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Revision 340 - (hide annotations) (download)
Fri Apr 18 20:00:21 2008 UTC (7 years ago) by ph10
File size: 154365 byte(s)
Fix incorrect error for patterns like /(?2)[]a()b](abc)/

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 321 Version 7.7 05-Mar-08
5     ---------------------
7     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
8     a string to a long long, pretend we don't even have a long long." This is
9     done by checking for the strtoq, strtoll, and _strtoi64 functions.
10 ph10 322
11     2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
12     pre-7.6 versions, which defined a global no_arg variable instead of putting
13 ph10 332 it in the RE class. (See also #8 below.)
14 ph10 323
15     3. Remove a line of dead code, identified by coverity and reported by Nuno
16     Lopes.
17 ph10 324
18     4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
19 ph10 321
20 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
21     of files, instead of just to the final components.
23     (2) If there was more than one level of directory, the subdirectories were
24     skipped unless they satisfied the include/exclude conditions. This is
25     inconsistent with GNU grep (and could even be seen as contrary to the
26     pcregrep specification - which I improved to make it absolutely clear).
27     The action now is always to scan all levels of directory, and just
28     apply the include/exclude patterns to regular files.
29 ph10 325
30     5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
31     --exclude_dir in the tests to avoid scanning .svn directories.
32 ph10 326
33     6. Applied Craig's patch to the QuoteMeta function so that it escapes the
34     NUL character as backslash + 0 rather than backslash + NUL, because PCRE
35     doesn't support NULs in patterns.
36 ph10 327
37     7. Added some missing "const"s to declarations of static tables in
38     pcre_compile.c and pcre_dfa_exec.c.
39 ph10 328
40     8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
41 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
42 ph10 330 first patch. And a third patch - this was a messy problem.)
43 ph10 331
44     9. Applied Craig's patch to remove the use of push_back().
45 ph10 321
46 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
47     matching function regexec().
48 ph10 333
49     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
50     which, however, unlike Perl's \g{...}, are subroutine calls, not back
51     references. PCRE supports relative numbers with this syntax (I don't think
52     Oniguruma does).
53 ph10 335
54     12. Previously, a group with a zero repeat such as (...){0} was completely
55     omitted from the compiled regex. However, this means that if the group
56     was called as a subroutine from elsewhere in the pattern, things went wrong
57     (an internal error was given). Such groups are now left in the compiled
58     pattern, with a new opcode that causes them to be skipped at execution
59     time.
60 ph10 336
61     13. Added the PCRE_JAVASCRIPT_COMPAT option. This currently does two things:
62     (a) A lone ] character is dis-allowed (Perl treats it as data).
63     (b) A back reference to an unmatched subpattern matches an empty string
64     (Perl fails the current match path).
65 ph10 340
66     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
67     non-existent subpattern following a character class starting with ']' and
68     containing () gave an internal compiling error instead of "reference to
69     non-existent subpattern". Fortunately, when the pattern did exist, the
70     compiled code was correct. (When scanning forwards to check for the
71     existencd of the subpattern, it was treating the data ']' as terminating
72     the class, so got the count wrong. When actually compiling, the reference
73     was subsequently set up correctly.)
74 ph10 324
75 ph10 332
76 ph10 319 Version 7.6 28-Jan-08
77 ph10 300 ---------------------
79 ph10 302 1. A character class containing a very large number of characters with
80     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
81     overflow.
82 ph10 309
83     2. Patch to cut out the "long long" test in pcrecpp_unittest when
84     HAVE_LONG_LONG is not defined.
86 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
87 ph10 304 bring them up to date and include new features. This patch includes:
88 ph10 309
89 ph10 304 - Fixed PH's badly added libz and libbz2 support.
90     - Fixed a problem with static linking.
91 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
92 ph10 304 - Fixed dftables problem and added an option.
93     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
95     - Added readline support for pcretest.
96 ph10 309 - Added an listing of the option settings after cmake has run.
98 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
99     "pcre.dll" under mingw when using Configure/Make. I added stuff to
100     Makefile.am that cause it to include this special target, without
101     affecting anything else. Note that the same mingw target plus all
102     the other distribution libraries and programs are now supported
103     when configuring with CMake (see 6 below) instead of with
104     Configure/Make.
105 ph10 309
106 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
107     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
108 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
109     solves the problem, but it does no harm.
110 ph10 313
111 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
112 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
113 ph10 314 with CMake, and also correct the comment about stack recursion.
114 ph10 313
115 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
116 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
117     of a program that users should build themselves after PCRE is installed, so
118     building it automatically is not really right. What is more, it gave
119 ph10 312 trouble in some build environments.
120 ph10 300
121 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
122 ph10 308
123 ph10 319
124 ph10 298 Version 7.5 10-Jan-08
125 ph10 263 ---------------------
127     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
128     values in parens when parsing an RE using the C++ wrapper."
129 ph10 286
130 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
131     Characters greater than 255 were excluded from the class instead of being
132     included.
133 ph10 286
134     3. The same bug as (2) above applied to negated POSIX classes such as
135 ph10 265 [:^space:].
136 ph10 286
137 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
138     defined or documented. It seems to have been a typo for PCRE_STATIC, so
139 ph10 286 I have changed it.
141 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
142 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
143     first named subpattern whose name started with "a" (in other words, the
144 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
145     expected" is now given for (?&) (a zero-length name), and this patch also
146     makes it give the same error for \k'' (previously it complained that that
147     was a reference to a non-existent subpattern).
148 ph10 286
149 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
150 ph10 286 this is right because (?- can be followed by option settings as well as by
151 ph10 269 digits. I have, however, made the messages clearer.
152 ph10 286
153 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
154     than the number used in the conditional) now cause a compile-time error.
155     This is actually not compatible with Perl, which accepts such patterns, but
156     treats the conditional as always being FALSE (as PCRE used to), but it
157     seems to me that giving a diagnostic is better.
158 ph10 286
159 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
160 ph10 275 and messages.
161 ph10 286
162     9. Fix two occurrences of "backslash" in comments that should have been
163     "backspace".
165     10. Remove two redundant lines of code that can never be obeyed (their function
166     was moved elsewhere).
168     11. The program that makes PCRE's Unicode character property table had a bug
169     which caused it to generate incorrect table entries for sequences of
170 ph10 277 characters that have the same character type, but are in different scripts.
171 ph10 286 It amalgamated them into a single range, with the script of the first of
172 ph10 277 them. In other words, some characters were in the wrong script. There were
173     thirteen such cases, affecting characters in the following ranges:
174 ph10 286
175 ph10 277 U+002b0 - U+002c1
176     U+0060c - U+0060d
177 ph10 286 U+0061e - U+00612
178 ph10 277 U+0064b - U+0065e
179     U+0074d - U+0076d
180     U+01800 - U+01805
181     U+01d00 - U+01d77
182     U+01d9b - U+01dbf
183     U+0200b - U+0200f
184     U+030fc - U+030fe
185     U+03260 - U+0327f
186     U+0fb46 - U+0fbb1
187     U+10450 - U+1049d
188 ph10 286
189 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
190     compatible with GNU grep in that, if there was more than one match in a
191     line, it showed only the first of them. It now behaves in the same way as
192     GNU grep.
193 ph10 286
194     13. If the -o and -v options were combined for pcregrep, it printed a blank
195     line for every non-matching line. GNU grep prints nothing, and pcregrep now
196     does the same. The return code can be used to tell if there were any
197     non-matching lines.
199 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
201     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
202 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
203 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
204     and both kinds of lookbehind were skipped).
206 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
207 ph10 284 inclusion of <windows.h> to before rather than after the definition of
208     INVALID_FILE_ATTRIBUTES (patch from David Byron).
209 ph10 263
210 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
211 ph10 286 character property caused pcre_compile() to compile bad code, which led at
212     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
213     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
214     caused the error; without that there was no problem.
215 ph10 263
216 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
217 ph10 286
218 ph10 289 19. Added --enable-pcretest-libreadline.
219 ph10 286
220 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
221 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
222 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
223     later patch that removed the other one (the right fix) and added unit tests
224     that check the return values (which was not done before).
225 ph10 292
226 ph10 291 21. Several CMake things:
227 ph10 287
228 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
229 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
230 ph10 288
231 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
232     linked with the newly-built libraries, not previously installed ones.
233 ph10 291
235 ph10 298
236     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
237     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
238     UTF-8 newline character). The key issue is that the pattern starts .*;
239     this means that the match must be either at the beginning, or after a
240     newline. The bug was in the code for advancing after a failed match and
241     checking that the new position followed a newline. It was not taking
242 ph10 294 account of UTF-8 characters correctly.
243 ph10 298
244     23. PCRE was behaving differently from Perl in the way it recognized POSIX
245     character classes. PCRE was not treating the sequence [:...:] as a
246     character class unless the ... were all letters. Perl, however, seems to
247     allow any characters between [: and :], though of course it rejects as
248     unknown any "names" that contain non-letters, because all the known class
249     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
250     for example, whereas PCRE did not - it did not recognize a POSIX character
251     class. This seemed a bit dangerous, so the code has been changed to be
252     closer to Perl. The behaviour is not identical to Perl, because PCRE will
253     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
254     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
255     Perl does, and where it didn't before.
257 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
258     Windows environments %n is disabled by default.
259 ph10 292
261 ph10 260 Version 7.4 21-Sep-07
262 ph10 230 ---------------------
264     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
265 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
266     LF". That isn't really right - the whole point of the change was to try to
267     help when there was an actual mention of one of the two characters. So now
268     the change happens only if \r or \n (or a literal CR or LF) character is
269 ph10 230 encountered.
270 ph10 231
271     2. The 32-bit options word was also used for 6 internal flags, but the numbers
272     of both had grown to the point where there were only 3 bits left.
273     Fortunately, there was spare space in the data structure, and so I have
274     moved the internal flags into a new 16-bit field to free up more option
275 ph10 230 bits.
276 ph10 231
277     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
278     but did not set the internal JCHANGED flag - either of these is enough to
279     control the way the "get" function works - but the PCRE_INFO_JCHANGED
280     facility is supposed to tell if (?J) was ever used, so now (?J) at the
281 ph10 230 start sets both bits.
283 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
284     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
285 ph10 230
286 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
288     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
289 ph10 233 compatibility, even though it is no longer used.
290 ph10 243
291     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
292 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
293 ph10 259 windows.h file is present (where different names are used). [This was
294 ph10 257 reversed later after testing - see 16 below.]
295 ph10 243
296     8. Changed all #include <config.h> to #include "config.h". There were also
297 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
298 ph10 243
299 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
300 ph10 243 sequence off the lines that it output.
302     10. It was pointed out to me that arrays of string pointers cause lots of
303     relocations when a shared library is dynamically loaded. A technique of
304     using a single long string with a table of offsets can drastically reduce
305     these. I have refactored PCRE in four places to do this. The result is
306 ph10 240 dramatic:
307 ph10 243
308 ph10 240 Originally: 290
309     After changing UCP table: 187
310 ph10 243 After changing error message table: 43
311 ph10 240 After changing table of "verbs" 36
312     After changing table of Posix names 22
313 ph10 243
314 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
315 ph10 247
316 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
317 ph10 247 unicode-properties was also set.
319 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
320 ph10 231
321 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
322     checked only for CRLF.
323 ph10 233
324 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
326 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
327 ph10 253
328 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
329 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
330     entirely. This removes changes made in 7 above.
331 ph10 256
332 ph10 261 17. The CMake files have been updated, and there is now more information about
333     building with CMake in the NON-UNIX-USE document.
334 ph10 257
335 ph10 261
336 ph10 228 Version 7.3 28-Aug-07
337 ph10 157 ---------------------
339 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
340     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
341     brackets there is not right, since it causes compilers to look for an
342     installed pcre.h, not the version that is in the source that is being
343     compiled (which of course may be different). I have changed it back to:
344 ph10 197
345 ph10 189 #include "pcre.h"
346 ph10 197
347     I have a vague recollection that the change was concerned with compiling in
348     different directories, but in the new build system, that is taken care of
349     by the VPATH setting the Makefile.
351 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
352     when the subject happened to end in the byte 0x85 (e.g. if the last
353     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
354     characters but of course it shouldn't be taken as a newline when it is part
355     of another character. The bug was that, for an unlimited repeat of . in
356     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
357     characters when looking for a newline.
358 ph10 197
359     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
361     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
362     in debug output.
364 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
365     long printing in the pcrecpp unittest when running under MinGW.
366 ph10 189
367 ph10 197 6. ESC_K was left out of the EBCDIC table.
368 ph10 189
369 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
370     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
371     limit also applies to "virtual nesting" when a pattern is recursive, and in
372     this case 1000 isn't so big. I have been able to remove this limit at the
373     expense of backing off one optimization in certain circumstances. Normally,
374     when pcre_exec() would call its internal match() function recursively and
375     immediately return the result unconditionally, it uses a "tail recursion"
376     feature to save stack. However, when a subpattern that can match an empty
377     string has an unlimited repetition quantifier, it no longer makes this
378     optimization. That gives it a stack frame in which to save the data for
379     checking that an empty string has been matched. Previously this was taken
380     from the 1000-entry workspace that had been reserved. So now there is no
381     explicit limit, but more stack is used.
382 ph10 189
383 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
384     syntax that is required for Windows, and which was going wrong for the
385     pcreposix and pcrecpp parts of the library. These were overlooked when this
386     problem was solved for the main library.
