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Revision 294 - (hide annotations) (download)
Sat Dec 29 16:55:59 2007 UTC (6 years, 6 months ago) by ph10
File size: 147358 byte(s)
Fix UTF-8/newline=ANY with .* crash.

1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 ph10 294 Version 7.5 29-Dec-07
5 ph10 263 ---------------------
6    
7     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
8     values in parens when parsing an RE using the C++ wrapper."
9 ph10 286
10 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
11     Characters greater than 255 were excluded from the class instead of being
12     included.
13 ph10 286
14     3. The same bug as (2) above applied to negated POSIX classes such as
15 ph10 265 [:^space:].
16 ph10 286
17 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18     defined or documented. It seems to have been a typo for PCRE_STATIC, so
19 ph10 286 I have changed it.
20    
21 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
22 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
23     first named subpattern whose name started with "a" (in other words, the
24 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
25     expected" is now given for (?&) (a zero-length name), and this patch also
26     makes it give the same error for \k'' (previously it complained that that
27     was a reference to a non-existent subpattern).
28 ph10 286
29 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
30 ph10 286 this is right because (?- can be followed by option settings as well as by
31 ph10 269 digits. I have, however, made the messages clearer.
32 ph10 286
33 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34     than the number used in the conditional) now cause a compile-time error.
35     This is actually not compatible with Perl, which accepts such patterns, but
36     treats the conditional as always being FALSE (as PCRE used to), but it
37     seems to me that giving a diagnostic is better.
38 ph10 286
39 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
40 ph10 275 and messages.
41 ph10 286
42     9. Fix two occurrences of "backslash" in comments that should have been
43     "backspace".
44    
45     10. Remove two redundant lines of code that can never be obeyed (their function
46     was moved elsewhere).
47    
48     11. The program that makes PCRE's Unicode character property table had a bug
49     which caused it to generate incorrect table entries for sequences of
50 ph10 277 characters that have the same character type, but are in different scripts.
51 ph10 286 It amalgamated them into a single range, with the script of the first of
52 ph10 277 them. In other words, some characters were in the wrong script. There were
53     thirteen such cases, affecting characters in the following ranges:
54 ph10 286
55 ph10 277 U+002b0 - U+002c1
56     U+0060c - U+0060d
57 ph10 286 U+0061e - U+00612
58 ph10 277 U+0064b - U+0065e
59     U+0074d - U+0076d
60     U+01800 - U+01805
61     U+01d00 - U+01d77
62     U+01d9b - U+01dbf
63     U+0200b - U+0200f
64     U+030fc - U+030fe
65     U+03260 - U+0327f
66     U+0fb46 - U+0fbb1
67     U+10450 - U+1049d
68 ph10 286
69 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
70     compatible with GNU grep in that, if there was more than one match in a
71     line, it showed only the first of them. It now behaves in the same way as
72     GNU grep.
73 ph10 286
74     13. If the -o and -v options were combined for pcregrep, it printed a blank
75     line for every non-matching line. GNU grep prints nothing, and pcregrep now
76     does the same. The return code can be used to tell if there were any
77     non-matching lines.
78    
79 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
80    
81     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
82 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
83 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
84     and both kinds of lookbehind were skipped).
85    
86 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
87 ph10 284 inclusion of <windows.h> to before rather than after the definition of
88     INVALID_FILE_ATTRIBUTES (patch from David Byron).
89 ph10 263
90 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
91 ph10 286 character property caused pcre_compile() to compile bad code, which led at
92     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
93     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
94     caused the error; without that there was no problem.
95 ph10 263
96 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
97 ph10 286
98 ph10 289 19. Added --enable-pcretest-libreadline.
99 ph10 286
100 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
101 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
102     double what it should be. I have removed one of the increments.
103 ph10 292
104 ph10 291 21. Several CMake things:
105 ph10 287
106 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
107 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
108 ph10 288
109 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
110     linked with the newly-built libraries, not previously installed ones.
111 ph10 291
112 ph10 292 (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
113 ph10 294
114     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
115     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
116     UTF-8 newline character). The key issue is that the pattern starts .*;
117     this means that the match must be either at the beginning, or after a
118     newline. The bug was in the code for advancing after a failed match and
119     checking that the new position followed a newline. It was not taking
120     account of UTF-8 characters correctly.
121 ph10 292
122    
123 ph10 260 Version 7.4 21-Sep-07
124 ph10 230 ---------------------
125    
126     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
127 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
128     LF". That isn't really right - the whole point of the change was to try to
129     help when there was an actual mention of one of the two characters. So now
130     the change happens only if \r or \n (or a literal CR or LF) character is
131 ph10 230 encountered.
132 ph10 231
133     2. The 32-bit options word was also used for 6 internal flags, but the numbers
134     of both had grown to the point where there were only 3 bits left.
135     Fortunately, there was spare space in the data structure, and so I have
136     moved the internal flags into a new 16-bit field to free up more option
137 ph10 230 bits.
138 ph10 231
139     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
140     but did not set the internal JCHANGED flag - either of these is enough to
141     control the way the "get" function works - but the PCRE_INFO_JCHANGED
142     facility is supposed to tell if (?J) was ever used, so now (?J) at the
143 ph10 230 start sets both bits.
144    
145 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
146     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
147 ph10 230
148 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
149    
150     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
151 ph10 233 compatibility, even though it is no longer used.
152 ph10 243
153     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
154 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
155 ph10 259 windows.h file is present (where different names are used). [This was
156 ph10 257 reversed later after testing - see 16 below.]
157 ph10 243
158     8. Changed all #include <config.h> to #include "config.h". There were also
159 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
160 ph10 243
161 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
162 ph10 243 sequence off the lines that it output.
163    
164     10. It was pointed out to me that arrays of string pointers cause lots of
165     relocations when a shared library is dynamically loaded. A technique of
166     using a single long string with a table of offsets can drastically reduce
167     these. I have refactored PCRE in four places to do this. The result is
168 ph10 240 dramatic:
169 ph10 243
170 ph10 240 Originally: 290
171     After changing UCP table: 187
172 ph10 243 After changing error message table: 43
173 ph10 240 After changing table of "verbs" 36
174     After changing table of Posix names 22
175 ph10 243
176 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
177 ph10 247
178 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
179 ph10 247 unicode-properties was also set.
180    
181 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
182 ph10 231
183 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
184     checked only for CRLF.
185 ph10 233
186 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
187    
188 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
189 ph10 253
190 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
191 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
192     entirely. This removes changes made in 7 above.
193 ph10 256
194 ph10 261 17. The CMake files have been updated, and there is now more information about
195     building with CMake in the NON-UNIX-USE document.
196 ph10 257
197 ph10 261
198 ph10 228 Version 7.3 28-Aug-07
199 ph10 157 ---------------------
200    
201 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
202     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
203     brackets there is not right, since it causes compilers to look for an
204     installed pcre.h, not the version that is in the source that is being
205     compiled (which of course may be different). I have changed it back to:
206 ph10 197
207 ph10 189 #include "pcre.h"
208 ph10 197
209     I have a vague recollection that the change was concerned with compiling in
210     different directories, but in the new build system, that is taken care of
211     by the VPATH setting the Makefile.
212    
213 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
214     when the subject happened to end in the byte 0x85 (e.g. if the last
215     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
216     characters but of course it shouldn't be taken as a newline when it is part
217     of another character. The bug was that, for an unlimited repeat of . in
218     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
219     characters when looking for a newline.
220 ph10 197
221     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
222    
223     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
224     in debug output.
225    
226 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
227     long printing in the pcrecpp unittest when running under MinGW.
228 ph10 189
229 ph10 197 6. ESC_K was left out of the EBCDIC table.
230 ph10 189
231 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
232     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
233     limit also applies to "virtual nesting" when a pattern is recursive, and in
234     this case 1000 isn't so big. I have been able to remove this limit at the
235     expense of backing off one optimization in certain circumstances. Normally,
236     when pcre_exec() would call its internal match() function recursively and
237     immediately return the result unconditionally, it uses a "tail recursion"
238     feature to save stack. However, when a subpattern that can match an empty
239     string has an unlimited repetition quantifier, it no longer makes this
240     optimization. That gives it a stack frame in which to save the data for
241     checking that an empty string has been matched. Previously this was taken
242     from the 1000-entry workspace that had been reserved. So now there is no
243     explicit limit, but more stack is used.
244 ph10 189
245 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
246     syntax that is required for Windows, and which was going wrong for the
247     pcreposix and pcrecpp parts of the library. These were overlooked when this
248     problem was solved for the main library.
249 ph10 197
250 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
251     the size of patterns that contain repeated groups with explicit upper
252     limits. As the maximum quantifier is 65535, the maximum group length was
253     set at 30,000 so that the product of these two numbers did not overflow a
254     32-bit integer. However, it turns out that people want to use groups that
255     are longer than 30,000 bytes (though not repeat them that many times).
256     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
257     made it possible to implement the integer overflow checks in a much more
258     dynamic way, which I have now done. The artificial limitation on group
259     length has been removed - we now have only the limit on the total length of
260     the compiled pattern, which depends on the LINK_SIZE setting.
261 ph10 208
262     10. Fixed a bug in the documentation for get/copy named substring when
263     duplicate names are permitted. If none of the named substrings are set, the
264     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
265     empty string.
266    
267     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
268     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
269     because the ] is interpreted as the first data character and the
270     terminating ] is not found. PCRE has been made compatible with Perl in this
271     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
272     cause memory overwriting.
273    
274 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
275     string has been matched (to stop an infinite loop). It was not recognizing
276 ph10 208 a conditional subpattern that could match an empty string if that
277 ph10 206 subpattern was within another subpattern. For example, it looped when
278 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
279 ph10 206 condition was not nested. This bug has been fixed.
280 ph10 208
281 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
282     past the start of the subject in the presence of bytes with the top bit
283     set, for example "\x8aBCD".
284 ph10 211
285 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
286     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
287 ph10 200
288 ph10 211 14. Optimized (?!) to (*FAIL).
289 ph10 202
290 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
291     This restricts code points to be within the range 0 to 0x10FFFF, excluding
292     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
293     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
294     does: it's just the validity check that is more restrictive.
295 ph10 220
296     16. Inserted checks for integer overflows during escape sequence (backslash)
297     processing, and also fixed erroneous offset values for syntax errors during
298     backslash processing.
299    
300 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
301 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
302    
303 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
304     caused an overrun.
305 ph10 220
306     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
307     something other than just ASCII characters) inside a group that had an
308     unlimited repeat caused a loop at compile time (while checking to see
309     whether the group could match an empty string).
310    
311 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
312     [\P{Any}] did so. (Error in the code for printing property names.)
313 ph10 210
314 ph10 220 21. An orphan \E inside a character class could cause a crash.
315    
316     22. A repeated capturing bracket such as (A)? could cause a wild memory
317 ph10 218 reference during compilation.
318 ph10 220
319     23. There are several functions in pcre_compile() that scan along a compiled
320     expression for various reasons (e.g. to see if it's fixed length for look
321 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
322 ph10 220 present in the pattern. These operators have additional parameters compared
323     with \d, etc, and these were not being taken into account when moving along
324 ph10 218 the compiled data. Specifically:
325 ph10 220
326     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
327     length.
328    
329     (b) An item such as \pL+ within a repeated group could cause crashes or
330 ph10 218 loops.
331 ph10 220
332 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
333 ph10 220 "reference to non-existent subpattern" error.
334    
335 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
336    
337 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
338 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
339 ph10 211
340 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
341 ph10 218
342 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
343 ph10 223 character were causing crashes (broken optimization).
344 ph10 227
345 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
346 ph10 227 \p or \P) caused a compile-time loop.
347    
348 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
349     break. For example, the unstudied pattern [\r\n]A does not match the string
350     "\r\nA" because change 7.0/46 below moves the current point on by two
351     characters after failing to match at the start. However, the pattern \nA
352 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
353     the same is true. There doesn't seem any very clean way out of this, but
354     what I have chosen to do makes the common cases work: PCRE now takes note
355     of whether there can be an explicit match for \r or \n anywhere in the
356     pattern, and if so, 7.0/46 no longer applies. As part of this change,
357     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
358     pattern has explicit CR or LF references.
359 ph10 222
360 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
361 ph10 223
362 ph10 227
363 ph10 189 Version 7.2 19-Jun-07
364     ---------------------
365    
366 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
367     which is apparently normally available under Windows.
368 ph10 159
369     2. Re-jig the pcregrep tests with different newline settings in an attempt
370     to make them independent of the local environment's newline setting.
371 ph10 157
372 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
373 ph10 165
374 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
375     was not 2, because the output contained actual offsets. The recent new
376 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
377     usable with all link sizes.
378    
379 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
380     stack recursion. This gives a massive performance boost under BSD, but just
381 ph10 165 a small improvement under Linux. However, it saves one field in the frame
382 ph10 164 in all cases.
383 ph10 172
384 ph10 166 6. Added more features from the forthcoming Perl 5.10:
385 ph10 172
386 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
387     recursion call. It refers to the nth most recently opened parentheses.
388 ph10 172
389 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
390 ph10 172 to be opened parentheses.
391    
392     (c) Conditions that refer to capturing parentheses can be specified
393 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
394 ph10 172
395 ph10 168 (d) \K resets the start of the current match so that everything before
396 ph10 172 is not part of it.
397    
398 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
399 ph10 172
400 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
401 ph10 172 reference syntax.
402 ph10 182
403 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
404 ph10 182 alternative starts with the same number.
405 ph10 172
406 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
407    
408 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
409     PCRE_INFO_JCHANGED.
410    
411     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
412     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
413 ph10 170 for detecting groups that can match an empty string.
