associated with each extraction so that
2709     their saving and restoring doesn't refer to uninitialized store.
2711     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2712     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2713     fix the problem.
2715     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2716     calls, and wasn't printing the correct value for compiling calls. Increased the
2717     default value of LOOPREPEAT, and the number of significant figures in the
2718     times.
2720     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2722     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2723     a building problem on Windows NT with a FAT file system.
2726 nigel 25 Version 2.01 21-Oct-98
2727     ----------------------
2729     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2730     to character tables built by pcre_maketables() in the current locale. If NULL
2731     is passed, the default tables are used.
2734 nigel 23 Version 2.00 24-Sep-98
2735 nigel 21 ----------------------
2737 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2738     it any more.
2740     2. Allow quantification of (?>) groups, and make it work correctly.
2742     3. The first character computation wasn't working for (?>) groups.
2744     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2745     end of the subject) and add 5.005's \z, which really does match only at the
2746     very end of the subject.
2748     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2750     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2751     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2752     localized options. All options to pcre_study() were also removed.
2754     7. Add other new features from 5.005:
2756     $(?<= positive lookbehind
2757     $(?<! negative lookbehind
2758     (?imsx-imsx) added the unsetting capability
2759     such a setting is global if at outer level; local otherwise
2760     (?imsx-imsx:) non-capturing groups with option setting
2761     (?(cond)re|re) conditional pattern matching
2763     A backreference to itself in a repeated group matches the previous
2764     captured string.
2766     8. General tidying up of studying (both automatic and via "study")
2767     consequential on the addition of new assertions.
2769     9. As in 5.005, unlimited repeated groups that could match an empty substring
2770     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2771     runtime if any iteration does actually match an empty substring.
2773     10. Include the RunTest script in the distribution.
2775     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2776     discrepancies, some of which were old and were also with respect to 5.004. They
2777     have now been fixed.
2780     Version 1.09 28-Apr-98
2781     ----------------------
2783 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2784     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2785     program crashes, or just wrong answers. This did not apply to negated classes
2786     containing more than one character, or to minima other than one.
2789 nigel 19 Version 1.08 27-Mar-98
2790     ----------------------
2792     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2794     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2795     latter must appear before anything that relies on it in the pattern.
2798 nigel 17 Version 1.07 16-Feb-98
2799     ----------------------
2801     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2802     repeat of a potentially empty string).
2805 nigel 15 Version 1.06 23-Jan-98
2806     ----------------------
2808     1. Added Markus Oberhumer's little patches for C++.
2810     2. Literal strings longer than 255 characters were broken.
2813 nigel 13 Version 1.05 23-Dec-97
2814     ----------------------
2816     1. Negated character classes containing more than one character were failing if
2817     PCRE_CASELESS was set at run time.
2820 nigel 11 Version 1.04 19-Dec-97
2821     ----------------------
2823     1. Corrected the man page, where some "const" qualifiers had been omitted.
2825     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2826     input syntax.
2828     3. Fixed memory leak which occurred when a regex with back references was
2829     matched with an offsets vector that wasn't big enough. The temporary memory
2830     that is used in this case wasn't being freed if the match failed.
2832     4. Tidied pcretest to ensure it frees memory that it gets.
2834     5. Temporary memory was being obtained in the case where the passed offsets
2835     vector was exactly big enough.
2837     6. Corrected definition of offsetof() from change 5 below.
2839     7. I had screwed up change 6 below and broken the rules for the use of
2840     setjmp(). Now fixed.
2843 nigel 9 Version 1.03 18-Dec-97
2844     ----------------------
2846     1. A erroneous regex with a missing opening parenthesis was correctly
2847     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2848     on some systems.
2850     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2851     it was reported that one broken compiler failed on the former because "code" is
2852     also an independent variable.
2854     3. The erroneous regex a[]b caused an array overrun reference.
2856     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2857     fail on data ending with that character. (It was going on too far, and checking
2858     the next character, typically a binary zero.) This was specific to the
2859     optimized code for single-character negative classes.
2861     5. Added a contributed patch from the TIN world which does the following:
2863     + Add an undef for memmove, in case the the system defines a macro for it.
2865     + Add a definition of offsetof(), in case there isn't one. (I don't know
2866     the reason behind this - offsetof() is part of the ANSI standard - but
2867     it does no harm).
2869     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2870     most of the places where whitespace preceded '#'. I have given up and
2871     allowed the remaining 2 cases to be at the margin.
2873     + Rename some variables in pcre to eliminate shadowing. This seems very
2874     pedantic, but does no harm, of course.
2876     6. Moved the call to setjmp() into its own function, to get rid of warnings
2877     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2879     7. Constructs such as \d{8,} were compiling into the equivalent of
2880 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2881 nigel 9 outcome, but in this particular case used more store than had been allocated,
2882     which caused the bug to be discovered because it threw up an internal error.
2884     8. The debugging code in both pcre and pcretest for outputting the compiled
2885     form of a regex was going wrong in the case of back references followed by
2886     curly-bracketed repeats.
2889 nigel 7 Version 1.02 12-Dec-97
2890     ----------------------
2892     1. Typos in pcre.3 and comments in the source fixed.