387 ph10 197
388 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
389     the size of patterns that contain repeated groups with explicit upper
390     limits. As the maximum quantifier is 65535, the maximum group length was
391     set at 30,000 so that the product of these two numbers did not overflow a
392     32-bit integer. However, it turns out that people want to use groups that
393     are longer than 30,000 bytes (though not repeat them that many times).
394     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
395     made it possible to implement the integer overflow checks in a much more
396     dynamic way, which I have now done. The artificial limitation on group
397     length has been removed - we now have only the limit on the total length of
398     the compiled pattern, which depends on the LINK_SIZE setting.
399 ph10 208
400     10. Fixed a bug in the documentation for get/copy named substring when
401     duplicate names are permitted. If none of the named substrings are set, the
402     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
403     empty string.
405     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
406     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
407     because the ] is interpreted as the first data character and the
408     terminating ] is not found. PCRE has been made compatible with Perl in this
409     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
410     cause memory overwriting.
412 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
413     string has been matched (to stop an infinite loop). It was not recognizing
414 ph10 208 a conditional subpattern that could match an empty string if that
415 ph10 206 subpattern was within another subpattern. For example, it looped when
416 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
417 ph10 206 condition was not nested. This bug has been fixed.
418 ph10 208
419 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
420     past the start of the subject in the presence of bytes with the top bit
421     set, for example "\x8aBCD".
422 ph10 211
423 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
424     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
425 ph10 200
426 ph10 211 14. Optimized (?!) to (*FAIL).
427 ph10 202
428 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
429     This restricts code points to be within the range 0 to 0x10FFFF, excluding
430     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
431     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
432     does: it's just the validity check that is more restrictive.
433 ph10 220
434     16. Inserted checks for integer overflows during escape sequence (backslash)
435     processing, and also fixed erroneous offset values for syntax errors during
436     backslash processing.
438 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
439 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
441 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
442     caused an overrun.
443 ph10 220
444     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
445     something other than just ASCII characters) inside a group that had an
446     unlimited repeat caused a loop at compile time (while checking to see
447     whether the group could match an empty string).
449 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
450     [\P{Any}] did so. (Error in the code for printing property names.)
451 ph10 210
452 ph10 220 21. An orphan \E inside a character class could cause a crash.
454     22. A repeated capturing bracket such as (A)? could cause a wild memory
455 ph10 218 reference during compilation.
456 ph10 220
457     23. There are several functions in pcre_compile() that scan along a compiled
458     expression for various reasons (e.g. to see if it's fixed length for look
459 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
460 ph10 220 present in the pattern. These operators have additional parameters compared
461     with \d, etc, and these were not being taken into account when moving along
462 ph10 218 the compiled data. Specifically:
463 ph10 220
464     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
465     length.
467     (b) An item such as \pL+ within a repeated group could cause crashes or
468 ph10 218 loops.
469 ph10 220
470 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
471 ph10 220 "reference to non-existent subpattern" error.
473 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
475 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
476 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
477 ph10 211
478 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
479 ph10 218
480 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
481 ph10 223 character were causing crashes (broken optimization).
482 ph10 227
483 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
484 ph10 227 \p or \P) caused a compile-time loop.
486 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
487     break. For example, the unstudied pattern [\r\n]A does not match the string
488     "\r\nA" because change 7.0/46 below moves the current point on by two
489     characters after failing to match at the start. However, the pattern \nA
490 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
491     the same is true. There doesn't seem any very clean way out of this, but
492     what I have chosen to do makes the common cases work: PCRE now takes note
493     of whether there can be an explicit match for \r or \n anywhere in the
494     pattern, and if so, 7.0/46 no longer applies. As part of this change,
495     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
496     pattern has explicit CR or LF references.
497 ph10 222
498 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
499 ph10 223
500 ph10 227
501 ph10 189 Version 7.2 19-Jun-07
502     ---------------------
504 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
505     which is apparently normally available under Windows.
506 ph10 159
507     2. Re-jig the pcregrep tests with different newline settings in an attempt
508     to make them independent of the local environment's newline setting.
509 ph10 157
510 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
511 ph10 165
512 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
513     was not 2, because the output contained actual offsets. The recent new
514 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
515     usable with all link sizes.
517 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
518     stack recursion. This gives a massive performance boost under BSD, but just
519 ph10 165 a small improvement under Linux. However, it saves one field in the frame
520 ph10 164 in all cases.
521 ph10 172
522 ph10 166 6. Added more features from the forthcoming Perl 5.10:
523 ph10 172
524 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
525     recursion call. It refers to the nth most recently opened parentheses.
526 ph10 172
527 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
528 ph10 172 to be opened parentheses.
530     (c) Conditions that refer to capturing parentheses can be specified
531 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
532 ph10 172
533 ph10 168 (d) \K resets the start of the current match so that everything before
534 ph10 172 is not part of it.
536 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
537 ph10 172
538 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
539 ph10 172 reference syntax.
540 ph10 182
541 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
542 ph10 182 alternative starts with the same number.
543 ph10 172
544 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
546 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
549     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
550     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
551 ph10 170 for detecting groups that can match an empty string.
552 ph10 159
553 ph10 172 9. A pattern with a very large number of alternatives (more than several
554     hundred) was running out of internal workspace during the pre-compile
555     phase, where pcre_compile() figures out how much memory will be needed. A
556     bit of new cunning has reduced the workspace needed for groups with
557     alternatives. The 1000-alternative test pattern now uses 12 bytes of
558     workspace instead of running out of the 4096 that are available.
559 ph10 182
560 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
561 ph10 172
562 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
563     The report of the bug said:
564 ph10 182
565 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
566     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
567 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
568 ph10 185
569 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
570 ph10 185 it matched the wrong number of bytes.
571 ph10 172
572 ph10 179
573 ph10 155 Version 7.1 24-Apr-07
574 ph10 98 ---------------------
576 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
577 ph10 122 that is more "standard", making use of automake and other Autotools. There
578 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
579     on this.
580 ph10 111
581     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
582     for recursive directory scanning broke on some systems because the files
583     are not scanned in any specific order and on different systems the order
584     was different. A call to "sort" has been inserted into RunGrepTest for the
585     approprate test as a short-term fix. In the longer term there may be an
586 ph10 100 alternative.
587 ph10 111
588 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
589 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
590     people do their own conversions for various reasons). The problems
591     concerned the use of low-level troff macros .br and .in. I have therefore
592     removed all such uses from the man pages (some were redundant, some could
593 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
594     HTML has been updated to handle .nf/.fi and to complain if it encounters
595     .br or .in.
596 ph10 111
597 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
598 ph10 123 arranged for config.h to be included in the distribution, with the name
599 ph10 111 config.h.generic, for the benefit of those who have to compile without
600     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
602     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
603     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
604 ph10 127 makevp.bat for the current PCRE, using the additional files
605 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
606 ph10 111
607     6. A Windows user reported a minor discrepancy with test 2, which turned out
608     to be caused by a trailing space on an input line that had got lost in his
609 ph10 102 copy. The trailing space was an accident, so I've just removed it.
610 ph10 111
611 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
612 ph10 111 that is needed.
614 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
615     as "const" (a) because they are and (b) because it helps the PHP
616     maintainers who have recently made a script to detect big data structures
617 ph10 111 in the php code that should be moved to the .rodata section. I remembered
618     to update Builducptable as well, so it won't revert if ucptable.h is ever
619 ph10 105 re-created.
620 ph10 111
621     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
622 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
623 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
624     support is not required. This saves 1.5-2K of code, which is important in
625 ph10 107 some applications.
626 ph10 111
627 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
628 ph10 111 so as not to refer to the tables, even though these functions will never be
629     called when UTF-8 support is disabled. Otherwise there are problems with a
630     shared library.
632 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
634     (a) It was defining its arguments as char * instead of void *.
636 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
637     a long time ago when I wrote it, but is no longer the case.
639 ph10 118 The emulated memove() is provided for those environments that have neither
640 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
641 ph10 118 is clearly not the case, as these two bugs were recently reported.
642 ph10 123
643 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
644 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
645     pages, and it removes trailing spaces from listed files. It also creates
646     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
647     case, it wraps all the #defines with #ifndefs. This script should be run
648 ph10 111 before "make dist".
649 ph10 123
650 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
651     with Unicode property support.
652 ph10 123
653     (a) For a maximizing quantifier, if the two different cases of the
654     character were of different lengths in their UTF-8 codings (there are
655     some cases like this - I found 11), and the matching function had to
656 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
657     were both the same length.
658 ph10 123
659     (b) When PCRE was configured to use the heap rather than the stack for
660     recursion during matching, it was not correctly preserving the data for
661     the other case of a UTF-8 character when checking ahead for a match
662     while processing a minimizing repeat. If the check also involved
663 ph10 115 matching a wide character, but failed, corruption could cause an
664     erroneous result when trying to check for a repeat of the original
665     character.
666 ph10 123
667 ph10 116 13. Some tidying changes to the testing mechanism:
668 ph10 98
669 ph10 116 (a) The RunTest script now detects the internal link size and whether there
670     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
671 ph10 123 values substituted by "configure". (The RunGrepTest script already did
672     this for UTF-8.) The configure.ac script no longer substitutes the
673     relevant variables.
675 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
676     with length and offset values. This means that the output is different
677     for different internal link sizes. Test 2 is skipped for link sizes
678     other than 2 because of this, bypassing the problem. Unfortunately,
679     there was also a test in test 3 (the locale tests) that used /B and
680 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
681     I have added a new /Z option to pcretest that replaces the length and
682     offset values with spaces. This is now used to make test 3 independent
683 ph10 122 of link size. (Test 2 will be tidied up later.)
684 ph10 123
685     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
686 ph10 122 segmentation fault instead of returning the appropriate error message.
687 ph10 134
688 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
689 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
690     This doesn't seem right; it now treats the CRLF combination as the line
691     ending, and so does not match in that case. It's only a pattern such as ^$
692     that would hit this one: something like ^ABC$ would have failed after \r
693     and then tried again after \r\n.
695 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
696 ph10 134 in an attempt to make files that differ only in their line terminators
697     compare equal. This works on Linux.
698 ph10 142
699 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
700     as it exited. This is now fixed, thanks to valgrind.
701 ph10 142
702 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
703 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
704     was because its rules for how to advance for /g after matching an empty
705 ph10 143 string at the end of a line did not allow for this case. They now check for
706     it specially.
707 ph10 150
708     20. pcretest is supposed to handle patterns and data of any length, by
709     extending its buffers when necessary. It was getting this wrong when the
710 ph10 147 buffer for a data line had to be extended.
711 ph10 150
712 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
713 ph10 150 CRLF as a newline sequence.
714 ph10 152
715 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
716 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
717     I have nevertheless tidied it up.
718 ph10 111
719 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
720 ph10 123
721 ph10 153 24. Added a man page for pcre-config.
722 ph10 152
723 ph10 153
724 nigel 93 Version 7.0 19-Dec-06
725     ---------------------
727     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
728     moving to gcc 4.1.1.
730     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
731     sys/time.h, which is documented as needed for this function. It doesn't
732     seem to matter on Linux, but it showed up on some releases of OS X.
734     3. It seems that there are systems where bytes whose values are greater than
735     127 match isprint() in the "C" locale. The "C" locale should be the
736     default when a C program starts up. In most systems, only ASCII printing
737     characters match isprint(). This difference caused the output from pcretest
738     to vary, making some of the tests fail. I have changed pcretest so that:
740     (a) When it is outputting text in the compiled version of a pattern, bytes
741     other than 32-126 are always shown as hex escapes.
743     (b) When it is outputting text that is a matched part of a subject string,
744     it does the same, unless a different locale has been set for the match
745     (using the /L modifier). In this case, it uses isprint() to decide.
747     4. Fixed a major bug that caused incorrect computation of the amount of memory
748     required for a compiled pattern when options that changed within the
749     pattern affected the logic of the preliminary scan that determines the
750     length. The relevant options are -x, and -i in UTF-8 mode. The result was
751     that the computed length was too small. The symptoms of this bug were
752     either the PCRE error "internal error: code overflow" from pcre_compile(),
753     or a glibc crash with a message such as "pcretest: free(): invalid next
754     size (fast)". Examples of patterns that provoked this bug (shown in
755     pcretest format) are:
757     /(?-x: )/x
758     /(?x)(?-x: \s*#\s*)/
759     /((?i)[\x{c0}])/8
760     /(?i:[\x{c0}])/8
762     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
763     is now done differently.
765     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
766     wrapper classes; (b) implement a new function in the C++ scanner that is
767     more efficient than the old way of doing things because it avoids levels of
768     recursion in the regex matching; (c) add a paragraph to the documentation
769     for the FullMatch() function.
771     6. The escape sequence \n was being treated as whatever was defined as
772     "newline". Not only was this contrary to the documentation, which states
773     that \n is character 10 (hex 0A), but it also went horribly wrong when
774     "newline" was defined as CRLF. This has been fixed.
776     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
777     was being set to -1 for the "end of line" case (supposedly a value that no
778     character can have). Though this value is never used (the check for end of
779     line is "zero bytes in current character"), it caused compiler complaints.
780     I've changed it to 0xffffffff.
782     8. In pcre_version.c, the version string was being built by a sequence of
783     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
784     string (as it is for production releases) called a macro with an empty
785     argument. The C standard says the result of this is undefined. The gcc
786     compiler treats it as an empty string (which was what was wanted) but it is
787     reported that Visual C gives an error. The source has been hacked around to
788     avoid this problem.