414 ph10 159
415 ph10 172 9. A pattern with a very large number of alternatives (more than several
416     hundred) was running out of internal workspace during the pre-compile
417     phase, where pcre_compile() figures out how much memory will be needed. A
418     bit of new cunning has reduced the workspace needed for groups with
419     alternatives. The 1000-alternative test pattern now uses 12 bytes of
420     workspace instead of running out of the 4096 that are available.
421 ph10 182
422 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
423 ph10 172
424 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
425     The report of the bug said:
426 ph10 182
427 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
428     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
429 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
430 ph10 185
431 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
432 ph10 185 it matched the wrong number of bytes.
433 ph10 172
434 ph10 179
435 ph10 155 Version 7.1 24-Apr-07
436 ph10 98 ---------------------
437    
438 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
439 ph10 122 that is more "standard", making use of automake and other Autotools. There
440 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
441     on this.
442 ph10 111
443     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
444     for recursive directory scanning broke on some systems because the files
445     are not scanned in any specific order and on different systems the order
446     was different. A call to "sort" has been inserted into RunGrepTest for the
447     approprate test as a short-term fix. In the longer term there may be an
448 ph10 100 alternative.
449 ph10 111
450 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
451 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
452     people do their own conversions for various reasons). The problems
453     concerned the use of low-level troff macros .br and .in. I have therefore
454     removed all such uses from the man pages (some were redundant, some could
455 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
456     HTML has been updated to handle .nf/.fi and to complain if it encounters
457     .br or .in.
458 ph10 111
459 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
460 ph10 123 arranged for config.h to be included in the distribution, with the name
461 ph10 111 config.h.generic, for the benefit of those who have to compile without
462     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
463    
464     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
465     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
466 ph10 127 makevp.bat for the current PCRE, using the additional files
467 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
468 ph10 111
469     6. A Windows user reported a minor discrepancy with test 2, which turned out
470     to be caused by a trailing space on an input line that had got lost in his
471 ph10 102 copy. The trailing space was an accident, so I've just removed it.
472 ph10 111
473 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
474 ph10 111 that is needed.
475    
476 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
477     as "const" (a) because they are and (b) because it helps the PHP
478     maintainers who have recently made a script to detect big data structures
479 ph10 111 in the php code that should be moved to the .rodata section. I remembered
480     to update Builducptable as well, so it won't revert if ucptable.h is ever
481 ph10 105 re-created.
482 ph10 111
483     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
484 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
485 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
486     support is not required. This saves 1.5-2K of code, which is important in
487 ph10 107 some applications.
488 ph10 111
489 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
490 ph10 111 so as not to refer to the tables, even though these functions will never be
491     called when UTF-8 support is disabled. Otherwise there are problems with a
492     shared library.
493    
494 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
495    
496     (a) It was defining its arguments as char * instead of void *.
497    
498 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
499     a long time ago when I wrote it, but is no longer the case.
500    
501 ph10 118 The emulated memove() is provided for those environments that have neither
502 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
503 ph10 118 is clearly not the case, as these two bugs were recently reported.
504 ph10 123
505 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
506 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
507     pages, and it removes trailing spaces from listed files. It also creates
508     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
509     case, it wraps all the #defines with #ifndefs. This script should be run
510 ph10 111 before "make dist".
511 ph10 123
512 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
513     with Unicode property support.
514 ph10 123
515     (a) For a maximizing quantifier, if the two different cases of the
516     character were of different lengths in their UTF-8 codings (there are
517     some cases like this - I found 11), and the matching function had to
518 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
519     were both the same length.
520 ph10 123
521     (b) When PCRE was configured to use the heap rather than the stack for
522     recursion during matching, it was not correctly preserving the data for
523     the other case of a UTF-8 character when checking ahead for a match
524     while processing a minimizing repeat. If the check also involved
525 ph10 115 matching a wide character, but failed, corruption could cause an
526     erroneous result when trying to check for a repeat of the original
527     character.
528 ph10 123
529 ph10 116 13. Some tidying changes to the testing mechanism:
530 ph10 98
531 ph10 116 (a) The RunTest script now detects the internal link size and whether there
532     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
533 ph10 123 values substituted by "configure". (The RunGrepTest script already did
534     this for UTF-8.) The configure.ac script no longer substitutes the
535     relevant variables.
536    
537 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
538     with length and offset values. This means that the output is different
539     for different internal link sizes. Test 2 is skipped for link sizes
540     other than 2 because of this, bypassing the problem. Unfortunately,
541     there was also a test in test 3 (the locale tests) that used /B and
542 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
543     I have added a new /Z option to pcretest that replaces the length and
544     offset values with spaces. This is now used to make test 3 independent
545 ph10 122 of link size. (Test 2 will be tidied up later.)
546 ph10 123
547     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
548 ph10 122 segmentation fault instead of returning the appropriate error message.
549 ph10 134
550 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
551 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
552     This doesn't seem right; it now treats the CRLF combination as the line
553     ending, and so does not match in that case. It's only a pattern such as ^$
554     that would hit this one: something like ^ABC$ would have failed after \r
555     and then tried again after \r\n.
556    
557 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
558 ph10 134 in an attempt to make files that differ only in their line terminators
559     compare equal. This works on Linux.
560 ph10 142
561 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
562     as it exited. This is now fixed, thanks to valgrind.
563 ph10 142
564 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
565 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
566     was because its rules for how to advance for /g after matching an empty
567 ph10 143 string at the end of a line did not allow for this case. They now check for
568     it specially.
569 ph10 150
570     20. pcretest is supposed to handle patterns and data of any length, by
571     extending its buffers when necessary. It was getting this wrong when the
572 ph10 147 buffer for a data line had to be extended.
573 ph10 150
574 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
575 ph10 150 CRLF as a newline sequence.
576 ph10 152
577 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
578 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
579     I have nevertheless tidied it up.
580 ph10 111
581 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
582 ph10 123
583 ph10 153 24. Added a man page for pcre-config.
584 ph10 152
585 ph10 153
586 nigel 93 Version 7.0 19-Dec-06
587     ---------------------
588    
589     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
590     moving to gcc 4.1.1.
591    
592     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
593     sys/time.h, which is documented as needed for this function. It doesn't
594     seem to matter on Linux, but it showed up on some releases of OS X.
595    
596     3. It seems that there are systems where bytes whose values are greater than
597     127 match isprint() in the "C" locale. The "C" locale should be the
598     default when a C program starts up. In most systems, only ASCII printing
599     characters match isprint(). This difference caused the output from pcretest
600     to vary, making some of the tests fail. I have changed pcretest so that:
601    
602     (a) When it is outputting text in the compiled version of a pattern, bytes
603     other than 32-126 are always shown as hex escapes.
604    
605     (b) When it is outputting text that is a matched part of a subject string,
606     it does the same, unless a different locale has been set for the match
607     (using the /L modifier). In this case, it uses isprint() to decide.
608    
609     4. Fixed a major bug that caused incorrect computation of the amount of memory
610     required for a compiled pattern when options that changed within the
611     pattern affected the logic of the preliminary scan that determines the
612     length. The relevant options are -x, and -i in UTF-8 mode. The result was
613     that the computed length was too small. The symptoms of this bug were
614     either the PCRE error "internal error: code overflow" from pcre_compile(),
615     or a glibc crash with a message such as "pcretest: free(): invalid next
616     size (fast)". Examples of patterns that provoked this bug (shown in
617     pcretest format) are:
618    
619     /(?-x: )/x
620     /(?x)(?-x: \s*#\s*)/
621     /((?i)[\x{c0}])/8
622     /(?i:[\x{c0}])/8
623    
624     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
625     is now done differently.
626    
627     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
628     wrapper classes; (b) implement a new function in the C++ scanner that is
629     more efficient than the old way of doing things because it avoids levels of
630     recursion in the regex matching; (c) add a paragraph to the documentation
631     for the FullMatch() function.
632    
633     6. The escape sequence \n was being treated as whatever was defined as
634     "newline". Not only was this contrary to the documentation, which states
635     that \n is character 10 (hex 0A), but it also went horribly wrong when
636     "newline" was defined as CRLF. This has been fixed.
637    
638     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
639     was being set to -1 for the "end of line" case (supposedly a value that no
640     character can have). Though this value is never used (the check for end of
641     line is "zero bytes in current character"), it caused compiler complaints.
642     I've changed it to 0xffffffff.
643    
644     8. In pcre_version.c, the version string was being built by a sequence of
645     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
646     string (as it is for production releases) called a macro with an empty
647     argument. The C standard says the result of this is undefined. The gcc
648     compiler treats it as an empty string (which was what was wanted) but it is
649     reported that Visual C gives an error. The source has been hacked around to
650     avoid this problem.
651    
652     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
653     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
654     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
655     of them did).
656    
657     10. Originally, pcretest opened its input and output without "b"; then I was
658     told that "b" was needed in some environments, so it was added for release
659     5.0 to both the input and output. (It makes no difference on Unix-like
660     systems.) Later I was told that it is wrong for the input on Windows. I've
661     now abstracted the modes into two macros, to make it easier to fiddle with
662     them, and removed "b" from the input mode under Windows.
663    
664     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
665    
666     12. Added -help and --help to pcretest as an official way of being reminded
667     of the options.
668    
669     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
670     and pcrecpp.cc because they annoy compilers at high warning levels.
671    
672     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
673    
674     15. Fixed an occurrence of == in configure.ac that should have been = (shell
675     scripts are not C programs :-) and which was not noticed because it works
676     on Linux.
677    
678     16. pcretest is supposed to handle any length of pattern and data line (as one
679     line or as a continued sequence of lines) by extending its input buffer if
680     necessary. This feature was broken for very long pattern lines, leading to
681     a string of junk being passed to pcre_compile() if the pattern was longer
682     than about 50K.
683    
684     17. I have done a major re-factoring of the way pcre_compile() computes the
685     amount of memory needed for a compiled pattern. Previously, there was code
686     that made a preliminary scan of the pattern in order to do this. That was
687     OK when PCRE was new, but as the facilities have expanded, it has become
688     harder and harder to keep it in step with the real compile phase, and there
689     have been a number of bugs (see for example, 4 above). I have now found a
690     cunning way of running the real compile function in a "fake" mode that
691     enables it to compute how much memory it would need, while actually only
692     ever using a few hundred bytes of working memory and without too many
693     tests of the mode. This should make future maintenance and development
694     easier. A side effect of this work is that the limit of 200 on the nesting
695     depth of parentheses has been removed (though this was never a serious
696     limitation, I suspect). However, there is a downside: pcre_compile() now
697     runs more slowly than before (30% or more, depending on the pattern). I
698     hope this isn't a big issue. There is no effect on runtime performance.
699    
700     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
701     newline (only possible for the last line of a file) and it was a
702     pattern that set a locale (followed by /Lsomething), pcretest crashed.
703    
704     19. Added additional timing features to pcretest. (1) The -tm option now times
705     matching only, not compiling. (2) Both -t and -tm can be followed, as a
706     separate command line item, by a number that specifies the number of
707     repeats to use when timing. The default is 50000; this gives better
708     precision, but takes uncomfortably long for very large patterns.
709    
710     20. Extended pcre_study() to be more clever in cases where a branch of a
711     subpattern has no definite first character. For example, (a*|b*)[cd] would
712     previously give no result from pcre_study(). Now it recognizes that the
713     first character must be a, b, c, or d.
714    
715     21. There was an incorrect error "recursive call could loop indefinitely" if
716     a subpattern (or the entire pattern) that was being tested for matching an
717     empty string contained only one non-empty item after a nested subpattern.
718     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
719     incorrectly, because the \d was being skipped in the check.
720    
721     22. The pcretest program now has a new pattern option /B and a command line
722     option -b, which is equivalent to adding /B to every pattern. This causes
723     it to show the compiled bytecode, without the additional information that
724     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
725     is the same as /B/I).
726    
727     23. A new optimization is now able automatically to treat some sequences such
728     as a*b as a*+b. More specifically, if something simple (such as a character
729     or a simple class like \d) has an unlimited quantifier, and is followed by
730     something that cannot possibly match the quantified thing, the quantifier
731     is automatically "possessified".
732    
733     24. A recursive reference to a subpattern whose number was greater than 39
734     went wrong under certain circumstances in UTF-8 mode. This bug could also
735     have affected the operation of pcre_study().
736    
737     25. Realized that a little bit of performance could be had by replacing
738     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
739    
740     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
741    
742     27. Possessive quantifiers such as a++ were previously implemented by turning
743     them into atomic groups such as ($>a+). Now they have their own opcodes,
744     which improves performance. This includes the automatically created ones
745     from 23 above.
746    
747     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
748     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
749     the first matched character to be a colon. This applied both to named and
750     numbered groups.
751    
752     29. The ucpinternal.h header file was missing its idempotency #ifdef.
753    
754     30. I was sent a "project" file called libpcre.a.dev which I understand makes
755     building PCRE on Windows easier, so I have included it in the distribution.
756    
757     31. There is now a check in pcretest against a ridiculously large number being
758     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
759     loop, the loop is abandoned.
760    
761     32. Forward references to subpatterns in conditions such as (?(2)...) where
762     subpattern 2 is defined later cause pcre_compile() to search forwards in
763     the pattern for the relevant set of parentheses. This search went wrong
764     when there were unescaped parentheses in a character class, parentheses
765     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
766    
767     33. "Subroutine" calls and backreferences were previously restricted to
768     referencing subpatterns earlier in the regex. This restriction has now
769     been removed.
770    
771     34. Added a number of extra features that are going to be in Perl 5.10. On the
772     whole, these are just syntactic alternatives for features that PCRE had
773     previously implemented using the Python syntax or my own invention. The
774     other formats are all retained for compatibility.