2894     2. Applied a contributed patch to get rid of places where it used to remove
2895     'const' from variables, and fixed some signed/unsigned and uninitialized
2896     variable warnings.
2898     3. Added the "runtest" target to Makefile.
2900     4. Set default compiler flag to -O2 rather than just -O.
2903 nigel 5 Version 1.01 19-Nov-97
2904     ----------------------
2906     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2907     like /([ab]*)*/, that is, for classes with more than one character in them.
2909     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2910     as /((?>a*))*/ (a PCRE_EXTRA facility).
2913     Version 1.00 18-Nov-97
2914     ----------------------
2916     1. Added compile-time macros to support systems such as SunOS4 which don't have
2917     memmove() or strerror() but have other things that can be used instead.
2919     2. Arranged that "make clean" removes the executables.
2922 nigel 3 Version 0.99 27-Oct-97
2923     ----------------------
2925     1. Fixed bug in code for optimizing classes with only one character. It was
2926     initializing a 32-byte map regardless, which could cause it to run off the end
2927     of the memory it had got.
2929     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2932     Version 0.98 22-Oct-97
2933     ----------------------
2935     1. Fixed bug in code for handling temporary memory usage when there are more
2936     back references than supplied space in the ovector. This could cause segfaults.
2939     Version 0.97 21-Oct-97
2940     ----------------------
2942     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2944     2. Optimized negated single characters not to use a bit map.
2946     3. Brought error texts together as macro definitions; clarified some of them;
2947     fixed one that was wrong - it said "range out of order" when it meant "invalid
2948     escape sequence".
2950     4. Changed some char * arguments to const char *.
2952     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2954     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2955     pcretest.
2958     Version 0.96 16-Oct-97
2959     ----------------------
2961     1. Added a simple "pgrep" utility to the distribution.
2963     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2964     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2965     where "ddd" means "one or more decimal digits".
2967     3. Fixed serious bug. If a pattern had a back reference, but the call to
2968     pcre_exec() didn't supply a large enough ovector to record the related
2969     identifying subpattern, the match always failed. PCRE now remembers the number
2970     of the largest back reference, and gets some temporary memory in which to save
2971     the offsets during matching if necessary, in order to ensure that
2972     backreferences always work.
2974     4. Increased the compatibility with Perl in a number of ways:
2976     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2977     to request this handling. The option can be set at compile or exec time.
2979     (b) $ matches before a terminating newline by default; an option
2980     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2981     mode). The option can be set at compile or exec time.
2983     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2984     the same as Perl's. If the decimal number it represents is less than 10
2985     or there aren't that many previous left capturing parentheses, an octal
2986     escape is read. Inside a character class, it's always an octal escape,
2987     even if it is a single digit.
2989     (d) An escaped but undefined alphabetic character is taken as a literal,
2990     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2991     escapes.
2993     (e) {0} is now permitted. (The previous item is removed from the compiled
2994     pattern).
2996     5. Changed all the names of code files so that the basic parts are no longer
2997     than 10 characters, and abolished the teeny "globals.c" file.
2999     6. Changed the handling of character classes; they are now done with a 32-byte
3000     bit map always.
3002     7. Added the -d and /D options to pcretest to make it possible to look at the
3003     internals of compilation without having to recompile pcre.
3006     Version 0.95 23-Sep-97
3007     ----------------------
3009     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3010     \x20 at the start of a run of normal characters. These were being treated as
3011     real characters, instead of the source characters being re-checked.
3014     Version 0.94 18-Sep-97
3015     ----------------------
3017     1. The functions are now thread-safe, with the caveat that the global variables
3018     containing pointers to malloc() and free() or alternative functions are the
3019     same for all threads.
3021     2. Get pcre_study() to generate a bitmap of initial characters for non-
3022     anchored patterns when this is possible, and use it if passed to pcre_exec().
3025     Version 0.93 15-Sep-97
3026     ----------------------
3028     1. /(b)|(:+)/ was computing an incorrect first character.
3030     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3031     but not actually doing anything yet.
3033     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3034     as Perl does (e.g. [-az] or [az-]).
3036     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3037     all possible positions.
3039     5. Split up into different modules to avoid including unneeded functions in a
3040     compiled binary. However, compile and exec are still in one module. The "study"
3041     function is split off.
3043     6. The character tables are now in a separate module whose source is generated
3044     by an auxiliary program - but can then be edited by hand if required. There are
3045     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3046     toupper() in the code.
3048     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3049     make them global. Abolish the function for setting them, as the caller can now
3050     set them directly.
3053     Version 0.92 11-Sep-97
3054     ----------------------
3056     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3057     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3059     2. Caseless matching was not working in character classes if the characters in
3060     the pattern were in upper case.
3062     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3064     4. Make PCRE_ANCHORED public and accept as a compile option.
3066     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3067     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3068     pass them.
3070     6. Give an error if bad option bits passed at compile or run time.
3072     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3073     pcretest to cause it to pass that flag.
3075     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3076     options, and the first character, if set.
3078     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3081     Version 0.91 10-Sep-97
3082     ----------------------
3084     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3085     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3087     2. PCRE was looping on encountering an indefinitely repeated back reference to
3088     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3089     Perl does - treats the match as successful.
3091     ****


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