790     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
791     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
792     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
793     of them did).
795     10. Originally, pcretest opened its input and output without "b"; then I was
796     told that "b" was needed in some environments, so it was added for release
797     5.0 to both the input and output. (It makes no difference on Unix-like
798     systems.) Later I was told that it is wrong for the input on Windows. I've
799     now abstracted the modes into two macros, to make it easier to fiddle with
800     them, and removed "b" from the input mode under Windows.
802     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
804     12. Added -help and --help to pcretest as an official way of being reminded
805     of the options.
807     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
808     and pcrecpp.cc because they annoy compilers at high warning levels.
810     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
812     15. Fixed an occurrence of == in configure.ac that should have been = (shell
813     scripts are not C programs :-) and which was not noticed because it works
814     on Linux.
816     16. pcretest is supposed to handle any length of pattern and data line (as one
817     line or as a continued sequence of lines) by extending its input buffer if
818     necessary. This feature was broken for very long pattern lines, leading to
819     a string of junk being passed to pcre_compile() if the pattern was longer
820     than about 50K.
822     17. I have done a major re-factoring of the way pcre_compile() computes the
823     amount of memory needed for a compiled pattern. Previously, there was code
824     that made a preliminary scan of the pattern in order to do this. That was
825     OK when PCRE was new, but as the facilities have expanded, it has become
826     harder and harder to keep it in step with the real compile phase, and there
827     have been a number of bugs (see for example, 4 above). I have now found a
828     cunning way of running the real compile function in a "fake" mode that
829     enables it to compute how much memory it would need, while actually only
830     ever using a few hundred bytes of working memory and without too many
831     tests of the mode. This should make future maintenance and development
832     easier. A side effect of this work is that the limit of 200 on the nesting
833     depth of parentheses has been removed (though this was never a serious
834     limitation, I suspect). However, there is a downside: pcre_compile() now
835     runs more slowly than before (30% or more, depending on the pattern). I
836     hope this isn't a big issue. There is no effect on runtime performance.
838     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
839     newline (only possible for the last line of a file) and it was a
840     pattern that set a locale (followed by /Lsomething), pcretest crashed.
842     19. Added additional timing features to pcretest. (1) The -tm option now times
843     matching only, not compiling. (2) Both -t and -tm can be followed, as a
844     separate command line item, by a number that specifies the number of
845     repeats to use when timing. The default is 50000; this gives better
846     precision, but takes uncomfortably long for very large patterns.
848     20. Extended pcre_study() to be more clever in cases where a branch of a
849     subpattern has no definite first character. For example, (a*|b*)[cd] would
850     previously give no result from pcre_study(). Now it recognizes that the
851     first character must be a, b, c, or d.
853     21. There was an incorrect error "recursive call could loop indefinitely" if
854     a subpattern (or the entire pattern) that was being tested for matching an
855     empty string contained only one non-empty item after a nested subpattern.
856     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
857     incorrectly, because the \d was being skipped in the check.
859     22. The pcretest program now has a new pattern option /B and a command line
860     option -b, which is equivalent to adding /B to every pattern. This causes
861     it to show the compiled bytecode, without the additional information that
862     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
863     is the same as /B/I).
865     23. A new optimization is now able automatically to treat some sequences such
866     as a*b as a*+b. More specifically, if something simple (such as a character
867     or a simple class like \d) has an unlimited quantifier, and is followed by
868     something that cannot possibly match the quantified thing, the quantifier
869     is automatically "possessified".
871     24. A recursive reference to a subpattern whose number was greater than 39
872     went wrong under certain circumstances in UTF-8 mode. This bug could also
873     have affected the operation of pcre_study().
875     25. Realized that a little bit of performance could be had by replacing
876     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
878     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
880     27. Possessive quantifiers such as a++ were previously implemented by turning
881     them into atomic groups such as ($>a+). Now they have their own opcodes,
882     which improves performance. This includes the automatically created ones
883     from 23 above.
885     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
886     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
887     the first matched character to be a colon. This applied both to named and
888     numbered groups.
890     29. The ucpinternal.h header file was missing its idempotency #ifdef.
892     30. I was sent a "project" file called libpcre.a.dev which I understand makes
893     building PCRE on Windows easier, so I have included it in the distribution.
895     31. There is now a check in pcretest against a ridiculously large number being
896     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
897     loop, the loop is abandoned.
899     32. Forward references to subpatterns in conditions such as (?(2)...) where
900     subpattern 2 is defined later cause pcre_compile() to search forwards in
901     the pattern for the relevant set of parentheses. This search went wrong
902     when there were unescaped parentheses in a character class, parentheses
903     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
905     33. "Subroutine" calls and backreferences were previously restricted to
906     referencing subpatterns earlier in the regex. This restriction has now
907     been removed.
909     34. Added a number of extra features that are going to be in Perl 5.10. On the
910     whole, these are just syntactic alternatives for features that PCRE had
911     previously implemented using the Python syntax or my own invention. The
912     other formats are all retained for compatibility.
914     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
915     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
916     also .NET compatible.
918     (b) A recursion or subroutine call to a named group can now be defined as
919     (?&name) as well as (?P>name).
921     (c) A backreference to a named group can now be defined as \k<name> or
922     \k'name' as well as (?P=name). The new forms, as well as being in Perl
923     5.10, are also .NET compatible.
925     (d) A conditional reference to a named group can now use the syntax
926     (?(<name>) or (?('name') as well as (?(name).
928     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
929     groups (named and numbered) that are never evaluated inline, but can be
930     called as "subroutines" from elsewhere. In effect, the DEFINE condition
931     is always false. There may be only one alternative in such a group.
933     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
934     as the simple (?(R). The condition is true only if the most recent
935     recursion is that of the given number or name. It does not search out
936     through the entire recursion stack.
938     (g) The escape \gN or \g{N} has been added, where N is a positive or
939     negative number, specifying an absolute or relative reference.
941     35. Tidied to get rid of some further signed/unsigned compiler warnings and
942     some "unreachable code" warnings.
944     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
945     things, this adds five new scripts.
947     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
948     There were also incompatibilities regarding the handling of \Q..\E inside
949     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
950     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
952     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
953     matches an empty string, and forcibly breaks the loop. There were bugs in
954     this code in non-simple cases. For a pattern such as ^(a()*)* matched
955     against aaaa the result was just "a" rather than "aaaa", for example. Two
956     separate and independent bugs (that affected different cases) have been
957     fixed.
959     39. Refactored the code to abolish the use of different opcodes for small
960     capturing bracket numbers. This is a tidy that I avoided doing when I
961     removed the limit on the number of capturing brackets for 3.5 back in 2001.
962     The new approach is not only tidier, it makes it possible to reduce the
963     memory needed to fix the previous bug (38).
965     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
966     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
967     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
968     mode.
970     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
971     report.
973     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
974     copy construction and assignment in the C++ wrapper.
976     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
977     couple of bugs that could have given wrong results in the "--newline=crlf"
978     case.
980     44. Added a number of casts and did some reorganization of signed/unsigned int
981     variables following suggestions from Dair Grant. Also renamed the variable
982     "this" as "item" because it is a C++ keyword.
984     45. Arranged for dftables to add
986     #include "pcre_internal.h"
988     to pcre_chartables.c because without it, gcc 4.x may remove the array
989     definition from the final binary if PCRE is built into a static library and
990     dead code stripping is activated.
992     46. For an unanchored pattern, if a match attempt fails at the start of a
993     newline sequence, and the newline setting is CRLF or ANY, and the next two
994     characters are CRLF, advance by two characters instead of one.
997 nigel 91 Version 6.7 04-Jul-06
998     ---------------------
1000     1. In order to handle tests when input lines are enormously long, pcretest has
1001     been re-factored so that it automatically extends its buffers when
1002     necessary. The code is crude, but this _is_ just a test program. The
1003     default size has been increased from 32K to 50K.
1005     2. The code in pcre_study() was using the value of the re argument before
1006     testing it for NULL. (Of course, in any sensible call of the function, it
1007     won't be NULL.)
1009     3. The memmove() emulation function in pcre_internal.h, which is used on
1010     systems that lack both memmove() and bcopy() - that is, hardly ever -
1011     was missing a "static" storage class specifier.
1013     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1014     containing an extended class (one that cannot be represented by a bitmap
1015     because it contains high-valued characters or Unicode property items, e.g.
1016     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1017     pattern, but PCRE should not loop if you do not (it no longer does).
1018     [Detail: two cases were found: (a) a repeated subpattern containing an
1019     extended class; (b) a recursive reference to a subpattern that followed a
1020     previous extended class. It wasn't skipping over the extended class
1021     correctly when UTF-8 mode was not set.]
1023     5. A negated single-character class was not being recognized as fixed-length
1024     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1025     compile error "lookbehind assertion is not fixed length".
1027     6. The RunPerlTest auxiliary script was showing an unexpected difference
1028     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1029     write a Perl script that can interpret lines of an input file either as
1030     byte characters or as UTF-8, which is what "perltest" was being required to
1031     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1032     can't do is switch easily at run time between having the "use utf8;" pragma
1033     or not. In the end, I fudged it by using the RunPerlTest script to insert
1034     "use utf8;" explicitly for the UTF-8 tests.
1036     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1037     the end of the subject string, contrary to the documentation and to what
1038     Perl does. This was true of both matching functions. Now it matches only at
1039     the start of the subject and immediately after *internal* newlines.
1041     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1042     a pointer to an int instead of a pointer to an unsigned long int. This
1043     caused problems on 64-bit systems.
1045     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1046     instance of the 'standard' template library not being so standard".
1048     10. There was no check on the number of named subpatterns nor the maximum
1049     length of a subpattern name. The product of these values is used to compute
1050     the size of the memory block for a compiled pattern. By supplying a very
1051     long subpattern name and a large number of named subpatterns, the size
1052     computation could be caused to overflow. This is now prevented by limiting
1053     the length of names to 32 characters, and the number of named subpatterns
1054     to 10,000.
1056     11. Subpatterns that are repeated with specific counts have to be replicated in
1057     the compiled pattern. The size of memory for this was computed from the
1058     length of the subpattern and the repeat count. The latter is limited to
1059     65535, but there was no limit on the former, meaning that integer overflow
1060     could in principle occur. The compiled length of a repeated subpattern is
1061     now limited to 30,000 bytes in order to prevent this.
1063     12. Added the optional facility to have named substrings with the same name.
1065     13. Added the ability to use a named substring as a condition, using the
1066     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1067     are numbers (not recommended). Forward references are permitted.
1069     14. Added forward references in named backreferences (if you see what I mean).
1071     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1072     pattern could run off the end of the subject. For example, the pattern
1073     "(?s)(.{1,5})"8 did this with the subject "ab".
1075     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1076     PCRE_CASELESS was set when matching characters that were quantified with ?
1077     or *.
1079     17. A character class other than a single negated character that had a minimum
1080     but no maximum quantifier - for example [ab]{6,} - was not handled
1081     correctly by pce_dfa_exec(). It would match only one character.
1083     18. A valid (though odd) pattern that looked like a POSIX character
1084     class but used an invalid character after [ (for example [[,abc,]]) caused
1085     pcre_compile() to give the error "Failed: internal error: code overflow" or
1086     in some cases to crash with a glibc free() error. This could even happen if
1087     the pattern terminated after [[ but there just happened to be a sequence of
1088     letters, a binary zero, and a closing ] in the memory that followed.
1090     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1091     over the years. Originally (before any Unicode support), just the bottom 8
1092     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1093     output from "man perlunicode" includes this:
1095     The regular expression compiler produces polymorphic opcodes. That
1096     is, the pattern adapts to the data and automatically switches to
1097     the Unicode character scheme when presented with Unicode data--or
1098     instead uses a traditional byte scheme when presented with byte
1099     data.
1101     Sadly, a wide octal escape does not cause a switch, and in a string with
1102     no other multibyte characters, these octal escapes are treated as before.
1103     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1104     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1105     Unicode string.
1107     I have not perpetrated such confusion in PCRE. Up till now, it took just
1108     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1109     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1110     translate to the appropriate multibyte character.
1112     29. Applied some refactoring to reduce the number of warnings from Microsoft
1113     and Borland compilers. This has included removing the fudge introduced
1114     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1115     a warning about an unused variable.
1117     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1118     characters since release 4.0, because Perl (from release 5.004) does not.
1119     [Or at least, is documented not to: some releases seem to be in conflict
1120     with the documentation.] However, when a pattern was studied with
1121     pcre_study() and all its branches started with \s, PCRE still included VT
1122     as a possible starting character. Of course, this did no harm; it just
1123     caused an unnecessary match attempt.
1125     22. Removed a now-redundant internal flag bit that recorded the fact that case
1126     dependency changed within the pattern. This was once needed for "required
1127     byte" processing, but is no longer used. This recovers a now-scarce options
1128     bit. Also moved the least significant internal flag bit to the most-
1129     significant bit of the word, which was not previously used (hangover from
1130     the days when it was an int rather than a uint) to free up another bit for
1131     the future.
1133     23. Added support for CRLF line endings as well as CR and LF. As well as the
1134     default being selectable at build time, it can now be changed at runtime
1135     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1136     specify that it is scanning data with non-default line endings.
1138     24. Changed the definition of CXXLINK to make it agree with the definition of
1139     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1141     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1142     recursions. This makes a big different to stack usage for some patterns.