775    
776     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
777     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
778     also .NET compatible.
779    
780     (b) A recursion or subroutine call to a named group can now be defined as
781     (?&name) as well as (?P>name).
782    
783     (c) A backreference to a named group can now be defined as \k<name> or
784     \k'name' as well as (?P=name). The new forms, as well as being in Perl
785     5.10, are also .NET compatible.
786    
787     (d) A conditional reference to a named group can now use the syntax
788     (?(<name>) or (?('name') as well as (?(name).
789    
790     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
791     groups (named and numbered) that are never evaluated inline, but can be
792     called as "subroutines" from elsewhere. In effect, the DEFINE condition
793     is always false. There may be only one alternative in such a group.
794    
795     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
796     as the simple (?(R). The condition is true only if the most recent
797     recursion is that of the given number or name. It does not search out
798     through the entire recursion stack.
799    
800     (g) The escape \gN or \g{N} has been added, where N is a positive or
801     negative number, specifying an absolute or relative reference.
802    
803     35. Tidied to get rid of some further signed/unsigned compiler warnings and
804     some "unreachable code" warnings.
805    
806     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
807     things, this adds five new scripts.
808    
809     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
810     There were also incompatibilities regarding the handling of \Q..\E inside
811     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
812     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
813    
814     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
815     matches an empty string, and forcibly breaks the loop. There were bugs in
816     this code in non-simple cases. For a pattern such as ^(a()*)* matched
817     against aaaa the result was just "a" rather than "aaaa", for example. Two
818     separate and independent bugs (that affected different cases) have been
819     fixed.
820    
821     39. Refactored the code to abolish the use of different opcodes for small
822     capturing bracket numbers. This is a tidy that I avoided doing when I
823     removed the limit on the number of capturing brackets for 3.5 back in 2001.
824     The new approach is not only tidier, it makes it possible to reduce the
825     memory needed to fix the previous bug (38).
826    
827     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
828     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
829     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
830     mode.
831    
832     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
833     report.
834    
835     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
836     copy construction and assignment in the C++ wrapper.
837    
838     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
839     couple of bugs that could have given wrong results in the "--newline=crlf"
840     case.
841    
842     44. Added a number of casts and did some reorganization of signed/unsigned int
843     variables following suggestions from Dair Grant. Also renamed the variable
844     "this" as "item" because it is a C++ keyword.
845    
846     45. Arranged for dftables to add
847    
848     #include "pcre_internal.h"
849    
850     to pcre_chartables.c because without it, gcc 4.x may remove the array
851     definition from the final binary if PCRE is built into a static library and
852     dead code stripping is activated.
853    
854     46. For an unanchored pattern, if a match attempt fails at the start of a
855     newline sequence, and the newline setting is CRLF or ANY, and the next two
856     characters are CRLF, advance by two characters instead of one.
857    
858    
859 nigel 91 Version 6.7 04-Jul-06
860     ---------------------
861    
862     1. In order to handle tests when input lines are enormously long, pcretest has
863     been re-factored so that it automatically extends its buffers when
864     necessary. The code is crude, but this _is_ just a test program. The
865     default size has been increased from 32K to 50K.
866    
867     2. The code in pcre_study() was using the value of the re argument before
868     testing it for NULL. (Of course, in any sensible call of the function, it
869     won't be NULL.)
870    
871     3. The memmove() emulation function in pcre_internal.h, which is used on
872     systems that lack both memmove() and bcopy() - that is, hardly ever -
873     was missing a "static" storage class specifier.
874    
875     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
876     containing an extended class (one that cannot be represented by a bitmap
877     because it contains high-valued characters or Unicode property items, e.g.
878     [\pZ]). Almost always one would set UTF-8 mode when processing such a
879     pattern, but PCRE should not loop if you do not (it no longer does).
880     [Detail: two cases were found: (a) a repeated subpattern containing an
881     extended class; (b) a recursive reference to a subpattern that followed a
882     previous extended class. It wasn't skipping over the extended class
883     correctly when UTF-8 mode was not set.]
884    
885     5. A negated single-character class was not being recognized as fixed-length
886     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
887     compile error "lookbehind assertion is not fixed length".
888    
889     6. The RunPerlTest auxiliary script was showing an unexpected difference
890     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
891     write a Perl script that can interpret lines of an input file either as
892     byte characters or as UTF-8, which is what "perltest" was being required to
893     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
894     can't do is switch easily at run time between having the "use utf8;" pragma
895     or not. In the end, I fudged it by using the RunPerlTest script to insert
896     "use utf8;" explicitly for the UTF-8 tests.
897    
898     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
899     the end of the subject string, contrary to the documentation and to what
900     Perl does. This was true of both matching functions. Now it matches only at
901     the start of the subject and immediately after *internal* newlines.
902    
903     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
904     a pointer to an int instead of a pointer to an unsigned long int. This
905     caused problems on 64-bit systems.
906    
907     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
908     instance of the 'standard' template library not being so standard".
909    
910     10. There was no check on the number of named subpatterns nor the maximum
911     length of a subpattern name. The product of these values is used to compute
912     the size of the memory block for a compiled pattern. By supplying a very
913     long subpattern name and a large number of named subpatterns, the size
914     computation could be caused to overflow. This is now prevented by limiting
915     the length of names to 32 characters, and the number of named subpatterns
916     to 10,000.
917    
918     11. Subpatterns that are repeated with specific counts have to be replicated in
919     the compiled pattern. The size of memory for this was computed from the
920     length of the subpattern and the repeat count. The latter is limited to
921     65535, but there was no limit on the former, meaning that integer overflow
922     could in principle occur. The compiled length of a repeated subpattern is
923     now limited to 30,000 bytes in order to prevent this.
924    
925     12. Added the optional facility to have named substrings with the same name.
926    
927     13. Added the ability to use a named substring as a condition, using the
928     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
929     are numbers (not recommended). Forward references are permitted.
930    
931     14. Added forward references in named backreferences (if you see what I mean).
932    
933     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
934     pattern could run off the end of the subject. For example, the pattern
935     "(?s)(.{1,5})"8 did this with the subject "ab".
936    
937     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
938     PCRE_CASELESS was set when matching characters that were quantified with ?
939     or *.
940    
941     17. A character class other than a single negated character that had a minimum
942     but no maximum quantifier - for example [ab]{6,} - was not handled
943     correctly by pce_dfa_exec(). It would match only one character.
944    
945     18. A valid (though odd) pattern that looked like a POSIX character
946     class but used an invalid character after [ (for example [[,abc,]]) caused
947     pcre_compile() to give the error "Failed: internal error: code overflow" or
948     in some cases to crash with a glibc free() error. This could even happen if
949     the pattern terminated after [[ but there just happened to be a sequence of
950     letters, a binary zero, and a closing ] in the memory that followed.
951    
952     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
953     over the years. Originally (before any Unicode support), just the bottom 8
954     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
955     output from "man perlunicode" includes this:
956    
957     The regular expression compiler produces polymorphic opcodes. That
958     is, the pattern adapts to the data and automatically switches to
959     the Unicode character scheme when presented with Unicode data--or
960     instead uses a traditional byte scheme when presented with byte
961     data.
962    
963     Sadly, a wide octal escape does not cause a switch, and in a string with
964     no other multibyte characters, these octal escapes are treated as before.
965     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
966     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
967     Unicode string.
968    
969     I have not perpetrated such confusion in PCRE. Up till now, it took just
970     the bottom 8 bits, as in old Perl. I have now made octal escapes with
971     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
972     translate to the appropriate multibyte character.
973    
974     29. Applied some refactoring to reduce the number of warnings from Microsoft
975     and Borland compilers. This has included removing the fudge introduced
976     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
977     a warning about an unused variable.
978    
979     21. PCRE has not included VT (character 0x0b) in the set of whitespace
980     characters since release 4.0, because Perl (from release 5.004) does not.
981     [Or at least, is documented not to: some releases seem to be in conflict
982     with the documentation.] However, when a pattern was studied with
983     pcre_study() and all its branches started with \s, PCRE still included VT
984     as a possible starting character. Of course, this did no harm; it just
985     caused an unnecessary match attempt.
986    
987     22. Removed a now-redundant internal flag bit that recorded the fact that case
988     dependency changed within the pattern. This was once needed for "required
989     byte" processing, but is no longer used. This recovers a now-scarce options
990     bit. Also moved the least significant internal flag bit to the most-
991     significant bit of the word, which was not previously used (hangover from
992     the days when it was an int rather than a uint) to free up another bit for
993     the future.
994    
995     23. Added support for CRLF line endings as well as CR and LF. As well as the
996     default being selectable at build time, it can now be changed at runtime
997     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
998     specify that it is scanning data with non-default line endings.
999    
1000     24. Changed the definition of CXXLINK to make it agree with the definition of
1001     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1002    
1003     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1004     recursions. This makes a big different to stack usage for some patterns.
1005    
1006     26. If a subpattern containing a named recursion or subroutine reference such
1007     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1008     the space required for the compiled pattern went wrong and gave too small a
1009     value. Depending on the environment, this could lead to "Failed: internal
1010     error: code overflow at offset 49" or "glibc detected double free or
1011     corruption" errors.
1012    
1013     27. Applied patches from Google (a) to support the new newline modes and (b) to
1014     advance over multibyte UTF-8 characters in GlobalReplace.
1015    
1016     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1017     difference for some implementation of PCRE in some Windows version.
1018    
1019     29. Added some extra testing facilities to pcretest:
1020    
1021     \q<number> in a data line sets the "match limit" value
1022     \Q<number> in a data line sets the "match recursion limt" value
1023     -S <number> sets the stack size, where <number> is in megabytes
1024    
1025     The -S option isn't available for Windows.
1026    
1027    
1028 nigel 89 Version 6.6 06-Feb-06
1029     ---------------------
1030    
1031     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1032     in pcreposix.h. I have copied the definition from pcre.h.
1033    
1034     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1035     because pcre.h is no longer a built file.
1036    
1037     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1038     not normally included in the compiled code.
1039    
1040    
1041 nigel 87 Version 6.5 01-Feb-06
1042     ---------------------
1043    
1044     1. When using the partial match feature with pcre_dfa_exec(), it was not
1045     anchoring the second and subsequent partial matches at the new starting
1046     point. This could lead to incorrect results. For example, with the pattern
1047     /1234/, partially matching against "123" and then "a4" gave a match.
1048    
1049     2. Changes to pcregrep:
1050    
1051     (a) All non-match returns from pcre_exec() were being treated as failures
1052     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1053     error message is output. Some extra information is given for the
1054     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1055     probably the only errors that are likely to be caused by users (by
1056     specifying a regex that has nested indefinite repeats, for instance).
1057     If there are more than 20 of these errors, pcregrep is abandoned.
1058    
1059     (b) A binary zero was treated as data while matching, but terminated the
1060     output line if it was written out. This has been fixed: binary zeroes
1061     are now no different to any other data bytes.
1062    
1063     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1064     used to set a locale for matching. The --locale=xxxx long option has
1065     been added (no short equivalent) to specify a locale explicitly on the
1066     pcregrep command, overriding the environment variables.
1067    
1068     (d) When -B was used with -n, some line numbers in the output were one less
1069     than they should have been.
1070    
1071     (e) Added the -o (--only-matching) option.
1072    
1073     (f) If -A or -C was used with -c (count only), some lines of context were
1074     accidentally printed for the final match.
1075    
1076     (g) Added the -H (--with-filename) option.
1077    
1078     (h) The combination of options -rh failed to suppress file names for files
1079     that were found from directory arguments.
1080    
1081     (i) Added the -D (--devices) and -d (--directories) options.
1082    
1083     (j) Added the -F (--fixed-strings) option.
1084    
1085     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1086    
1087     (l) Added the --colo(u)r option.
1088    
1089     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1090     is not present by default.
1091    
1092     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1093     items such as (?R) or (?1), when the recursion could match a number of
1094     alternatives. If it matched one of the alternatives, but subsequently,
1095     outside the recursion, there was a failure, the code tried to back up into
1096     the recursion. However, because of the way PCRE is implemented, this is not
1097     possible, and the result was an incorrect result from the match.
1098    
1099     In order to prevent this happening, the specification of recursion has
1100     been changed so that all such subpatterns are automatically treated as
1101     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1102    
1103     4. I had overlooked the fact that, in some locales, there are characters for
1104     which isalpha() is true but neither isupper() nor islower() are true. In
1105     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1106     and ordfeminine) are like this. This affected the treatment of \w and \W
1107     when they appeared in character classes, but not when they appeared outside
1108     a character class. The bit map for "word" characters is now created
1109     separately from the results of isalnum() instead of just taking it from the
1110     upper, lower, and digit maps. (Plus the underscore character, of course.)
1111    
1112     5. The above bug also affected the handling of POSIX character classes such as
1113     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1114     permanent tables. Instead, the bit maps for such a class were previously
1115     created as the appropriate unions of the upper, lower, and digit bitmaps.
1116     Now they are created by subtraction from the [[:word:]] class, which has
1117     its own bitmap.
1118    
1119     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1120     It is created by subtracting the vertical space characters (\x09, \x0a,
1121     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1122     subtraction was done in the overall bitmap for a character class, meaning
1123     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1124     be recognized. This bug has been fixed.
1125    
1126     7. Patches from the folks at Google:
1127    
1128     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1129     real life, but is still worth protecting against".
1130    
1131     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1132     regular expressions".
1133    
1134     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1135     have it.
1136    
1137     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1138     "configure" and the latter not, in order to fix a problem somebody had
1139     with compiling the Arg class on HP-UX.
1140    
1141     (e) Improve the error-handling of the C++ wrapper a little bit.
1142    
1143     (f) New tests for checking recursion limiting.
1144    
1145     8. The pcre_memmove() function, which is used only if the environment does not
1146     have a standard memmove() function (and is therefore rarely compiled),
1147     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1148     returning a result (though PCRE never actually uses the result).
1149    
1150     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1151     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1152     returned instead of calling malloc() with an overflowing number that would
1153     most likely cause subsequent chaos.
1154    
1155     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1156    
1157     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1158     with this option is matched, the nmatch and pmatch options of regexec() are
1159     ignored.
1160    
1161     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1162     provided in case anyone wants to the the POSIX interface with UTF-8
1163     strings.
1164    
1165     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1166     C++ linking (needed for some HP-UX environments).
1167    
1168     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1169     (unused parameter) and in the pcre_printint() function (omitted "default"
1170     switch label when the default is to do nothing).
1171    
1172     15. Added some code to make it possible, when PCRE is compiled as a C++
1173     library, to replace subject pointers for pcre_exec() with a smart pointer
1174     class, thus making it possible to process discontinuous strings.
1175    
1176     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1177     much the same function. They were added by different people who were trying
1178     to make PCRE easy to compile on non-Unix systems. It has been suggested
1179     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1180     for compiling on Windows systems. I have therefore replaced it with
1181     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1182     defaults to "extern" for C or "extern C" for C++, which works fine on
1183     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1184     SCOPE with something explicit in config.h. In addition:
1185    
1186     (a) pcreposix.h still had just "extern" instead of either of these macros;
1187     I have replaced it with PCRE_DATA_SCOPE.
1188    
1189     (b) Functions such as _pcre_xclass(), which are internal to the library,
1190     but external in the C sense, all had PCRE_EXPORT in their definitions.
1191     This is apparently wrong for the Windows case, so I have removed it.
1192     (It makes no difference on Unix-like systems.)
1193    
1194     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1195     of recursive calls to match(). This is different to MATCH_LIMIT because
1196     that limits the total number of calls to match(), not all of which increase
1197     the depth of recursion. Limiting the recursion depth limits the amount of
1198     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1199     when PCRE is compiled, and changed at run time. A patch from Google adds
1200     this functionality to the C++ interface.
1201    
1202     18. Changes to the handling of Unicode character properties:
1203    
1204     (a) Updated the table to Unicode 4.1.0.
1205    
1206     (b) Recognize characters that are not in the table as "Cn" (undefined).
1207    
1208     (c) I revised the way the table is implemented to a much improved format
1209     which includes recognition of ranges. It now supports the ranges that
1210     are defined in UnicodeData.txt, and it also amalgamates other
1211     characters into ranges. This has reduced the number of entries in the
1212     table from around 16,000 to around 3,000, thus reducing its size
1213     considerably. I realized I did not need to use a tree structure after
1214     all - a binary chop search is just as efficient. Having reduced the
1215     number of entries, I extended their size from 6 bytes to 8 bytes to
1216     allow for more data.
1217    
1218     (d) Added support for Unicode script names via properties such as \p{Han}.
1219    
1220     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1221     matching that character.
1222    
1223     20. When matching a repeated Unicode property with a minimum greater than zero,
1224     (for example \pL{2,}), PCRE could look past the end of the subject if it
1225     reached it while seeking the minimum number of characters. This could
1226     happen only if some of the characters were more than one byte long, because
1227     there is a check for at least the minimum number of bytes.
1228    
1229     21. Refactored the implementation of \p and \P so as to be more general, to
1230     allow for more different types of property in future. This has changed the
1231     compiled form incompatibly. Anybody with saved compiled patterns that use
1232     \p or \P will have to recompile them.
1233    
1234     22. Added "Any" and "L&" to the supported property types.
1235    
1236     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1237     but give a compile time error if the value is greater than 0xff.
1238    
1239     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1240     accidentally not being installed or uninstalled.
1241    
1242     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1243     made were to insert the current release number. This seemed silly, because
1244     it made things harder for people building PCRE on systems that don't run
1245     "configure". I have turned pcre.h into a distributed file, no longer built
1246     by "configure", with the version identification directly included. There is
1247     no longer a pcre.h.in file.
1248    
1249     However, this change necessitated a change to the pcre-config script as
1250     well. It is built from pcre-config.in, and one of the substitutions was the
1251     release number. I have updated configure.ac so that ./configure now finds
1252     the release number by grepping pcre.h.
1253    
1254     26. Added the ability to run the tests under valgrind.
1255    
1256    
1257 nigel 85 Version 6.4 05-Sep-05
1258     ---------------------
1259    
1260     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1261     "--" to be printed when multiple files were scanned, even when none of the
1262     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1263     consider it to be a bug, and have restored the previous behaviour.
1264    
1265     2. A couple of code tidies to get rid of compiler warnings.
1266    
1267     3. The pcretest program used to cheat by referring to symbols in the library
1268     whose names begin with _pcre_. These are internal symbols that are not
1269     really supposed to be visible externally, and in some environments it is
1270     possible to suppress them. The cheating is now confined to including
1271     certain files from the library's source, which is a bit cleaner.
1272    
1273     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1274     file's purpose clearer.
1275    
1276     5. Reorganized pcre_ucp_findchar().
1277    
1278    
1279 nigel 83 Version 6.3 15-Aug-05
1280     ---------------------
1281    
1282     1. The file libpcre.pc.in did not have general read permission in the tarball.
1283    
1284     2. There were some problems when building without C++ support:
1285    
1286     (a) If C++ support was not built, "make install" and "make test" still
1287     tried to test it.
1288    
1289     (b) There were problems when the value of CXX was explicitly set. Some
1290     changes have been made to try to fix these, and ...
1291    
1292     (c) --disable-cpp can now be used to explicitly disable C++ support.
1293    
1294     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1295     backslash in a target when C++ was disabled. This confuses some
1296     versions of "make", apparently. Using an intermediate variable solves
1297     this. (Same for CPP_LOBJ.)
1298    
1299     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1300     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1301     necessary on certain architectures.
1302    
1303     4. Added a setting of -export-symbols-regex to the link command to remove
1304     those symbols that are exported in the C sense, but actually are local
1305     within the library, and not documented. Their names all begin with
1306     "_pcre_". This is not a perfect job, because (a) we have to except some
1307     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1308     available (and never for static libraries). I have made a note to try to
1309     find a way round (a) in the future.
1310    
1311    
1312 nigel 81 Version 6.2 01-Aug-05
1313     ---------------------
1314    
1315     1. There was no test for integer overflow of quantifier values. A construction
1316     such as {1111111111111111} would give undefined results. What is worse, if
1317     a minimum quantifier for a parenthesized subpattern overflowed and became
1318     negative, the calculation of the memory size went wrong. This could have
1319     led to memory overwriting.
1320    
1321     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1322    
1323     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1324     operating environments where this matters.
1325    
1326     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1327     PCRE options from within the C++ wrapper.
1328    
1329     5. Named capturing subpatterns were not being correctly counted when a pattern
1330     was compiled. This caused two problems: (a) If there were more than 100
1331     such subpatterns, the calculation of the memory needed for the whole
1332     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1333     back references of the form \12, where the number was greater than 9, were
1334     not recognized as back references, even though there were sufficient
1335     previous subpatterns.
1336    
1337     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1338     versions of gcc, e.g. 2.95.4.
1339    
1340    
1341 nigel 79 Version 6.1 21-Jun-05
1342     ---------------------
1343    
1344     1. There was one reference to the variable "posix" in pcretest.c that was not
1345     surrounded by "#if !defined NOPOSIX".
1346    
1347     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1348     the cross-check on the old pcre_info() function, for the benefit of the
1349     cut-down version of PCRE that is currently imported into Exim.
1350    
1351     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1352     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1353     patterns that start (?i) but I don't think that matters. The use of (?i) is
1354     just an example; this all applies to the other options as well.
1355    
1356     4. Since libtool seems to echo the compile commands it is issuing, the output
1357     from "make" can be reduced a bit by putting "@" in front of each libtool
1358     compile command.
1359    
1360     5. Patch from the folks at Google for configure.in to be a bit more thorough
1361     in checking for a suitable C++ installation before trying to compile the
1362     C++ stuff. This should fix a reported problem when a compiler was present,
1363     but no suitable headers.
1364    
1365     6. The man pages all had just "PCRE" as their title. I have changed them to
1366     be the relevant file name. I have also arranged that these names are
1367     retained in the file doc/pcre.txt, which is a concatenation in text format
1368     of all the man pages except the little individual ones for each function.
1369    
1370     7. The NON-UNIX-USE file had not been updated for the different set of source
1371     files that come with release 6. I also added a few comments about the C++
1372     wrapper.
1373    
1374    
1375 nigel 77 Version 6.0 07-Jun-05
1376     ---------------------
1377    
1378     1. Some minor internal re-organization to help with my DFA experiments.
1379    
1380     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1381     didn't matter for the library itself when fully configured, but did matter
1382     when compiling without UCP support, or within Exim, where the ucp files are
1383     not imported.
1384    
1385     3. Refactoring of the library code to split up the various functions into
1386     different source modules. The addition of the new DFA matching code (see
1387     below) to a single monolithic source would have made it really too
1388     unwieldy, quite apart from causing all the code to be include in a
1389     statically linked application, when only some functions are used. This is
1390     relevant even without the DFA addition now that patterns can be compiled in
1391     one application and matched in another.
1392    
1393     The downside of splitting up is that there have to be some external
1394     functions and data tables that are used internally in different modules of
1395     the library but which are not part of the API. These have all had their
1396     names changed to start with "_pcre_" so that they are unlikely to clash
1397     with other external names.
1398    
1399     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1400     a different (DFA) algorithm. Although it is slower than the original
1401     function, it does have some advantages for certain types of matching
1402     problem.
1403    
1404     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1405     including restarting after a partial match.
1406    
1407     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1408     defined when compiling for Windows was sent to me. I have put it into the
1409     code, though I have no means of testing or verifying it.
1410    
1411     7. Added the pcre_refcount() auxiliary function.
1412    
1413     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1414     match before or at the first newline in the subject string. In pcretest,
1415     the /f option on a pattern can be used to set this.
1416    
1417     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1418     would behave wrongly. This has been present in PCRE since release 4.0.
1419    
1420     10. A number of changes to the pcregrep command:
1421    
1422     (a) Refactored how -x works; insert ^(...)$ instead of setting
1423     PCRE_ANCHORED and checking the length, in preparation for adding
1424     something similar for -w.
1425    
1426     (b) Added the -w (match as a word) option.
1427    
1428     (c) Refactored the way lines are read and buffered so as to have more
1429     than one at a time available.
1430    
1431     (d) Implemented a pcregrep test script.
1432    
1433     (e) Added the -M (multiline match) option. This allows patterns to match
1434     over several lines of the subject. The buffering ensures that at least
1435     8K, or the rest of the document (whichever is the shorter) is available
1436     for matching (and similarly the previous 8K for lookbehind assertions).
1437    
1438     (f) Changed the --help output so that it now says
1439    
1440     -w, --word-regex(p)
1441    
1442     instead of two lines, one with "regex" and the other with "regexp"
1443     because that confused at least one person since the short forms are the
1444     same. (This required a bit of code, as the output is generated
1445     automatically from a table. It wasn't just a text change.)
1446    
1447     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1448     option but starts with a hyphen. Could be a pattern or a path name
1449     starting with a hyphen, for instance.
1450    
1451     (h) "-" can be given as a file name to represent stdin.
1452    
1453     (i) When file names are being printed, "(standard input)" is used for
1454     the standard input, for compatibility with GNU grep. Previously
1455     "<stdin>" was used.
1456    
1457     (j) The option --label=xxx can be used to supply a name to be used for
1458     stdin when file names are being printed. There is no short form.
1459    
1460     (k) Re-factored the options decoding logic because we are going to add
1461     two more options that take data. Such options can now be given in four
1462     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1463    
1464     (l) Added the -A, -B, and -C options for requesting that lines of context
1465     around matches be printed.
1466    
1467     (m) Added the -L option to print the names of files that do not contain
1468     any matching lines, that is, the complement of -l.
1469    
1470     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1471     continue to scan other files.
1472    
1473     (o) The -s option was incorrectly implemented. For compatibility with other
1474     greps, it now suppresses the error message for a non-existent or non-
1475     accessible file (but not the return code). There is a new option called
1476     -q that suppresses the output of matching lines, which was what -s was
1477     previously doing.
1478    
1479     (p) Added --include and --exclude options to specify files for inclusion
1480     and exclusion when recursing.
1481    
1482     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1483     Hopefully, it now does.
1484    
1485     12. Missing cast in pcre_study().
1486    
1487     13. Added an "uninstall" target to the makefile.
1488    
1489     14. Replaced "extern" in the function prototypes in Makefile.in with
1490     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1491     world, but is set differently for Windows.
1492    
1493     15. Added a second compiling function called pcre_compile2(). The only
1494     difference is that it has an extra argument, which is a pointer to an
1495     integer error code. When there is a compile-time failure, this is set
1496     non-zero, in addition to the error test pointer being set to point to an
1497     error message. The new argument may be NULL if no error number is required
1498     (but then you may as well call pcre_compile(), which is now just a
1499     wrapper). This facility is provided because some applications need a
1500     numeric error indication, but it has also enabled me to tidy up the way
1501     compile-time errors are handled in the POSIX wrapper.
1502    
1503     16. Added VPATH=.libs to the makefile; this should help when building with one
1504     prefix path and installing with another. (Or so I'm told by someone who
1505     knows more about this stuff than I do.)
1506    
1507     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1508     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1509     match everything, including newlines. This is not POSIX-compatible, but
1510     somebody wanted the feature. From pcretest it can be activated by using
1511     both the P and the s flags.