1144     26. If a subpattern containing a named recursion or subroutine reference such
1145     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1146     the space required for the compiled pattern went wrong and gave too small a
1147     value. Depending on the environment, this could lead to "Failed: internal
1148     error: code overflow at offset 49" or "glibc detected double free or
1149     corruption" errors.
1151     27. Applied patches from Google (a) to support the new newline modes and (b) to
1152     advance over multibyte UTF-8 characters in GlobalReplace.
1154     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1155     difference for some implementation of PCRE in some Windows version.
1157     29. Added some extra testing facilities to pcretest:
1159     \q<number> in a data line sets the "match limit" value
1160     \Q<number> in a data line sets the "match recursion limt" value
1161     -S <number> sets the stack size, where <number> is in megabytes
1163     The -S option isn't available for Windows.
1166 nigel 89 Version 6.6 06-Feb-06
1167     ---------------------
1169     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1170     in pcreposix.h. I have copied the definition from pcre.h.
1172     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1173     because pcre.h is no longer a built file.
1175     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1176     not normally included in the compiled code.
1179 nigel 87 Version 6.5 01-Feb-06
1180     ---------------------
1182     1. When using the partial match feature with pcre_dfa_exec(), it was not
1183     anchoring the second and subsequent partial matches at the new starting
1184     point. This could lead to incorrect results. For example, with the pattern
1185     /1234/, partially matching against "123" and then "a4" gave a match.
1187     2. Changes to pcregrep:
1189     (a) All non-match returns from pcre_exec() were being treated as failures
1190     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1191     error message is output. Some extra information is given for the
1193     probably the only errors that are likely to be caused by users (by
1194     specifying a regex that has nested indefinite repeats, for instance).
1195     If there are more than 20 of these errors, pcregrep is abandoned.
1197     (b) A binary zero was treated as data while matching, but terminated the
1198     output line if it was written out. This has been fixed: binary zeroes
1199     are now no different to any other data bytes.
1201     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1202     used to set a locale for matching. The --locale=xxxx long option has
1203     been added (no short equivalent) to specify a locale explicitly on the
1204     pcregrep command, overriding the environment variables.
1206     (d) When -B was used with -n, some line numbers in the output were one less
1207     than they should have been.
1209     (e) Added the -o (--only-matching) option.
1211     (f) If -A or -C was used with -c (count only), some lines of context were
1212     accidentally printed for the final match.
1214     (g) Added the -H (--with-filename) option.
1216     (h) The combination of options -rh failed to suppress file names for files
1217     that were found from directory arguments.
1219     (i) Added the -D (--devices) and -d (--directories) options.
1221     (j) Added the -F (--fixed-strings) option.
1223     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1225     (l) Added the --colo(u)r option.
1227     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1228     is not present by default.
1230     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1231     items such as (?R) or (?1), when the recursion could match a number of
1232     alternatives. If it matched one of the alternatives, but subsequently,
1233     outside the recursion, there was a failure, the code tried to back up into
1234     the recursion. However, because of the way PCRE is implemented, this is not
1235     possible, and the result was an incorrect result from the match.
1237     In order to prevent this happening, the specification of recursion has
1238     been changed so that all such subpatterns are automatically treated as
1239     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1241     4. I had overlooked the fact that, in some locales, there are characters for
1242     which isalpha() is true but neither isupper() nor islower() are true. In
1243     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1244     and ordfeminine) are like this. This affected the treatment of \w and \W
1245     when they appeared in character classes, but not when they appeared outside
1246     a character class. The bit map for "word" characters is now created
1247     separately from the results of isalnum() instead of just taking it from the
1248     upper, lower, and digit maps. (Plus the underscore character, of course.)
1250     5. The above bug also affected the handling of POSIX character classes such as
1251     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1252     permanent tables. Instead, the bit maps for such a class were previously
1253     created as the appropriate unions of the upper, lower, and digit bitmaps.
1254     Now they are created by subtraction from the [[:word:]] class, which has
1255     its own bitmap.
1257     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1258     It is created by subtracting the vertical space characters (\x09, \x0a,
1259     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1260     subtraction was done in the overall bitmap for a character class, meaning
1261     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1262     be recognized. This bug has been fixed.
1264     7. Patches from the folks at Google:
1266     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1267     real life, but is still worth protecting against".
1269     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1270     regular expressions".
1272     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1273     have it.
1275     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1276     "configure" and the latter not, in order to fix a problem somebody had
1277     with compiling the Arg class on HP-UX.
1279     (e) Improve the error-handling of the C++ wrapper a little bit.
1281     (f) New tests for checking recursion limiting.
1283     8. The pcre_memmove() function, which is used only if the environment does not
1284     have a standard memmove() function (and is therefore rarely compiled),
1285     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1286     returning a result (though PCRE never actually uses the result).
1288     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1289     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1290     returned instead of calling malloc() with an overflowing number that would
1291     most likely cause subsequent chaos.
1293     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1295     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1296     with this option is matched, the nmatch and pmatch options of regexec() are
1297     ignored.
1299     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1300     provided in case anyone wants to the the POSIX interface with UTF-8
1301     strings.
1303     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1304     C++ linking (needed for some HP-UX environments).
1306     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1307     (unused parameter) and in the pcre_printint() function (omitted "default"
1308     switch label when the default is to do nothing).
1310     15. Added some code to make it possible, when PCRE is compiled as a C++
1311     library, to replace subject pointers for pcre_exec() with a smart pointer
1312     class, thus making it possible to process discontinuous strings.
1314     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1315     much the same function. They were added by different people who were trying
1316     to make PCRE easy to compile on non-Unix systems. It has been suggested
1317     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1318     for compiling on Windows systems. I have therefore replaced it with
1319     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1320     defaults to "extern" for C or "extern C" for C++, which works fine on
1321     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1322     SCOPE with something explicit in config.h. In addition:
1324     (a) pcreposix.h still had just "extern" instead of either of these macros;
1325     I have replaced it with PCRE_DATA_SCOPE.
1327     (b) Functions such as _pcre_xclass(), which are internal to the library,
1328     but external in the C sense, all had PCRE_EXPORT in their definitions.
1329     This is apparently wrong for the Windows case, so I have removed it.
1330     (It makes no difference on Unix-like systems.)
1332     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1333     of recursive calls to match(). This is different to MATCH_LIMIT because
1334     that limits the total number of calls to match(), not all of which increase
1335     the depth of recursion. Limiting the recursion depth limits the amount of
1336     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1337     when PCRE is compiled, and changed at run time. A patch from Google adds
1338     this functionality to the C++ interface.
1340     18. Changes to the handling of Unicode character properties:
1342     (a) Updated the table to Unicode 4.1.0.
1344     (b) Recognize characters that are not in the table as "Cn" (undefined).
1346     (c) I revised the way the table is implemented to a much improved format
1347     which includes recognition of ranges. It now supports the ranges that
1348     are defined in UnicodeData.txt, and it also amalgamates other
1349     characters into ranges. This has reduced the number of entries in the
1350     table from around 16,000 to around 3,000, thus reducing its size
1351     considerably. I realized I did not need to use a tree structure after
1352     all - a binary chop search is just as efficient. Having reduced the
1353     number of entries, I extended their size from 6 bytes to 8 bytes to
1354     allow for more data.
1356     (d) Added support for Unicode script names via properties such as \p{Han}.
1358     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1359     matching that character.
1361     20. When matching a repeated Unicode property with a minimum greater than zero,
1362     (for example \pL{2,}), PCRE could look past the end of the subject if it
1363     reached it while seeking the minimum number of characters. This could
1364     happen only if some of the characters were more than one byte long, because
1365     there is a check for at least the minimum number of bytes.
1367     21. Refactored the implementation of \p and \P so as to be more general, to
1368     allow for more different types of property in future. This has changed the
1369     compiled form incompatibly. Anybody with saved compiled patterns that use
1370     \p or \P will have to recompile them.
1372     22. Added "Any" and "L&" to the supported property types.
1374     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1375     but give a compile time error if the value is greater than 0xff.
1377     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1378     accidentally not being installed or uninstalled.
1380     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1381     made were to insert the current release number. This seemed silly, because
1382     it made things harder for people building PCRE on systems that don't run
1383     "configure". I have turned pcre.h into a distributed file, no longer built
1384     by "configure", with the version identification directly included. There is
1385     no longer a pcre.h.in file.
1387     However, this change necessitated a change to the pcre-config script as
1388     well. It is built from pcre-config.in, and one of the substitutions was the
1389     release number. I have updated configure.ac so that ./configure now finds
1390     the release number by grepping pcre.h.
1392     26. Added the ability to run the tests under valgrind.
1395 nigel 85 Version 6.4 05-Sep-05
1396     ---------------------
1398     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1399     "--" to be printed when multiple files were scanned, even when none of the
1400     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1401     consider it to be a bug, and have restored the previous behaviour.
1403     2. A couple of code tidies to get rid of compiler warnings.
1405     3. The pcretest program used to cheat by referring to symbols in the library
1406     whose names begin with _pcre_. These are internal symbols that are not
1407     really supposed to be visible externally, and in some environments it is
1408     possible to suppress them. The cheating is now confined to including
1409     certain files from the library's source, which is a bit cleaner.
1411     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1412     file's purpose clearer.
1414     5. Reorganized pcre_ucp_findchar().
1417 nigel 83 Version 6.3 15-Aug-05
1418     ---------------------
1420     1. The file libpcre.pc.in did not have general read permission in the tarball.
1422     2. There were some problems when building without C++ support:
1424     (a) If C++ support was not built, "make install" and "make test" still
1425     tried to test it.
1427     (b) There were problems when the value of CXX was explicitly set. Some
1428     changes have been made to try to fix these, and ...
1430     (c) --disable-cpp can now be used to explicitly disable C++ support.
1432     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1433     backslash in a target when C++ was disabled. This confuses some
1434     versions of "make", apparently. Using an intermediate variable solves
1435     this. (Same for CPP_LOBJ.)
1437     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1438     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1439     necessary on certain architectures.
1441     4. Added a setting of -export-symbols-regex to the link command to remove
1442     those symbols that are exported in the C sense, but actually are local
1443     within the library, and not documented. Their names all begin with
1444     "_pcre_". This is not a perfect job, because (a) we have to except some
1445     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1446     available (and never for static libraries). I have made a note to try to
1447     find a way round (a) in the future.
1450 nigel 81 Version 6.2 01-Aug-05
1451     ---------------------
1453     1. There was no test for integer overflow of quantifier values. A construction
1454     such as {1111111111111111} would give undefined results. What is worse, if
1455     a minimum quantifier for a parenthesized subpattern overflowed and became
1456     negative, the calculation of the memory size went wrong. This could have
1457     led to memory overwriting.
1459     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1461     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1462     operating environments where this matters.
1464     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1465     PCRE options from within the C++ wrapper.
1467     5. Named capturing subpatterns were not being correctly counted when a pattern
1468     was compiled. This caused two problems: (a) If there were more than 100
1469     such subpatterns, the calculation of the memory needed for the whole
1470     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1471     back references of the form \12, where the number was greater than 9, were
1472     not recognized as back references, even though there were sufficient
1473     previous subpatterns.
1475     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1476     versions of gcc, e.g. 2.95.4.
1479 nigel 79 Version 6.1 21-Jun-05
1480     ---------------------
1482     1. There was one reference to the variable "posix" in pcretest.c that was not
1483     surrounded by "#if !defined NOPOSIX".
1485     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1486     the cross-check on the old pcre_info() function, for the benefit of the
1487     cut-down version of PCRE that is currently imported into Exim.
1489     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1490     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1491     patterns that start (?i) but I don't think that matters. The use of (?i) is
1492     just an example; this all applies to the other options as well.
1494     4. Since libtool seems to echo the compile commands it is issuing, the output
1495     from "make" can be reduced a bit by putting "@" in front of each libtool
1496     compile command.
1498     5. Patch from the folks at Google for configure.in to be a bit more thorough
1499     in checking for a suitable C++ installation before trying to compile the
1500     C++ stuff. This should fix a reported problem when a compiler was present,
1501     but no suitable headers.
1503     6. The man pages all had just "PCRE" as their title. I have changed them to
1504     be the relevant file name. I have also arranged that these names are
1505     retained in the file doc/pcre.txt, which is a concatenation in text format
1506     of all the man pages except the little individual ones for each function.
1508     7. The NON-UNIX-USE file had not been updated for the different set of source
1509     files that come with release 6. I also added a few comments about the C++
1510     wrapper.
1513 nigel 77 Version 6.0 07-Jun-05
1514     ---------------------
1516     1. Some minor internal re-organization to help with my DFA experiments.
1518     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1519     didn't matter for the library itself when fully configured, but did matter
1520     when compiling without UCP support, or within Exim, where the ucp files are
1521     not imported.
1523     3. Refactoring of the library code to split up the various functions into
1524     different source modules. The addition of the new DFA matching code (see
1525     below) to a single monolithic source would have made it really too
1526     unwieldy, quite apart from causing all the code to be include in a
1527     statically linked application, when only some functions are used. This is
1528     relevant even without the DFA addition now that patterns can be compiled in
1529     one application and matched in another.
1531     The downside of splitting up is that there have to be some external
1532     functions and data tables that are used internally in different modules of
1533     the library but which are not part of the API. These have all had their
1534     names changed to start with "_pcre_" so that they are unlikely to clash
1535     with other external names.