1512    
1513     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1514    
1515     19. libpcre.pc was being incorrectly installed as executable.
1516    
1517     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1518     it now also looks for '\r' so that it will work unmodified on Windows.
1519    
1520     21. Added Google's contributed C++ wrapper to the distribution.
1521    
1522     22. Added some untidy missing memory free() calls in pcretest, to keep
1523     Electric Fence happy when testing.
1524    
1525    
1526    
1527 nigel 75 Version 5.0 13-Sep-04
1528     ---------------------
1529    
1530     1. Internal change: literal characters are no longer packed up into items
1531     containing multiple characters in a single byte-string. Each character
1532     is now matched using a separate opcode. However, there may be more than one
1533     byte in the character in UTF-8 mode.
1534    
1535     2. The pcre_callout_block structure has two new fields: pattern_position and
1536     next_item_length. These contain the offset in the pattern to the next match
1537     item, and its length, respectively.
1538    
1539     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1540     insertion of callouts before each pattern item. Added the /C option to
1541     pcretest to make use of this.
1542    
1543     4. On the advice of a Windows user, the lines
1544    
1545     #if defined(_WIN32) || defined(WIN32)
1546     _setmode( _fileno( stdout ), 0x8000 );
1547     #endif /* defined(_WIN32) || defined(WIN32) */
1548    
1549     have been added to the source of pcretest. This apparently does useful
1550     magic in relation to line terminators.
1551    
1552     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1553     for the benefit of those environments where the "b" makes a difference.
1554    
1555     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1556     to know about it. I have put a hack into configure.in that adds in code
1557     to set GCC=yes if CC=icc. This seems to end up at a point in the
1558     generated configure script that is early enough to affect the setting of
1559     compiler options, which is what is needed, but I have no means of testing
1560     whether it really works. (The user who reported this had patched the
1561     generated configure script, which of course I cannot do.)
1562    
1563     LATER: After change 22 below (new libtool files), the configure script
1564     seems to know about icc (and also ecc). Therefore, I have commented out
1565     this hack in configure.in.
1566    
1567     7. Added support for pkg-config (2 patches were sent in).
1568    
1569     8. Negated POSIX character classes that used a combination of internal tables
1570     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1571     [[:^ascii]]. Typically, they would match almost any characters. The other
1572     POSIX classes were not broken in this way.
1573    
1574     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1575     to find the match, as PCRE was deluded into thinking that the match had to
1576     start at the start point or following a newline. The same bug applied to
1577     patterns with negative forward assertions or any backward assertions
1578     preceding ".*" at the start, unless the pattern required a fixed first
1579     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1580    
1581     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1582     starting at the last subject character, bytes beyond the end of the subject
1583     string were read.
1584    
1585     11. Renamed the variable "class" as "classbits" to make life easier for C++
1586     users. (Previously there was a macro definition, but it apparently wasn't
1587     enough.)
1588    
1589     12. Added the new field "tables" to the extra data so that tables can be passed
1590     in at exec time, or the internal tables can be re-selected. This allows
1591     a compiled regex to be saved and re-used at a later time by a different
1592     program that might have everything at different addresses.
1593    
1594     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1595     -R library as well as a -L library.
1596    
1597     14. The debugging options of pcretest (-d on the command line or D on a
1598     pattern) showed incorrect output for anything following an extended class
1599     that contained multibyte characters and which was followed by a quantifier.
1600    
1601     15. Added optional support for general category Unicode character properties
1602     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1603     support. It adds about 90K to the size of the library. The meanings of the
1604     inbuilt class escapes such as \d and \s have NOT been changed.
1605    
1606     16. Updated pcredemo.c to include calls to free() to release the memory for the
1607     compiled pattern.
1608    
1609     17. The generated file chartables.c was being created in the source directory
1610     instead of in the building directory. This caused the build to fail if the
1611     source directory was different from the building directory, and was
1612     read-only.
1613    
1614     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1615     file. No doubt somebody will tell me if they don't make sense... Also added
1616     Dan Mooney's comments about building on OpenVMS.
1617    
1618     19. Added support for partial matching via the PCRE_PARTIAL option for
1619     pcre_exec() and the \P data escape in pcretest.
1620    
1621     20. Extended pcretest with 3 new pattern features:
1622    
1623     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1624     write the compiled pattern to the file whose name is "rest-of-line".
1625     This is a straight binary dump of the data, with the saved pointer to
1626     the character tables forced to be NULL. The study data, if any, is
1627     written too. After writing, pcretest reads a new pattern.
1628    
1629     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1630     compiled pattern from the given file. There must not be any
1631     occurrences of "<" in the file name (pretty unlikely); if there are,
1632     pcretest will instead treat the initial "<" as a pattern delimiter.
1633     After reading in the pattern, pcretest goes on to read data lines as
1634     usual.
1635    
1636     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1637     and 16-bit fields in a compiled pattern, to simulate a pattern that
1638     was compiled on a host of opposite endianness.
1639    
1640     21. The pcre-exec() function can now cope with patterns that were compiled on
1641     hosts of opposite endianness, with this restriction:
1642    
1643     As for any compiled expression that is saved and used later, the tables
1644     pointer field cannot be preserved; the extra_data field in the arguments
1645     to pcre_exec() should be used to pass in a tables address if a value
1646     other than the default internal tables were used at compile time.
1647    
1648     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1649     now diagnosed as an error. Previously, most of the time, a negative number
1650     would have been treated as zero, but if in addition "ovector" was passed as
1651     NULL, a crash could occur.
1652    
1653     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1654     new versions from the libtool 1.5 distribution (the last one is a copy of
1655     a file called libtool.m4). This seems to have fixed the need to patch
1656     "configure" to support Darwin 1.3 (which I used to do). However, I still
1657     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1658     workstation).
1659    
1660     24. Changed the PCRE licence to be the more standard "BSD" licence.
1661    
1662    
1663 nigel 73 Version 4.5 01-Dec-03
1664     ---------------------
1665    
1666     1. There has been some re-arrangement of the code for the match() function so
1667     that it can be compiled in a version that does not call itself recursively.
1668     Instead, it keeps those local variables that need separate instances for
1669     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1670     needs to "recurse". Keeping track of where control must go is done by means
1671     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1672     hide most of the details from the main code, and operates only if
1673     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1674     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1675     operating.
1676    
1677     To make it easier for callers to provide specially tailored get/free
1678     functions for this usage, two new functions, pcre_stack_malloc, and
1679     pcre_stack_free, are used. They are always called in strict stacking order,
1680     and the size of block requested is always the same.
1681    
1682     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1683     PCRE has been compiled to use the stack or the heap for recursion. The
1684     -C option of pcretest uses this to show which version is compiled.
1685    
1686     A new data escape \S, is added to pcretest; it causes the amounts of store
1687     obtained and freed by both kinds of malloc/free at match time to be added
1688     to the output.
1689    
1690     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1691     what's available on my current Linux desktop machine.
1692    
1693     3. When matching a UTF-8 string, the test for a valid string at the start has
1694     been extended. If start_offset is not zero, PCRE now checks that it points
1695     to a byte that is the start of a UTF-8 character. If not, it returns
1696     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1697     this is necessary because there may be backward assertions in the pattern.
1698     When matching the same subject several times, it may save resources to use
1699     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1700    
1701     4. The code for checking the validity of UTF-8 strings has been tightened so
1702     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1703     containing "overlong sequences".
1704    
1705     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1706     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1707     should have been "&", but it just so happened that all the cases this let
1708     through by mistake were picked up later in the function.
1709    
1710     6. I had used a variable called "isblank" - this is a C99 function, causing
1711     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1712    
1713     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1714     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1715     so the version is shown; (c) stop "make test" echoing "./RunTest".
1716    
1717     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1718    
1719     9. The prototype for memmove() for systems that don't have it was using
1720     size_t, but the inclusion of the header that defines size_t was later. I've
1721     moved the #includes for the C headers earlier to avoid this.
1722    
1723     10. Added some adjustments to the code to make it easier to compiler on certain
1724     special systems:
1725    
1726     (a) Some "const" qualifiers were missing.
1727     (b) Added the macro EXPORT before all exported functions; by default this
1728     is defined to be empty.
1729     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1730     that it reads its output file name as an argument instead of writing
1731     to the standard output and assuming this can be redirected.
1732    
1733     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1734     class containing characters with values greater than 255, PCRE compilation
1735     went into a loop.
1736    
1737     12. A recursive reference to a subpattern that was within another subpattern
1738     that had a minimum quantifier of zero caused PCRE to crash. For example,
1739     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1740     recursion. If the recursively-called subpattern itself had a zero repeat,
1741     that was OK.
1742    
1743     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1744     buffer into which it was copied (for escape processing) was still set at
1745     1024, so long lines caused crashes.
1746    
1747     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1748     "internal error: code overflow...". This applied to any character class
1749     that was followed by a possessive quantifier.
1750    
1751     15. Modified the Makefile to add libpcre.la as a prerequisite for
1752     libpcreposix.la because I was told this is needed for a parallel build to
1753     work.
1754    
1755     16. If a pattern that contained .* following optional items at the start was
1756     studied, the wrong optimizing data was generated, leading to matching
1757     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1758     matching string must start with a or b or c. The correct conclusion for
1759     this pattern is that a match can start with any character.
1760    
1761    
1762 nigel 71 Version 4.4 13-Aug-03
1763     ---------------------
1764    
1765     1. In UTF-8 mode, a character class containing characters with values between
1766     127 and 255 was not handled correctly if the compiled pattern was studied.
1767     In fixing this, I have also improved the studying algorithm for such
1768     classes (slightly).
1769    
1770     2. Three internal functions had redundant arguments passed to them. Removal
1771     might give a very teeny performance improvement.
1772    
1773     3. Documentation bug: the value of the capture_top field in a callout is *one
1774     more than* the number of the hightest numbered captured substring.
1775    
1776     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1777     in incorrectly linking with a previously installed version. They now link
1778     explicitly with libpcre.la.
1779    
1780     5. configure.in no longer needs to recognize Cygwin specially.
1781    
1782     6. A problem in pcre.in for Windows platforms is fixed.
1783    
1784     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1785     pcretest, it used to include the size of the study block as part of its
1786     output. Unfortunately, the structure contains a field that has a different
1787     size on different hardware architectures. This meant that the tests that
1788     showed this size failed. As the block is currently always of a fixed size,
1789     this information isn't actually particularly useful in pcretest output, so
1790     I have just removed it.
1791    
1792     8. Three pre-processor statements accidentally did not start in column 1.
1793     Sadly, there are *still* compilers around that complain, even though
1794     standard C has not required this for well over a decade. Sigh.
1795    
1796     9. In pcretest, the code for checking callouts passed small integers in the
1797     callout_data field, which is a void * field. However, some picky compilers
1798     complained about the casts involved for this on 64-bit systems. Now
1799     pcretest passes the address of the small integer instead, which should get
1800     rid of the warnings.
1801    
1802     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1803     both compile and run time, and gives an error if an invalid UTF-8 sequence
1804     is found. There is a option for disabling this check in cases where the
1805     string is known to be correct and/or the maximum performance is wanted.
1806    
1807     11. In response to a bug report, I changed one line in Makefile.in from
1808    
1809     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1810     to
1811     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1812    
1813     to look similar to other lines, but I have no way of telling whether this
1814     is the right thing to do, as I do not use Windows. No doubt I'll get told
1815     if it's wrong...
1816    
1817    
1818 nigel 69 Version 4.3 21-May-03
1819     ---------------------
1820    
1821     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1822     Makefile.
1823    
1824     2. Some refactoring to improve the quality of the code:
1825    
1826     (i) The utf8_table... variables are now declared "const".
1827    
1828     (ii) The code for \cx, which used the "case flipping" table to upper case
1829     lower case letters, now just substracts 32. This is ASCII-specific,
1830     but the whole concept of \cx is ASCII-specific, so it seems
1831     reasonable.
1832    
1833     (iii) PCRE was using its character types table to recognize decimal and
1834     hexadecimal digits in the pattern. This is silly, because it handles
1835     only 0-9, a-f, and A-F, but the character types table is locale-
1836     specific, which means strange things might happen. A private
1837     table is now used for this - though it costs 256 bytes, a table is
1838     much faster than multiple explicit tests. Of course, the standard
1839     character types table is still used for matching digits in subject
1840     strings against \d.
1841    
1842     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1843     ending in _t are). So I've renamed it as ESC_tee.
1844    
1845     3. The first argument for regexec() in the POSIX wrapper should have been
1846     defined as "const".
1847    
1848     4. Changed pcretest to use malloc() for its buffers so that they can be
1849     Electric Fenced for debugging.
1850    
1851     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1852     to read one or more bytes before the start of the subject string. Often this
1853     had no effect on PCRE's behaviour, but in some circumstances it could
1854     provoke a segmentation fault.
1855    
1856     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1857     to try to read one or more bytes before the start of the subject string.
1858    
1859     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1860     UTF-8 support could misbehave in various ways if the subject string
1861     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1862     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1863     back over UTF-8 characters.)
1864    
1865    
1866 nigel 67 Version 4.2 14-Apr-03
1867     ---------------------
1868    
1869     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1870    
1871     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1872     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1873     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1874     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1875     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1876     and BUILD_EXEEXT
1877     Note: automatic setting of the BUILD variables is not yet working
1878     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1879     compile-time but not at link-time
1880     [LINK]: use for linking executables only
1881     make different versions for Windows and non-Windows
1882     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1883     libraries
1884     [LINK_FOR_BUILD]: new variable
1885     [OBJEXT]: use throughout
1886     [EXEEXT]: use throughout
1887     <winshared>: new target
1888     <wininstall>: new target
1889     <dftables.o>: use native compiler
1890     <dftables>: use native linker
1891     <install>: handle Windows platform correctly
1892     <clean>: ditto
1893     <check>: ditto
1894     copy DLL to top builddir before testing
1895    
1896     As part of these changes, -no-undefined was removed again. This was reported
1897     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1898     in any case.
1899    
1900     3. Some tidies to get rid of compiler warnings:
1901    
1902     . In the match_data structure, match_limit was an unsigned long int, whereas
1903     match_call_count was an int. I've made them both unsigned long ints.
1904    
1905     . In pcretest the fact that a const uschar * doesn't automatically cast to
1906     a void * provoked a warning.
1907    
1908     . Turning on some more compiler warnings threw up some "shadow" variables
1909     and a few more missing casts.
1910    
1911     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1912     option, a class that contained a single character with a value between 128
1913     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1914    
1915     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1916     option, a class that contained several characters, but with at least one
1917     whose value was between 128 and 255 caused PCRE to crash.
1918    
1919    
1920 nigel 65 Version 4.1 12-Mar-03
1921     ---------------------
1922 nigel 63
1923 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1924     needed, and a string in dftables.c that was longer than standard compilers are
1925     required to support.
1926    
1927     2. Compiling with Sun's compiler found a few more places where the code could
1928     be tidied up in order to avoid warnings.
1929    
1930     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1931     first of these names is deprecated in the latest Autoconf in favour of the name
1932     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1933     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1934     analogy I have changed it to CFLAGS_FOR_BUILD.
1935    
1936     4. Added -no-undefined to the linking command in the Makefile, because this is
1937     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1938     linking step for the pcreposix library.
1939    
1940     5. PCRE was failing to diagnose the case of two named groups with the same
1941     name.
1942    
1943     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1944     literal character that is needed in the subject for a match, and scans along to
1945     ensure that it is present before embarking on the full matching process. This
1946     saves time in cases of nested unlimited repeats that are never going to match.
1947     Problem: the scan can take a lot of time if the subject is very long (e.g.
1948     megabytes), thus penalizing straightforward matches. It is now done only if the
1949     amount of subject to be scanned is less than 1000 bytes.
1950    
1951     7. A lesser problem with the same optimization is that it was recording the
1952     first character of an anchored pattern as "needed", thus provoking a search
1953     right along the subject, even when the first match of the pattern was going to
1954     fail. The "needed" character is now not set for anchored patterns, unless it
1955     follows something in the pattern that is of non-fixed length. Thus, it still
1956     fulfils its original purpose of finding quick non-matches in cases of nested
1957     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1958    
1959    
1960     Version 4.0 17-Feb-03
1961     ---------------------
1962    
1963 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1964     extended to the end of string, PCRE compiled incorrect data. This could lead to
1965     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1966    
1967     2. Moved to autoconf 2.53 and libtool 1.4.2.
1968    
1969     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1970     the special perltest8 script is no longer needed - all the tests can be run
1971     from a single perltest script.
1972    
1973     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1974     by \s. It has now been removed in PCRE. This means it isn't recognized as
1975     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1976     class [:space:] *does* include VT, thereby creating a mess.
1977    
1978     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1979     space and tab.
1980    
1981     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1982     its new features into the main test script, reducing the number of scripts.
1983    
1984     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1985     were backward compatible, and made the (?i) apply to the whole pattern, as if
1986     /i were given. Now it behaves more logically, and applies the option setting
1987     only to what follows. PCRE has been changed to follow suit. However, if it
1988     finds options settings right at the start of the pattern, it extracts them into
1989     the global options, as before. Thus, they show up in the info data.
1990    
1991     8. Added support for the \Q...\E escape sequence. Characters in between are
1992     treated as literals. This is slightly different from Perl in that $ and @ are
1993     also handled as literals inside the quotes. In Perl, they will cause variable
1994     interpolation. Note the following examples:
1995    
1996     Pattern PCRE matches Perl matches
1997    
1998     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1999     \Qabc\$xyz\E abc\$xyz abc\$xyz
2000     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2001    
2002     For compatibility with Perl, \Q...\E sequences are recognized inside character
2003     classes as well as outside them.
2004    
2005     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2006     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2007     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2008     signed/unsigned warnings.
2009    
2010     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2011     option for pcretest, so I've replaced it by a simple function that does just
2012     that job.
2013    
2014     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2015     "pcregrep -".
2016    
2017     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2018     Java package. This provides some syntactic sugar for simple cases of what my
2019     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2020     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2021     item, you can use this simplified notation. Note that only makes sense with
2022     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2023     greediness, whatever the setting of the PCRE_UNGREEDY option.
2024    
2025     13. A change of greediness default within a pattern was not taking effect at
2026     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2027     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2028     was abstracted outside.
2029    
2030     14. PCRE now supports the \G assertion. It is true when the current matching
2031     position is at the start point of the match. This differs from \A when the
2032     starting offset is non-zero. Used with the /g option of pcretest (or similar
2033     code), it works in the same way as it does for Perl's /g option. If all
2034     alternatives of a regex begin with \G, the expression is anchored to the start
2035     match position, and the "anchored" flag is set in the compiled expression.
2036    
2037     15. Some bugs concerning the handling of certain option changes within patterns
2038     have been fixed. These applied to options other than (?ims). For example,
2039     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2040     been the other way round. Some of this was related to change 7 above.
2041    
2042     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2043     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2044     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2045     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2046    
2047     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2048     mode. Unlike ".", it always matches newline, whatever the setting of
2049     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2050     assertions. Perl allows it, but it doesn't (in general) work because it can't
2051     calculate the length of the lookbehind. At least, that's the case for Perl
2052     5.8.0 - I've been told they are going to document that it doesn't work in
2053     future.
2054    
2055     18. Added an error diagnosis for escapes that PCRE does not support: these are
2056     \L, \l, \N, \P, \p, \U, \u, and \X.
2057    
2058     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2059     reading past the end of the pattern in cases such as /[abcd/.
2060    
2061     20. PCRE was getting more memory than necessary for patterns with classes that
2062     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2063    
2064     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2065     compiling PCRE for use with Virtual Pascal.
2066    
2067     22. Small fix to the Makefile to make it work properly if the build is done
2068     outside the source tree.
2069    
2070     23. Added a new extension: a condition to go with recursion. If a conditional
2071     subpattern starts with (?(R) the "true" branch is used if recursion has
2072     happened, whereas the "false" branch is used only at the top level.
2073    
2074     24. When there was a very long string of literal characters (over 255 bytes
2075     without UTF support, over 250 bytes with UTF support), the computation of how
2076     much memory was required could be incorrect, leading to segfaults or other
2077     strange effects.
2078    
2079     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2080     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2081     there was a subsequent back reference to those brackets. This meant that, for
2082     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2083     possible to check for precisely this case. All we can do is abandon the
2084     optimization if .* occurs inside capturing brackets when there are any back
2085     references whatsoever. (See below for a better fix that came later.)
2086    
2087     26. The handling of the optimization for finding the first character of a
2088     non-anchored pattern, and for finding a character that is required later in the
2089     match were failing in some cases. This didn't break the matching; it just
2090     failed to optimize when it could. The way this is done has been re-implemented.
2091    
2092     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2093    
2094     28. Added a new feature that provides some of the functionality that Perl
2095     provides with (?{...}). The facility is termed a "callout". The way it is done
2096     in PCRE is for the caller to provide an optional function, by setting
2097     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2098     global variable. By default it is unset, which disables all calling out. To get
2099     the function called, the regex must include (?C) at appropriate points. This
2100     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2101     This provides a means of identifying different callout points. When PCRE
2102     reaches such a point in the regex, if pcre_callout has been set, the external
2103     function is called. It is provided with data in a structure called
2104     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2105     matching continues; if it returns a non-zero value, the match at the current
2106     point fails. However, backtracking will occur if possible. [This was changed
2107     later and other features added - see item 49 below.]
2108    
2109     29. pcretest is upgraded to test the callout functionality. It provides a
2110     callout function that displays information. By default, it shows the start of
2111     the match and the current position in the text. There are some new data escapes
2112     to vary what happens:
2113    
2114     \C+ in addition, show current contents of captured substrings
2115     \C- do not supply a callout function
2116     \C!n return 1 when callout number n is reached
2117     \C!n!m return 1 when callout number n is reached for the mth time
2118    
2119     30. If pcregrep was called with the -l option and just a single file name, it
2120     output "<stdin>" if a match was found, instead of the file name.
2121    
2122     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2123     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2124     pcre_exec(). This saves a malloc/free per call. The default value of
2125     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2126     when configuring.
2127    
2128     32. The default maximum size of a compiled pattern is 64K. There have been a
2129     few cases of people hitting this limit. The code now uses macros to handle the
2130     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2131     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2132     configuring. Tests 2 and 5 work only with 2-byte links because they output
2133     debugging information about compiled patterns.
2134    
2135     33. Internal code re-arrangements:
2136    
2137     (a) Moved the debugging function for printing out a compiled regex into
2138     its own source file (printint.c) and used #include to pull it into
2139     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2140     separate copies.
2141    
2142     (b) Defined the list of op-code names for debugging as a macro in
2143     internal.h so that it is next to the definition of the opcodes.
2144    
2145     (c) Defined a table of op-code lengths for simpler skipping along compiled
2146     code. This is again a macro in internal.h so that it is next to the
2147     definition of the opcodes.
2148    
2149     34. Added support for recursive calls to individual subpatterns, along the
2150     lines of Robin Houston's patch (but implemented somewhat differently).
2151    
2152     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2153     allow it to read and process whole directories in Win32. This code was
2154     contributed by Lionel Fourquaux; it has not been tested by me.
2155    
2156     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2157     used to name a group. Names consist of alphanumerics and underscores, and must
2158     be unique. Back references use the syntax (?P=name) and recursive calls use
2159     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2160     numbers. The function pcre_fullinfo() can be used after compilation to extract
2161     a name/number map. There are three relevant calls:
2162    
2163     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2164     PCRE_INFO_NAMECOUNT yields the number of entries
2165     PCRE_INFO_NAMETABLE yields a pointer to the map.
2166    
2167     The map is a vector of fixed-size entries. The size of each entry depends on
2168     the length of the longest name used. The first two bytes of each entry are the
2169     group number, most significant byte first. There follows the corresponding
2170     name, zero terminated. The names are in alphabetical order.
2171    
2172     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2173     case instead of 255. Making it the same both with and without UTF-8 support
2174     means that the same test output works with both.
2175    
2176     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2177     calling malloc() with a zero argument.
2178    
2179     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2180     optimization. I've improved things by keeping a bitmap of backreferences with
2181     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2182     fact referenced, the optimization can be applied. It is unlikely that a
2183     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2184     the match to follow \n) will appear inside brackets with a number greater than
2185     31, but if it does, any back reference > 31 suppresses the optimization.
2186    
2187     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2188     of disabling numbered capturing parentheses. Any opening parenthesis that is
2189     not followed by ? behaves as if it were followed by ?: but named parentheses
2190     can still be used for capturing (and they will acquire numbers in the usual
2191     way).
2192    
2193     41. Redesigned the return codes from the match() function into yes/no/error so
2194     that errors can be passed back from deep inside the nested calls. A malloc
2195     failure while inside a recursive subpattern call now causes the
2196     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2197    
2198     42. It is now possible to set a limit on the number of times the match()
2199     function is called in a call to pcre_exec(). This facility makes it possible to
2200     limit the amount of recursion and backtracking, though not in a directly
2201     obvious way, because the match() function is used in a number of different
2202     circumstances. The count starts from zero for each position in the subject
2203     string (for non-anchored patterns). The default limit is, for compatibility, a
2204     large number, namely 10 000 000. You can change this in two ways:
2205    
2206     (a) When configuring PCRE before making, you can use --with-match-limit=n
2207     to set a default value for the compiled library.
2208    
2209     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2210     a different value is set. See 45 below.
2211    
2212     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2213    
2214     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2215     of things that can be changed at compile time. The first argument specifies
2216     what is wanted and the second points to where the information is to be placed.
2217     The current list of available information is:
2218    
2219     PCRE_CONFIG_UTF8
2220    
2221     The output is an integer that is set to one if UTF-8 support is available;
2222     otherwise it is set to zero.
2223    
2224     PCRE_CONFIG_NEWLINE
2225    
2226     The output is an integer that it set to the value of the code that is used for
2227     newline. It is either LF (10) or CR (13).
2228    
2229     PCRE_CONFIG_LINK_SIZE
2230    
2231     The output is an integer that contains the number of bytes used for internal
2232     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2233    
2234     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2235    
2236     The output is an integer that contains the threshold above which the POSIX
2237     interface uses malloc() for output vectors. See item 31 above.
2238    
2239     PCRE_CONFIG_MATCH_LIMIT
2240    
2241     The output is an unsigned integer that contains the default limit of the number
2242     of match() calls in a pcre_exec() execution. See 42 above.
2243    
2244     44. pcretest has been upgraded by the addition of the -C option. This causes it
2245     to extract all the available output from the new pcre_config() function, and to
2246     output it. The program then exits immediately.
2247    
2248     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2249     order to support additional features. One way would have been to define
2250     pcre_exec2() (for example) with extra arguments, but this would not have been
2251     extensible, and would also have required all calls to the original function to
2252     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2253     is used for passing in "extra" data from pcre_study().