1537     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1538     a different (DFA) algorithm. Although it is slower than the original
1539     function, it does have some advantages for certain types of matching
1540     problem.
1542     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1543     including restarting after a partial match.
1545     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1546     defined when compiling for Windows was sent to me. I have put it into the
1547     code, though I have no means of testing or verifying it.
1549     7. Added the pcre_refcount() auxiliary function.
1551     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1552     match before or at the first newline in the subject string. In pcretest,
1553     the /f option on a pattern can be used to set this.
1555     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1556     would behave wrongly. This has been present in PCRE since release 4.0.
1558     10. A number of changes to the pcregrep command:
1560     (a) Refactored how -x works; insert ^(...)$ instead of setting
1561     PCRE_ANCHORED and checking the length, in preparation for adding
1562     something similar for -w.
1564     (b) Added the -w (match as a word) option.
1566     (c) Refactored the way lines are read and buffered so as to have more
1567     than one at a time available.
1569     (d) Implemented a pcregrep test script.
1571     (e) Added the -M (multiline match) option. This allows patterns to match
1572     over several lines of the subject. The buffering ensures that at least
1573     8K, or the rest of the document (whichever is the shorter) is available
1574     for matching (and similarly the previous 8K for lookbehind assertions).
1576     (f) Changed the --help output so that it now says
1578     -w, --word-regex(p)
1580     instead of two lines, one with "regex" and the other with "regexp"
1581     because that confused at least one person since the short forms are the
1582     same. (This required a bit of code, as the output is generated
1583     automatically from a table. It wasn't just a text change.)
1585     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1586     option but starts with a hyphen. Could be a pattern or a path name
1587     starting with a hyphen, for instance.
1589     (h) "-" can be given as a file name to represent stdin.
1591     (i) When file names are being printed, "(standard input)" is used for
1592     the standard input, for compatibility with GNU grep. Previously
1593     "<stdin>" was used.
1595     (j) The option --label=xxx can be used to supply a name to be used for
1596     stdin when file names are being printed. There is no short form.
1598     (k) Re-factored the options decoding logic because we are going to add
1599     two more options that take data. Such options can now be given in four
1600     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1602     (l) Added the -A, -B, and -C options for requesting that lines of context
1603     around matches be printed.
1605     (m) Added the -L option to print the names of files that do not contain
1606     any matching lines, that is, the complement of -l.
1608     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1609     continue to scan other files.
1611     (o) The -s option was incorrectly implemented. For compatibility with other
1612     greps, it now suppresses the error message for a non-existent or non-
1613     accessible file (but not the return code). There is a new option called
1614     -q that suppresses the output of matching lines, which was what -s was
1615     previously doing.
1617     (p) Added --include and --exclude options to specify files for inclusion
1618     and exclusion when recursing.
1620     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1621     Hopefully, it now does.
1623     12. Missing cast in pcre_study().
1625     13. Added an "uninstall" target to the makefile.
1627     14. Replaced "extern" in the function prototypes in Makefile.in with
1628     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1629     world, but is set differently for Windows.
1631     15. Added a second compiling function called pcre_compile2(). The only
1632     difference is that it has an extra argument, which is a pointer to an
1633     integer error code. When there is a compile-time failure, this is set
1634     non-zero, in addition to the error test pointer being set to point to an
1635     error message. The new argument may be NULL if no error number is required
1636     (but then you may as well call pcre_compile(), which is now just a
1637     wrapper). This facility is provided because some applications need a
1638     numeric error indication, but it has also enabled me to tidy up the way
1639     compile-time errors are handled in the POSIX wrapper.
1641     16. Added VPATH=.libs to the makefile; this should help when building with one
1642     prefix path and installing with another. (Or so I'm told by someone who
1643     knows more about this stuff than I do.)
1645     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1646     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1647     match everything, including newlines. This is not POSIX-compatible, but
1648     somebody wanted the feature. From pcretest it can be activated by using
1649     both the P and the s flags.
1651     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1653     19. libpcre.pc was being incorrectly installed as executable.
1655     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1656     it now also looks for '\r' so that it will work unmodified on Windows.
1658     21. Added Google's contributed C++ wrapper to the distribution.
1660     22. Added some untidy missing memory free() calls in pcretest, to keep
1661     Electric Fence happy when testing.
1665 nigel 75 Version 5.0 13-Sep-04
1666     ---------------------
1668     1. Internal change: literal characters are no longer packed up into items
1669     containing multiple characters in a single byte-string. Each character
1670     is now matched using a separate opcode. However, there may be more than one
1671     byte in the character in UTF-8 mode.
1673     2. The pcre_callout_block structure has two new fields: pattern_position and
1674     next_item_length. These contain the offset in the pattern to the next match
1675     item, and its length, respectively.
1677     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1678     insertion of callouts before each pattern item. Added the /C option to
1679     pcretest to make use of this.
1681     4. On the advice of a Windows user, the lines
1683     #if defined(_WIN32) || defined(WIN32)
1684     _setmode( _fileno( stdout ), 0x8000 );
1685     #endif /* defined(_WIN32) || defined(WIN32) */
1687     have been added to the source of pcretest. This apparently does useful
1688     magic in relation to line terminators.
1690     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1691     for the benefit of those environments where the "b" makes a difference.
1693     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1694     to know about it. I have put a hack into configure.in that adds in code
1695     to set GCC=yes if CC=icc. This seems to end up at a point in the
1696     generated configure script that is early enough to affect the setting of
1697     compiler options, which is what is needed, but I have no means of testing
1698     whether it really works. (The user who reported this had patched the
1699     generated configure script, which of course I cannot do.)
1701     LATER: After change 22 below (new libtool files), the configure script
1702     seems to know about icc (and also ecc). Therefore, I have commented out
1703     this hack in configure.in.
1705     7. Added support for pkg-config (2 patches were sent in).
1707     8. Negated POSIX character classes that used a combination of internal tables
1708     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1709     [[:^ascii]]. Typically, they would match almost any characters. The other
1710     POSIX classes were not broken in this way.
1712     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1713     to find the match, as PCRE was deluded into thinking that the match had to
1714     start at the start point or following a newline. The same bug applied to
1715     patterns with negative forward assertions or any backward assertions
1716     preceding ".*" at the start, unless the pattern required a fixed first
1717     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1719     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1720     starting at the last subject character, bytes beyond the end of the subject
1721     string were read.
1723     11. Renamed the variable "class" as "classbits" to make life easier for C++
1724     users. (Previously there was a macro definition, but it apparently wasn't
1725     enough.)
1727     12. Added the new field "tables" to the extra data so that tables can be passed
1728     in at exec time, or the internal tables can be re-selected. This allows
1729     a compiled regex to be saved and re-used at a later time by a different
1730     program that might have everything at different addresses.
1732     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1733     -R library as well as a -L library.
1735     14. The debugging options of pcretest (-d on the command line or D on a
1736     pattern) showed incorrect output for anything following an extended class
1737     that contained multibyte characters and which was followed by a quantifier.
1739     15. Added optional support for general category Unicode character properties
1740     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1741     support. It adds about 90K to the size of the library. The meanings of the
1742     inbuilt class escapes such as \d and \s have NOT been changed.
1744     16. Updated pcredemo.c to include calls to free() to release the memory for the
1745     compiled pattern.
1747     17. The generated file chartables.c was being created in the source directory
1748     instead of in the building directory. This caused the build to fail if the
1749     source directory was different from the building directory, and was
1750     read-only.
1752     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1753     file. No doubt somebody will tell me if they don't make sense... Also added
1754     Dan Mooney's comments about building on OpenVMS.
1756     19. Added support for partial matching via the PCRE_PARTIAL option for
1757     pcre_exec() and the \P data escape in pcretest.
1759     20. Extended pcretest with 3 new pattern features:
1761     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1762     write the compiled pattern to the file whose name is "rest-of-line".
1763     This is a straight binary dump of the data, with the saved pointer to
1764     the character tables forced to be NULL. The study data, if any, is
1765     written too. After writing, pcretest reads a new pattern.
1767     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1768     compiled pattern from the given file. There must not be any
1769     occurrences of "<" in the file name (pretty unlikely); if there are,
1770     pcretest will instead treat the initial "<" as a pattern delimiter.
1771     After reading in the pattern, pcretest goes on to read data lines as
1772     usual.
1774     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1775     and 16-bit fields in a compiled pattern, to simulate a pattern that
1776     was compiled on a host of opposite endianness.
1778     21. The pcre-exec() function can now cope with patterns that were compiled on
1779     hosts of opposite endianness, with this restriction:
1781     As for any compiled expression that is saved and used later, the tables
1782     pointer field cannot be preserved; the extra_data field in the arguments
1783     to pcre_exec() should be used to pass in a tables address if a value
1784     other than the default internal tables were used at compile time.
1786     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1787     now diagnosed as an error. Previously, most of the time, a negative number
1788     would have been treated as zero, but if in addition "ovector" was passed as
1789     NULL, a crash could occur.
1791     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1792     new versions from the libtool 1.5 distribution (the last one is a copy of
1793     a file called libtool.m4). This seems to have fixed the need to patch
1794     "configure" to support Darwin 1.3 (which I used to do). However, I still
1795     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1796     workstation).
1798     24. Changed the PCRE licence to be the more standard "BSD" licence.
1801 nigel 73 Version 4.5 01-Dec-03
1802     ---------------------
1804     1. There has been some re-arrangement of the code for the match() function so
1805     that it can be compiled in a version that does not call itself recursively.
1806     Instead, it keeps those local variables that need separate instances for
1807     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1808     needs to "recurse". Keeping track of where control must go is done by means
1809     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1810     hide most of the details from the main code, and operates only if
1811     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1812     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1813     operating.
1815     To make it easier for callers to provide specially tailored get/free
1816     functions for this usage, two new functions, pcre_stack_malloc, and
1817     pcre_stack_free, are used. They are always called in strict stacking order,
1818     and the size of block requested is always the same.
1820     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1821     PCRE has been compiled to use the stack or the heap for recursion. The
1822     -C option of pcretest uses this to show which version is compiled.
1824     A new data escape \S, is added to pcretest; it causes the amounts of store
1825     obtained and freed by both kinds of malloc/free at match time to be added
1826     to the output.
1828     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1829     what's available on my current Linux desktop machine.
1831     3. When matching a UTF-8 string, the test for a valid string at the start has
1832     been extended. If start_offset is not zero, PCRE now checks that it points
1833     to a byte that is the start of a UTF-8 character. If not, it returns
1834     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1835     this is necessary because there may be backward assertions in the pattern.
1836     When matching the same subject several times, it may save resources to use
1837     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1839     4. The code for checking the validity of UTF-8 strings has been tightened so
1840     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1841     containing "overlong sequences".
1843     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1844     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1845     should have been "&", but it just so happened that all the cases this let
1846     through by mistake were picked up later in the function.
1848     6. I had used a variable called "isblank" - this is a C99 function, causing
1849     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1851     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1852     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1853     so the version is shown; (c) stop "make test" echoing "./RunTest".
1855     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1857     9. The prototype for memmove() for systems that don't have it was using
1858     size_t, but the inclusion of the header that defines size_t was later. I've
1859     moved the #includes for the C headers earlier to avoid this.
1861     10. Added some adjustments to the code to make it easier to compiler on certain
1862     special systems:
1864     (a) Some "const" qualifiers were missing.
1865     (b) Added the macro EXPORT before all exported functions; by default this
1866     is defined to be empty.
1867     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1868     that it reads its output file name as an argument instead of writing
1869     to the standard output and assuming this can be redirected.
1871     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1872     class containing characters with values greater than 255, PCRE compilation
1873     went into a loop.
1875     12. A recursive reference to a subpattern that was within another subpattern
1876     that had a minimum quantifier of zero caused PCRE to crash. For example,
1877     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1878     recursion. If the recursively-called subpattern itself had a zero repeat,
1879     that was OK.
1881     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1882     buffer into which it was copied (for escape processing) was still set at
1883     1024, so long lines caused crashes.
1885     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1886     "internal error: code overflow...". This applied to any character class
1887     that was followed by a possessive quantifier.
1889     15. Modified the Makefile to add libpcre.la as a prerequisite for
1890     libpcreposix.la because I was told this is needed for a parallel build to
1891     work.
1893     16. If a pattern that contained .* following optional items at the start was
1894     studied, the wrong optimizing data was generated, leading to matching
1895     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1896     matching string must start with a or b or c. The correct conclusion for
1897     this pattern is that a match can start with any character.
1900 nigel 71 Version 4.4 13-Aug-03
1901     ---------------------
1903     1. In UTF-8 mode, a character class containing characters with values between
1904     127 and 255 was not handled correctly if the compiled pattern was studied.
1905     In fixing this, I have also improved the studying algorithm for such
1906     classes (slightly).
1908     2. Three internal functions had redundant arguments passed to them. Removal
1909     might give a very teeny performance improvement.
1911     3. Documentation bug: the value of the capture_top field in a callout is *one
1912     more than* the number of the hightest numbered captured substring.
1914     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1915     in incorrectly linking with a previously installed version. They now link
1916     explicitly with libpcre.la.
1918     5. configure.in no longer needs to recognize Cygwin specially.
1920     6. A problem in pcre.in for Windows platforms is fixed.
1922     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1923     pcretest, it used to include the size of the study block as part of its
1924     output. Unfortunately, the structure contains a field that has a different
1925     size on different hardware architectures. This meant that the tests that
1926     showed this size failed. As the block is currently always of a fixed size,
1927     this information isn't actually particularly useful in pcretest output, so
1928     I have just removed it.
1930     8. Three pre-processor statements accidentally did not start in column 1.