2254    
2255     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2256     contains the following fields:
2257    
2258     flags a bitmap indicating which of the following fields are set
2259     study_data opaque data from pcre_study()
2260     match_limit a way of specifying a limit on match() calls for a specific
2261     call to pcre_exec()
2262     callout_data data for callouts (see 49 below)
2263    
2264     The flag bits are also defined in pcre.h, and are
2265    
2266     PCRE_EXTRA_STUDY_DATA
2267     PCRE_EXTRA_MATCH_LIMIT
2268     PCRE_EXTRA_CALLOUT_DATA
2269    
2270     The pcre_study() function now returns one of these new pcre_extra blocks, with
2271     the actual study data pointed to by the study_data field, and the
2272     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2273     before. That is, this change is entirely upwards-compatible and requires no
2274     change to existing code.
2275    
2276     If you want to pass in additional data to pcre_exec(), you can either place it
2277     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2278     block.
2279    
2280     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2281     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2282     times with different match limits, until it finds the minimum value needed for
2283     pcre_exec() to complete. The value is then output. This can be instructive; for
2284     most simple matches the number is quite small, but for pathological cases it
2285     gets very large very quickly.
2286    
2287     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2288     returns the size of the data block pointed to by the study_data field in a
2289     pcre_extra block, that is, the value that was passed as the argument to
2290     pcre_malloc() when PCRE was getting memory in which to place the information
2291     created by pcre_study(). The fourth argument should point to a size_t variable.
2292     pcretest has been extended so that this information is shown after a successful
2293     pcre_study() call when information about the compiled regex is being displayed.
2294    
2295     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2296     because what follows is always an absolute path. (Later: it turns out that this
2297     is more than cosmetic for MinGW, because it doesn't like empty path
2298     components.)
2299    
2300     49. Some changes have been made to the callout feature (see 28 above):
2301    
2302     (i) A callout function now has three choices for what it returns:
2303    
2304     0 => success, carry on matching
2305     > 0 => failure at this point, but backtrack if possible
2306     < 0 => serious error, return this value from pcre_exec()
2307    
2308     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2309     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2310     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2311     use by callout functions. It will never be used by PCRE itself.
2312    
2313     (ii) The pcre_extra structure (see 45 above) has a void * field called
2314     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2315     pcre_callout_block structure has a field of the same name. The contents of
2316     the field passed in the pcre_extra structure are passed to the callout
2317     function in the corresponding field in the callout block. This makes it
2318     easier to use the same callout-containing regex from multiple threads. For
2319     testing, the pcretest program has a new data escape
2320    
2321     \C*n pass the number n (may be negative) as callout_data
2322    
2323     If the callout function in pcretest receives a non-zero value as
2324     callout_data, it returns that value.
2325    
2326     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2327     there were some redundant $(CFLAGS) in commands that are now specified as
2328     $(LINK), which already includes $(CFLAGS).
2329    
2330     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2331     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2332     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2333     one-byte characters throughout. Note that case-insensitive matching applies
2334     only to characters whose values are less than 256. PCRE doesn't support the
2335     notion of cases for higher-valued characters.
2336    
2337     (i) A character class whose characters are all within 0-255 is handled as
2338     a bit map, and the map is inverted for negative classes. Previously, a
2339     character > 255 always failed to match such a class; however it should
2340     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2341    
2342     (ii) A negated character class with a single character < 255 is coded as
2343     "not this character" (OP_NOT). This wasn't working properly when the test
2344     character was multibyte, either singly or repeated.
2345    
2346     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2347     mode, for example: \x{100}{2,3}.
2348    
2349     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2350     singly or repeated) now correctly test multibyte characters. However,
2351     PCRE doesn't recognize any characters with values greater than 255 as
2352     digits, spaces, or word characters. Such characters always match \D, \S,
2353     and \W, and never match \d, \s, or \w.
2354    
2355     (v) Classes may now contain characters and character ranges with values
2356     greater than 255. For example: [ab\x{100}-\x{400}].
2357    
2358     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2359     PCRE in UTF-8 mode.
2360    
2361     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2362     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2363     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2364     value.)
2365    
2366     53. The single man page has become too large. I have therefore split it up into
2367     a number of separate man pages. These also give rise to individual HTML pages;
2368     these are now put in a separate directory, and there is an index.html page that
2369     lists them all. Some hyperlinking between the pages has been installed.
2370    
2371     54. Added convenience functions for handling named capturing parentheses.
2372    
2373     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2374     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2375     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2376     are faulted.
2377    
2378     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2379     calling configure. These values are used when compiling the dftables.c program
2380     which is run to generate the source of the default character tables. They
2381     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2382     you will need to set these values.
2383    
2384     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2385    
2386    
2387     Version 3.9 02-Jan-02
2388 nigel 61 ---------------------
2389    
2390     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2391    
2392     2. If --disable-static was given, the building process failed when trying to
2393     build pcretest and pcregrep. (For some reason it was using libtool to compile
2394     them, which is not right, as they aren't part of the library.)
2395    
2396    
2397 nigel 59 Version 3.8 18-Dec-01
2398     ---------------------
2399    
2400     1. The experimental UTF-8 code was completely screwed up. It was packing the
2401     bytes in the wrong order. How dumb can you get?
2402    
2403    
2404 nigel 57 Version 3.7 29-Oct-01
2405     ---------------------
2406    
2407     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2408     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2409     this didn't happen under Solaris 8, where I normally test things.
2410    
2411 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2412     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2413     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2414     this fix an hour or so after the initial 3.7 release.)
2415 nigel 57
2416 nigel 59
2417 nigel 55 Version 3.6 23-Oct-01
2418     ---------------------
2419    
2420     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2421     offsets passed as NULL with zero offset count.
2422    
2423     2. The config.guess and config.sub files had not been updated when I moved to
2424     the latest autoconf.
2425    
2426    
2427 nigel 53 Version 3.5 15-Aug-01
2428     ---------------------
2429 nigel 5
2430 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2431     had been forgotten.
2432    
2433     2. By using declared but undefined structures, we can avoid using "void"
2434     definitions in pcre.h while keeping the internal definitions of the structures
2435     private.
2436    
2437     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2438     user point of view, this means that both static and shared libraries are built
2439     by default, but this can be individually controlled. More of the work of
2440     handling this static/shared cases is now inside libtool instead of PCRE's make
2441     file.
2442    
2443     4. The pcretest utility is now installed along with pcregrep because it is
2444     useful for users (to test regexs) and by doing this, it automatically gets
2445     relinked by libtool. The documentation has been turned into a man page, so
2446     there are now .1, .txt, and .html versions in /doc.
2447    
2448     5. Upgrades to pcregrep:
2449     (i) Added long-form option names like gnu grep.
2450     (ii) Added --help to list all options with an explanatory phrase.
2451     (iii) Added -r, --recursive to recurse into sub-directories.
2452     (iv) Added -f, --file to read patterns from a file.
2453    
2454     6. pcre_exec() was referring to its "code" argument before testing that
2455     argument for NULL (and giving an error if it was NULL).
2456    
2457     7. Upgraded Makefile.in to allow for compiling in a different directory from
2458     the source directory.
2459    
2460     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2461     options bits, the pointer it was passed was to an int instead of to an unsigned
2462     long int. This mattered only on 64-bit systems.
2463    
2464     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2465     generated) instead of pcre.in, which it its source. Also made the same change
2466     in several of the .c files.
2467    
2468     10. A new release of gcc defines printf() as a macro, which broke pcretest
2469     because it had an ifdef in the middle of a string argument for printf(). Fixed
2470     by using separate calls to printf().
2471    
2472     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2473     script, to force use of CR or LF instead of \n in the source. On non-Unix
2474     systems, the value can be set in config.h.
2475    
2476     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2477     absolute limit. Changed the text of the error message to make this clear, and
2478     likewise updated the man page.
2479    
2480     13. The limit of 99 on the number of capturing subpatterns has been removed.
2481     The new limit is 65535, which I hope will not be a "real" limit.
2482    
2483    
2484 nigel 51 Version 3.4 22-Aug-00
2485     ---------------------
2486    
2487     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2488    
2489     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2490    
2491    
2492 nigel 49 Version 3.3 01-Aug-00
2493     ---------------------
2494    
2495     1. If an octal character was given, but the value was greater than \377, it
2496     was not getting masked to the least significant bits, as documented. This could
2497     lead to crashes in some systems.
2498    
2499     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2500     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2501    
2502     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2503     These just pass their arguments on to (pcre_free)(), but they are provided
2504     because some uses of PCRE bind it to non-C systems that can call its functions,
2505     but cannot call free() or pcre_free() directly.
2506    
2507     4. Add "make test" as a synonym for "make check". Corrected some comments in
2508     the Makefile.
2509    
2510     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2511     Makefile.
2512    
2513     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2514     command called pgrep for grepping around the active processes.
2515    
2516     7. Added the beginnings of support for UTF-8 character strings.
2517    
2518     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2519     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2520     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2521     out for the ar command.)
2522    
2523    
2524 nigel 47 Version 3.2 12-May-00
2525     ---------------------
2526    
2527     This is purely a bug fixing release.
2528    
2529     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2530     of ZA. This was just one example of several cases that could provoke this bug,
2531     which was introduced by change 9 of version 2.00. The code for breaking
2532     infinite loops after an iteration that matches an empty string was't working
2533     correctly.
2534    
2535     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2536     when matched against abbab (for example). After matching an empty string, it
2537     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2538     caused it to match further down the string than it should.
2539    
2540     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2541     was there because it doesn't seem to be needed, and it causes trouble on some
2542     systems, as it is not a Standard C header. It has been removed.
2543    
2544     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2545     were reported on the Macintosh. The changes were from
2546    
2547     while ((c = *(++ptr)) != 0 && c != '\n');
2548     to
2549     while ((c = *(++ptr)) != 0 && c != '\n') ;
2550    
2551     Totally extraordinary, but if that's what it takes...
2552    
2553     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2554     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2555     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2556     assumes the way PCRE uses memmove() (always moving upwards).
2557    
2558     6. PCRE is being used in one environment where strchr() is not available. There
2559     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2560     faster code anyway.
2561    
2562    
2563 nigel 45 Version 3.1 09-Feb-00
2564     ---------------------
2565    
2566     The only change in this release is the fixing of some bugs in Makefile.in for
2567     the "install" target:
2568    
2569     (1) It was failing to install pcreposix.h.
2570    
2571     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2572    
2573    
2574 nigel 43 Version 3.0 01-Feb-00
2575     ---------------------
2576 nigel 41
2577     1. Add support for the /+ modifier to perltest (to output $` like it does in
2578     pcretest).
2579    
2580     2. Add support for the /g modifier to perltest.
2581    
2582     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2583     matches null strings.
2584    
2585     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2586     pattern. Perl treats empty patterns specially - it reuses the most recent
2587     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2588     effect.
2589    
2590     5. The POSIX interface was broken in that it was just handing over the POSIX
2591     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2592     required a bigger vector, with some working space on the end. This means that
2593     the POSIX wrapper now has to get and free some memory, and copy the results.
2594    
2595 nigel 43 6. Added some simple autoconf support, placing the test data and the
2596     documentation in separate directories, re-organizing some of the
2597     information files, and making it build pcre-config (a GNU standard). Also added
2598     libtool support for building PCRE as a shared library, which is now the
2599     default.
2600 nigel 41
2601 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2602     09 are not valid octal constants. Single digits will be used for minor values
2603     less than 10.
2604    
2605     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2606     existing programs that set these in the POSIX interface can use PCRE without
2607     modification.
2608    
2609     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2610     return all that pcre_info() returns, plus additional data. The pcre_info()
2611     function is retained for compatibility, but is considered to be obsolete.
2612    
2613     10. Added experimental recursion feature (?R) to handle one common case that
2614     Perl 5.6 will be able to do with (?p{...}).
2615    
2616     11. Added support for POSIX character classes like [:alpha:], which Perl is
2617     adopting.
2618    
2619    
2620 nigel 39 Version 2.08 31-Aug-99
2621     ----------------------
2622    
2623     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2624     trying to match at the startoffset position, but instead was moving forward to
2625     the next newline as if a previous match had failed.
2626    
2627     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2628     and could get into a loop if a null string was matched other than at the start
2629     of the subject.
2630    
2631     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2632     be distinguished at compile time, and for completeness also added PCRE_DATE.
2633    
2634     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2635     in GnuWin32 environments.
2636    
2637    
2638 nigel 37 Version 2.07 29-Jul-99
2639     ----------------------
2640    
2641     1. The documentation is now supplied in plain text form and HTML as well as in
2642     the form of man page sources.
2643    
2644     2. C++ compilers don't like assigning (void *) values to other pointer types.
2645     In particular this affects malloc(). Although there is no problem in Standard
2646     C, I've put in casts to keep C++ compilers happy.
2647    
2648     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2649     should be (const char *).
2650    
2651     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2652     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2653     However, I haven't made this a standard facility. The documentation doesn't
2654     mention it, and the Makefile doesn't support it.
2655    
2656     5. The Makefile now contains an "install" target, with editable destinations at
2657     the top of the file. The pcretest program is not installed.
2658    
2659     6. pgrep -V now gives the PCRE version number and date.
2660    
2661     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2662     causing the entire string to be ignored, instead of just the last character.
2663    
2664     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2665     non-matching string, it can take a very, very long time, even for strings of
2666     quite modest length, because of the nested recursion. PCRE now does better in
2667     some of these cases. It does this by remembering the last required literal
2668     character in the pattern, and pre-searching the subject to ensure it is present
2669     before running the real match. In other words, it applies a heuristic to detect
2670     some types of certain failure quickly, and in the above example, if presented
2671     with a string that has no trailing " it gives "no match" very quickly.
2672    
2673     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2674     other alternatives are tried instead.
2675    
2676    
2677 nigel 35 Version 2.06 09-Jun-99
2678     ----------------------
2679    
2680     1. Change pcretest's output for amount of store used to show just the code
2681     space, because the remainder (the data block) varies in size between 32-bit and
2682     64-bit systems.