1931     Sadly, there are *still* compilers around that complain, even though
1932     standard C has not required this for well over a decade. Sigh.
1934     9. In pcretest, the code for checking callouts passed small integers in the
1935     callout_data field, which is a void * field. However, some picky compilers
1936     complained about the casts involved for this on 64-bit systems. Now
1937     pcretest passes the address of the small integer instead, which should get
1938     rid of the warnings.
1940     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1941     both compile and run time, and gives an error if an invalid UTF-8 sequence
1942     is found. There is a option for disabling this check in cases where the
1943     string is known to be correct and/or the maximum performance is wanted.
1945     11. In response to a bug report, I changed one line in Makefile.in from
1947     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1948     to
1949     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1951     to look similar to other lines, but I have no way of telling whether this
1952     is the right thing to do, as I do not use Windows. No doubt I'll get told
1953     if it's wrong...
1956 nigel 69 Version 4.3 21-May-03
1957     ---------------------
1959     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1960     Makefile.
1962     2. Some refactoring to improve the quality of the code:
1964     (i) The utf8_table... variables are now declared "const".
1966     (ii) The code for \cx, which used the "case flipping" table to upper case
1967     lower case letters, now just substracts 32. This is ASCII-specific,
1968     but the whole concept of \cx is ASCII-specific, so it seems
1969     reasonable.
1971     (iii) PCRE was using its character types table to recognize decimal and
1972     hexadecimal digits in the pattern. This is silly, because it handles
1973     only 0-9, a-f, and A-F, but the character types table is locale-
1974     specific, which means strange things might happen. A private
1975     table is now used for this - though it costs 256 bytes, a table is
1976     much faster than multiple explicit tests. Of course, the standard
1977     character types table is still used for matching digits in subject
1978     strings against \d.
1980     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1981     ending in _t are). So I've renamed it as ESC_tee.
1983     3. The first argument for regexec() in the POSIX wrapper should have been
1984     defined as "const".
1986     4. Changed pcretest to use malloc() for its buffers so that they can be
1987     Electric Fenced for debugging.
1989     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1990     to read one or more bytes before the start of the subject string. Often this
1991     had no effect on PCRE's behaviour, but in some circumstances it could
1992     provoke a segmentation fault.
1994     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1995     to try to read one or more bytes before the start of the subject string.
1997     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1998     UTF-8 support could misbehave in various ways if the subject string
1999     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2000     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2001     back over UTF-8 characters.)
2004 nigel 67 Version 4.2 14-Apr-03
2005     ---------------------
2007     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2009     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2010     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2011     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2012     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2013     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2014     and BUILD_EXEEXT
2015     Note: automatic setting of the BUILD variables is not yet working
2016     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2017     compile-time but not at link-time
2018     [LINK]: use for linking executables only
2019     make different versions for Windows and non-Windows
2020     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2021     libraries
2022     [LINK_FOR_BUILD]: new variable
2023     [OBJEXT]: use throughout
2024     [EXEEXT]: use throughout
2025     <winshared>: new target
2026     <wininstall>: new target
2027     <dftables.o>: use native compiler
2028     <dftables>: use native linker
2029     <install>: handle Windows platform correctly
2030     <clean>: ditto
2031     <check>: ditto
2032     copy DLL to top builddir before testing
2034     As part of these changes, -no-undefined was removed again. This was reported
2035     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2036     in any case.
2038     3. Some tidies to get rid of compiler warnings:
2040     . In the match_data structure, match_limit was an unsigned long int, whereas
2041     match_call_count was an int. I've made them both unsigned long ints.
2043     . In pcretest the fact that a const uschar * doesn't automatically cast to
2044     a void * provoked a warning.
2046     . Turning on some more compiler warnings threw up some "shadow" variables
2047     and a few more missing casts.
2049     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2050     option, a class that contained a single character with a value between 128
2051     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2053     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2054     option, a class that contained several characters, but with at least one
2055     whose value was between 128 and 255 caused PCRE to crash.
2058 nigel 65 Version 4.1 12-Mar-03
2059     ---------------------
2060 nigel 63
2061 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2062     needed, and a string in dftables.c that was longer than standard compilers are
2063     required to support.
2065     2. Compiling with Sun's compiler found a few more places where the code could
2066     be tidied up in order to avoid warnings.
2068     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2069     first of these names is deprecated in the latest Autoconf in favour of the name
2070     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2071     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2072     analogy I have changed it to CFLAGS_FOR_BUILD.
2074     4. Added -no-undefined to the linking command in the Makefile, because this is
2075     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2076     linking step for the pcreposix library.
2078     5. PCRE was failing to diagnose the case of two named groups with the same
2079     name.
2081     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2082     literal character that is needed in the subject for a match, and scans along to
2083     ensure that it is present before embarking on the full matching process. This
2084     saves time in cases of nested unlimited repeats that are never going to match.
2085     Problem: the scan can take a lot of time if the subject is very long (e.g.
2086     megabytes), thus penalizing straightforward matches. It is now done only if the
2087     amount of subject to be scanned is less than 1000 bytes.
2089     7. A lesser problem with the same optimization is that it was recording the
2090     first character of an anchored pattern as "needed", thus provoking a search
2091     right along the subject, even when the first match of the pattern was going to
2092     fail. The "needed" character is now not set for anchored patterns, unless it
2093     follows something in the pattern that is of non-fixed length. Thus, it still
2094     fulfils its original purpose of finding quick non-matches in cases of nested
2095     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2098     Version 4.0 17-Feb-03
2099     ---------------------
2101 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2102     extended to the end of string, PCRE compiled incorrect data. This could lead to
2103     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2105     2. Moved to autoconf 2.53 and libtool 1.4.2.
2107     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2108     the special perltest8 script is no longer needed - all the tests can be run
2109     from a single perltest script.
2111     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2112     by \s. It has now been removed in PCRE. This means it isn't recognized as
2113     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2114     class [:space:] *does* include VT, thereby creating a mess.
2116     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2117     space and tab.
2119     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2120     its new features into the main test script, reducing the number of scripts.
2122     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2123     were backward compatible, and made the (?i) apply to the whole pattern, as if
2124     /i were given. Now it behaves more logically, and applies the option setting
2125     only to what follows. PCRE has been changed to follow suit. However, if it
2126     finds options settings right at the start of the pattern, it extracts them into
2127     the global options, as before. Thus, they show up in the info data.
2129     8. Added support for the \Q...\E escape sequence. Characters in between are
2130     treated as literals. This is slightly different from Perl in that $ and @ are
2131     also handled as literals inside the quotes. In Perl, they will cause variable
2132     interpolation. Note the following examples:
2134     Pattern PCRE matches Perl matches
2136     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2137     \Qabc\$xyz\E abc\$xyz abc\$xyz
2138     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2140     For compatibility with Perl, \Q...\E sequences are recognized inside character
2141     classes as well as outside them.
2143     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2144     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2145     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2146     signed/unsigned warnings.
2148     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2149     option for pcretest, so I've replaced it by a simple function that does just
2150     that job.
2152     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2153     "pcregrep -".
2155     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2156     Java package. This provides some syntactic sugar for simple cases of what my
2157     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2158     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2159     item, you can use this simplified notation. Note that only makes sense with
2160     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2161     greediness, whatever the setting of the PCRE_UNGREEDY option.
2163     13. A change of greediness default within a pattern was not taking effect at
2164     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2165     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2166     was abstracted outside.
2168     14. PCRE now supports the \G assertion. It is true when the current matching
2169     position is at the start point of the match. This differs from \A when the
2170     starting offset is non-zero. Used with the /g option of pcretest (or similar
2171     code), it works in the same way as it does for Perl's /g option. If all
2172     alternatives of a regex begin with \G, the expression is anchored to the start
2173     match position, and the "anchored" flag is set in the compiled expression.
2175     15. Some bugs concerning the handling of certain option changes within patterns
2176     have been fixed. These applied to options other than (?ims). For example,
2177     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2178     been the other way round. Some of this was related to change 7 above.
2180     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2181     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2182     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2183     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2185     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2186     mode. Unlike ".", it always matches newline, whatever the setting of
2187     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2188     assertions. Perl allows it, but it doesn't (in general) work because it can't
2189     calculate the length of the lookbehind. At least, that's the case for Perl
2190     5.8.0 - I've been told they are going to document that it doesn't work in
2191     future.
2193     18. Added an error diagnosis for escapes that PCRE does not support: these are
2194     \L, \l, \N, \P, \p, \U, \u, and \X.
2196     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2197     reading past the end of the pattern in cases such as /[abcd/.
2199     20. PCRE was getting more memory than necessary for patterns with classes that
2200     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2202     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2203     compiling PCRE for use with Virtual Pascal.
2205     22. Small fix to the Makefile to make it work properly if the build is done
2206     outside the source tree.
2208     23. Added a new extension: a condition to go with recursion. If a conditional
2209     subpattern starts with (?(R) the "true" branch is used if recursion has
2210     happened, whereas the "false" branch is used only at the top level.
2212     24. When there was a very long string of literal characters (over 255 bytes
2213     without UTF support, over 250 bytes with UTF support), the computation of how
2214     much memory was required could be incorrect, leading to segfaults or other
2215     strange effects.
2217     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2218     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2219     there was a subsequent back reference to those brackets. This meant that, for
2220     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2221     possible to check for precisely this case. All we can do is abandon the
2222     optimization if .* occurs inside capturing brackets when there are any back
2223     references whatsoever. (See below for a better fix that came later.)
2225     26. The handling of the optimization for finding the first character of a
2226     non-anchored pattern, and for finding a character that is required later in the
2227     match were failing in some cases. This didn't break the matching; it just
2228     failed to optimize when it could. The way this is done has been re-implemented.
2230     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2232     28. Added a new feature that provides some of the functionality that Perl
2233     provides with (?{...}). The facility is termed a "callout". The way it is done
2234     in PCRE is for the caller to provide an optional function, by setting
2235     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2236     global variable. By default it is unset, which disables all calling out. To get
2237     the function called, the regex must include (?C) at appropriate points. This
2238     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2239     This provides a means of identifying different callout points. When PCRE
2240     reaches such a point in the regex, if pcre_callout has been set, the external
2241     function is called. It is provided with data in a structure called
2242     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2243     matching continues; if it returns a non-zero value, the match at the current
2244     point fails. However, backtracking will occur if possible. [This was changed
2245     later and other features added - see item 49 below.]
2247     29. pcretest is upgraded to test the callout functionality. It provides a
2248     callout function that displays information. By default, it shows the start of
2249     the match and the current position in the text. There are some new data escapes
2250     to vary what happens:
2252     \C+ in addition, show current contents of captured substrings
2253     \C- do not supply a callout function
2254     \C!n return 1 when callout number n is reached
2255     \C!n!m return 1 when callout number n is reached for the mth time
2257     30. If pcregrep was called with the -l option and just a single file name, it
2258     output "<stdin>" if a match was found, instead of the file name.
2260     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2261     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2262     pcre_exec(). This saves a malloc/free per call. The default value of
2263     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2264     when configuring.
2266     32. The default maximum size of a compiled pattern is 64K. There have been a
2267     few cases of people hitting this limit. The code now uses macros to handle the
2268     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2269     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2270     configuring. Tests 2 and 5 work only with 2-byte links because they output
2271     debugging information about compiled patterns.
2273     33. Internal code re-arrangements:
2275     (a) Moved the debugging function for printing out a compiled regex into
2276     its own source file (printint.c) and used #include to pull it into
2277     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2278     separate copies.
2280     (b) Defined the list of op-code names for debugging as a macro in
2281     internal.h so that it is next to the definition of the opcodes.
2283     (c) Defined a table of op-code lengths for simpler skipping along compiled
2284     code. This is again a macro in internal.h so that it is next to the
2285     definition of the opcodes.
2287     34. Added support for recursive calls to individual subpatterns, along the
2288     lines of Robin Houston's patch (but implemented somewhat differently).
2290     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2291     allow it to read and process whole directories in Win32. This code was
2292     contributed by Lionel Fourquaux; it has not been tested by me.
2294     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2295     used to name a group. Names consist of alphanumerics and underscores, and must
2296     be unique. Back references use the syntax (?P=name) and recursive calls use
2297     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2298     numbers. The function pcre_fullinfo() can be used after compilation to extract
2299     a name/number map. There are three relevant calls:
2301     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2302     PCRE_INFO_NAMECOUNT yields the number of entries
2303     PCRE_INFO_NAMETABLE yields a pointer to the map.
2305     The map is a vector of fixed-size entries. The size of each entry depends on
2306     the length of the longest name used. The first two bytes of each entry are the
2307     group number, most significant byte first. There follows the corresponding
2308     name, zero terminated. The names are in alphabetical order.
2310     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2311     case instead of 255. Making it the same both with and without UTF-8 support
2312     means that the same test output works with both.
2314     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2315     calling malloc() with a zero argument.
2317     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2318     optimization. I've improved things by keeping a bitmap of backreferences with
2319     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2320     fact referenced, the optimization can be applied. It is unlikely that a
2321     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2322     the match to follow \n) will appear inside brackets with a number greater than
2323     31, but if it does, any back reference > 31 suppresses the optimization.
2325     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2326     of disabling numbered capturing parentheses. Any opening parenthesis that is
2327     not followed by ? behaves as if it were followed by ?: but named parentheses
2328     can still be used for capturing (and they will acquire numbers in the usual
2329     way).
2331     41. Redesigned the return codes from the match() function into yes/no/error so
2332     that errors can be passed back from deep inside the nested calls. A malloc
2333     failure while inside a recursive subpattern call now causes the
2334     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2336     42. It is now possible to set a limit on the number of times the match()
2337     function is called in a call to pcre_exec(). This facility makes it possible to
2338     limit the amount of recursion and backtracking, though not in a directly
2339     obvious way, because the match() function is used in a number of different
2340     circumstances. The count starts from zero for each position in the subject
2341     string (for non-anchored patterns). The default limit is, for compatibility, a
2342     large number, namely 10 000 000. You can change this in two ways:
2344     (a) When configuring PCRE before making, you can use --with-match-limit=n
2345     to set a default value for the compiled library.
2347     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2348     a different value is set. See 45 below.
2350     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2352     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2353     of things that can be changed at compile time. The first argument specifies
2354     what is wanted and the second points to where the information is to be placed.
2355     The current list of available information is:
2359     The output is an integer that is set to one if UTF-8 support is available;
2360     otherwise it is set to zero.
2364     The output is an integer that it set to the value of the code that is used for
2365     newline. It is either LF (10) or CR (13).
2369     The output is an integer that contains the number of bytes used for internal
2370     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2374     The output is an integer that contains the threshold above which the POSIX
2375     interface uses malloc() for output vectors. See item 31 above.
2379     The output is an unsigned integer that contains the default limit of the number
2380     of match() calls in a pcre_exec() execution. See 42 above.
2382     44. pcretest has been upgraded by the addition of the -C option. This causes it
2383     to extract all the available output from the new pcre_config() function, and to
2384     output it. The program then exits immediately.
2386     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2387     order to support additional features. One way would have been to define
2388     pcre_exec2() (for example) with extra arguments, but this would not have been
2389     extensible, and would also have required all calls to the original function to
2390     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2391     is used for passing in "extra" data from pcre_study().
2393     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2394     contains the following fields:
2396     flags a bitmap indicating which of the following fields are set
2397     study_data opaque data from pcre_study()
2398     match_limit a way of specifying a limit on match() calls for a specific
2399     call to pcre_exec()
2400     callout_data data for callouts (see 49 below)
2402     The flag bits are also defined in pcre.h, and are
2408     The pcre_study() function now returns one of these new pcre_extra blocks, with
2409     the actual study data pointed to by the study_data field, and the
2410     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2411     before. That is, this change is entirely upwards-compatible and requires no
2412     change to existing code.
2414     If you want to pass in additional data to pcre_exec(), you can either place it
2415     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2416     block.
2418     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2419     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2420     times with different match limits, until it finds the minimum value needed for
2421     pcre_exec() to complete. The value is then output. This can be instructive; for
2422     most simple matches the number is quite small, but for pathological cases it
2423     gets very large very quickly.
2425     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2426     returns the size of the data block pointed to by the study_data field in a
2427     pcre_extra block, that is, the value that was passed as the argument to
2428     pcre_malloc() when PCRE was getting memory in which to place the information
2429     created by pcre_study(). The fourth argument should point to a size_t variable.
2430     pcretest has been extended so that this information is shown after a successful
2431     pcre_study() call when information about the compiled regex is being displayed.
2433     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2434     because what follows is always an absolute path. (Later: it turns out that this
2435     is more than cosmetic for MinGW, because it doesn't like empty path
2436     components.)
2438     49. Some changes have been made to the callout feature (see 28 above):
2440     (i) A callout function now has three choices for what it returns:
2442     0 => success, carry on matching
2443     > 0 => failure at this point, but backtrack if possible
2444     < 0 => serious error, return this value from pcre_exec()
2446     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2447     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2448     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2449     use by callout functions. It will never be used by PCRE itself.
2451     (ii) The pcre_extra structure (see 45 above) has a void * field called
2452     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2453     pcre_callout_block structure has a field of the same name. The contents of
2454     the field passed in the pcre_extra structure are passed to the callout
2455     function in the corresponding field in the callout block. This makes it
2456     easier to use the same callout-containing regex from multiple threads. For
2457     testing, the pcretest program has a new data escape
2459     \C*n pass the number n (may be negative) as callout_data
2461     If the callout function in pcretest receives a non-zero value as
2462     callout_data, it returns that value.
2464     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2465     there were some redundant $(CFLAGS) in commands that are now specified as
2466     $(LINK), which already includes $(CFLAGS).
2468     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2469     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2470     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2471     one-byte characters throughout. Note that case-insensitive matching applies
2472     only to characters whose values are less than 256. PCRE doesn't support the
2473     notion of cases for higher-valued characters.
2475     (i) A character class whose characters are all within 0-255 is handled as
2476     a bit map, and the map is inverted for negative classes. Previously, a
2477     character > 255 always failed to match such a class; however it should
2478     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2480     (ii) A negated character class with a single character < 255 is coded as
2481     "not this character" (OP_NOT). This wasn't working properly when the test
2482     character was multibyte, either singly or repeated.
2484     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2485     mode, for example: \x{100}{2,3}.
2487     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2488     singly or repeated) now correctly test multibyte characters. However,
2489     PCRE doesn't recognize any characters with values greater than 255 as
2490     digits, spaces, or word characters. Such characters always match \D, \S,
2491     and \W, and never match \d, \s, or \w.
2493     (v) Classes may now contain characters and character ranges with values
2494     greater than 255. For example: [ab\x{100}-\x{400}].
2496     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2497     PCRE in UTF-8 mode.
2499     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2500     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2501     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2502     value.)
2504     53. The single man page has become too large. I have therefore split it up into
2505     a number of separate man pages. These also give rise to individual HTML pages;
2506     these are now put in a separate directory, and there is an index.html page that
2507     lists them all. Some hyperlinking between the pages has been installed.
2509     54. Added convenience functions for handling named capturing parentheses.
2511     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2512     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2513     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2514     are faulted.
2516     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2517     calling configure. These values are used when compiling the dftables.c program
2518     which is run to generate the source of the default character tables. They
2519     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2520     you will need to set these values.
2522     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2525     Version 3.9 02-Jan-02
2526 nigel 61 ---------------------
2528     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2530     2. If --disable-static was given, the building process failed when trying to
2531     build pcretest and pcregrep. (For some reason it was using libtool to compile
2532     them, which is not right, as they aren't part of the library.)
2535 nigel 59 Version 3.8 18-Dec-01
2536     ---------------------
2538     1. The experimental UTF-8 code was completely screwed up. It was packing the
2539     bytes in the wrong order. How dumb can you get?
2542 nigel 57 Version 3.7 29-Oct-01
2543     ---------------------
2545     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2546     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2547     this didn't happen under Solaris 8, where I normally test things.
2549 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2550     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2551     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2552     this fix an hour or so after the initial 3.7 release.)
2553 nigel 57
2554 nigel 59
2555 nigel 55 Version 3.6 23-Oct-01
2556     ---------------------
2558     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2559     offsets passed as NULL with zero offset count.
2561     2. The config.guess and config.sub files had not been updated when I moved to
2562     the latest autoconf.
2565 nigel 53 Version 3.5 15-Aug-01
2566     ---------------------
2567 nigel 5
2568 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2569     had been forgotten.
2571     2. By using declared but undefined structures, we can avoid using "void"
2572     definitions in pcre.h while keeping the internal definitions of the structures
2573     private.
2575     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2576     user point of view, this means that both static and shared libraries are built
2577     by default, but this can be individually controlled. More of the work of
2578     handling this static/shared cases is now inside libtool instead of PCRE's make
2579     file.
2581     4. The pcretest utility is now installed along with pcregrep because it is
2582     useful for users (to test regexs) and by doing this, it automatically gets
2583     relinked by libtool. The documentation has been turned into a man page, so
2584     there are now .1, .txt, and .html versions in /doc.
2586     5. Upgrades to pcregrep:
2587     (i) Added long-form option names like gnu grep.
2588     (ii) Added --help to list all options with an explanatory phrase.
2589     (iii) Added -r, --recursive to recurse into sub-directories.
2590     (iv) Added -f, --file to read patterns from a file.
2592     6. pcre_exec() was referring to its "code" argument before testing that
2593     argument for NULL (and giving an error if it was NULL).
2595     7. Upgraded Makefile.in to allow for compiling in a different directory from
2596     the source directory.
2598     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2599     options bits, the pointer it was passed was to an int instead of to an unsigned
2600     long int. This mattered only on 64-bit systems.
2602     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2603     generated) instead of pcre.in, which it its source. Also made the same change
2604     in several of the .c files.
2606     10. A new release of gcc defines printf() as a macro, which broke pcretest
2607     because it had an ifdef in the middle of a string argument for printf(). Fixed
2608     by using separate calls to printf().
2610     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2611     script, to force use of CR or LF instead of \n in the source. On non-Unix
2612     systems, the value can be set in config.h.
2614     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2615     absolute limit. Changed the text of the error message to make this clear, and
2616     likewise updated the man page.
2618     13. The limit of 99 on the number of capturing subpatterns has been removed.
2619     The new limit is 65535, which I hope will not be a "real" limit.
2622 nigel 51 Version 3.4 22-Aug-00
2623     ---------------------
2625     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2627     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2630 nigel 49 Version 3.3 01-Aug-00
2631     ---------------------
2633     1. If an octal character was given, but the value was greater than \377, it
2634     was not getting masked to the least significant bits, as documented. This could
2635     lead to crashes in some systems.
2637     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2638     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2640     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2641     These just pass their arguments on to (pcre_free)(), but they are provided
2642     because some uses of PCRE bind it to non-C systems that can call its functions,
2643     but cannot call free() or pcre_free() directly.
2645     4. Add "make test" as a synonym for "make check". Corrected some comments in
2646     the Makefile.
2648     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2649     Makefile.
2651     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2652     command called pgrep for grepping around the active processes.
2654     7. Added the beginnings of support for UTF-8 character strings.
2656     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2657     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2658     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2659     out for the ar command.)
2662 nigel 47 Version 3.2 12-May-00
2663     ---------------------
2665     This is purely a bug fixing release.
2667     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2668     of ZA. This was just one example of several cases that could provoke this bug,
2669     which was introduced by change 9 of version 2.00. The code for breaking
2670     infinite loops after an iteration that matches an empty string was't working
2671     correctly.
2673     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2674     when matched against abbab (for example). After matching an empty string, it
2675     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2676     caused it to match further down the string than it should.
2678     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2679     was there because it doesn't seem to be needed, and it causes trouble on some
2680     systems, as it is not a Standard C header. It has been removed.
2682     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2683     were reported on the Macintosh. The changes were from
2685     while ((c = *(++ptr)) != 0 && c != '\n');
2686     to
2687     while ((c = *(++ptr)) != 0 && c != '\n') ;
2689     Totally extraordinary, but if that's what it takes...
2691     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2692     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2693     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2694     assumes the way PCRE uses memmove() (always moving upwards).
2696     6. PCRE is being used in one environment where strchr() is not available. There
2697     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2698     faster code anyway.
2701 nigel 45 Version 3.1 09-Feb-00
2702     ---------------------
2704     The only change in this release is the fixing of some bugs in Makefile.in for
2705     the "install" target:
2707     (1) It was failing to install pcreposix.h.
2709     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2712 nigel 43 Version 3.0 01-Feb-00
2713     ---------------------
2714 nigel 41
2715     1. Add support for the /+ modifier to perltest (to output $` like it does in
2716     pcretest).
2718     2. Add support for the /g modifier to perltest.
2720     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2721     matches null strings.
2723     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2724     pattern. Perl treats empty patterns specially - it reuses the most recent
2725     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2726     effect.
2728     5. The POSIX interface was broken in that it was just handing over the POSIX
2729     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2730     required a bigger vector, with some working space on the end. This means that
2731     the POSIX wrapper now has to get and free some memory, and copy the results.
2733 nigel 43 6. Added some simple autoconf support, placing the test data and the
2734     documentation in separate directories, re-organizing some of the
2735     information files, and making it build pcre-config (a GNU standard). Also added
2736     libtool support for building PCRE as a shared library, which is now the
2737     default.
2738 nigel 41
2739 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2740     09 are not valid octal constants. Single digits will be used for minor values
2741     less than 10.
2743     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2744     existing programs that set these in the POSIX interface can use PCRE without
2745     modification.
2747     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2748     return all that pcre_info() returns, plus additional data. The pcre_info()
2749     function is retained for compatibility, but is considered to be obsolete.
2751     10. Added experimental recursion feature (?R) to handle one common case that
2752     Perl 5.6 will be able to do with (?p{...}).
2754     11. Added support for POSIX character classes like [:alpha:], which Perl is
2755     adopting.
2758 nigel 39 Version 2.08 31-Aug-99
2759     ----------------------
2761     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2762     trying to match at the startoffset position, but instead was moving forward to
2763     the next newline as if a previous match had failed.
2765     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2766     and could get into a loop if a null string was matched other than at the start
2767     of the subject.
2769     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2770     be distinguished at compile time, and for completeness also added PCRE_DATE.
2772     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2773     in GnuWin32 environments.
2776 nigel 37 Version 2.07 29-Jul-99
2777     ----------------------
2779     1. The documentation is now supplied in plain text form and HTML as well as in
2780     the form of man page sources.
2782     2. C++ compilers don't like assigning (void *) values to other pointer types.