2683    
2684     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2685     start matching at. This allows lookbehinds to work when searching for multiple
2686     occurrences in a string.
2687    
2688     3. Added additional options to pcretest for testing multiple occurrences:
2689    
2690     /+ outputs the rest of the string that follows a match
2691     /g loops for multiple occurrences, using the new startoffset argument
2692     /G loops for multiple occurrences by passing an incremented pointer
2693    
2694     4. PCRE wasn't doing the "first character" optimization for patterns starting
2695     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2696     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2697     the letter 'x'. On long subject strings, this gives a significant speed-up.
2698    
2699    
2700 nigel 33 Version 2.05 21-Apr-99
2701     ----------------------
2702    
2703     1. Changed the type of magic_number from int to long int so that it works
2704     properly on 16-bit systems.
2705    
2706     2. Fixed a bug which caused patterns starting with .* not to work correctly
2707     when the subject string contained newline characters. PCRE was assuming
2708     anchoring for such patterns in all cases, which is not correct because .* will
2709     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2710     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2711     must be retried after every newline in the subject.
2712    
2713    
2714 nigel 31 Version 2.04 18-Feb-99
2715     ----------------------
2716    
2717     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2718     computation of the store needed to hold the pattern was incorrect (too large).
2719     If such patterns were nested a few deep, this could multiply and become a real
2720     problem.
2721    
2722     2. Added /M option to pcretest to show the memory requirement of a specific
2723     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2724    
2725     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2726     compiled in such a way that the backtracking after subsequent failure was
2727     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2728     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2729    
2730    
2731 nigel 29 Version 2.03 02-Feb-99
2732     ----------------------
2733    
2734     1. Fixed typo and small mistake in man page.
2735    
2736 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2737     LICENCE file containing the conditions.
2738 nigel 29
2739     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2740     Perl, that is the internal \ allows the delimiter to be included in the
2741     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2742     the final delimiter, add \ to the end of the pattern (to test the error).
2743    
2744     4. Added the convenience functions for extracting substrings after a successful
2745     match. Updated pcretest to make it able to test these functions.
2746    
2747    
2748 nigel 27 Version 2.02 14-Jan-99
2749     ----------------------
2750    
2751     1. Initialized the working variables associated with each extraction so that
2752     their saving and restoring doesn't refer to uninitialized store.
2753    
2754     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2755     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2756     fix the problem.
2757    
2758     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2759     calls, and wasn't printing the correct value for compiling calls. Increased the
2760     default value of LOOPREPEAT, and the number of significant figures in the
2761     times.
2762    
2763     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2764    
2765     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2766     a building problem on Windows NT with a FAT file system.
2767    
2768    
2769 nigel 25 Version 2.01 21-Oct-98
2770     ----------------------
2771    
2772     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2773     to character tables built by pcre_maketables() in the current locale. If NULL
2774     is passed, the default tables are used.
2775    
2776    
2777 nigel 23 Version 2.00 24-Sep-98
2778 nigel 21 ----------------------
2779    
2780 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2781     it any more.
2782    
2783     2. Allow quantification of (?>) groups, and make it work correctly.
2784    
2785     3. The first character computation wasn't working for (?>) groups.
2786    
2787     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2788     end of the subject) and add 5.005's \z, which really does match only at the
2789     very end of the subject.
2790    
2791     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2792    
2793     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2794     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2795     localized options. All options to pcre_study() were also removed.
2796    
2797     7. Add other new features from 5.005:
2798    
2799     $(?<= positive lookbehind
2800     $(?<! negative lookbehind
2801     (?imsx-imsx) added the unsetting capability
2802     such a setting is global if at outer level; local otherwise
2803     (?imsx-imsx:) non-capturing groups with option setting
2804     (?(cond)re|re) conditional pattern matching
2805    
2806     A backreference to itself in a repeated group matches the previous
2807     captured string.
2808    
2809     8. General tidying up of studying (both automatic and via "study")
2810     consequential on the addition of new assertions.
2811    
2812     9. As in 5.005, unlimited repeated groups that could match an empty substring
2813     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2814     runtime if any iteration does actually match an empty substring.
2815    
2816     10. Include the RunTest script in the distribution.
2817    
2818     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2819     discrepancies, some of which were old and were also with respect to 5.004. They
2820     have now been fixed.
2821    
2822    
2823     Version 1.09 28-Apr-98
2824     ----------------------
2825    
2826 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2827     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2828     program crashes, or just wrong answers. This did not apply to negated classes
2829     containing more than one character, or to minima other than one.
2830    
2831    
2832 nigel 19 Version 1.08 27-Mar-98
2833     ----------------------
2834    
2835     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2836    
2837     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2838     latter must appear before anything that relies on it in the pattern.
2839    
2840    
2841 nigel 17 Version 1.07 16-Feb-98
2842     ----------------------
2843    
2844     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2845     repeat of a potentially empty string).
2846    
2847    
2848 nigel 15 Version 1.06 23-Jan-98
2849     ----------------------
2850    
2851     1. Added Markus Oberhumer's little patches for C++.
2852    
2853     2. Literal strings longer than 255 characters were broken.
2854    
2855    
2856 nigel 13 Version 1.05 23-Dec-97
2857     ----------------------
2858    
2859     1. Negated character classes containing more than one character were failing if
2860     PCRE_CASELESS was set at run time.
2861    
2862    
2863 nigel 11 Version 1.04 19-Dec-97
2864     ----------------------
2865    
2866     1. Corrected the man page, where some "const" qualifiers had been omitted.
2867    
2868     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2869     input syntax.
2870    
2871     3. Fixed memory leak which occurred when a regex with back references was
2872     matched with an offsets vector that wasn't big enough. The temporary memory
2873     that is used in this case wasn't being freed if the match failed.
2874    
2875     4. Tidied pcretest to ensure it frees memory that it gets.
2876    
2877     5. Temporary memory was being obtained in the case where the passed offsets
2878     vector was exactly big enough.
2879    
2880     6. Corrected definition of offsetof() from change 5 below.
2881    
2882     7. I had screwed up change 6 below and broken the rules for the use of
2883     setjmp(). Now fixed.
2884    
2885    
2886 nigel 9 Version 1.03 18-Dec-97
2887     ----------------------
2888    
2889     1. A erroneous regex with a missing opening parenthesis was correctly
2890     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2891     on some systems.
2892    
2893     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2894     it was reported that one broken compiler failed on the former because "code" is
2895     also an independent variable.
2896    
2897     3. The erroneous regex a[]b caused an array overrun reference.
2898    
2899     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2900     fail on data ending with that character. (It was going on too far, and checking
2901     the next character, typically a binary zero.) This was specific to the
2902     optimized code for single-character negative classes.
2903    
2904     5. Added a contributed patch from the TIN world which does the following:
2905    
2906     + Add an undef for memmove, in case the the system defines a macro for it.
2907    
2908     + Add a definition of offsetof(), in case there isn't one. (I don't know
2909     the reason behind this - offsetof() is part of the ANSI standard - but
2910     it does no harm).
2911    
2912     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2913     most of the places where whitespace preceded '#'. I have given up and
2914     allowed the remaining 2 cases to be at the margin.
2915    
2916     + Rename some variables in pcre to eliminate shadowing. This seems very
2917     pedantic, but does no harm, of course.
2918    
2919     6. Moved the call to setjmp() into its own function, to get rid of warnings
2920     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2921    
2922     7. Constructs such as \d{8,} were compiling into the equivalent of
2923 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2924 nigel 9 outcome, but in this particular case used more store than had been allocated,
2925     which caused the bug to be discovered because it threw up an internal error.
2926    
2927     8. The debugging code in both pcre and pcretest for outputting the compiled
2928     form of a regex was going wrong in the case of back references followed by
2929     curly-bracketed repeats.
2930    
2931    
2932 nigel 7 Version 1.02 12-Dec-97
2933     ----------------------
2934    
2935     1. Typos in pcre.3 and comments in the source fixed.
2936    
2937     2. Applied a contributed patch to get rid of places where it used to remove
2938     'const' from variables, and fixed some signed/unsigned and uninitialized
2939     variable warnings.
2940    
2941     3. Added the "runtest" target to Makefile.
2942    
2943     4. Set default compiler flag to -O2 rather than just -O.
2944    
2945    
2946 nigel 5 Version 1.01 19-Nov-97
2947     ----------------------
2948    
2949     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2950     like /([ab]*)*/, that is, for classes with more than one character in them.
2951    
2952     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2953     as /((?>a*))*/ (a PCRE_EXTRA facility).
2954    
2955    
2956     Version 1.00 18-Nov-97
2957     ----------------------
2958    
2959     1. Added compile-time macros to support systems such as SunOS4 which don't have
2960     memmove() or strerror() but have other things that can be used instead.
2961    
2962     2. Arranged that "make clean" removes the executables.
2963    
2964    
2965 nigel 3 Version 0.99 27-Oct-97
2966     ----------------------
2967    
2968     1. Fixed bug in code for optimizing classes with only one character. It was
2969     initializing a 32-byte map regardless, which could cause it to run off the end
2970     of the memory it had got.
2971    
2972     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2973    
2974    
2975     Version 0.98 22-Oct-97
2976     ----------------------
2977    
2978     1. Fixed bug in code for handling temporary memory usage when there are more
2979     back references than supplied space in the ovector. This could cause segfaults.
2980    
2981    
2982     Version 0.97 21-Oct-97
2983     ----------------------
2984    
2985     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2986    
2987     2. Optimized negated single characters not to use a bit map.
2988    
2989     3. Brought error texts together as macro definitions; clarified some of them;
2990     fixed one that was wrong - it said "range out of order" when it meant "invalid
2991     escape sequence".
2992    
2993     4. Changed some char * arguments to const char *.
2994    
2995     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2996    
2997     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2998     pcretest.
2999    
3000    
3001     Version 0.96 16-Oct-97
3002     ----------------------
3003    
3004     1. Added a simple "pgrep" utility to the distribution.
3005    
3006     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3007     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3008     where "ddd" means "one or more decimal digits".
3009    
3010     3. Fixed serious bug. If a pattern had a back reference, but the call to
3011     pcre_exec() didn't supply a large enough ovector to record the related
3012     identifying subpattern, the match always failed. PCRE now remembers the number
3013     of the largest back reference, and gets some temporary memory in which to save
3014     the offsets during matching if necessary, in order to ensure that
3015     backreferences always work.
3016    
3017     4. Increased the compatibility with Perl in a number of ways:
3018    
3019     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3020     to request this handling. The option can be set at compile or exec time.
3021    
3022     (b) $ matches before a terminating newline by default; an option
3023     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3024     mode). The option can be set at compile or exec time.
3025    
3026     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3027     the same as Perl's. If the decimal number it represents is less than 10
3028     or there aren't that many previous left capturing parentheses, an octal
3029     escape is read. Inside a character class, it's always an octal escape,
3030     even if it is a single digit.
3031    
3032     (d) An escaped but undefined alphabetic character is taken as a literal,
3033     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3034     escapes.
3035    
3036     (e) {0} is now permitted. (The previous item is removed from the compiled
3037     pattern).
3038    
3039     5. Changed all the names of code files so that the basic parts are no longer
3040     than 10 characters, and abolished the teeny "globals.c" file.
3041    
3042     6. Changed the handling of character classes; they are now done with a 32-byte
3043     bit map always.
3044    
3045     7. Added the -d and /D options to pcretest to make it possible to look at the
3046     internals of compilation without having to recompile pcre.
3047    
3048    
3049     Version 0.95 23-Sep-97
3050     ----------------------
3051    
3052     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3053     \x20 at the start of a run of normal characters. These were being treated as
3054     real characters, instead of the source characters being re-checked.
3055    
3056    
3057     Version 0.94 18-Sep-97
3058     ----------------------
3059    
3060     1. The functions are now thread-safe, with the caveat that the global variables
3061     containing pointers to malloc() and free() or alternative functions are the
3062     same for all threads.
3063    
3064     2. Get pcre_study() to generate a bitmap of initial characters for non-
3065     anchored patterns when this is possible, and use it if passed to pcre_exec().
3066    
3067    
3068     Version 0.93 15-Sep-97
3069     ----------------------
3070    
3071     1. /(b)|(:+)/ was computing an incorrect first character.
3072    
3073     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3074     but not actually doing anything yet.
3075    
3076     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3077     as Perl does (e.g. [-az] or [az-]).
3078    
3079     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3080     all possible positions.
3081    
3082     5. Split up into different modules to avoid including unneeded functions in a
3083     compiled binary. However, compile and exec are still in one module. The "study"
3084     function is split off.
3085    
3086     6. The character tables are now in a separate module whose source is generated
3087     by an auxiliary program - but can then be edited by hand if required. There are
3088     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3089     toupper() in the code.
3090    
3091     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3092     make them global. Abolish the function for setting them, as the caller can now
3093     set them directly.
3094    
3095    
3096     Version 0.92 11-Sep-97
3097     ----------------------
3098    
3099     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3100     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3101    
3102     2. Caseless matching was not working in character classes if the characters in
3103     the pattern were in upper case.
3104    
3105     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3106    
3107     4. Make PCRE_ANCHORED public and accept as a compile option.
3108    
3109     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3110     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3111     pass them.
3112    
3113     6. Give an error if bad option bits passed at compile or run time.
3114    
3115     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3116     pcretest to cause it to pass that flag.
3117    
3118     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3119     options, and the first character, if set.
3120    
3121     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3122    
3123    
3124     Version 0.91 10-Sep-97
3125     ----------------------
3126    
3127     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3128     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3129    
3130     2. PCRE was looping on encountering an indefinitely repeated back reference to
3131     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3132     Perl does - treats the match as successful.
3133    
3134     ****

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