2783     In particular this affects malloc(). Although there is no problem in Standard
2784     C, I've put in casts to keep C++ compilers happy.
2786     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2787     should be (const char *).
2789     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2790     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2791     However, I haven't made this a standard facility. The documentation doesn't
2792     mention it, and the Makefile doesn't support it.
2794     5. The Makefile now contains an "install" target, with editable destinations at
2795     the top of the file. The pcretest program is not installed.
2797     6. pgrep -V now gives the PCRE version number and date.
2799     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2800     causing the entire string to be ignored, instead of just the last character.
2802     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2803     non-matching string, it can take a very, very long time, even for strings of
2804     quite modest length, because of the nested recursion. PCRE now does better in
2805     some of these cases. It does this by remembering the last required literal
2806     character in the pattern, and pre-searching the subject to ensure it is present
2807     before running the real match. In other words, it applies a heuristic to detect
2808     some types of certain failure quickly, and in the above example, if presented
2809     with a string that has no trailing " it gives "no match" very quickly.
2811     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2812     other alternatives are tried instead.
2815 nigel 35 Version 2.06 09-Jun-99
2816     ----------------------
2818     1. Change pcretest's output for amount of store used to show just the code
2819     space, because the remainder (the data block) varies in size between 32-bit and
2820     64-bit systems.
2822     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2823     start matching at. This allows lookbehinds to work when searching for multiple
2824     occurrences in a string.
2826     3. Added additional options to pcretest for testing multiple occurrences:
2828     /+ outputs the rest of the string that follows a match
2829     /g loops for multiple occurrences, using the new startoffset argument
2830     /G loops for multiple occurrences by passing an incremented pointer
2832     4. PCRE wasn't doing the "first character" optimization for patterns starting
2833     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2834     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2835     the letter 'x'. On long subject strings, this gives a significant speed-up.
2838 nigel 33 Version 2.05 21-Apr-99
2839     ----------------------
2841     1. Changed the type of magic_number from int to long int so that it works
2842     properly on 16-bit systems.
2844     2. Fixed a bug which caused patterns starting with .* not to work correctly
2845     when the subject string contained newline characters. PCRE was assuming
2846     anchoring for such patterns in all cases, which is not correct because .* will
2847     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2848     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2849     must be retried after every newline in the subject.
2852 nigel 31 Version 2.04 18-Feb-99
2853     ----------------------
2855     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2856     computation of the store needed to hold the pattern was incorrect (too large).
2857     If such patterns were nested a few deep, this could multiply and become a real
2858     problem.
2860     2. Added /M option to pcretest to show the memory requirement of a specific
2861     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2863     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2864     compiled in such a way that the backtracking after subsequent failure was
2865     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2866     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2869 nigel 29 Version 2.03 02-Feb-99
2870     ----------------------
2872     1. Fixed typo and small mistake in man page.
2874 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2875     LICENCE file containing the conditions.
2876 nigel 29
2877     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2878     Perl, that is the internal \ allows the delimiter to be included in the
2879     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2880     the final delimiter, add \ to the end of the pattern (to test the error).
2882     4. Added the convenience functions for extracting substrings after a successful
2883     match. Updated pcretest to make it able to test these functions.
2886 nigel 27 Version 2.02 14-Jan-99
2887     ----------------------
2889     1. Initialized the working variables associated with each extraction so that
2890     their saving and restoring doesn't refer to uninitialized store.
2892     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2893     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2894     fix the problem.
2896     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2897     calls, and wasn't printing the correct value for compiling calls. Increased the
2898     default value of LOOPREPEAT, and the number of significant figures in the
2899     times.
2901     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2903     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2904     a building problem on Windows NT with a FAT file system.
2907 nigel 25 Version 2.01 21-Oct-98
2908     ----------------------
2910     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2911     to character tables built by pcre_maketables() in the current locale. If NULL
2912     is passed, the default tables are used.
2915 nigel 23 Version 2.00 24-Sep-98
2916 nigel 21 ----------------------
2918 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2919     it any more.
2921     2. Allow quantification of (?>) groups, and make it work correctly.
2923     3. The first character computation wasn't working for (?>) groups.
2925     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2926     end of the subject) and add 5.005's \z, which really does match only at the
2927     very end of the subject.
2929     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2931     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2932     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2933     localized options. All options to pcre_study() were also removed.
2935     7. Add other new features from 5.005:
2937     $(?<= positive lookbehind
2938     $(?<! negative lookbehind
2939     (?imsx-imsx) added the unsetting capability
2940     such a setting is global if at outer level; local otherwise
2941     (?imsx-imsx:) non-capturing groups with option setting
2942     (?(cond)re|re) conditional pattern matching
2944     A backreference to itself in a repeated group matches the previous
2945     captured string.
2947     8. General tidying up of studying (both automatic and via "study")
2948     consequential on the addition of new assertions.
2950     9. As in 5.005, unlimited repeated groups that could match an empty substring
2951     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2952     runtime if any iteration does actually match an empty substring.
2954     10. Include the RunTest script in the distribution.
2956     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2957     discrepancies, some of which were old and were also with respect to 5.004. They
2958     have now been fixed.
2961     Version 1.09 28-Apr-98
2962     ----------------------
2964 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2965     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2966     program crashes, or just wrong answers. This did not apply to negated classes
2967     containing more than one character, or to minima other than one.
2970 nigel 19 Version 1.08 27-Mar-98
2971     ----------------------
2973     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2975     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2976     latter must appear before anything that relies on it in the pattern.
2979 nigel 17 Version 1.07 16-Feb-98
2980     ----------------------
2982     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2983     repeat of a potentially empty string).
2986 nigel 15 Version 1.06 23-Jan-98
2987     ----------------------
2989     1. Added Markus Oberhumer's little patches for C++.
2991     2. Literal strings longer than 255 characters were broken.
2994 nigel 13 Version 1.05 23-Dec-97
2995     ----------------------
2997     1. Negated character classes containing more than one character were failing if
2998     PCRE_CASELESS was set at run time.
3001 nigel 11 Version 1.04 19-Dec-97
3002     ----------------------
3004     1. Corrected the man page, where some "const" qualifiers had been omitted.
3006     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3007     input syntax.
3009     3. Fixed memory leak which occurred when a regex with back references was
3010     matched with an offsets vector that wasn't big enough. The temporary memory
3011     that is used in this case wasn't being freed if the match failed.
3013     4. Tidied pcretest to ensure it frees memory that it gets.
3015     5. Temporary memory was being obtained in the case where the passed offsets
3016     vector was exactly big enough.
3018     6. Corrected definition of offsetof() from change 5 below.
3020     7. I had screwed up change 6 below and broken the rules for the use of
3021     setjmp(). Now fixed.
3024 nigel 9 Version 1.03 18-Dec-97
3025     ----------------------
3027     1. A erroneous regex with a missing opening parenthesis was correctly
3028     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3029     on some systems.
3031     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3032     it was reported that one broken compiler failed on the former because "code" is
3033     also an independent variable.
3035     3. The erroneous regex a[]b caused an array overrun reference.
3037     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3038     fail on data ending with that character. (It was going on too far, and checking
3039     the next character, typically a binary zero.) This was specific to the
3040     optimized code for single-character negative classes.
3042     5. Added a contributed patch from the TIN world which does the following:
3044     + Add an undef for memmove, in case the the system defines a macro for it.
3046     + Add a definition of offsetof(), in case there isn't one. (I don't know
3047     the reason behind this - offsetof() is part of the ANSI standard - but
3048     it does no harm).
3050     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3051     most of the places where whitespace preceded '#'. I have given up and
3052     allowed the remaining 2 cases to be at the margin.
3054     + Rename some variables in pcre to eliminate shadowing. This seems very
3055     pedantic, but does no harm, of course.
3057     6. Moved the call to setjmp() into its own function, to get rid of warnings
3058     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3060     7. Constructs such as \d{8,} were compiling into the equivalent of
3061 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3062 nigel 9 outcome, but in this particular case used more store than had been allocated,
3063     which caused the bug to be discovered because it threw up an internal error.
3065     8. The debugging code in both pcre and pcretest for outputting the compiled
3066     form of a regex was going wrong in the case of back references followed by
3067     curly-bracketed repeats.
3070 nigel 7 Version 1.02 12-Dec-97
3071     ----------------------
3073     1. Typos in pcre.3 and comments in the source fixed.
3075     2. Applied a contributed patch to get rid of places where it used to remove
3076     'const' from variables, and fixed some signed/unsigned and uninitialized
3077     variable warnings.
3079     3. Added the "runtest" target to Makefile.
3081     4. Set default compiler flag to -O2 rather than just -O.
3084 nigel 5 Version 1.01 19-Nov-97
3085     ----------------------
3087     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3088     like /([ab]*)*/, that is, for classes with more than one character in them.
3090     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3091     as /((?>a*))*/ (a PCRE_EXTRA facility).
3094     Version 1.00 18-Nov-97
3095     ----------------------
3097     1. Added compile-time macros to support systems such as SunOS4 which don't have
3098     memmove() or strerror() but have other things that can be used instead.
3100     2. Arranged that "make clean" removes the executables.
3103 nigel 3 Version 0.99 27-Oct-97
3104     ----------------------
3106     1. Fixed bug in code for optimizing classes with only one character. It was
3107     initializing a 32-byte map regardless, which could cause it to run off the end
3108     of the memory it had got.
3110     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3113     Version 0.98 22-Oct-97
3114     ----------------------
3116     1. Fixed bug in code for handling temporary memory usage when there are more
3117     back references than supplied space in the ovector. This could cause segfaults.
3120     Version 0.97 21-Oct-97
3121     ----------------------
3123     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3125     2. Optimized negated single characters not to use a bit map.
3127     3. Brought error texts together as macro definitions; clarified some of them;
3128     fixed one that was wrong - it said "range out of order" when it meant "invalid
3129     escape sequence".
3131     4. Changed some char * arguments to const char *.
3133     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3135     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3136     pcretest.
3139     Version 0.96 16-Oct-97
3140     ----------------------
3142     1. Added a simple "pgrep" utility to the distribution.
3144     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3145     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3146     where "ddd" means "one or more decimal digits".
3148     3. Fixed serious bug. If a pattern had a back reference, but the call to
3149     pcre_exec() didn't supply a large enough ovector to record the related
3150     identifying subpattern, the match always failed. PCRE now remembers the number
3151     of the largest back reference, and gets some temporary memory in which to save
3152     the offsets during matching if necessary, in order to ensure that
3153     backreferences always work.
3155     4. Increased the compatibility with Perl in a number of ways:
3157     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3158     to request this handling. The option can be set at compile or exec time.
3160     (b) $ matches before a terminating newline by default; an option
3161     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3162     mode). The option can be set at compile or exec time.
3164     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3165     the same as Perl's. If the decimal number it represents is less than 10
3166     or there aren't that many previous left capturing parentheses, an octal
3167     escape is read. Inside a character class, it's always an octal escape,
3168     even if it is a single digit.
3170     (d) An escaped but undefined alphabetic character is taken as a literal,
3171     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3172     escapes.
3174     (e) {0} is now permitted. (The previous item is removed from the compiled
3175     pattern).
3177     5. Changed all the names of code files so that the basic parts are no longer
3178     than 10 characters, and abolished the teeny "globals.c" file.
3180     6. Changed the handling of character classes; they are now done with a 32-byte
3181     bit map always.
3183     7. Added the -d and /D options to pcretest to make it possible to look at the
3184     internals of compilation without having to recompile pcre.
3187     Version 0.95 23-Sep-97
3188     ----------------------
3190     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3191     \x20 at the start of a run of normal characters. These were being treated as
3192     real characters, instead of the source characters being re-checked.
3195     Version 0.94 18-Sep-97
3196     ----------------------
3198     1. The functions are now thread-safe, with the caveat that the global variables
3199     containing pointers to malloc() and free() or alternative functions are the
3200     same for all threads.
3202     2. Get pcre_study() to generate a bitmap of initial characters for non-
3203     anchored patterns when this is possible, and use it if passed to pcre_exec().
3206     Version 0.93 15-Sep-97
3207     ----------------------
3209     1. /(b)|(:+)/ was computing an incorrect first character.
3211     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3212     but not actually doing anything yet.
3214     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3215     as Perl does (e.g. [-az] or [az-]).
3217     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3218     all possible positions.
3220     5. Split up into different modules to avoid including unneeded functions in a
3221     compiled binary. However, compile and exec are still in one module. The "study"
3222     function is split off.
3224     6. The character tables are now in a separate module whose source is generated
3225     by an auxiliary program - but can then be edited by hand if required. There are
3226     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3227     toupper() in the code.
3229     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3230     make them global. Abolish the function for setting them, as the caller can now
3231     set them directly.
3234     Version 0.92 11-Sep-97
3235     ----------------------
3237     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3238     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3240     2. Caseless matching was not working in character classes if the characters in
3241     the pattern were in upper case.
3243     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3245     4. Make PCRE_ANCHORED public and accept as a compile option.
3247     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3248     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3249     pass them.
3251     6. Give an error if bad option bits passed at compile or run time.
3253     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3254     pcretest to cause it to pass that flag.
3256     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3257     options, and the first character, if set.
3259     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3262     Version 0.91 10-Sep-97
3263     ----------------------
3265     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3266     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3268     2. PCRE was looping on encountering an indefinitely repeated back reference to
3269     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3270     Perl does - treats the match as successful.
3272     ****


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